* [RFC PATCH 1/3] basic_mmio_gpio: split into a gpio library and platform device
2011-05-04 15:07 [RFC PATCH 0/3] Use basic_mmio_gpio to implement a generic gpio chip Jamie Iles
@ 2011-05-04 15:07 ` Jamie Iles
0 siblings, 0 replies; 3+ messages in thread
From: Jamie Iles @ 2011-05-04 15:07 UTC (permalink / raw)
To: linux-kernel
Cc: grant.likely, cbouatmailru, linux, tglx, arnd, nico, alan, Jamie Iles
Allow GPIO_BASIC_MMIO_CORE to be used to provide an accessor library
for implementing GPIO drivers whilst abstracting the register access
detail. Based on a patch from Anton Vorontsov[1] and adapted to allow
bgpio_chip to be embedded in another structure.
1. https://lkml.org/lkml/2011/4/19/401
---
drivers/gpio/Kconfig | 6 +
drivers/gpio/Makefile | 1 +
drivers/gpio/basic_mmio_gpio.c | 317 +++++++++++++++++++++------------------
include/linux/basic_mmio_gpio.h | 55 +++++++
4 files changed, 231 insertions(+), 148 deletions(-)
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b7fac15..ca16a30 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -70,8 +70,14 @@ config GPIO_MAX730X
comment "Memory mapped GPIO drivers:"
+config GPIO_BASIC_MMIO_CORE
+ tristate
+ help
+ Provides core functionality for basic memory-mapped GPIO controllers.
+
config GPIO_BASIC_MMIO
tristate "Basic memory-mapped GPIO controllers support"
+ select GPIO_BASIC_MMIO_CORE
help
Say yes here to support basic memory-mapped GPIO controllers.
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index cfbdef1..91a295d 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_GPIOLIB) += gpiolib.o
obj-$(CONFIG_GPIO_ADP5520) += adp5520-gpio.o
obj-$(CONFIG_GPIO_ADP5588) += adp5588-gpio.o
+obj-$(CONFIG_GPIO_BASIC_MMIO_CORE) += basic_mmio_gpio.o
obj-$(CONFIG_GPIO_BASIC_MMIO) += basic_mmio_gpio.o
obj-$(CONFIG_GPIO_LANGWELL) += langwell_gpio.o
obj-$(CONFIG_GPIO_MAX730X) += max730x.o
diff --git a/drivers/gpio/basic_mmio_gpio.c b/drivers/gpio/basic_mmio_gpio.c
index b2ec45f..6b1c6e5 100644
--- a/drivers/gpio/basic_mmio_gpio.c
+++ b/drivers/gpio/basic_mmio_gpio.c
@@ -45,6 +45,7 @@ o ` ~~~~\___/~~~~ ` controller in FPGA is ,.`
*/
#include <linux/init.h>
+#include <linux/err.h>
#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -61,44 +62,6 @@ o ` ~~~~\___/~~~~ ` controller in FPGA is ,.`
#include <linux/mod_devicetable.h>
#include <linux/basic_mmio_gpio.h>
-struct bgpio_chip {
- struct gpio_chip gc;
-
- unsigned long (*read_reg)(void __iomem *reg);
- void (*write_reg)(void __iomem *reg, unsigned long data);
-
- void __iomem *reg_dat;
- void __iomem *reg_set;
- void __iomem *reg_clr;
- void __iomem *reg_dir;
-
- /* Number of bits (GPIOs): <register width> * 8. */
- int bits;
-
- /*
- * Some GPIO controllers work with the big-endian bits notation,
- * e.g. in a 8-bits register, GPIO7 is the least significant bit.
- */
- unsigned long (*pin2mask)(struct bgpio_chip *bgc, unsigned int pin);
-
- /*
- * Used to lock bgpio_chip->data. Also, this is needed to keep
- * shadowed and real data registers writes together.
- */
- spinlock_t lock;
-
- /* Shadowed data register to clear/set bits safely. */
- unsigned long data;
-
- /* Shadowed direction registers to clear/set direction safely. */
- unsigned long dir;
-};
-
-static struct bgpio_chip *to_bgpio_chip(struct gpio_chip *gc)
-{
- return container_of(gc, struct bgpio_chip, gc);
-}
-
static void bgpio_write8(void __iomem *reg, unsigned long data)
{
writeb(data, reg);
@@ -284,20 +247,10 @@ static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
return 0;
}
-static void __iomem *bgpio_request_and_map(struct device *dev,
- struct resource *res)
-{
- if (!devm_request_mem_region(dev, res->start, resource_size(res),
- res->name ?: "mmio_gpio"))
- return NULL;
-
- return devm_ioremap(dev, res->start, resource_size(res));
-}
-
-static int bgpio_setup_accessors(struct platform_device *pdev,
- struct bgpio_chip *bgc)
+static int bgpio_setup_accessors(struct device *dev,
+ struct bgpio_chip *bgc,
+ bool be)
{
- const struct platform_device_id *platid = platform_get_device_id(pdev);
switch (bgc->bits) {
case 8:
@@ -319,13 +272,11 @@ static int bgpio_setup_accessors(struct platform_device *pdev,
break;
#endif /* BITS_PER_LONG >= 64 */
default:
- dev_err(&pdev->dev, "unsupported data width %u bits\n",
- bgc->bits);
+ dev_err(dev, "unsupported data width %u bits\n", bgc->bits);
return -EINVAL;
}
- bgc->pin2mask = strcmp(platid->name, "basic-mmio-gpio-be") ?
- bgpio_pin2mask : bgpio_pin2mask_be;
+ bgc->pin2mask = be ? bgpio_pin2mask_be : bgpio_pin2mask;
return 0;
}
@@ -352,51 +303,22 @@ static int bgpio_setup_accessors(struct platform_device *pdev,
* - an input direction register (named "dirin") where a 1 bit indicates
* the GPIO is an input.
*/
-static int bgpio_setup_io(struct platform_device *pdev,
- struct bgpio_chip *bgc)
+static int bgpio_setup_io(struct bgpio_chip *bgc,
+ void __iomem *dat,
+ void __iomem *set,
+ void __iomem *clr)
{
- struct resource *res_set;
- struct resource *res_clr;
- struct resource *res_dat;
- resource_size_t dat_sz;
- res_dat = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
- if (!res_dat)
- return -EINVAL;
-
- dat_sz = resource_size(res_dat);
- if (!is_power_of_2(dat_sz))
- return -EINVAL;
-
- bgc->bits = dat_sz * 8;
- if (bgc->bits > BITS_PER_LONG)
- return -EINVAL;
-
- bgc->reg_dat = bgpio_request_and_map(&pdev->dev, res_dat);
+ bgc->reg_dat = dat;
if (!bgc->reg_dat)
- return -ENOMEM;
-
- res_set = platform_get_resource_byname(pdev, IORESOURCE_MEM, "set");
- res_clr = platform_get_resource_byname(pdev, IORESOURCE_MEM, "clr");
- if (res_set && res_clr) {
- if (resource_size(res_set) != resource_size(res_clr) ||
- resource_size(res_set) != resource_size(res_dat))
- return -EINVAL;
-
- bgc->reg_set = bgpio_request_and_map(&pdev->dev, res_set);
- bgc->reg_clr = bgpio_request_and_map(&pdev->dev, res_clr);
- if (!bgc->reg_set || !bgc->reg_clr)
- return -ENOMEM;
+ return -EINVAL;
+ if (set && clr) {
+ bgc->reg_set = set;
+ bgc->reg_clr = clr;
bgc->gc.set = bgpio_set_with_clear;
- } else if (res_set && !res_clr) {
- if (resource_size(res_set) != resource_size(res_dat))
- return -EINVAL;
-
- bgc->reg_set = bgpio_request_and_map(&pdev->dev, res_set);
- if (!bgc->reg_set)
- return -ENOMEM;
-
+ } else if (set && !clr) {
+ bgc->reg_set = set;
bgc->gc.set = bgpio_set_set;
} else {
bgc->gc.set = bgpio_set;
@@ -407,27 +329,18 @@ static int bgpio_setup_io(struct platform_device *pdev,
return 0;
}
-static int bgpio_setup_direction(struct platform_device *pdev,
- struct bgpio_chip *bgc)
+static int bgpio_setup_direction(struct bgpio_chip *bgc,
+ void __iomem *dirout,
+ void __iomem *dirin)
{
- struct resource *res_dirout;
- struct resource *res_dirin;
-
- res_dirout = platform_get_resource_byname(pdev, IORESOURCE_MEM,
- "dirout");
- res_dirin = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dirin");
- if (res_dirout && res_dirin) {
+ if (dirout && dirin) {
return -EINVAL;
- } else if (res_dirout) {
- bgc->reg_dir = bgpio_request_and_map(&pdev->dev, res_dirout);
- if (!bgc->reg_dir)
- return -ENOMEM;
+ } else if (dirout) {
+ bgc->reg_dir = dirout;
bgc->gc.direction_output = bgpio_dir_out;
bgc->gc.direction_input = bgpio_dir_in;
- } else if (res_dirin) {
- bgc->reg_dir = bgpio_request_and_map(&pdev->dev, res_dirin);
- if (!bgc->reg_dir)
- return -ENOMEM;
+ } else if (dirin) {
+ bgc->reg_dir = dirin;
bgc->gc.direction_output = bgpio_dir_out_inv;
bgc->gc.direction_input = bgpio_dir_in_inv;
} else {
@@ -438,60 +351,166 @@ static int bgpio_setup_direction(struct platform_device *pdev,
return 0;
}
-static int __devinit bgpio_probe(struct platform_device *pdev)
+int __devexit bgpio_remove(struct bgpio_chip *bgc)
+{
+ int err = gpiochip_remove(&bgc->gc);
+
+ kfree(bgc);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(bgpio_remove);
+
+int __devinit bgpio_init(struct bgpio_chip *bgc,
+ struct device *dev,
+ unsigned long sz,
+ void __iomem *dat,
+ void __iomem *set,
+ void __iomem *clr,
+ void __iomem *dirout,
+ void __iomem *dirin,
+ bool big_endian)
{
- struct device *dev = &pdev->dev;
- struct bgpio_pdata *pdata = dev_get_platdata(dev);
- struct bgpio_chip *bgc;
int ret;
- int ngpio;
- bgc = devm_kzalloc(dev, sizeof(*bgc), GFP_KERNEL);
- if (!bgc)
- return -ENOMEM;
+ if (!is_power_of_2(sz))
+ return -EINVAL;
- ret = bgpio_setup_io(pdev, bgc);
+ bgc->bits = sz * 8;
+ if (bgc->bits > BITS_PER_LONG)
+ return -EINVAL;
+
+ spin_lock_init(&bgc->lock);
+ bgc->gc.dev = dev;
+ bgc->gc.label = dev_name(dev);
+ bgc->gc.base = -1;
+ bgc->gc.ngpio = bgc->bits;
+
+ ret = bgpio_setup_io(bgc, dat, set, clr);
if (ret)
return ret;
- ngpio = bgc->bits;
- if (pdata) {
- bgc->gc.base = pdata->base;
- if (pdata->ngpio > 0)
- ngpio = pdata->ngpio;
- } else {
- bgc->gc.base = -1;
- }
-
- ret = bgpio_setup_accessors(pdev, bgc);
+ ret = bgpio_setup_accessors(dev, bgc, big_endian);
if (ret)
return ret;
- spin_lock_init(&bgc->lock);
- ret = bgpio_setup_direction(pdev, bgc);
+ ret = bgpio_setup_direction(bgc, dirout, dirin);
if (ret)
return ret;
bgc->data = bgc->read_reg(bgc->reg_dat);
- bgc->gc.ngpio = ngpio;
- bgc->gc.dev = dev;
- bgc->gc.label = dev_name(dev);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(bgpio_init);
- platform_set_drvdata(pdev, bgc);
+#ifdef CONFIG_GPIO_BASIC_MMIO
- ret = gpiochip_add(&bgc->gc);
- if (ret)
- dev_err(dev, "gpiochip_add() failed: %d\n", ret);
+static void __iomem *bgpio_map(struct platform_device *pdev,
+ const char *name,
+ resource_size_t sane_sz,
+ int *err)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *r;
+ resource_size_t start;
+ resource_size_t sz;
+ void __iomem *ret;
+
+ *err = 0;
+
+ r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
+ if (!r)
+ return NULL;
+
+ sz = resource_size(r);
+ if (sz != sane_sz) {
+ *err = -EINVAL;
+ return NULL;
+ }
+
+ start = r->start;
+ if (!devm_request_mem_region(dev, start, sz, r->name)) {
+ *err = -EBUSY;
+ return NULL;
+ }
+
+ ret = devm_ioremap(dev, start, sz);
+ if (!ret) {
+ *err = -ENOMEM;
+ return NULL;
+ }
return ret;
}
-static int __devexit bgpio_remove(struct platform_device *pdev)
+static int __devinit bgpio_pdev_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *r;
+ void __iomem *dat;
+ void __iomem *set;
+ void __iomem *clr;
+ void __iomem *dirout;
+ void __iomem *dirin;
+ unsigned long sz;
+ bool be;
+ int err;
+ struct bgpio_chip *bgc;
+ struct bgpio_pdata *pdata = dev_get_platdata(dev);
+
+ r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
+ if (!r)
+ return -EINVAL;
+
+ sz = resource_size(r);
+
+ dat = bgpio_map(pdev, "dat", sz, &err);
+ if (!dat)
+ return err ? err : -EINVAL;
+
+ set = bgpio_map(pdev, "set", sz, &err);
+ if (err)
+ return err;
+
+ clr = bgpio_map(pdev, "clr", sz, &err);
+ if (err)
+ return err;
+
+ dirout = bgpio_map(pdev, "dirout", sz, &err);
+ if (err)
+ return err;
+
+ dirin = bgpio_map(pdev, "dirin", sz, &err);
+ if (err)
+ return err;
+
+ be = !strcmp(platform_get_device_id(pdev)->name, "basic-mmio-gpio-be");
+
+ bgc = devm_kzalloc(&pdev->dev, sizeof(*bgc), GFP_KERNEL);
+ if (!bgc)
+ return -ENOMEM;
+
+ err = bgpio_init(bgc, dev, sz, dat, set, clr, dirout, dirin, be);
+ if (err)
+ return err;
+
+ if (pdata) {
+ bgc->gc.base = pdata->base;
+ if (pdata->ngpio > 0)
+ bgc->gc.ngpio = pdata->ngpio;
+ }
+
+ platform_set_drvdata(pdev, bgc);
+
+ return 0;
+}
+
+static int __devexit bgpio_pdev_remove(struct platform_device *pdev)
{
struct bgpio_chip *bgc = platform_get_drvdata(pdev);
- return gpiochip_remove(&bgc->gc);
+ return bgpio_remove(bgc);
}
static const struct platform_device_id bgpio_id_table[] = {
@@ -506,21 +525,23 @@ static struct platform_driver bgpio_driver = {
.name = "basic-mmio-gpio",
},
.id_table = bgpio_id_table,
- .probe = bgpio_probe,
- .remove = __devexit_p(bgpio_remove),
+ .probe = bgpio_pdev_probe,
+ .remove = __devexit_p(bgpio_pdev_remove),
};
-static int __init bgpio_init(void)
+static int __init bgpio_platform_init(void)
{
return platform_driver_register(&bgpio_driver);
}
-module_init(bgpio_init);
+module_init(bgpio_platform_init);
-static void __exit bgpio_exit(void)
+static void __exit bgpio_platform_exit(void)
{
platform_driver_unregister(&bgpio_driver);
}
-module_exit(bgpio_exit);
+module_exit(bgpio_platform_exit);
+
+#endif /* CONFIG_GPIO_BASIC_MMIO */
MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
diff --git a/include/linux/basic_mmio_gpio.h b/include/linux/basic_mmio_gpio.h
index f23ec73..1ae1271 100644
--- a/include/linux/basic_mmio_gpio.h
+++ b/include/linux/basic_mmio_gpio.h
@@ -13,9 +13,64 @@
#ifndef __BASIC_MMIO_GPIO_H
#define __BASIC_MMIO_GPIO_H
+#include <linux/gpio.h>
+#include <linux/types.h>
+#include <linux/compiler.h>
+
struct bgpio_pdata {
int base;
int ngpio;
};
+struct device;
+
+struct bgpio_chip {
+ struct gpio_chip gc;
+
+ unsigned long (*read_reg)(void __iomem *reg);
+ void (*write_reg)(void __iomem *reg, unsigned long data);
+
+ void __iomem *reg_dat;
+ void __iomem *reg_set;
+ void __iomem *reg_clr;
+ void __iomem *reg_dir;
+
+ /* Number of bits (GPIOs): <register width> * 8. */
+ int bits;
+
+ /*
+ * Some GPIO controllers work with the big-endian bits notation,
+ * e.g. in a 8-bits register, GPIO7 is the least significant bit.
+ */
+ unsigned long (*pin2mask)(struct bgpio_chip *bgc, unsigned int pin);
+
+ /*
+ * Used to lock bgpio_chip->data. Also, this is needed to keep
+ * shadowed and real data registers writes together.
+ */
+ spinlock_t lock;
+
+ /* Shadowed data register to clear/set bits safely. */
+ unsigned long data;
+
+ /* Shadowed direction registers to clear/set direction safely. */
+ unsigned long dir;
+};
+
+static inline struct bgpio_chip *to_bgpio_chip(struct gpio_chip *gc)
+{
+ return container_of(gc, struct bgpio_chip, gc);
+}
+
+int __devexit bgpio_remove(struct bgpio_chip *bgc);
+int __devinit bgpio_init(struct bgpio_chip *bgc,
+ struct device *dev,
+ unsigned long sz,
+ void __iomem *dat,
+ void __iomem *set,
+ void __iomem *clr,
+ void __iomem *dirout,
+ void __iomem *dirin,
+ bool big_endian);
+
#endif /* __BASIC_MMIO_GPIO_H */
--
1.7.4.4
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