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Subject[PATCH 06/23] gpio: sysfs: clean up chip class-device handling
Date
Clean gpio-chip class device registration and deregistration.

The class device is registered when a gpio-chip is added (or from
gpiolib_sysfs_init post-core init call), and deregistered when the chip
is removed.

Store the class device in struct gpio_chip directly rather than do a
class-device lookup on deregistration. This also removes the need for
the exported flag.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/gpio/gpiolib-sysfs.c | 39 +++++++++++++--------------------------
include/linux/gpio/driver.h | 4 ++--
2 files changed, 15 insertions(+), 28 deletions(-)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index c433f075f349..2f8bdce792f6 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -567,7 +567,7 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
mutex_lock(&sysfs_lock);

/* check if chip is being removed */
- if (!chip || !chip->exported) {
+ if (!chip || !chip->cdev) {
status = -ENODEV;
goto fail_unlock;
}
@@ -752,7 +752,6 @@ EXPORT_SYMBOL_GPL(gpiod_unexport);

int gpiochip_export(struct gpio_chip *chip)
{
- int status;
struct device *dev;

/* Many systems register gpio chips for SOC support very early,
@@ -768,41 +767,29 @@ int gpiochip_export(struct gpio_chip *chip)
chip, gpiochip_groups,
"gpiochip%d", chip->base);
if (IS_ERR(dev))
- status = PTR_ERR(dev);
- else
- status = 0;
+ return PTR_ERR(dev);

mutex_lock(&sysfs_lock);
- chip->exported = (status == 0);
+ chip->cdev = dev;
mutex_unlock(&sysfs_lock);

- if (status)
- chip_dbg(chip, "%s: status %d\n", __func__, status);
-
- return status;
+ return 0;
}

void gpiochip_unexport(struct gpio_chip *chip)
{
- int status;
- struct device *dev;
struct gpio_desc *desc;
unsigned int i;

- dev = class_find_device(&gpio_class, NULL, chip, match_export);
- if (dev) {
- put_device(dev);
- device_unregister(dev);
- /* prevent further gpiod exports */
- mutex_lock(&sysfs_lock);
- chip->exported = false;
- mutex_unlock(&sysfs_lock);
- status = 0;
- } else
- status = -ENODEV;
+ if (!chip->cdev)
+ return;

- if (status)
- chip_dbg(chip, "%s: status %d\n", __func__, status);
+ device_unregister(chip->cdev);
+
+ /* prevent further gpiod exports */
+ mutex_lock(&sysfs_lock);
+ chip->cdev = NULL;
+ mutex_unlock(&sysfs_lock);

/* unregister gpiod class devices owned by sysfs */
for (i = 0; i < chip->ngpio; i++) {
@@ -830,7 +817,7 @@ static int __init gpiolib_sysfs_init(void)
*/
spin_lock_irqsave(&gpio_lock, flags);
list_for_each_entry(chip, &gpio_chips, list) {
- if (chip->exported)
+ if (chip->cdev)
continue;

/*
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index f1b36593ec9f..8c26855fc6ec 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -20,6 +20,7 @@ struct seq_file;
* struct gpio_chip - abstract a GPIO controller
* @label: for diagnostics
* @dev: optional device providing the GPIOs
+ * @cdev: class device (may be NULL)
* @owner: helps prevent removal of modules exporting active GPIOs
* @list: links gpio_chips together for traversal
* @request: optional hook for chip-specific activation, such as
@@ -57,7 +58,6 @@ struct seq_file;
* implies that if the chip supports IRQs, these IRQs need to be threaded
* as the chip access may sleep when e.g. reading out the IRQ status
* registers.
- * @exported: flags if the gpiochip is exported for use from sysfs. Private.
* @irq_not_threaded: flag must be set if @can_sleep is set but the
* IRQs don't need to be threaded
*
@@ -74,6 +74,7 @@ struct seq_file;
struct gpio_chip {
const char *label;
struct device *dev;
+ struct device *cdev;
struct module *owner;
struct list_head list;

@@ -109,7 +110,6 @@ struct gpio_chip {
const char *const *names;
bool can_sleep;
bool irq_not_threaded;
- bool exported;

#ifdef CONFIG_GPIOLIB_IRQCHIP
/*
--
2.0.5


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