[PATCH 4.14 04/36] gpio: No NULL owner

Greg Kroah-Hartman
2018-06-14T14:31:04Z

From: Linus Walleij <linus.walleij@linaro.org>

commit 7d18f0a14aa6a0d6bad39111c1fb655f07f71d59 upstream.

Sometimes a GPIO is fetched with NULL as parent device, and
that is just fine. So under these circumstances, avoid using
dev_name() to provide a name for the GPIO line.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Daniel Rosenberg <drosen@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpio/gpiolib.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3313,6 +3313,8 @@ struct gpio_desc *__must_check gpiod_get
struct gpio_desc *desc = NULL;
int status;
enum gpio_lookup_flags lookupflags = 0;
+ /* Maybe we have a device name, maybe not */
+ const char *devname = dev ? dev_name(dev) : "?";

dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);

@@ -3341,8 +3343,11 @@ struct gpio_desc *__must_check gpiod_get
return desc;
}

- /* If a connection label was passed use that, else use the device name as label */
- status = gpiod_request(desc, con_id ? con_id : dev_name(dev));
+ /*
+ * If a connection label was passed use that, else attempt to use
+ * the device name as label
+ */
+ status = gpiod_request(desc, con_id ? con_id : devname);
if (status < 0)
return ERR_PTR(status);