[PATCH v2] gpiolib: use of_node_name if line-name is missing

[Frank Wunderlich <linux@fw-web.de>]

From: Frank Wunderlich <frank-w@public-files.de>

Until v7.0, GPIO hogs inherited the DT node name when no line-name
property was specified. This was implemented as a fallback in
of_parse_own_gpio().

Commit d1d564ec4992 ("gpio: move hogs into GPIO core") moved hog parsing
into the GPIO core and removed this fallback.

Consequently, GPIO hogs without a line-name property are now displayed
with a ? in /sys/kernel/debug/gpio. Restore the old fallback.

Fixes: d1d564ec4992 ("gpio: move hogs into GPIO core")
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
---
v2:
- move code into loop as suggested by Andy and add comment about the reason
---
 drivers/gpio/gpiolib.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index ef8ccaf17c9c..28f7265c5d56 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1029,6 +1029,13 @@ int gpiochip_add_hog(struct gpio_chip *gc, struct fwnode_handle *fwnode)
 			ret = of_gpiochip_get_lflags(gc, &gpiospec, &lflags);
 			if (ret)
 				return ret;
+
+			/*
+			 * If no line-name property is present, fall back to the OF
+			 * node name as in the previous implementation.
+			 */
+			if (!name)
+				name = to_of_node(fwnode)->name;
 		} else {
 			/*
 			 * GPIO_ACTIVE_LOW is currently the only lookup flag
-- 
2.53.0