[PATCH v2 4/5] soc: Add SoC bus driver for Freescale Vybrid Platform

[Sanchayan Maity <maitysanchayan@gmail.com>]

This adds a SoC driver to be used by Freescale Vybrid SoC's.
Driver utilises syscon and nvmem consumer API's to get the
various register values needed and sysfs exposes the SoC specific
properties.

A sample output from Colibri Vybrid VF61 is below:

root@colibri-vf:~# cd /sys/bus/soc/devices/soc0
root@colibri-vf:/sys/bus/soc/devices/soc0# ls
family     machine    power      revision   soc_id     subsystem  uevent
root@colibri-vf:/sys/bus/soc/devices/soc0# cat family
Freescale Vybrid VF610
root@colibri-vf:/sys/bus/soc/devices/soc0# cat machine
Freescale Vybrid
root@colibri-vf:/sys/bus/soc/devices/soc0# cat revision
00000013
root@colibri-vf:/sys/bus/soc/devices/soc0# cat soc_id
df6472a6130f29d4

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
---
 drivers/soc/Kconfig         |   1 +
 drivers/soc/fsl/Kconfig     |  10 +++
 drivers/soc/fsl/Makefile    |   1 +
 drivers/soc/fsl/soc-vf610.c | 160 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 172 insertions(+)
 create mode 100644 drivers/soc/fsl/Kconfig
 create mode 100644 drivers/soc/fsl/soc-vf610.c

diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index cb58ef0..4410eb7 100644
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -2,6 +2,7 @@ menu "SOC (System On Chip) specific Drivers"
 
 source "drivers/soc/bcm/Kconfig"
 source "drivers/soc/brcmstb/Kconfig"
+source "drivers/soc/fsl/Kconfig"
 source "drivers/soc/fsl/qe/Kconfig"
 source "drivers/soc/mediatek/Kconfig"
 source "drivers/soc/qcom/Kconfig"
diff --git a/drivers/soc/fsl/Kconfig b/drivers/soc/fsl/Kconfig
new file mode 100644
index 0000000..029ea17
--- /dev/null
+++ b/drivers/soc/fsl/Kconfig
@@ -0,0 +1,10 @@
+#
+# Freescale SoC drivers
+
+config SOC_BUS_VF610
+	bool "SoC bus device for the Freescale Vybrid platform"
+	depends on NVMEM && NVMEM_VF610_OCOTP
+	select SOC_BUS
+	help
+	 Include support for the SoC bus on the Freescale Vybrid platform
+	 providing sysfs information about the module variant.
diff --git a/drivers/soc/fsl/Makefile b/drivers/soc/fsl/Makefile
index 203307f..afaf092 100644
--- a/drivers/soc/fsl/Makefile
+++ b/drivers/soc/fsl/Makefile
@@ -2,5 +2,6 @@
 # Makefile for the Linux Kernel SOC fsl specific device drivers
 #
 
+obj-$(CONFIG_SOC_VF610)			+= soc-vf610.o
 obj-$(CONFIG_QUICC_ENGINE)		+= qe/
 obj-$(CONFIG_CPM)			+= qe/
diff --git a/drivers/soc/fsl/soc-vf610.c b/drivers/soc/fsl/soc-vf610.c
new file mode 100644
index 0000000..99bf641
--- /dev/null
+++ b/drivers/soc/fsl/soc-vf610.c
@@ -0,0 +1,160 @@
+/*
+ * Copyright (C) 2016 Toradex AG.
+ *
+ * Author: Sanchayan Maity <sanchayan.maity@toradex.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#include <linux/device.h>
+#include <linux/mfd/syscon.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/random.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
+
+struct vf610_soc {
+	struct device *dev;
+	struct soc_device_attribute *soc_dev_attr;
+	struct soc_device *soc_dev;
+	struct nvmem_cell *ocotp_cfg0;
+	struct nvmem_cell *ocotp_cfg1;
+};
+
+static int vf610_soc_probe(struct platform_device *pdev)
+{
+	struct vf610_soc *info;
+	struct device *dev = &pdev->dev;
+	struct device_node *soc_node;
+	char soc_type[] = "xx0";
+	size_t id1_len;
+	size_t id2_len;
+	u32 cpucount;
+	u32 l2size;
+	u32 rom_rev;
+	u8 *socid1;
+	u8 *socid2;
+	int ret;
+
+	info = devm_kzalloc(dev, sizeof(struct vf610_soc), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+	info->dev = dev;
+
+	info->ocotp_cfg0 = devm_nvmem_cell_get(dev, "cfg0");
+	if (IS_ERR(info->ocotp_cfg0))
+		return -EPROBE_DEFER;
+
+	info->ocotp_cfg1 = devm_nvmem_cell_get(dev, "cfg1");
+	if (IS_ERR(info->ocotp_cfg1))
+		return -EPROBE_DEFER;
+
+	socid1 = nvmem_cell_read(info->ocotp_cfg0, &id1_len);
+	if (IS_ERR(socid1)) {
+		dev_err(dev, "Could not read nvmem cell %ld\n",
+			PTR_ERR(socid1));
+		return PTR_ERR(socid1);
+	}
+
+	socid2 = nvmem_cell_read(info->ocotp_cfg1, &id2_len);
+	if (IS_ERR(socid2)) {
+		dev_err(dev, "Could not read nvmem cell %ld\n",
+			PTR_ERR(socid2));
+		return PTR_ERR(socid2);
+	}
+	add_device_randomness(socid1, id1_len);
+	add_device_randomness(socid2, id2_len);
+
+	soc_node = of_find_node_by_path("/soc");
+	if (soc_node == NULL)
+		return -ENODEV;
+
+	ret = syscon_regmap_read_from_offset(soc_node,
+					"fsl,rom-revision", &rom_rev);
+	if (ret) {
+		of_node_put(soc_node);
+		return ret;
+	}
+
+	ret = syscon_regmap_read_from_offset(soc_node,
+					"fsl,cpu-count", &cpucount);
+	if (ret) {
+		of_node_put(soc_node);
+		return ret;
+	}
+
+	ret = syscon_regmap_read_from_offset(soc_node,
+					"fsl,l2-size", &l2size);
+	if (ret) {
+		of_node_put(soc_node);
+		return ret;
+	}
+
+	of_node_put(soc_node);
+
+	soc_type[0] = cpucount ? '6' : '5'; /* Dual Core => VF6x0 */
+	soc_type[1] = l2size ? '1' : '0'; /* L2 Cache => VFx10 */
+
+	info->soc_dev_attr = devm_kzalloc(dev,
+				sizeof(info->soc_dev_attr), GFP_KERNEL);
+	if (!info->soc_dev_attr)
+		return -ENOMEM;
+
+	info->soc_dev_attr->machine = devm_kasprintf(dev,
+					GFP_KERNEL, "Freescale Vybrid");
+	info->soc_dev_attr->soc_id = devm_kasprintf(dev,
+					GFP_KERNEL,
+					"%02x%02x%02x%02x%02x%02x%02x%02x",
+					socid1[3], socid1[2], socid1[1],
+					socid1[0], socid2[3], socid2[2],
+					socid2[1], socid2[0]);
+	info->soc_dev_attr->family = devm_kasprintf(&pdev->dev,
+					GFP_KERNEL, "Freescale Vybrid VF%s",
+					soc_type);
+	info->soc_dev_attr->revision = devm_kasprintf(dev,
+					GFP_KERNEL, "%08x", rom_rev);
+
+	platform_set_drvdata(pdev, info);
+
+	info->soc_dev = soc_device_register(info->soc_dev_attr);
+	if (IS_ERR(info->soc_dev))
+		return -ENODEV;
+
+	return 0;
+}
+
+static int vf610_soc_remove(struct platform_device *pdev)
+{
+	struct vf610_soc *info = platform_get_drvdata(pdev);
+
+	if (info->soc_dev)
+		soc_device_unregister(info->soc_dev);
+
+	return 0;
+}
+
+static const struct of_device_id vf610_soc_bus_match[] = {
+	{ .compatible = "fsl,vf610-soc-bus", },
+	{ /* */ }
+};
+
+static struct platform_driver vf610_soc_driver = {
+	.probe		= vf610_soc_probe,
+	.remove		= vf610_soc_remove,
+	.driver		= {
+		.name = "vf610-soc-bus",
+		.of_match_table = vf610_soc_bus_match,
+	},
+};
+builtin_platform_driver(vf610_soc_driver);
-- 
2.8.2