[patch 1/5] i2c: xtensa s6000 i2c driver

[patch 1/5] i2c: xtensa s6000 i2c driver

[Daniel Glöckner]

From: Oskar Schirmer <os@emlix.com>

Support for the s6000 on-chip i2c controller.

Signed-off-by: Oskar Schirmer <os@emlix.com>
Signed-off-by: Daniel Glöckner <dg@emlix.com>
---
 drivers/i2c/busses/Kconfig     |   10 +
 drivers/i2c/busses/Makefile    |    1 +
 drivers/i2c/busses/i2c-s6000.c |  380 ++++++++++++++++++++++++++++++++++++++++
 drivers/i2c/busses/i2c-s6000.h |   79 +++++++++
 include/linux/i2c/s6000.h      |   10 +
 5 files changed, 480 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/busses/i2c-s6000.c
 create mode 100644 drivers/i2c/busses/i2c-s6000.h
 create mode 100644 include/linux/i2c/s6000.h

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 7f95905..904def4 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -461,6 +461,16 @@ config I2C_S3C2410
 	  Say Y here to include support for I2C controller in the
 	  Samsung S3C2410 based System-on-Chip devices.
 
+config I2C_S6000
+	tristate "S6000 I2C support"
+	depends on XTENSA_VARIANT_S6000
+	help
+	  This driver supports the on chip I2C device on the
+	  S6000 xtensa processor family.
+
+	  To compile this driver as a module, choose M here. The module
+	  will be called i2c-s6000.
+
 config I2C_SH7760
 	tristate "Renesas SH7760 I2C Controller"
 	depends on CPU_SUBTYPE_SH7760
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 0c2c4b2..f7989d1 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi.o
 obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o
 obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
 obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o
+obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
 obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
 obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o
 obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o
diff --git a/drivers/i2c/busses/i2c-s6000.c b/drivers/i2c/busses/i2c-s6000.c
new file mode 100644
index 0000000..88e3fdc
--- /dev/null
+++ b/drivers/i2c/busses/i2c-s6000.c
@@ -0,0 +1,380 @@
+/*
+ * drivers/i2c/busses/i2c-s6000.c
+ *
+ * Description: Driver for S6000 Family I2C Interface
+ *	(c) 2008 emlix GmbH <info@emlix.com>
+ * Author:	Oskar Schirmer <os@emlix.com>
+ *
+ * Partially based on i2c-bfin-twi.c driver by <sonic.zhang@analog.com>
+ * Copyright (c) 2005-2007 Analog Devices, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/i2c/s6000.h>
+#include <linux/timer.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+
+#include <asm/io.h>
+#include "i2c-s6000.h"
+
+#define POLL_TIMEOUT	(2 * HZ)
+
+struct s6i2c_if {
+	u8 __iomem		*reg;
+	int			irq;
+	spinlock_t		lock;
+	struct i2c_msg		*msgs;
+	int			msgs_num, msgs_push, msgs_done;
+	unsigned		push, done;
+	int			timeout_count;
+	struct timer_list	timeout_timer;
+	struct i2c_adapter	adap;
+	struct completion	complete;
+	struct clk		*clk;
+	struct resource		*res;
+};
+
+#define I2C_RD16(iface, n) readw(iface->reg + (n))
+#define I2C_WR16(iface, n, v) writew(v, iface->reg + (n))
+#define I2C_RD32(iface, n) readl(iface->reg + (n))
+#define I2C_WR32(iface, n, v) writel(v, iface->reg + (n))
+
+static struct s6i2c_if s6i2c_if;
+
+static void s6i2c_handle_interrupt(struct s6i2c_if *iface)
+{
+	if (I2C_RD16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {
+		I2C_RD16(iface, S6_I2C_CLRTXABRT);
+		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
+		complete(&iface->complete);
+		return;
+	}
+	if (iface->msgs_done >= iface->msgs_num) {
+		printk(KERN_DEBUG "spurious I2C irq: %x\n",
+		       I2C_RD16(iface, S6_I2C_INTRSTAT));
+		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
+		return;
+	}
+	while ((iface->msgs_push < iface->msgs_num)
+	    && (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {
+		struct i2c_msg *m = &iface->msgs[iface->msgs_push];
+		if (!(m->flags & I2C_M_RD))
+			I2C_WR16(iface, S6_I2C_DATACMD, m->buf[iface->push]);
+		else
+			I2C_WR16(iface, S6_I2C_DATACMD,
+				 1 << S6_I2C_DATACMD_READ);
+		if (++iface->push >= m->len) {
+			iface->push = 0;
+			iface->msgs_push += 1;
+		}
+	}
+	do {
+		struct i2c_msg *m = &iface->msgs[iface->msgs_done];
+		if (!(m->flags & I2C_M_RD)) {
+			if (iface->msgs_done < iface->msgs_push)
+				iface->msgs_done += 1;
+			else
+				break;
+		} else if (I2C_RD16(iface, S6_I2C_STATUS)
+				& (1 << S6_I2C_STATUS_RFNE)) {
+			m->buf[iface->done] = I2C_RD16(iface, S6_I2C_DATACMD);
+			if (++iface->done >= m->len) {
+				iface->done = 0;
+				iface->msgs_done += 1;
+			}
+		} else{
+			break;
+		}
+	} while (iface->msgs_done < iface->msgs_num);
+	if (iface->msgs_done >= iface->msgs_num) {
+		I2C_WR16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);
+		complete(&iface->complete);
+	} else if (iface->msgs_push >= iface->msgs_num) {
+		I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
+						 (1 << S6_I2C_INTR_RXFULL));
+	} else {
+		I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
+						 (1 << S6_I2C_INTR_TXEMPTY) |
+						 (1 << S6_I2C_INTR_RXFULL));
+	}
+}
+
+static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)
+{
+	struct s6i2c_if *iface = dev_id;
+	if (!(I2C_RD16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)
+					      | (1 << S6_I2C_INTR_RXOVER)
+					      | (1 << S6_I2C_INTR_RXFULL)
+					      | (1 << S6_I2C_INTR_TXOVER)
+					      | (1 << S6_I2C_INTR_TXEMPTY)
+					      | (1 << S6_I2C_INTR_RDREQ)
+					      | (1 << S6_I2C_INTR_TXABRT)
+					      | (1 << S6_I2C_INTR_RXDONE)
+					      | (1 << S6_I2C_INTR_ACTIVITY)
+					      | (1 << S6_I2C_INTR_STOPDET)
+					      | (1 << S6_I2C_INTR_STARTDET)
+					      | (1 << S6_I2C_INTR_GENCALL))))
+		return IRQ_NONE;
+
+	spin_lock(&iface->lock);
+	del_timer(&iface->timeout_timer);
+	s6i2c_handle_interrupt(iface);
+	spin_unlock(&iface->lock);
+	return IRQ_HANDLED;
+}
+
+static void s6i2c_timeout(unsigned long data)
+{
+	struct s6i2c_if *iface = (struct s6i2c_if *)data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&iface->lock, flags);
+	s6i2c_handle_interrupt(iface);
+	if (--iface->timeout_count > 0) {
+		iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
+		add_timer(&iface->timeout_timer);
+	} else {
+		complete(&iface->complete);
+		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
+	}
+	spin_unlock_irqrestore(&iface->lock, flags);
+}
+
+static int s6i2c_master_xfer(struct i2c_adapter *adap,
+				struct i2c_msg *msgs, int num)
+{
+	struct s6i2c_if *iface = adap->algo_data;
+	int i;
+	if (num == 0)
+		return 0;
+	if (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
+		yield();
+	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
+	I2C_RD16(iface, S6_I2C_CLRINTR);
+	for (i = 0; i < num; i++) {
+		if (msgs[i].flags & I2C_M_TEN) {
+			dev_err(&(adap->dev),
+				"s6i2c: 10 bits addr not supported\n");
+			return -EINVAL;
+		}
+		if (msgs[i].len == 0) {
+			dev_err(&(adap->dev),
+				"s6i2c: zero length message not supported\n");
+			return -EINVAL;
+		}
+		if (msgs[i].addr != msgs[0].addr) {
+			dev_err(&(adap->dev),
+				"s6i2c: multiple xfer cannot change target\n");
+			return -EINVAL;
+		}
+	}
+	iface->msgs = msgs;
+	iface->msgs_num = num;
+	iface->msgs_push = 0;
+	iface->msgs_done = 0;
+	iface->push = 0;
+	iface->done = 0;
+	iface->timeout_count = 10;
+	I2C_WR16(iface, S6_I2C_TAR, msgs[0].addr);
+	I2C_WR16(iface, S6_I2C_ENABLE, 1);
+	I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) |
+					 (1 << S6_I2C_INTR_TXABRT));
+	iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
+	add_timer(&iface->timeout_timer);
+	wait_for_completion(&iface->complete);
+	del_timer_sync(&iface->timeout_timer);
+	while (I2C_RD32(iface, S6_I2C_TXFLR) > 0)
+		schedule();
+	while (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
+		schedule();
+	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
+	I2C_WR16(iface, S6_I2C_ENABLE, 0);
+	return iface->msgs_done;
+}
+
+static u32 s6i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm s6i2c_algorithm = {
+	.master_xfer   = s6i2c_master_xfer,
+	.functionality = s6i2c_functionality,
+};
+
+static u16 __devinit nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)
+{
+	u64 dividend = (u64)ns * clk_get_rate(iface->clk);
+	do_div(dividend, 1000000000);
+	if (dividend > 0xffff)
+		return 0xffff;
+	return dividend;
+}
+
+static int __devinit s6i2c_probe(struct platform_device *dev)
+{
+	struct s6i2c_if *iface = &s6i2c_if;
+	struct i2c_adapter *p_adap;
+	const char *clock;
+	int bus_num, rc;
+	spin_lock_init(&(iface->lock));
+	init_completion(&(iface->complete));
+	iface->irq = platform_get_irq(dev, 0);
+	if (iface->irq < 0) {
+		rc = iface->irq;
+		goto err_out;
+	}
+	iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+	if (!iface->res) {
+		rc = -ENXIO;
+		goto err_out;
+	}
+	iface->res = request_mem_region(iface->res->start,
+					iface->res->end - iface->res->start + 1,
+					dev->dev.bus_id);
+	if (!iface->res) {
+		rc = -EBUSY;
+		goto err_out;
+	}
+	iface->reg = ioremap_nocache(iface->res->start,
+				     iface->res->end - iface->res->start + 1);
+	if (!iface->reg) {
+		rc = -ENOMEM;
+		goto err_reg;
+	}
+	clock = 0;
+	bus_num = -1;
+	if (dev->dev.platform_data) {
+		struct s6_i2c_platform_data *pdata = dev->dev.platform_data;
+		bus_num = pdata->bus_num;
+		clock = pdata->clock;
+	}
+	iface->clk = clk_get(&dev->dev, clock);
+	if (IS_ERR(iface->clk)) {
+		rc = PTR_ERR(iface->clk);
+		goto err_map;
+	}
+	rc = clk_enable(iface->clk);
+	if (rc < 0)
+		goto err_clk_put;
+	init_timer(&(iface->timeout_timer));
+	iface->timeout_timer.function = s6i2c_timeout;
+	iface->timeout_timer.data = (unsigned long)iface;
+	p_adap = &iface->adap;
+	strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
+	p_adap->algo = &s6i2c_algorithm;
+	p_adap->algo_data = iface;
+	p_adap->nr = bus_num;
+	p_adap->class = 0;
+	p_adap->dev.parent = &dev->dev;
+	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
+	rc = request_irq(iface->irq, s6i2c_interrupt_entry,
+			 IRQF_SHARED, dev->name, iface);
+	if (rc) {
+		dev_err(&(p_adap->dev), "s6i2c: cant get IRQ %d\n", iface->irq);
+		goto err_clk_dis;
+	}
+	I2C_WR16(iface, S6_I2C_ENABLE, 0);
+	udelay(1);
+	I2C_WR32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);
+	I2C_WR16(iface, S6_I2C_CLRTXABRT, 1);
+	I2C_WR16(iface, S6_I2C_CON,
+			(1 << S6_I2C_CON_MASTER) |
+			(S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) |
+			(0 << S6_I2C_CON_10BITSLAVE) |
+			(0 << S6_I2C_CON_10BITMASTER) |
+			(1 << S6_I2C_CON_RESTARTENA) |
+			(1 << S6_I2C_CON_SLAVEDISABLE));
+	I2C_WR16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));
+	I2C_WR16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));
+	I2C_WR16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));
+	I2C_WR16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));
+	I2C_WR16(iface, S6_I2C_RXTL, 0);
+	I2C_WR16(iface, S6_I2C_TXTL, 0);
+	platform_set_drvdata(dev, iface);
+	if (bus_num < 0)
+		rc = i2c_add_adapter(p_adap);
+	else
+		rc = i2c_add_numbered_adapter(p_adap);
+	if (rc)
+		goto err_irq_free;
+	return 0;
+
+err_irq_free:
+	free_irq(iface->irq, iface);
+err_clk_dis:
+	clk_disable(iface->clk);
+err_clk_put:
+	clk_put(iface->clk);
+err_map:
+	iounmap(iface->reg);
+err_reg:
+	release_mem_region(iface->res->start,
+			   iface->res->end - iface->res->start + 1);
+err_out:
+	return rc;
+}
+
+static int __devexit s6i2c_remove(struct platform_device *pdev)
+{
+	struct s6i2c_if *iface = platform_get_drvdata(pdev);
+	I2C_WR16(iface, S6_I2C_ENABLE, 0);
+	platform_set_drvdata(pdev, NULL);
+	i2c_del_adapter(&(iface->adap));
+	free_irq(iface->irq, iface);
+	clk_disable(iface->clk);
+	clk_put(iface->clk);
+	iounmap(iface->reg);
+	release_mem_region(iface->res->start,
+			   iface->res->end - iface->res->start + 1);
+	return 0;
+}
+
+static struct platform_driver s6i2c_driver = {
+	.probe		= s6i2c_probe,
+	.remove		= __devexit_p(s6i2c_remove),
+	.driver		= {
+		.name	= "i2c-s6000",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init s6i2c_init(void)
+{
+	pr_info("I2C: S6000 I2C driver\n");
+	return platform_driver_register(&s6i2c_driver);
+}
+
+static void __exit s6i2c_exit(void)
+{
+	platform_driver_unregister(&s6i2c_driver);
+}
+
+MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");
+MODULE_LICENSE("GPL");
+
+subsys_initcall(s6i2c_init);
+module_exit(s6i2c_exit);
diff --git a/drivers/i2c/busses/i2c-s6000.h b/drivers/i2c/busses/i2c-s6000.h
new file mode 100644
index 0000000..ff23b81
--- /dev/null
+++ b/drivers/i2c/busses/i2c-s6000.h
@@ -0,0 +1,79 @@
+/*
+ * drivers/i2c/busses/i2c-s6000.h
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2008 Emlix GmbH <info@emlix.com>
+ * Author:	Oskar Schirmer <os@emlix.com>
+ */
+
+#ifndef __DRIVERS_I2C_BUSSES_I2C_S6000_H
+#define __DRIVERS_I2C_BUSSES_I2C_S6000_H
+
+#define S6_I2C_CON		0x000
+#define S6_I2C_CON_MASTER		0
+#define S6_I2C_CON_SPEED		1
+#define S6_I2C_CON_SPEED_NORMAL			1
+#define S6_I2C_CON_SPEED_FAST			2
+#define S6_I2C_CON_SPEED_MASK			3
+#define S6_I2C_CON_10BITSLAVE		3
+#define S6_I2C_CON_10BITMASTER		4
+#define S6_I2C_CON_RESTARTENA		5
+#define S6_I2C_CON_SLAVEDISABLE		6
+#define S6_I2C_TAR		0x004
+#define S6_I2C_TAR_GCORSTART		10
+#define S6_I2C_TAR_SPECIAL		11
+#define S6_I2C_SAR		0x008
+#define S6_I2C_HSMADDR		0x00C
+#define S6_I2C_DATACMD		0x010
+#define S6_I2C_DATACMD_READ		8
+#define S6_I2C_SSHCNT		0x014
+#define S6_I2C_SSLCNT		0x018
+#define S6_I2C_FSHCNT		0x01C
+#define S6_I2C_FSLCNT		0x020
+#define S6_I2C_INTRSTAT		0x02C
+#define S6_I2C_INTRMASK		0x030
+#define S6_I2C_RAWINTR		0x034
+#define S6_I2C_INTR_RXUNDER		0
+#define S6_I2C_INTR_RXOVER		1
+#define S6_I2C_INTR_RXFULL		2
+#define S6_I2C_INTR_TXOVER		3
+#define S6_I2C_INTR_TXEMPTY		4
+#define S6_I2C_INTR_RDREQ		5
+#define S6_I2C_INTR_TXABRT		6
+#define S6_I2C_INTR_RXDONE		7
+#define S6_I2C_INTR_ACTIVITY		8
+#define S6_I2C_INTR_STOPDET		9
+#define S6_I2C_INTR_STARTDET		10
+#define S6_I2C_INTR_GENCALL		11
+#define S6_I2C_RXTL		0x038
+#define S6_I2C_TXTL		0x03C
+#define S6_I2C_CLRINTR		0x040
+#define S6_I2C_CLRRXUNDER	0x044
+#define S6_I2C_CLRRXOVER	0x048
+#define S6_I2C_CLRTXOVER	0x04C
+#define S6_I2C_CLRRDREQ		0x050
+#define S6_I2C_CLRTXABRT	0x054
+#define S6_I2C_CLRRXDONE	0x058
+#define S6_I2C_CLRACTIVITY	0x05C
+#define S6_I2C_CLRSTOPDET	0x060
+#define S6_I2C_CLRSTARTDET	0x064
+#define S6_I2C_CLRGENCALL	0x068
+#define S6_I2C_ENABLE		0x06C
+#define S6_I2C_STATUS		0x070
+#define S6_I2C_STATUS_ACTIVITY		0
+#define S6_I2C_STATUS_TFNF		1
+#define S6_I2C_STATUS_TFE		2
+#define S6_I2C_STATUS_RFNE		3
+#define S6_I2C_STATUS_RFF		4
+#define S6_I2C_TXFLR		0x074
+#define S6_I2C_RXFLR		0x078
+#define S6_I2C_SRESET		0x07C
+#define S6_I2C_SRESET_IC_SRST		0
+#define S6_I2C_SRESET_IC_MASTER_SRST	1
+#define S6_I2C_SRESET_IC_SLAVE_SRST	2
+#define S6_I2C_TXABRTSOURCE	0x080
+
+#endif
diff --git a/include/linux/i2c/s6000.h b/include/linux/i2c/s6000.h
new file mode 100644
index 0000000..0b6b0c6
--- /dev/null
+++ b/include/linux/i2c/s6000.h
@@ -0,0 +1,10 @@
+#ifndef __LINUX_I2C_S6000_H
+#define __LINUX_I2C_S6000_H
+
+struct s6_i2c_platform_data {
+	const char *clock;
+	int bus_num;
+};
+
+#endif
+
-- 
1.6.2.107.ge47ee

[patch 2/5] xtensa: s6105 specific configuration for the s6000 i2c host

[Daniel Glöckner]

Signed-off-by: Daniel Glöckner <dg@emlix.com>
Signed-off-by: Oskar Schirmer <os@emlix.com>
---
 arch/xtensa/platforms/s6105/device.c |   51 ++++++++++++++++++++++++++++++++++
 1 files changed, 51 insertions(+), 0 deletions(-)

diff --git a/arch/xtensa/platforms/s6105/device.c b/arch/xtensa/platforms/s6105/device.c
index 963634a..00f52ee 100644
--- a/arch/xtensa/platforms/s6105/device.c
+++ b/arch/xtensa/platforms/s6105/device.c
@@ -6,6 +6,8 @@
 
 #include <linux/kernel.h>
 #include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/i2c/s6000.h>
 #include <linux/init.h>
 #include <linux/irq.h>
 #include <linux/phy.h>
@@ -21,6 +23,7 @@
 #define GPIO3_INTNUM		3
 #define UART_INTNUM		4
 #define GMAC_INTNUM		5
+#define I2C_INTNUM		6
 
 static const signed char gpio3_irq_mappings[] = {
 	S6_INTC_GPIO(3),
@@ -41,10 +44,16 @@ static const signed char gmac_irq_mappings[] = {
 	-1
 };
 
+static const signed char i2c_irq_mappings[] = {
+	S6_INTC_I2C,
+	-1
+};
+
 const signed char *platform_irq_mappings[NR_IRQS] = {
 	[GPIO3_INTNUM] = gpio3_irq_mappings,
 	[UART_INTNUM] = uart_irq_mappings,
 	[GMAC_INTNUM] = gmac_irq_mappings,
+	[I2C_INTNUM] = i2c_irq_mappings,
 };
 
 static struct plat_serial8250_port serial_platform_data[] = {
@@ -129,6 +138,38 @@ fail:
 	return PHY_POLL;
 }
 
+#define S6_I2C_BUS_NUM 0
+
+static __devinitdata struct s6_i2c_platform_data s6_i2c_pdata = {
+	.bus_num = S6_I2C_BUS_NUM,
+	.clock = "PCLK",
+};
+
+static struct resource s6_i2c_resource[] = {
+	{
+		.name   = "mem",
+		.start  = (resource_size_t)S6_REG_I2C,
+		.end    = (resource_size_t)S6_REG_I2C + 0x1000 - 1,
+		.flags  = IORESOURCE_MEM,
+	},
+	{
+		.name   = "irq",
+		.start  = (resource_size_t)I2C_INTNUM,
+		.flags  = IORESOURCE_IRQ,
+	},
+};
+
+#define S6I2C_ADDR_TLV320AIC31	0x18
+#define S6I2C_ADDR_SAA7121	0x44
+#define S6I2C_ADDR_MT9D131	0x48
+#define S6I2C_ADDR_AT24HC02B	0x57
+#define S6I2C_ADDR_M41T62	0x68
+#define S6I2C_ADDR_CDCE906	0x69
+#define S6I2C_ADDR_PCA9543	0x73
+
+static struct i2c_board_info __initdata s6_i2c_devices[] = {
+};
+
 static struct platform_device platform_devices[] = {
 	{
 		.name = "serial8250",
@@ -143,12 +184,22 @@ static struct platform_device platform_devices[] = {
 		.resource = s6_gmac_resource,
 		.num_resources = ARRAY_SIZE(s6_gmac_resource),
 	},
+	{
+		.name = "i2c-s6000",
+		.resource = s6_i2c_resource,
+		.num_resources = ARRAY_SIZE(s6_i2c_resource),
+		.dev = {
+			.platform_data = &s6_i2c_pdata,
+		},
+	},
 };
 
 static int __init device_init(void)
 {
 	int i;
 
+	i2c_register_board_info(S6_I2C_BUS_NUM, s6_i2c_devices,
+				ARRAY_SIZE(s6_i2c_devices));
 	s6_gmac_resource[5].start = prepare_phy_irq(GPIO_PHY_IRQ);
 
 	for (i = 0; i < ARRAY_SIZE(platform_devices); i++)
-- 
1.6.2.107.ge47ee

[patch 3/5] xtensa: add at24hc02b to s6105 platform

[Daniel Glöckner]

This is particularly used to read the MAC address of the ethernet
controller from an EEPROM.

Signed-off-by: Daniel Glöckner <dg@emlix.com>
---
 arch/xtensa/platforms/s6105/device.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/xtensa/platforms/s6105/device.c b/arch/xtensa/platforms/s6105/device.c
index 00f52ee..9394e6f 100644
--- a/arch/xtensa/platforms/s6105/device.c
+++ b/arch/xtensa/platforms/s6105/device.c
@@ -168,6 +168,9 @@ static struct resource s6_i2c_resource[] = {
 #define S6I2C_ADDR_PCA9543	0x73
 
 static struct i2c_board_info __initdata s6_i2c_devices[] = {
+	{
+		I2C_BOARD_INFO("24c02", S6I2C_ADDR_AT24HC02B),
+	},
 };
 
 static struct platform_device platform_devices[] = {
-- 
1.6.2.107.ge47ee

[patch 4/5] xtensa: enable s6000 i2c host driver in s6105_defconfig

[Daniel Glöckner]

Signed-off-by: Daniel Glöckner <dg@emlix.com>
---
 arch/xtensa/configs/s6105_defconfig |   54 +++++++++++++++++++++++++++++++++-
 1 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/arch/xtensa/configs/s6105_defconfig b/arch/xtensa/configs/s6105_defconfig
index a130c8d..a9a0de9 100644
--- a/arch/xtensa/configs/s6105_defconfig
+++ b/arch/xtensa/configs/s6105_defconfig
@@ -1,7 +1,7 @@
 #
 # Automatically generated make config: don't edit
 # Linux kernel version: 2.6.29-rc7-s6
-# Tue Mar 10 11:09:26 2009
+# Wed Mar 11 13:38:31 2009
 #
 # CONFIG_FRAME_POINTER is not set
 CONFIG_ZONE_DMA=y
@@ -357,7 +357,48 @@ CONFIG_UNIX98_PTYS=y
 # CONFIG_R3964 is not set
 # CONFIG_RAW_DRIVER is not set
 # CONFIG_TCG_TPM is not set
-# CONFIG_I2C is not set
+CONFIG_I2C=y
+CONFIG_I2C_BOARDINFO=y
+# CONFIG_I2C_CHARDEV is not set
+CONFIG_I2C_HELPER_AUTO=y
+
+#
+# I2C Hardware Bus support
+#
+
+#
+# I2C system bus drivers (mostly embedded / system-on-chip)
+#
+# CONFIG_I2C_GPIO is not set
+# CONFIG_I2C_OCORES is not set
+CONFIG_I2C_S6000=y
+# CONFIG_I2C_SIMTEC is not set
+
+#
+# External I2C/SMBus adapter drivers
+#
+# CONFIG_I2C_PARPORT_LIGHT is not set
+# CONFIG_I2C_TAOS_EVM is not set
+
+#
+# Other I2C/SMBus bus drivers
+#
+# CONFIG_I2C_PCA_PLATFORM is not set
+
+#
+# Miscellaneous I2C Chip support
+#
+# CONFIG_DS1682 is not set
+# CONFIG_SENSORS_PCF8574 is not set
+# CONFIG_PCF8575 is not set
+# CONFIG_SENSORS_PCA9539 is not set
+# CONFIG_SENSORS_PCF8591 is not set
+# CONFIG_SENSORS_MAX6875 is not set
+# CONFIG_SENSORS_TSL2550 is not set
+# CONFIG_I2C_DEBUG_CORE is not set
+# CONFIG_I2C_DEBUG_ALGO is not set
+# CONFIG_I2C_DEBUG_BUS is not set
+# CONFIG_I2C_DEBUG_CHIP is not set
 # CONFIG_SPI is not set
 CONFIG_ARCH_REQUIRE_GPIOLIB=y
 CONFIG_GPIOLIB=y
@@ -371,6 +412,9 @@ CONFIG_GPIOLIB=y
 #
 # I2C GPIO expanders:
 #
+# CONFIG_GPIO_MAX732X is not set
+# CONFIG_GPIO_PCA953X is not set
+# CONFIG_GPIO_PCF857X is not set
 
 #
 # PCI GPIO expanders:
@@ -398,7 +442,13 @@ CONFIG_SSB_POSSIBLE=y
 # CONFIG_MFD_CORE is not set
 # CONFIG_MFD_SM501 is not set
 # CONFIG_HTC_PASIC3 is not set
+# CONFIG_TPS65010 is not set
+# CONFIG_TWL4030_CORE is not set
 # CONFIG_MFD_TMIO is not set
+# CONFIG_PMIC_DA903X is not set
+# CONFIG_MFD_WM8400 is not set
+# CONFIG_MFD_WM8350_I2C is not set
+# CONFIG_MFD_PCF50633 is not set
 # CONFIG_REGULATOR is not set
 
 #
-- 
1.6.2.107.ge47ee

[patch 5/5] xtensa: enable at24 driver in s6105_defconfig

[Daniel Glöckner]

Signed-off-by: Daniel Glöckner <dg@emlix.com>
---
 arch/xtensa/configs/s6105_defconfig |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/arch/xtensa/configs/s6105_defconfig b/arch/xtensa/configs/s6105_defconfig
index a9a0de9..e398710 100644
--- a/arch/xtensa/configs/s6105_defconfig
+++ b/arch/xtensa/configs/s6105_defconfig
@@ -251,7 +251,17 @@ CONFIG_BLK_DEV_RAM_SIZE=4096
 # CONFIG_CDROM_PKTCDVD is not set
 # CONFIG_ATA_OVER_ETH is not set
 # CONFIG_BLK_DEV_HD is not set
-# CONFIG_MISC_DEVICES is not set
+CONFIG_MISC_DEVICES=y
+# CONFIG_ICS932S401 is not set
+# CONFIG_ENCLOSURE_SERVICES is not set
+# CONFIG_C2PORT is not set
+
+#
+# EEPROM support
+#
+CONFIG_EEPROM_AT24=y
+# CONFIG_EEPROM_LEGACY is not set
+# CONFIG_EEPROM_93CX6 is not set
 CONFIG_HAVE_IDE=y
 # CONFIG_IDE is not set
 
-- 
1.6.2.107.ge47ee

Re: [patch 1/5] i2c: xtensa s6000 i2c driver

[Ben Dooks]

On Mon, Mar 23, 2009 at 04:05:14PM +0100, Daniel Gl??ckner wrote:
> From: Oskar Schirmer <os@emlix.com>
> 
> Support for the s6000 on-chip i2c controller.
> 
> Signed-off-by: Oskar Schirmer <os@emlix.com>
> Signed-off-by: Daniel Gl??ckner <dg@emlix.com>

Not going to merge this on my first pull request to linus, there's
a few things that I'd like to get answered before.

> ---
>  drivers/i2c/busses/Kconfig     |   10 +
>  drivers/i2c/busses/Makefile    |    1 +
>  drivers/i2c/busses/i2c-s6000.c |  380 ++++++++++++++++++++++++++++++++++++++++
>  drivers/i2c/busses/i2c-s6000.h |   79 +++++++++
>  include/linux/i2c/s6000.h      |   10 +
>  5 files changed, 480 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/i2c/busses/i2c-s6000.c
>  create mode 100644 drivers/i2c/busses/i2c-s6000.h
>  create mode 100644 include/linux/i2c/s6000.h
> 
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 7f95905..904def4 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -461,6 +461,16 @@ config I2C_S3C2410
>  	  Say Y here to include support for I2C controller in the
>  	  Samsung S3C2410 based System-on-Chip devices.
>  
> +config I2C_S6000
> +	tristate "S6000 I2C support"
> +	depends on XTENSA_VARIANT_S6000
> +	help
> +	  This driver supports the on chip I2C device on the
> +	  S6000 xtensa processor family.
> +
> +	  To compile this driver as a module, choose M here. The module
> +	  will be called i2c-s6000.
> +
>  config I2C_SH7760
>  	tristate "Renesas SH7760 I2C Controller"
>  	depends on CPU_SUBTYPE_SH7760
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 0c2c4b2..f7989d1 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi.o
>  obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o
>  obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
>  obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o
> +obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
>  obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
>  obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o
>  obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o
> diff --git a/drivers/i2c/busses/i2c-s6000.c b/drivers/i2c/busses/i2c-s6000.c
> new file mode 100644
> index 0000000..88e3fdc
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-s6000.c
> @@ -0,0 +1,380 @@
> +/*
> + * drivers/i2c/busses/i2c-s6000.c
> + *
> + * Description: Driver for S6000 Family I2C Interface
> + *	(c) 2008 emlix GmbH <info@emlix.com>

Note, I think you need Copyright here as well, (c) needs to be a
proper c in circle i've been informed.

> + * Author:	Oskar Schirmer <os@emlix.com>
> + *
> + * Partially based on i2c-bfin-twi.c driver by <sonic.zhang@analog.com>
> + * Copyright (c) 2005-2007 Analog Devices, Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/i2c/s6000.h>
> +#include <linux/timer.h>
> +#include <linux/spinlock.h>
> +#include <linux/completion.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +
> +#include <asm/io.h>
> +#include "i2c-s6000.h"
> +
> +#define POLL_TIMEOUT	(2 * HZ)
> +

would be nice to have some documentation for each of the members
of this.

> +struct s6i2c_if {
> +	u8 __iomem		*reg;
> +	int			irq;
> +	spinlock_t		lock;
> +	struct i2c_msg		*msgs;
> +	int			msgs_num, msgs_push, msgs_done;
> +	unsigned		push, done;
> +	int			timeout_count;
> +	struct timer_list	timeout_timer;
> +	struct i2c_adapter	adap;
> +	struct completion	complete;
> +	struct clk		*clk;
> +	struct resource		*res;
> +};
> +
> +#define I2C_RD16(iface, n) readw(iface->reg + (n))
> +#define I2C_WR16(iface, n, v) writew(v, iface->reg + (n))
> +#define I2C_RD32(iface, n) readl(iface->reg + (n))
> +#define I2C_WR32(iface, n, v) writel(v, iface->reg + (n))

tried inline functions for these?

> +
> +static struct s6i2c_if s6i2c_if;
> +
> +static void s6i2c_handle_interrupt(struct s6i2c_if *iface)
> +{
> +	if (I2C_RD16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {
> +		I2C_RD16(iface, S6_I2C_CLRTXABRT);
> +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> +		complete(&iface->complete);
> +		return;
> +	}
> +	if (iface->msgs_done >= iface->msgs_num) {
> +		printk(KERN_DEBUG "spurious I2C irq: %x\n",
> +		       I2C_RD16(iface, S6_I2C_INTRSTAT));
> +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> +		return;
> +	}
> +	while ((iface->msgs_push < iface->msgs_num)
> +	    && (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {
> +		struct i2c_msg *m = &iface->msgs[iface->msgs_push];
> +		if (!(m->flags & I2C_M_RD))
> +			I2C_WR16(iface, S6_I2C_DATACMD, m->buf[iface->push]);
> +		else
> +			I2C_WR16(iface, S6_I2C_DATACMD,
> +				 1 << S6_I2C_DATACMD_READ);
> +		if (++iface->push >= m->len) {
> +			iface->push = 0;
> +			iface->msgs_push += 1;
> +		}
> +	}
> +	do {
> +		struct i2c_msg *m = &iface->msgs[iface->msgs_done];
> +		if (!(m->flags & I2C_M_RD)) {
> +			if (iface->msgs_done < iface->msgs_push)
> +				iface->msgs_done += 1;
> +			else
> +				break;
> +		} else if (I2C_RD16(iface, S6_I2C_STATUS)
> +				& (1 << S6_I2C_STATUS_RFNE)) {
> +			m->buf[iface->done] = I2C_RD16(iface, S6_I2C_DATACMD);
> +			if (++iface->done >= m->len) {
> +				iface->done = 0;
> +				iface->msgs_done += 1;
> +			}
> +		} else{
> +			break;
> +		}
> +	} while (iface->msgs_done < iface->msgs_num);
> +	if (iface->msgs_done >= iface->msgs_num) {
> +		I2C_WR16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);
> +		complete(&iface->complete);
> +	} else if (iface->msgs_push >= iface->msgs_num) {
> +		I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
> +						 (1 << S6_I2C_INTR_RXFULL));
> +	} else {
> +		I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
> +						 (1 << S6_I2C_INTR_TXEMPTY) |
> +						 (1 << S6_I2C_INTR_RXFULL));
> +	}
> +}
> +
> +static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)
> +{
> +	struct s6i2c_if *iface = dev_id;
> +	if (!(I2C_RD16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)
> +					      | (1 << S6_I2C_INTR_RXOVER)
> +					      | (1 << S6_I2C_INTR_RXFULL)
> +					      | (1 << S6_I2C_INTR_TXOVER)
> +					      | (1 << S6_I2C_INTR_TXEMPTY)
> +					      | (1 << S6_I2C_INTR_RDREQ)
> +					      | (1 << S6_I2C_INTR_TXABRT)
> +					      | (1 << S6_I2C_INTR_RXDONE)
> +					      | (1 << S6_I2C_INTR_ACTIVITY)
> +					      | (1 << S6_I2C_INTR_STOPDET)
> +					      | (1 << S6_I2C_INTR_STARTDET)
> +					      | (1 << S6_I2C_INTR_GENCALL))))
> +		return IRQ_NONE;
> +
> +	spin_lock(&iface->lock);
> +	del_timer(&iface->timeout_timer);
> +	s6i2c_handle_interrupt(iface);
> +	spin_unlock(&iface->lock);
> +	return IRQ_HANDLED;
> +}
> +
> +static void s6i2c_timeout(unsigned long data)
> +{
> +	struct s6i2c_if *iface = (struct s6i2c_if *)data;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&iface->lock, flags);
> +	s6i2c_handle_interrupt(iface);
> +	if (--iface->timeout_count > 0) {
> +		iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
> +		add_timer(&iface->timeout_timer);
> +	} else {
> +		complete(&iface->complete);
> +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> +	}
> +	spin_unlock_irqrestore(&iface->lock, flags);
> +}
> +
> +static int s6i2c_master_xfer(struct i2c_adapter *adap,
> +				struct i2c_msg *msgs, int num)
> +{
> +	struct s6i2c_if *iface = adap->algo_data;
> +	int i;
> +	if (num == 0)
> +		return 0;
> +	if (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
> +		yield();
> +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> +	I2C_RD16(iface, S6_I2C_CLRINTR);
> +	for (i = 0; i < num; i++) {
> +		if (msgs[i].flags & I2C_M_TEN) {
> +			dev_err(&(adap->dev),
> +				"s6i2c: 10 bits addr not supported\n");
> +			return -EINVAL;
> +		}
> +		if (msgs[i].len == 0) {
> +			dev_err(&(adap->dev),
> +				"s6i2c: zero length message not supported\n");
> +			return -EINVAL;
> +		}
> +		if (msgs[i].addr != msgs[0].addr) {
> +			dev_err(&(adap->dev),
> +				"s6i2c: multiple xfer cannot change target\n");
> +			return -EINVAL;
> +		}
> +	}
> +	iface->msgs = msgs;
> +	iface->msgs_num = num;
> +	iface->msgs_push = 0;
> +	iface->msgs_done = 0;
> +	iface->push = 0;
> +	iface->done = 0;
> +	iface->timeout_count = 10;
> +	I2C_WR16(iface, S6_I2C_TAR, msgs[0].addr);
> +	I2C_WR16(iface, S6_I2C_ENABLE, 1);
> +	I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) |
> +					 (1 << S6_I2C_INTR_TXABRT));
> +	iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
> +	add_timer(&iface->timeout_timer);
> +	wait_for_completion(&iface->complete);
> +	del_timer_sync(&iface->timeout_timer);
> +	while (I2C_RD32(iface, S6_I2C_TXFLR) > 0)
> +		schedule();
> +	while (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
> +		schedule();
> +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> +	return iface->msgs_done;
> +}
> +
> +static u32 s6i2c_functionality(struct i2c_adapter *adap)
> +{
> +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static struct i2c_algorithm s6i2c_algorithm = {
> +	.master_xfer   = s6i2c_master_xfer,
> +	.functionality = s6i2c_functionality,
> +};
> +
> +static u16 __devinit nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)
> +{
> +	u64 dividend = (u64)ns * clk_get_rate(iface->clk);
> +	do_div(dividend, 1000000000);
> +	if (dividend > 0xffff)
> +		return 0xffff;
> +	return dividend;
> +}

do you desperately need to be _that_ accurate?

> +static int __devinit s6i2c_probe(struct platform_device *dev)
> +{
> +	struct s6i2c_if *iface = &s6i2c_if;
> +	struct i2c_adapter *p_adap;
> +	const char *clock;
> +	int bus_num, rc;
> +	spin_lock_init(&(iface->lock));
> +	init_completion(&(iface->complete));

please don't do &(variable) it is fugly.

> +	iface->irq = platform_get_irq(dev, 0);
> +	if (iface->irq < 0) {
> +		rc = iface->irq;
> +		goto err_out;
> +	}
> +	iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);
> +	if (!iface->res) {
> +		rc = -ENXIO;
> +		goto err_out;
> +	}
> +	iface->res = request_mem_region(iface->res->start,
> +					iface->res->end - iface->res->start + 1,
> +					dev->dev.bus_id);
> +	if (!iface->res) {
> +		rc = -EBUSY;
> +		goto err_out;
> +	}
> +	iface->reg = ioremap_nocache(iface->res->start,
> +				     iface->res->end - iface->res->start + 1);
> +	if (!iface->reg) {
> +		rc = -ENOMEM;
> +		goto err_reg;
> +	}
> +	clock = 0;
> +	bus_num = -1;
> +	if (dev->dev.platform_data) {
> +		struct s6_i2c_platform_data *pdata = dev->dev.platform_data;
> +		bus_num = pdata->bus_num;
> +		clock = pdata->clock;
> +	}
> +	iface->clk = clk_get(&dev->dev, clock);
> +	if (IS_ERR(iface->clk)) {
> +		rc = PTR_ERR(iface->clk);
> +		goto err_map;
> +	}

passing the name in the platform device is a bit nasty, if there's
only one clock for the device then it should have been dealt with
at the arch level and doing clk_get(&dev->dev, NULL) should be
acceptable.

> +	rc = clk_enable(iface->clk);
> +	if (rc < 0)
> +		goto err_clk_put;
> +	init_timer(&(iface->timeout_timer));
> +	iface->timeout_timer.function = s6i2c_timeout;
> +	iface->timeout_timer.data = (unsigned long)iface;
> +	p_adap = &iface->adap;
> +	strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
> +	p_adap->algo = &s6i2c_algorithm;
> +	p_adap->algo_data = iface;
> +	p_adap->nr = bus_num;
> +	p_adap->class = 0;
> +	p_adap->dev.parent = &dev->dev;

some spacing for readability would be nice.

> +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> +	rc = request_irq(iface->irq, s6i2c_interrupt_entry,
> +			 IRQF_SHARED, dev->name, iface);
> +	if (rc) {
> +		dev_err(&(p_adap->dev), "s6i2c: cant get IRQ %d\n", iface->irq);
> +		goto err_clk_dis;
> +	}
> +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> +	udelay(1);
> +	I2C_WR32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);
> +	I2C_WR16(iface, S6_I2C_CLRTXABRT, 1);
> +	I2C_WR16(iface, S6_I2C_CON,
> +			(1 << S6_I2C_CON_MASTER) |
> +			(S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) |
> +			(0 << S6_I2C_CON_10BITSLAVE) |
> +			(0 << S6_I2C_CON_10BITMASTER) |
> +			(1 << S6_I2C_CON_RESTARTENA) |
> +			(1 << S6_I2C_CON_SLAVEDISABLE));
> +	I2C_WR16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));
> +	I2C_WR16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));
> +	I2C_WR16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));
> +	I2C_WR16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));
> +	I2C_WR16(iface, S6_I2C_RXTL, 0);
> +	I2C_WR16(iface, S6_I2C_TXTL, 0);
> +	platform_set_drvdata(dev, iface);
> +	if (bus_num < 0)
> +		rc = i2c_add_adapter(p_adap);
> +	else
> +		rc = i2c_add_numbered_adapter(p_adap);
> +	if (rc)
> +		goto err_irq_free;
> +	return 0;
> +
> +err_irq_free:
> +	free_irq(iface->irq, iface);
> +err_clk_dis:
> +	clk_disable(iface->clk);
> +err_clk_put:
> +	clk_put(iface->clk);
> +err_map:
> +	iounmap(iface->reg);
> +err_reg:
> +	release_mem_region(iface->res->start,
> +			   iface->res->end - iface->res->start + 1);
> +err_out:
> +	return rc;
> +}
> +
> +static int __devexit s6i2c_remove(struct platform_device *pdev)
> +{
> +	struct s6i2c_if *iface = platform_get_drvdata(pdev);
> +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> +	platform_set_drvdata(pdev, NULL);
> +	i2c_del_adapter(&(iface->adap));
> +	free_irq(iface->irq, iface);
> +	clk_disable(iface->clk);
> +	clk_put(iface->clk);
> +	iounmap(iface->reg);
> +	release_mem_region(iface->res->start,
> +			   iface->res->end - iface->res->start + 1);

resource_size() would be good here, and elsewhere in the driver.

> +	return 0;
> +}
> +
> +static struct platform_driver s6i2c_driver = {
> +	.probe		= s6i2c_probe,
> +	.remove		= __devexit_p(s6i2c_remove),
> +	.driver		= {
> +		.name	= "i2c-s6000",
> +		.owner	= THIS_MODULE,
> +	},
> +};
> +
> +static int __init s6i2c_init(void)
> +{
> +	pr_info("I2C: S6000 I2C driver\n");
> +	return platform_driver_register(&s6i2c_driver);
> +}
> +
> +static void __exit s6i2c_exit(void)
> +{
> +	platform_driver_unregister(&s6i2c_driver);
> +}
> +
> +MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");
> +MODULE_LICENSE("GPL");
> +
> +subsys_initcall(s6i2c_init);
> +module_exit(s6i2c_exit);


as a note, the code is quite dense, a few blank lines would be
nice.

> diff --git a/drivers/i2c/busses/i2c-s6000.h b/drivers/i2c/busses/i2c-s6000.h
> new file mode 100644
> index 0000000..ff23b81
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-s6000.h
> @@ -0,0 +1,79 @@
> +/*
> + * drivers/i2c/busses/i2c-s6000.h
> + *
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License.  See the file "COPYING" in the main directory of this archive
> + * for more details.
> + *
> + * Copyright (C) 2008 Emlix GmbH <info@emlix.com>
> + * Author:	Oskar Schirmer <os@emlix.com>
> + */
> +
> +#ifndef __DRIVERS_I2C_BUSSES_I2C_S6000_H
> +#define __DRIVERS_I2C_BUSSES_I2C_S6000_H
> +
> +#define S6_I2C_CON		0x000
> +#define S6_I2C_CON_MASTER		0
> +#define S6_I2C_CON_SPEED		1
> +#define S6_I2C_CON_SPEED_NORMAL			1
> +#define S6_I2C_CON_SPEED_FAST			2
> +#define S6_I2C_CON_SPEED_MASK			3
> +#define S6_I2C_CON_10BITSLAVE		3
> +#define S6_I2C_CON_10BITMASTER		4
> +#define S6_I2C_CON_RESTARTENA		5
> +#define S6_I2C_CON_SLAVEDISABLE		6
> +#define S6_I2C_TAR		0x004
> +#define S6_I2C_TAR_GCORSTART		10
> +#define S6_I2C_TAR_SPECIAL		11
> +#define S6_I2C_SAR		0x008
> +#define S6_I2C_HSMADDR		0x00C
> +#define S6_I2C_DATACMD		0x010
> +#define S6_I2C_DATACMD_READ		8
> +#define S6_I2C_SSHCNT		0x014
> +#define S6_I2C_SSLCNT		0x018
> +#define S6_I2C_FSHCNT		0x01C
> +#define S6_I2C_FSLCNT		0x020
> +#define S6_I2C_INTRSTAT		0x02C
> +#define S6_I2C_INTRMASK		0x030
> +#define S6_I2C_RAWINTR		0x034
> +#define S6_I2C_INTR_RXUNDER		0
> +#define S6_I2C_INTR_RXOVER		1
> +#define S6_I2C_INTR_RXFULL		2
> +#define S6_I2C_INTR_TXOVER		3
> +#define S6_I2C_INTR_TXEMPTY		4
> +#define S6_I2C_INTR_RDREQ		5
> +#define S6_I2C_INTR_TXABRT		6
> +#define S6_I2C_INTR_RXDONE		7
> +#define S6_I2C_INTR_ACTIVITY		8
> +#define S6_I2C_INTR_STOPDET		9
> +#define S6_I2C_INTR_STARTDET		10
> +#define S6_I2C_INTR_GENCALL		11
> +#define S6_I2C_RXTL		0x038
> +#define S6_I2C_TXTL		0x03C
> +#define S6_I2C_CLRINTR		0x040
> +#define S6_I2C_CLRRXUNDER	0x044
> +#define S6_I2C_CLRRXOVER	0x048
> +#define S6_I2C_CLRTXOVER	0x04C
> +#define S6_I2C_CLRRDREQ		0x050
> +#define S6_I2C_CLRTXABRT	0x054
> +#define S6_I2C_CLRRXDONE	0x058
> +#define S6_I2C_CLRACTIVITY	0x05C
> +#define S6_I2C_CLRSTOPDET	0x060
> +#define S6_I2C_CLRSTARTDET	0x064
> +#define S6_I2C_CLRGENCALL	0x068
> +#define S6_I2C_ENABLE		0x06C
> +#define S6_I2C_STATUS		0x070
> +#define S6_I2C_STATUS_ACTIVITY		0
> +#define S6_I2C_STATUS_TFNF		1
> +#define S6_I2C_STATUS_TFE		2
> +#define S6_I2C_STATUS_RFNE		3
> +#define S6_I2C_STATUS_RFF		4
> +#define S6_I2C_TXFLR		0x074
> +#define S6_I2C_RXFLR		0x078
> +#define S6_I2C_SRESET		0x07C
> +#define S6_I2C_SRESET_IC_SRST		0
> +#define S6_I2C_SRESET_IC_MASTER_SRST	1
> +#define S6_I2C_SRESET_IC_SLAVE_SRST	2
> +#define S6_I2C_TXABRTSOURCE	0x080
> +
> +#endif
> diff --git a/include/linux/i2c/s6000.h b/include/linux/i2c/s6000.h

and again.

> new file mode 100644
> index 0000000..0b6b0c6
> --- /dev/null
> +++ b/include/linux/i2c/s6000.h
> @@ -0,0 +1,10 @@
> +#ifndef __LINUX_I2C_S6000_H
> +#define __LINUX_I2C_S6000_H
> +

documentation comments would be nice here too.

> +struct s6_i2c_platform_data {
> +	const char *clock;
> +	int bus_num;
> +};
> +
> +#endif
> +
> -- 
> 1.6.2.107.ge47ee
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Ben (ben@fluff.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

Re: [patch 1/5] i2c: xtensa s6000 i2c driver

[Ben Dooks]

On Tue, Mar 31, 2009 at 11:52:58PM +0100, Ben Dooks wrote:
> On Mon, Mar 23, 2009 at 04:05:14PM +0100, Daniel Gl??ckner wrote:
> > From: Oskar Schirmer <os@emlix.com>
> > 
> > Support for the s6000 on-chip i2c controller.
> > 
> > Signed-off-by: Oskar Schirmer <os@emlix.com>
> > Signed-off-by: Daniel Gl??ckner <dg@emlix.com>
> 
> Not going to merge this on my first pull request to linus, there's
> a few things that I'd like to get answered before.

and a few other things i've just noticed:
 
> > ---
> >  drivers/i2c/busses/Kconfig     |   10 +
> >  drivers/i2c/busses/Makefile    |    1 +
> >  drivers/i2c/busses/i2c-s6000.c |  380 ++++++++++++++++++++++++++++++++++++++++
> >  drivers/i2c/busses/i2c-s6000.h |   79 +++++++++
> >  include/linux/i2c/s6000.h      |   10 +
> >  5 files changed, 480 insertions(+), 0 deletions(-)
> >  create mode 100644 drivers/i2c/busses/i2c-s6000.c
> >  create mode 100644 drivers/i2c/busses/i2c-s6000.h
> >  create mode 100644 include/linux/i2c/s6000.h
> > 
> > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> > index 7f95905..904def4 100644
> > --- a/drivers/i2c/busses/Kconfig
> > +++ b/drivers/i2c/busses/Kconfig
> > @@ -461,6 +461,16 @@ config I2C_S3C2410
> >  	  Say Y here to include support for I2C controller in the
> >  	  Samsung S3C2410 based System-on-Chip devices.
> >  
> > +config I2C_S6000
> > +	tristate "S6000 I2C support"
> > +	depends on XTENSA_VARIANT_S6000
> > +	help
> > +	  This driver supports the on chip I2C device on the
> > +	  S6000 xtensa processor family.
> > +
> > +	  To compile this driver as a module, choose M here. The module
> > +	  will be called i2c-s6000.
> > +
> >  config I2C_SH7760
> >  	tristate "Renesas SH7760 I2C Controller"
> >  	depends on CPU_SUBTYPE_SH7760
> > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> > index 0c2c4b2..f7989d1 100644
> > --- a/drivers/i2c/busses/Makefile
> > +++ b/drivers/i2c/busses/Makefile
> > @@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi.o
> >  obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o
> >  obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
> >  obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o
> > +obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
> >  obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
> >  obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o
> >  obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o
> > diff --git a/drivers/i2c/busses/i2c-s6000.c b/drivers/i2c/busses/i2c-s6000.c
> > new file mode 100644
> > index 0000000..88e3fdc
> > --- /dev/null
> > +++ b/drivers/i2c/busses/i2c-s6000.c
> > @@ -0,0 +1,380 @@
> > +/*
> > + * drivers/i2c/busses/i2c-s6000.c
> > + *
> > + * Description: Driver for S6000 Family I2C Interface
> > + *	(c) 2008 emlix GmbH <info@emlix.com>
> 
> Note, I think you need Copyright here as well, (c) needs to be a
> proper c in circle i've been informed.
> 
> > + * Author:	Oskar Schirmer <os@emlix.com>
> > + *
> > + * Partially based on i2c-bfin-twi.c driver by <sonic.zhang@analog.com>
> > + * Copyright (c) 2005-2007 Analog Devices, Inc.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/err.h>
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/init.h>
> > +#include <linux/delay.h>
> > +#include <linux/i2c.h>
> > +#include <linux/i2c/s6000.h>
> > +#include <linux/timer.h>
> > +#include <linux/spinlock.h>
> > +#include <linux/completion.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/platform_device.h>
> > +
> > +#include <asm/io.h>
> > +#include "i2c-s6000.h"
> > +
> > +#define POLL_TIMEOUT	(2 * HZ)
> > +
> 
> would be nice to have some documentation for each of the members
> of this.
> 
> > +struct s6i2c_if {
> > +	u8 __iomem		*reg;
> > +	int			irq;
> > +	spinlock_t		lock;
> > +	struct i2c_msg		*msgs;
> > +	int			msgs_num, msgs_push, msgs_done;
> > +	unsigned		push, done;
> > +	int			timeout_count;
> > +	struct timer_list	timeout_timer;
> > +	struct i2c_adapter	adap;
> > +	struct completion	complete;
> > +	struct clk		*clk;
> > +	struct resource		*res;
> > +};
> > +
> > +#define I2C_RD16(iface, n) readw(iface->reg + (n))
> > +#define I2C_WR16(iface, n, v) writew(v, iface->reg + (n))
> > +#define I2C_RD32(iface, n) readl(iface->reg + (n))
> > +#define I2C_WR32(iface, n, v) writel(v, iface->reg + (n))
> 
> tried inline functions for these?
> 
> > +
> > +static struct s6i2c_if s6i2c_if;
> > +
> > +static void s6i2c_handle_interrupt(struct s6i2c_if *iface)
> > +{
> > +	if (I2C_RD16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {
> > +		I2C_RD16(iface, S6_I2C_CLRTXABRT);
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +		complete(&iface->complete);
> > +		return;
> > +	}
> > +	if (iface->msgs_done >= iface->msgs_num) {
> > +		printk(KERN_DEBUG "spurious I2C irq: %x\n",
> > +		       I2C_RD16(iface, S6_I2C_INTRSTAT));

storing the device and using dev_ functions would be much better.

> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +		return;
> > +	}
> > +	while ((iface->msgs_push < iface->msgs_num)
> > +	    && (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {
> > +		struct i2c_msg *m = &iface->msgs[iface->msgs_push];
> > +		if (!(m->flags & I2C_M_RD))
> > +			I2C_WR16(iface, S6_I2C_DATACMD, m->buf[iface->push]);
> > +		else
> > +			I2C_WR16(iface, S6_I2C_DATACMD,
> > +				 1 << S6_I2C_DATACMD_READ);
> > +		if (++iface->push >= m->len) {
> > +			iface->push = 0;
> > +			iface->msgs_push += 1;
> > +		}
> > +	}
> > +	do {
> > +		struct i2c_msg *m = &iface->msgs[iface->msgs_done];
> > +		if (!(m->flags & I2C_M_RD)) {
> > +			if (iface->msgs_done < iface->msgs_push)
> > +				iface->msgs_done += 1;
> > +			else
> > +				break;
> > +		} else if (I2C_RD16(iface, S6_I2C_STATUS)
> > +				& (1 << S6_I2C_STATUS_RFNE)) {
> > +			m->buf[iface->done] = I2C_RD16(iface, S6_I2C_DATACMD);
> > +			if (++iface->done >= m->len) {
> > +				iface->done = 0;
> > +				iface->msgs_done += 1;
> > +			}
> > +		} else{
> > +			break;
> > +		}
> > +	} while (iface->msgs_done < iface->msgs_num);
> > +	if (iface->msgs_done >= iface->msgs_num) {
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);
> > +		complete(&iface->complete);
> > +	} else if (iface->msgs_push >= iface->msgs_num) {
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
> > +						 (1 << S6_I2C_INTR_RXFULL));
> > +	} else {
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
> > +						 (1 << S6_I2C_INTR_TXEMPTY) |
> > +						 (1 << S6_I2C_INTR_RXFULL));
> > +	}
> > +}
> > +
> > +static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)
> > +{
> > +	struct s6i2c_if *iface = dev_id;
> > +	if (!(I2C_RD16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)
> > +					      | (1 << S6_I2C_INTR_RXOVER)
> > +					      | (1 << S6_I2C_INTR_RXFULL)
> > +					      | (1 << S6_I2C_INTR_TXOVER)
> > +					      | (1 << S6_I2C_INTR_TXEMPTY)
> > +					      | (1 << S6_I2C_INTR_RDREQ)
> > +					      | (1 << S6_I2C_INTR_TXABRT)
> > +					      | (1 << S6_I2C_INTR_RXDONE)
> > +					      | (1 << S6_I2C_INTR_ACTIVITY)
> > +					      | (1 << S6_I2C_INTR_STOPDET)
> > +					      | (1 << S6_I2C_INTR_STARTDET)
> > +					      | (1 << S6_I2C_INTR_GENCALL))))
> > +		return IRQ_NONE;
> > +
> > +	spin_lock(&iface->lock);
> > +	del_timer(&iface->timeout_timer);
> > +	s6i2c_handle_interrupt(iface);
> > +	spin_unlock(&iface->lock);
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static void s6i2c_timeout(unsigned long data)
> > +{
> > +	struct s6i2c_if *iface = (struct s6i2c_if *)data;
> > +	unsigned long flags;
> > +
> > +	spin_lock_irqsave(&iface->lock, flags);
> > +	s6i2c_handle_interrupt(iface);
> > +	if (--iface->timeout_count > 0) {
> > +		iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
> > +		add_timer(&iface->timeout_timer);
> > +	} else {
> > +		complete(&iface->complete);
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	}
> > +	spin_unlock_irqrestore(&iface->lock, flags);
> > +}
> > +
> > +static int s6i2c_master_xfer(struct i2c_adapter *adap,
> > +				struct i2c_msg *msgs, int num)
> > +{
> > +	struct s6i2c_if *iface = adap->algo_data;
> > +	int i;
> > +	if (num == 0)
> > +		return 0;
> > +	if (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
> > +		yield();
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	I2C_RD16(iface, S6_I2C_CLRINTR);
> > +	for (i = 0; i < num; i++) {
> > +		if (msgs[i].flags & I2C_M_TEN) {
> > +			dev_err(&(adap->dev),
> > +				"s6i2c: 10 bits addr not supported\n");
> > +			return -EINVAL;
> > +		}
> > +		if (msgs[i].len == 0) {
> > +			dev_err(&(adap->dev),
> > +				"s6i2c: zero length message not supported\n");
> > +			return -EINVAL;
> > +		}
> > +		if (msgs[i].addr != msgs[0].addr) {
> > +			dev_err(&(adap->dev),
> > +				"s6i2c: multiple xfer cannot change target\n");
> > +			return -EINVAL;
> > +		}
> > +	}
> > +	iface->msgs = msgs;
> > +	iface->msgs_num = num;
> > +	iface->msgs_push = 0;
> > +	iface->msgs_done = 0;
> > +	iface->push = 0;
> > +	iface->done = 0;
> > +	iface->timeout_count = 10;
> > +	I2C_WR16(iface, S6_I2C_TAR, msgs[0].addr);
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 1);
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) |
> > +					 (1 << S6_I2C_INTR_TXABRT));
> > +	iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
> > +	add_timer(&iface->timeout_timer);
> > +	wait_for_completion(&iface->complete);
> > +	del_timer_sync(&iface->timeout_timer);
> > +	while (I2C_RD32(iface, S6_I2C_TXFLR) > 0)
> > +		schedule();
> > +	while (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
> > +		schedule();
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> > +	return iface->msgs_done;
> > +}
> > +
> > +static u32 s6i2c_functionality(struct i2c_adapter *adap)
> > +{
> > +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> > +}
> > +
> > +static struct i2c_algorithm s6i2c_algorithm = {
> > +	.master_xfer   = s6i2c_master_xfer,
> > +	.functionality = s6i2c_functionality,
> > +};
> > +
> > +static u16 __devinit nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)
> > +{
> > +	u64 dividend = (u64)ns * clk_get_rate(iface->clk);
> > +	do_div(dividend, 1000000000);
> > +	if (dividend > 0xffff)
> > +		return 0xffff;
> > +	return dividend;
> > +}
> 
> do you desperately need to be _that_ accurate?
> 
> > +static int __devinit s6i2c_probe(struct platform_device *dev)
> > +{
> > +	struct s6i2c_if *iface = &s6i2c_if;
> > +	struct i2c_adapter *p_adap;
> > +	const char *clock;
> > +	int bus_num, rc;
> > +	spin_lock_init(&(iface->lock));
> > +	init_completion(&(iface->complete));
> 
> please don't do &(variable) it is fugly.
> 
> > +	iface->irq = platform_get_irq(dev, 0);
> > +	if (iface->irq < 0) {
> > +		rc = iface->irq;
> > +		goto err_out;
> > +	}
> > +	iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);
> > +	if (!iface->res) {
> > +		rc = -ENXIO;
> > +		goto err_out;
> > +	}
> > +	iface->res = request_mem_region(iface->res->start,
> > +					iface->res->end - iface->res->start + 1,
> > +					dev->dev.bus_id);

resource_size() is your friend here too, and in various others bits
of the code.

> > +	if (!iface->res) {
> > +		rc = -EBUSY;
> > +		goto err_out;
> > +	}
> > +	iface->reg = ioremap_nocache(iface->res->start,
> > +				     iface->res->end - iface->res->start + 1);
> > +	if (!iface->reg) {
> > +		rc = -ENOMEM;
> > +		goto err_reg;
> > +	}
> > +	clock = 0;
> > +	bus_num = -1;
> > +	if (dev->dev.platform_data) {
> > +		struct s6_i2c_platform_data *pdata = dev->dev.platform_data;
> > +		bus_num = pdata->bus_num;
> > +		clock = pdata->clock;
> > +	}
> > +	iface->clk = clk_get(&dev->dev, clock);
> > +	if (IS_ERR(iface->clk)) {
> > +		rc = PTR_ERR(iface->clk);
> > +		goto err_map;
> > +	}
> 
> passing the name in the platform device is a bit nasty, if there's
> only one clock for the device then it should have been dealt with
> at the arch level and doing clk_get(&dev->dev, NULL) should be
> acceptable.
> 
> > +	rc = clk_enable(iface->clk);
> > +	if (rc < 0)
> > +		goto err_clk_put;
> > +	init_timer(&(iface->timeout_timer));
> > +	iface->timeout_timer.function = s6i2c_timeout;
> > +	iface->timeout_timer.data = (unsigned long)iface;
> > +	p_adap = &iface->adap;
> > +	strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
> > +	p_adap->algo = &s6i2c_algorithm;
> > +	p_adap->algo_data = iface;
> > +	p_adap->nr = bus_num;
> > +	p_adap->class = 0;
> > +	p_adap->dev.parent = &dev->dev;
> 
> some spacing for readability would be nice.
> 
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	rc = request_irq(iface->irq, s6i2c_interrupt_entry,
> > +			 IRQF_SHARED, dev->name, iface);
> > +	if (rc) {
> > +		dev_err(&(p_adap->dev), "s6i2c: cant get IRQ %d\n", iface->irq);
> > +		goto err_clk_dis;
> > +	}
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> > +	udelay(1);
> > +	I2C_WR32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);
> > +	I2C_WR16(iface, S6_I2C_CLRTXABRT, 1);
> > +	I2C_WR16(iface, S6_I2C_CON,
> > +			(1 << S6_I2C_CON_MASTER) |
> > +			(S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) |
> > +			(0 << S6_I2C_CON_10BITSLAVE) |
> > +			(0 << S6_I2C_CON_10BITMASTER) |
> > +			(1 << S6_I2C_CON_RESTARTENA) |
> > +			(1 << S6_I2C_CON_SLAVEDISABLE));
> > +	I2C_WR16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));
> > +	I2C_WR16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));
> > +	I2C_WR16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));
> > +	I2C_WR16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));
> > +	I2C_WR16(iface, S6_I2C_RXTL, 0);
> > +	I2C_WR16(iface, S6_I2C_TXTL, 0);
> > +	platform_set_drvdata(dev, iface);
> > +	if (bus_num < 0)
> > +		rc = i2c_add_adapter(p_adap);
> > +	else
> > +		rc = i2c_add_numbered_adapter(p_adap);
> > +	if (rc)
> > +		goto err_irq_free;
> > +	return 0;
> > +
> > +err_irq_free:
> > +	free_irq(iface->irq, iface);
> > +err_clk_dis:
> > +	clk_disable(iface->clk);
> > +err_clk_put:
> > +	clk_put(iface->clk);
> > +err_map:
> > +	iounmap(iface->reg);
> > +err_reg:
> > +	release_mem_region(iface->res->start,
> > +			   iface->res->end - iface->res->start + 1);
> > +err_out:
> > +	return rc;
> > +}
> > +
> > +static int __devexit s6i2c_remove(struct platform_device *pdev)
> > +{
> > +	struct s6i2c_if *iface = platform_get_drvdata(pdev);
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> > +	platform_set_drvdata(pdev, NULL);
> > +	i2c_del_adapter(&(iface->adap));
> > +	free_irq(iface->irq, iface);
> > +	clk_disable(iface->clk);
> > +	clk_put(iface->clk);
> > +	iounmap(iface->reg);
> > +	release_mem_region(iface->res->start,
> > +			   iface->res->end - iface->res->start + 1);
> 
> resource_size() would be good here, and elsewhere in the driver.
> 
> > +	return 0;
> > +}
> > +
> > +static struct platform_driver s6i2c_driver = {
> > +	.probe		= s6i2c_probe,
> > +	.remove		= __devexit_p(s6i2c_remove),
> > +	.driver		= {
> > +		.name	= "i2c-s6000",
> > +		.owner	= THIS_MODULE,
> > +	},
> > +};
> > +
> > +static int __init s6i2c_init(void)
> > +{
> > +	pr_info("I2C: S6000 I2C driver\n");
> > +	return platform_driver_register(&s6i2c_driver);
> > +}
> > +
> > +static void __exit s6i2c_exit(void)
> > +{
> > +	platform_driver_unregister(&s6i2c_driver);
> > +}
> > +
> > +MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");
> > +MODULE_LICENSE("GPL");

alias for module loading would also be useful.

> > +
> > +subsys_initcall(s6i2c_init);
> > +module_exit(s6i2c_exit);


> as a note, the code is quite dense, a few blank lines would be
> nice.
> 
> > diff --git a/drivers/i2c/busses/i2c-s6000.h b/drivers/i2c/busses/i2c-s6000.h
> > new file mode 100644
> > index 0000000..ff23b81
> > --- /dev/null
> > +++ b/drivers/i2c/busses/i2c-s6000.h
> > @@ -0,0 +1,79 @@
> > +/*
> > + * drivers/i2c/busses/i2c-s6000.h
> > + *
> > + * This file is subject to the terms and conditions of the GNU General Public
> > + * License.  See the file "COPYING" in the main directory of this archive
> > + * for more details.
> > + *
> > + * Copyright (C) 2008 Emlix GmbH <info@emlix.com>
> > + * Author:	Oskar Schirmer <os@emlix.com>
> > + */
> > +
> > +#ifndef __DRIVERS_I2C_BUSSES_I2C_S6000_H
> > +#define __DRIVERS_I2C_BUSSES_I2C_S6000_H
> > +
> > +#define S6_I2C_CON		0x000
> > +#define S6_I2C_CON_MASTER		0
> > +#define S6_I2C_CON_SPEED		1
> > +#define S6_I2C_CON_SPEED_NORMAL			1
> > +#define S6_I2C_CON_SPEED_FAST			2
> > +#define S6_I2C_CON_SPEED_MASK			3
> > +#define S6_I2C_CON_10BITSLAVE		3
> > +#define S6_I2C_CON_10BITMASTER		4
> > +#define S6_I2C_CON_RESTARTENA		5
> > +#define S6_I2C_CON_SLAVEDISABLE		6
> > +#define S6_I2C_TAR		0x004
> > +#define S6_I2C_TAR_GCORSTART		10
> > +#define S6_I2C_TAR_SPECIAL		11
> > +#define S6_I2C_SAR		0x008
> > +#define S6_I2C_HSMADDR		0x00C
> > +#define S6_I2C_DATACMD		0x010
> > +#define S6_I2C_DATACMD_READ		8
> > +#define S6_I2C_SSHCNT		0x014
> > +#define S6_I2C_SSLCNT		0x018
> > +#define S6_I2C_FSHCNT		0x01C
> > +#define S6_I2C_FSLCNT		0x020
> > +#define S6_I2C_INTRSTAT		0x02C
> > +#define S6_I2C_INTRMASK		0x030
> > +#define S6_I2C_RAWINTR		0x034
> > +#define S6_I2C_INTR_RXUNDER		0
> > +#define S6_I2C_INTR_RXOVER		1
> > +#define S6_I2C_INTR_RXFULL		2
> > +#define S6_I2C_INTR_TXOVER		3
> > +#define S6_I2C_INTR_TXEMPTY		4
> > +#define S6_I2C_INTR_RDREQ		5
> > +#define S6_I2C_INTR_TXABRT		6
> > +#define S6_I2C_INTR_RXDONE		7
> > +#define S6_I2C_INTR_ACTIVITY		8
> > +#define S6_I2C_INTR_STOPDET		9
> > +#define S6_I2C_INTR_STARTDET		10
> > +#define S6_I2C_INTR_GENCALL		11
> > +#define S6_I2C_RXTL		0x038
> > +#define S6_I2C_TXTL		0x03C
> > +#define S6_I2C_CLRINTR		0x040
> > +#define S6_I2C_CLRRXUNDER	0x044
> > +#define S6_I2C_CLRRXOVER	0x048
> > +#define S6_I2C_CLRTXOVER	0x04C
> > +#define S6_I2C_CLRRDREQ		0x050
> > +#define S6_I2C_CLRTXABRT	0x054
> > +#define S6_I2C_CLRRXDONE	0x058
> > +#define S6_I2C_CLRACTIVITY	0x05C
> > +#define S6_I2C_CLRSTOPDET	0x060
> > +#define S6_I2C_CLRSTARTDET	0x064
> > +#define S6_I2C_CLRGENCALL	0x068
> > +#define S6_I2C_ENABLE		0x06C
> > +#define S6_I2C_STATUS		0x070
> > +#define S6_I2C_STATUS_ACTIVITY		0
> > +#define S6_I2C_STATUS_TFNF		1
> > +#define S6_I2C_STATUS_TFE		2
> > +#define S6_I2C_STATUS_RFNE		3
> > +#define S6_I2C_STATUS_RFF		4
> > +#define S6_I2C_TXFLR		0x074
> > +#define S6_I2C_RXFLR		0x078
> > +#define S6_I2C_SRESET		0x07C
> > +#define S6_I2C_SRESET_IC_SRST		0
> > +#define S6_I2C_SRESET_IC_MASTER_SRST	1
> > +#define S6_I2C_SRESET_IC_SLAVE_SRST	2
> > +#define S6_I2C_TXABRTSOURCE	0x080
> > +
> > +#endif
> > diff --git a/include/linux/i2c/s6000.h b/include/linux/i2c/s6000.h
> 
> and again.
> 
> > new file mode 100644
> > index 0000000..0b6b0c6
> > --- /dev/null
> > +++ b/include/linux/i2c/s6000.h
> > @@ -0,0 +1,10 @@
> > +#ifndef __LINUX_I2C_S6000_H
> > +#define __LINUX_I2C_S6000_H
> > +
> 
> documentation comments would be nice here too.
> 
> > +struct s6_i2c_platform_data {
> > +	const char *clock;
> > +	int bus_num;
> > +};
> > +
> > +#endif
> > +
> > -- 
> > 1.6.2.107.ge47ee
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> -- 
> Ben (ben@fluff.org, http://www.fluff.org/)
> 
>   'a smiley only costs 4 bytes'
> --
> To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Ben (ben@fluff.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

[patch v2] i2c: xtensa s6000 i2c driver

[Oskar Schirmer]

Support for the s6000 on-chip i2c controller.

Signed-off-by: Oskar Schirmer <os@emlix.com>
Signed-off-by: Daniel Glöckner <dg@emlix.com>
---
 drivers/i2c/busses/Kconfig     |   10 +
 drivers/i2c/busses/Makefile    |    1 +
 drivers/i2c/busses/i2c-s6000.c |  407 ++++++++++++++++++++++++++++++++++++++++
 drivers/i2c/busses/i2c-s6000.h |   79 ++++++++
 include/linux/i2c/s6000.h      |   10 +
 5 files changed, 507 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/busses/i2c-s6000.c
 create mode 100644 drivers/i2c/busses/i2c-s6000.h
 create mode 100644 include/linux/i2c/s6000.h

Version 2:
  o fix copyright notice
  o document interface state structure
  o translate io helpers from cpp to c
  o use dev_printk()
  o dropped parens in '&(expression)'
  o use resource_size()
  o added common i2c module alias
  o newlines between logically separate blocks
  o clock-to-ns calculation: less accurate, much less object code

Ben, we left the clk-by-name thing in there.  The clk API is an
abstraction of the platform and some implementations don't even
support passing NULL as a name (sh, some arms, avr32, mips, ...).
Passing in a string works everywhere so we are on the safe side.

Any objections?

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 7f95905..904def4 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -461,6 +461,16 @@ config I2C_S3C2410
 	  Say Y here to include support for I2C controller in the
 	  Samsung S3C2410 based System-on-Chip devices.
 
+config I2C_S6000
+	tristate "S6000 I2C support"
+	depends on XTENSA_VARIANT_S6000
+	help
+	  This driver supports the on chip I2C device on the
+	  S6000 xtensa processor family.
+
+	  To compile this driver as a module, choose M here. The module
+	  will be called i2c-s6000.
+
 config I2C_SH7760
 	tristate "Renesas SH7760 I2C Controller"
 	depends on CPU_SUBTYPE_SH7760
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 0c2c4b2..f7989d1 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi.o
 obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o
 obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
 obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o
+obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
 obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
 obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o
 obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o
diff --git a/drivers/i2c/busses/i2c-s6000.c b/drivers/i2c/busses/i2c-s6000.c
new file mode 100644
index 0000000..c91359f
--- /dev/null
+++ b/drivers/i2c/busses/i2c-s6000.c
@@ -0,0 +1,407 @@
+/*
+ * drivers/i2c/busses/i2c-s6000.c
+ *
+ * Description: Driver for S6000 Family I2C Interface
+ * Copyright (c) 2008 emlix GmbH
+ * Author:	Oskar Schirmer <os@emlix.com>
+ *
+ * Partially based on i2c-bfin-twi.c driver by <sonic.zhang@analog.com>
+ * Copyright (c) 2005-2007 Analog Devices, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/i2c/s6000.h>
+#include <linux/timer.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+
+#include <asm/io.h>
+#include "i2c-s6000.h"
+
+#define DRV_NAME "i2c-s6000"
+
+#define POLL_TIMEOUT	(2 * HZ)
+
+struct s6i2c_if {
+	u8 __iomem		*reg; /* memory mapped registers */
+	int			irq;
+	spinlock_t		lock;
+	struct i2c_msg		*msgs; /* messages currently handled */
+	int			msgs_num; /* nb of msgs to do */
+	int			msgs_push; /* nb of msgs read/written */
+	int			msgs_done; /* nb of msgs finally handled */
+	unsigned		push; /* nb of bytes read/written in msg */
+	unsigned		done; /* nb of bytes finally handled */
+	int			timeout_count; /* timeout retries left */
+	struct timer_list	timeout_timer;
+	struct i2c_adapter	adap;
+	struct completion	complete;
+	struct clk		*clk;
+	struct resource		*res;
+};
+
+static inline u16 i2c_rd16(struct s6i2c_if *iface, unsigned n)
+{
+	return readw(iface->reg + (n));
+}
+
+static inline void i2c_wr16(struct s6i2c_if *iface, unsigned n, u16 v)
+{
+	writew(v, iface->reg + (n));
+}
+
+static inline u32 i2c_rd32(struct s6i2c_if *iface, unsigned n)
+{
+	return readl(iface->reg + (n));
+}
+
+static inline void i2c_wr32(struct s6i2c_if *iface, unsigned n, u32 v)
+{
+	writel(v, iface->reg + (n));
+}
+
+static struct s6i2c_if s6i2c_if;
+
+static void s6i2c_handle_interrupt(struct s6i2c_if *iface)
+{
+	if (i2c_rd16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {
+		i2c_rd16(iface, S6_I2C_CLRTXABRT);
+		i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+		complete(&iface->complete);
+		return;
+	}
+	if (iface->msgs_done >= iface->msgs_num) {
+		dev_err(&iface->adap.dev, "s6i2c: spurious I2C irq: %04x\n",
+			i2c_rd16(iface, S6_I2C_INTRSTAT));
+		i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+		return;
+	}
+	while ((iface->msgs_push < iface->msgs_num)
+	    && (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {
+		struct i2c_msg *m = &iface->msgs[iface->msgs_push];
+		if (!(m->flags & I2C_M_RD))
+			i2c_wr16(iface, S6_I2C_DATACMD, m->buf[iface->push]);
+		else
+			i2c_wr16(iface, S6_I2C_DATACMD,
+				 1 << S6_I2C_DATACMD_READ);
+		if (++iface->push >= m->len) {
+			iface->push = 0;
+			iface->msgs_push += 1;
+		}
+	}
+	do {
+		struct i2c_msg *m = &iface->msgs[iface->msgs_done];
+		if (!(m->flags & I2C_M_RD)) {
+			if (iface->msgs_done < iface->msgs_push)
+				iface->msgs_done += 1;
+			else
+				break;
+		} else if (i2c_rd16(iface, S6_I2C_STATUS)
+				& (1 << S6_I2C_STATUS_RFNE)) {
+			m->buf[iface->done] = i2c_rd16(iface, S6_I2C_DATACMD);
+			if (++iface->done >= m->len) {
+				iface->done = 0;
+				iface->msgs_done += 1;
+			}
+		} else{
+			break;
+		}
+	} while (iface->msgs_done < iface->msgs_num);
+	if (iface->msgs_done >= iface->msgs_num) {
+		i2c_wr16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);
+		complete(&iface->complete);
+	} else if (iface->msgs_push >= iface->msgs_num) {
+		i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
+						 (1 << S6_I2C_INTR_RXFULL));
+	} else {
+		i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
+						 (1 << S6_I2C_INTR_TXEMPTY) |
+						 (1 << S6_I2C_INTR_RXFULL));
+	}
+}
+
+static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)
+{
+	struct s6i2c_if *iface = dev_id;
+	if (!(i2c_rd16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)
+					      | (1 << S6_I2C_INTR_RXOVER)
+					      | (1 << S6_I2C_INTR_RXFULL)
+					      | (1 << S6_I2C_INTR_TXOVER)
+					      | (1 << S6_I2C_INTR_TXEMPTY)
+					      | (1 << S6_I2C_INTR_RDREQ)
+					      | (1 << S6_I2C_INTR_TXABRT)
+					      | (1 << S6_I2C_INTR_RXDONE)
+					      | (1 << S6_I2C_INTR_ACTIVITY)
+					      | (1 << S6_I2C_INTR_STOPDET)
+					      | (1 << S6_I2C_INTR_STARTDET)
+					      | (1 << S6_I2C_INTR_GENCALL))))
+		return IRQ_NONE;
+
+	spin_lock(&iface->lock);
+	del_timer(&iface->timeout_timer);
+	s6i2c_handle_interrupt(iface);
+	spin_unlock(&iface->lock);
+	return IRQ_HANDLED;
+}
+
+static void s6i2c_timeout(unsigned long data)
+{
+	struct s6i2c_if *iface = (struct s6i2c_if *)data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&iface->lock, flags);
+	s6i2c_handle_interrupt(iface);
+	if (--iface->timeout_count > 0) {
+		iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
+		add_timer(&iface->timeout_timer);
+	} else {
+		complete(&iface->complete);
+		i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+	}
+	spin_unlock_irqrestore(&iface->lock, flags);
+}
+
+static int s6i2c_master_xfer(struct i2c_adapter *adap,
+				struct i2c_msg *msgs, int num)
+{
+	struct s6i2c_if *iface = adap->algo_data;
+	int i;
+	if (num == 0)
+		return 0;
+	if (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
+		yield();
+	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+	i2c_rd16(iface, S6_I2C_CLRINTR);
+	for (i = 0; i < num; i++) {
+		if (msgs[i].flags & I2C_M_TEN) {
+			dev_err(&adap->dev,
+				"s6i2c: 10 bits addr not supported\n");
+			return -EINVAL;
+		}
+		if (msgs[i].len == 0) {
+			dev_err(&adap->dev,
+				"s6i2c: zero length message not supported\n");
+			return -EINVAL;
+		}
+		if (msgs[i].addr != msgs[0].addr) {
+			dev_err(&adap->dev,
+				"s6i2c: multiple xfer cannot change target\n");
+			return -EINVAL;
+		}
+	}
+
+	iface->msgs = msgs;
+	iface->msgs_num = num;
+	iface->msgs_push = 0;
+	iface->msgs_done = 0;
+	iface->push = 0;
+	iface->done = 0;
+	iface->timeout_count = 10;
+	i2c_wr16(iface, S6_I2C_TAR, msgs[0].addr);
+	i2c_wr16(iface, S6_I2C_ENABLE, 1);
+	i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) |
+					 (1 << S6_I2C_INTR_TXABRT));
+
+	iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
+	add_timer(&iface->timeout_timer);
+	wait_for_completion(&iface->complete);
+	del_timer_sync(&iface->timeout_timer);
+	while (i2c_rd32(iface, S6_I2C_TXFLR) > 0)
+		schedule();
+	while (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
+		schedule();
+
+	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+	i2c_wr16(iface, S6_I2C_ENABLE, 0);
+	return iface->msgs_done;
+}
+
+static u32 s6i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm s6i2c_algorithm = {
+	.master_xfer   = s6i2c_master_xfer,
+	.functionality = s6i2c_functionality,
+};
+
+static u16 __devinit nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)
+{
+	u32 dividend = ((clk_get_rate(iface->clk) / 1000) * ns) / 1000000;
+	if (dividend > 0xffff)
+		return 0xffff;
+	return dividend;
+}
+
+static int __devinit s6i2c_probe(struct platform_device *dev)
+{
+	struct s6i2c_if *iface = &s6i2c_if;
+	struct i2c_adapter *p_adap;
+	const char *clock;
+	int bus_num, rc;
+	spin_lock_init(&iface->lock);
+	init_completion(&iface->complete);
+	iface->irq = platform_get_irq(dev, 0);
+	if (iface->irq < 0) {
+		rc = iface->irq;
+		goto err_out;
+	}
+	iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+	if (!iface->res) {
+		rc = -ENXIO;
+		goto err_out;
+	}
+	iface->res = request_mem_region(iface->res->start,
+					resource_size(iface->res),
+					dev->dev.bus_id);
+	if (!iface->res) {
+		rc = -EBUSY;
+		goto err_out;
+	}
+	iface->reg = ioremap_nocache(iface->res->start,
+				     resource_size(iface->res));
+	if (!iface->reg) {
+		rc = -ENOMEM;
+		goto err_reg;
+	}
+
+	clock = 0;
+	bus_num = -1;
+	if (dev->dev.platform_data) {
+		struct s6_i2c_platform_data *pdata = dev->dev.platform_data;
+		bus_num = pdata->bus_num;
+		clock = pdata->clock;
+	}
+	iface->clk = clk_get(&dev->dev, clock);
+	if (IS_ERR(iface->clk)) {
+		rc = PTR_ERR(iface->clk);
+		goto err_map;
+	}
+	rc = clk_enable(iface->clk);
+	if (rc < 0)
+		goto err_clk_put;
+	init_timer(&iface->timeout_timer);
+	iface->timeout_timer.function = s6i2c_timeout;
+	iface->timeout_timer.data = (unsigned long)iface;
+
+	p_adap = &iface->adap;
+	strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
+	p_adap->algo = &s6i2c_algorithm;
+	p_adap->algo_data = iface;
+	p_adap->nr = bus_num;
+	p_adap->class = 0;
+	p_adap->dev.parent = &dev->dev;
+	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+	rc = request_irq(iface->irq, s6i2c_interrupt_entry,
+			 IRQF_SHARED, dev->name, iface);
+	if (rc) {
+		dev_err(&p_adap->dev, "s6i2c: cant get IRQ %d\n", iface->irq);
+		goto err_clk_dis;
+	}
+
+	i2c_wr16(iface, S6_I2C_ENABLE, 0);
+	udelay(1);
+	i2c_wr32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);
+	i2c_wr16(iface, S6_I2C_CLRTXABRT, 1);
+	i2c_wr16(iface, S6_I2C_CON,
+			(1 << S6_I2C_CON_MASTER) |
+			(S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) |
+			(0 << S6_I2C_CON_10BITSLAVE) |
+			(0 << S6_I2C_CON_10BITMASTER) |
+			(1 << S6_I2C_CON_RESTARTENA) |
+			(1 << S6_I2C_CON_SLAVEDISABLE));
+	i2c_wr16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));
+	i2c_wr16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));
+	i2c_wr16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));
+	i2c_wr16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));
+	i2c_wr16(iface, S6_I2C_RXTL, 0);
+	i2c_wr16(iface, S6_I2C_TXTL, 0);
+
+	platform_set_drvdata(dev, iface);
+	if (bus_num < 0)
+		rc = i2c_add_adapter(p_adap);
+	else
+		rc = i2c_add_numbered_adapter(p_adap);
+	if (rc)
+		goto err_irq_free;
+	return 0;
+
+err_irq_free:
+	free_irq(iface->irq, iface);
+err_clk_dis:
+	clk_disable(iface->clk);
+err_clk_put:
+	clk_put(iface->clk);
+err_map:
+	iounmap(iface->reg);
+err_reg:
+	release_mem_region(iface->res->start,
+			   resource_size(iface->res));
+err_out:
+	return rc;
+}
+
+static int __devexit s6i2c_remove(struct platform_device *pdev)
+{
+	struct s6i2c_if *iface = platform_get_drvdata(pdev);
+	i2c_wr16(iface, S6_I2C_ENABLE, 0);
+	platform_set_drvdata(pdev, NULL);
+	i2c_del_adapter(&iface->adap);
+	free_irq(iface->irq, iface);
+	clk_disable(iface->clk);
+	clk_put(iface->clk);
+	iounmap(iface->reg);
+	release_mem_region(iface->res->start,
+			   resource_size(iface->res));
+	return 0;
+}
+
+static struct platform_driver s6i2c_driver = {
+	.probe		= s6i2c_probe,
+	.remove		= __devexit_p(s6i2c_remove),
+	.driver		= {
+		.name	= DRV_NAME,
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init s6i2c_init(void)
+{
+	pr_info("I2C: S6000 I2C driver\n");
+	return platform_driver_register(&s6i2c_driver);
+}
+
+static void __exit s6i2c_exit(void)
+{
+	platform_driver_unregister(&s6i2c_driver);
+}
+
+MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);
+
+subsys_initcall(s6i2c_init);
+module_exit(s6i2c_exit);
diff --git a/drivers/i2c/busses/i2c-s6000.h b/drivers/i2c/busses/i2c-s6000.h
new file mode 100644
index 0000000..ff23b81
--- /dev/null
+++ b/drivers/i2c/busses/i2c-s6000.h
@@ -0,0 +1,79 @@
+/*
+ * drivers/i2c/busses/i2c-s6000.h
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2008 Emlix GmbH <info@emlix.com>
+ * Author:	Oskar Schirmer <os@emlix.com>
+ */
+
+#ifndef __DRIVERS_I2C_BUSSES_I2C_S6000_H
+#define __DRIVERS_I2C_BUSSES_I2C_S6000_H
+
+#define S6_I2C_CON		0x000
+#define S6_I2C_CON_MASTER		0
+#define S6_I2C_CON_SPEED		1
+#define S6_I2C_CON_SPEED_NORMAL			1
+#define S6_I2C_CON_SPEED_FAST			2
+#define S6_I2C_CON_SPEED_MASK			3
+#define S6_I2C_CON_10BITSLAVE		3
+#define S6_I2C_CON_10BITMASTER		4
+#define S6_I2C_CON_RESTARTENA		5
+#define S6_I2C_CON_SLAVEDISABLE		6
+#define S6_I2C_TAR		0x004
+#define S6_I2C_TAR_GCORSTART		10
+#define S6_I2C_TAR_SPECIAL		11
+#define S6_I2C_SAR		0x008
+#define S6_I2C_HSMADDR		0x00C
+#define S6_I2C_DATACMD		0x010
+#define S6_I2C_DATACMD_READ		8
+#define S6_I2C_SSHCNT		0x014
+#define S6_I2C_SSLCNT		0x018
+#define S6_I2C_FSHCNT		0x01C
+#define S6_I2C_FSLCNT		0x020
+#define S6_I2C_INTRSTAT		0x02C
+#define S6_I2C_INTRMASK		0x030
+#define S6_I2C_RAWINTR		0x034
+#define S6_I2C_INTR_RXUNDER		0
+#define S6_I2C_INTR_RXOVER		1
+#define S6_I2C_INTR_RXFULL		2
+#define S6_I2C_INTR_TXOVER		3
+#define S6_I2C_INTR_TXEMPTY		4
+#define S6_I2C_INTR_RDREQ		5
+#define S6_I2C_INTR_TXABRT		6
+#define S6_I2C_INTR_RXDONE		7
+#define S6_I2C_INTR_ACTIVITY		8
+#define S6_I2C_INTR_STOPDET		9
+#define S6_I2C_INTR_STARTDET		10
+#define S6_I2C_INTR_GENCALL		11
+#define S6_I2C_RXTL		0x038
+#define S6_I2C_TXTL		0x03C
+#define S6_I2C_CLRINTR		0x040
+#define S6_I2C_CLRRXUNDER	0x044
+#define S6_I2C_CLRRXOVER	0x048
+#define S6_I2C_CLRTXOVER	0x04C
+#define S6_I2C_CLRRDREQ		0x050
+#define S6_I2C_CLRTXABRT	0x054
+#define S6_I2C_CLRRXDONE	0x058
+#define S6_I2C_CLRACTIVITY	0x05C
+#define S6_I2C_CLRSTOPDET	0x060
+#define S6_I2C_CLRSTARTDET	0x064
+#define S6_I2C_CLRGENCALL	0x068
+#define S6_I2C_ENABLE		0x06C
+#define S6_I2C_STATUS		0x070
+#define S6_I2C_STATUS_ACTIVITY		0
+#define S6_I2C_STATUS_TFNF		1
+#define S6_I2C_STATUS_TFE		2
+#define S6_I2C_STATUS_RFNE		3
+#define S6_I2C_STATUS_RFF		4
+#define S6_I2C_TXFLR		0x074
+#define S6_I2C_RXFLR		0x078
+#define S6_I2C_SRESET		0x07C
+#define S6_I2C_SRESET_IC_SRST		0
+#define S6_I2C_SRESET_IC_MASTER_SRST	1
+#define S6_I2C_SRESET_IC_SLAVE_SRST	2
+#define S6_I2C_TXABRTSOURCE	0x080
+
+#endif
diff --git a/include/linux/i2c/s6000.h b/include/linux/i2c/s6000.h
new file mode 100644
index 0000000..d9b34bf
--- /dev/null
+++ b/include/linux/i2c/s6000.h
@@ -0,0 +1,10 @@
+#ifndef __LINUX_I2C_S6000_H
+#define __LINUX_I2C_S6000_H
+
+struct s6_i2c_platform_data {
+	const char *clock; /* the clock to use */
+	int bus_num; /* the bus number to register */
+};
+
+#endif
+
-- 
1.6.2.107.ge47ee