[PATCH next v2] gpiolib: check for parent device in devprop_gpiochip_set_names()

From: Bartosz Golaszewski
Date: Thu Sep 17 2020 - 03:49:10 EST

From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>

It's possible for a GPIO chip to not have a parent device (whose
properties we inspect for 'gpio-line-names'). In this case we should
simply return from devprop_gpiochip_set_names(). Add an appropriate
check for this use-case.

Fixes: 7cba1a4d5e16 ("gpiolib: generalize devprop_gpiochip_set_names() for device properties")
Reported-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Tested-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
v1 -> v2:
- added a comment as requested by Andy

drivers/gpio/gpiolib.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index b7b608ef9e6b..dfcff5d24b18 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -375,6 +375,10 @@ static int devprop_gpiochip_set_names(struct gpio_chip *chip)
int ret, i;
int count;

+ /* GPIO chip may not have a parent device whose properties we inspect. */
+ if (!dev)
+ return 0;
count = device_property_string_array_count(dev, "gpio-line-names");
if (count < 0)
return 0;