gpio: fix abi regression in sysfs

We started to assign the gpio_device as parent for the sysfs
but this changes the expected layout of sysfs. Restore the
previous behaviour.

Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index c563094..932e510 100644 (file)
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -721,6 +721,7 @@ EXPORT_SYMBOL_GPL(gpiod_unexport);
 int gpiochip_sysfs_register(struct gpio_device *gdev)
 {
        struct device   *dev;
+       struct device   *parent;
        struct gpio_chip *chip = gdev->chip;
 
        /*
@@ -732,8 +733,17 @@ int gpiochip_sysfs_register(struct gpio_device *gdev)
        if (!gpio_class.p)
                return 0;
 
+       /*
+        * For sysfs backward compatibility we need to preserve this
+        * preferred parenting to the gpio_chip parent field, if set.
+        */
+       if (chip->parent)
+               parent = chip->parent;
+       else
+               parent = &gdev->dev;
+
        /* use chip->base for the ID; it's already known to be unique */
-       dev = device_create_with_groups(&gpio_class, &gdev->dev,
+       dev = device_create_with_groups(&gpio_class, parent,
                                        MKDEV(0, 0),
                                        chip, gpiochip_groups,
                                        "gpiochip%d", chip->base);