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Commit c43960fb authored by Johan Hovold's avatar Johan Hovold Committed by Linus Walleij
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gpio: sysfs: add gpiod class-device data 



Add gpiod class-device data.

This is a first step in getting rid of the insane gpio-descriptor flag
overloading, backward irq-interface implementation, and course grained
sysfs-interface locking (a single static mutex for every operation on
all exported gpios in a system).

Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Reviewed-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent f0b7866a

drivers/gpio/gpiolib-sysfs.c

+46 −16
Original line number Diff line number Diff line
@@ -6,9 +6,14 @@ 
#include <linux/gpio/driver.h>

#include <linux/interrupt.h>

#include <linux/kdev_t.h>

#include <linux/slab.h>



#include "gpiolib.h"



struct gpiod_data {

	struct gpio_desc *desc;

};



static DEFINE_IDR(dirent_idr);
@@ -41,7 +46,8 @@ static DEFINE_MUTEX(sysfs_lock); 
static ssize_t direction_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	struct gpio_desc	*desc = dev_get_drvdata(dev);

	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;

	ssize_t			status;



	mutex_lock(&sysfs_lock);
@@ -58,7 +64,8 @@ static ssize_t direction_show(struct device *dev, 
static ssize_t direction_store(struct device *dev,

		struct device_attribute *attr, const char *buf, size_t size)

{

	struct gpio_desc	*desc = dev_get_drvdata(dev);

	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;

	ssize_t			status;



	mutex_lock(&sysfs_lock);
@@ -80,7 +87,8 @@ static DEVICE_ATTR_RW(direction); 
static ssize_t value_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	struct gpio_desc	*desc = dev_get_drvdata(dev);

	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;

	ssize_t			status;



	mutex_lock(&sysfs_lock);
@@ -94,7 +102,8 @@ static ssize_t value_show(struct device *dev, 
static ssize_t value_store(struct device *dev,

		struct device_attribute *attr, const char *buf, size_t size)

{

	struct gpio_desc	*desc = dev_get_drvdata(dev);

	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;

	ssize_t			status;



	mutex_lock(&sysfs_lock);
@@ -225,7 +234,8 @@ static const struct { 
static ssize_t edge_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	const struct gpio_desc	*desc = dev_get_drvdata(dev);

	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;

	unsigned long mask;

	ssize_t	status = 0;

	int i;
@@ -247,7 +257,8 @@ static ssize_t edge_show(struct device *dev, 
static ssize_t edge_store(struct device *dev,

		struct device_attribute *attr, const char *buf, size_t size)

{

	struct gpio_desc	*desc = dev_get_drvdata(dev);

	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;

	ssize_t			status;

	int			i;
@@ -297,7 +308,8 @@ static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev, 
static ssize_t active_low_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	const struct gpio_desc	*desc = dev_get_drvdata(dev);

	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;

	ssize_t			status;



	mutex_lock(&sysfs_lock);
@@ -313,7 +325,8 @@ static ssize_t active_low_show(struct device *dev, 
static ssize_t active_low_store(struct device *dev,

		struct device_attribute *attr, const char *buf, size_t size)

{

	struct gpio_desc	*desc = dev_get_drvdata(dev);

	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;

	ssize_t			status;

	long			value;
@@ -333,7 +346,8 @@ static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr, 
			       int n)

{

	struct device *dev = container_of(kobj, struct device, kobj);

	struct gpio_desc *desc = dev_get_drvdata(dev);

	struct gpiod_data *data = dev_get_drvdata(dev);

	struct gpio_desc *desc = data->desc;

	umode_t mode = attr->mode;

	bool show_direction = test_bit(FLAG_SYSFS_DIR, &desc->flags);
@@ -525,6 +539,7 @@ static struct class gpio_class = { 
int gpiod_export(struct gpio_desc *desc, bool direction_may_change)

{

	struct gpio_chip	*chip;

	struct gpiod_data	*data;

	unsigned long		flags;

	int			status;

	const char		*ioname = NULL;
@@ -549,7 +564,7 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) 
	/* check if chip is being removed */

	if (!chip || !chip->cdev) {

		status = -ENODEV;

		goto fail_unlock;

		goto err_unlock;

	}



	spin_lock_irqsave(&gpio_lock, flags);
@@ -561,7 +576,7 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) 
				test_bit(FLAG_REQUESTED, &desc->flags),

				test_bit(FLAG_EXPORT, &desc->flags));

		status = -EPERM;

		goto fail_unlock;

		goto err_unlock;

	}



	if (chip->direction_input && chip->direction_output &&
@@ -571,33 +586,45 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) 


	spin_unlock_irqrestore(&gpio_lock, flags);



	data = kzalloc(sizeof(*data), GFP_KERNEL);

	if (!data) {

		status = -ENOMEM;

		goto err_unlock;

	}



	data->desc = desc;



	offset = gpio_chip_hwgpio(desc);

	if (chip->names && chip->names[offset])

		ioname = chip->names[offset];



	dev = device_create_with_groups(&gpio_class, chip->dev,

					MKDEV(0, 0), desc, gpio_groups,

					MKDEV(0, 0), data, gpio_groups,

					ioname ? ioname : "gpio%u",

					desc_to_gpio(desc));

	if (IS_ERR(dev)) {

		status = PTR_ERR(dev);

		goto fail_unlock;

		goto err_free_data;

	}



	set_bit(FLAG_EXPORT, &desc->flags);

	mutex_unlock(&sysfs_lock);

	return 0;



fail_unlock:

err_free_data:

	kfree(data);

err_unlock:

	mutex_unlock(&sysfs_lock);

	gpiod_dbg(desc, "%s: status %d\n", __func__, status);

	return status;

}

EXPORT_SYMBOL_GPL(gpiod_export);



static int match_export(struct device *dev, const void *data)

static int match_export(struct device *dev, const void *desc)

{

	return dev_get_drvdata(dev) == data;

	struct gpiod_data *data = dev_get_drvdata(dev);



	return data->desc == desc;

}



/**
@@ -653,6 +680,7 @@ EXPORT_SYMBOL_GPL(gpiod_export_link); 
 */

void gpiod_unexport(struct gpio_desc *desc)

{

	struct gpiod_data	*data;

	int			status = 0;

	struct device		*dev = NULL;
@@ -676,6 +704,7 @@ void gpiod_unexport(struct gpio_desc *desc) 
	mutex_unlock(&sysfs_lock);



	if (dev) {

		data = dev_get_drvdata(dev);

		device_unregister(dev);

		/*

		 * Release irq after deregistration to prevent race with
@@ -683,6 +712,7 @@ void gpiod_unexport(struct gpio_desc *desc) 
		 */

		gpio_setup_irq(desc, dev, 0);

		put_device(dev);

		kfree(data);

	}



	if (status)