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>

1 files changed, 13 insertions, 26 deletions

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index d19bf234e878..767b79adb9a4 100644
--- 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;
 
                 /*