gpio: sysfs: clean up chip class-device handling

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>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index d19bf23..767b79a 100644 (file)
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -582,7 +582,7 @@ 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;
        }
@@ -767,7 +767,6 @@ 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,
@@ -783,41 +782,29 @@ 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++) {
@@ -845,7 +832,7 @@ 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 f1b3659..2c1e639 100644 (file)
--- 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 used by sysfs interface (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
        /*