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gpio: sysfs: add gpiod class-device data

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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: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Johan Hovold 2015-05-04 17:10:37 +02:00 committed by Linus Walleij
parent f0b7866a02
commit c43960fbcc
1 changed files with 46 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
drivers/gpio/gpiolib-sysfs.c
View File

@ -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)