linux-kernel - [PATCH next v2] gpiolib: check for parent device in devprop_gpiochip_set

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Message-Id: <20200917074857.6716-1-brgl@bgdev.pl>
Date:   Thu, 17 Sep 2020 09:48:57 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Kent Gibson <warthog618@...il.com>,
        Anders Roxell <anders.roxell@...aro.org>
Cc:     linux-gpio@...r.kernel.org, linux-next@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: [PATCH next v2] gpiolib: check for parent device in devprop_gpiochip_set_names()

From: Bartosz Golaszewski <bgolaszewski@...libre.com>

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@...aro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Tested-by: Anders Roxell <anders.roxell@...aro.org>
---
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;
-- 
2.26.1