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Subject[PATCH 12/23] gpio: sysfs: add gpiod class-device data
Date
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>
---
drivers/gpio/gpiolib-sysfs.c | 62 ++++++++++++++++++++++++++++++++------------
1 file changed, 46 insertions(+), 16 deletions(-)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index b77f29cd1603..4cc90f7ce14b 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -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);
@@ -210,7 +219,8 @@ 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;
@@ -232,7 +242,8 @@ 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;

@@ -282,7 +293,8 @@ 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);
@@ -298,7 +310,8 @@ 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;

@@ -318,7 +331,8 @@ 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);

@@ -510,6 +524,7 @@ 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;
@@ -534,7 +549,7 @@ 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);
@@ -546,7 +561,7 @@ 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 &&
@@ -556,33 +571,45 @@ 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;
}

/**
@@ -638,6 +665,7 @@ EXPORT_SYMBOL_GPL(gpiod_export_link);
*/
void gpiod_unexport(struct gpio_desc *desc)
{
+ struct gpiod_data *data;
int status = 0;
struct device *dev = NULL;

@@ -661,6 +689,7 @@ 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
@@ -668,6 +697,7 @@ void gpiod_unexport(struct gpio_desc *desc)
*/
gpio_setup_irq(desc, dev, 0);
put_device(dev);
+ kfree(data);
}

if (status)
--
2.0.5


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