[PATCH] Revert "gpio: Access `gpio_bus_type` in gpiochip_setup_dev()"

[Tzung-Bi Shih]

This reverts commit cc11f4ef666fbca02c8a2f11d0184d57e6b75579.

Commit cc11f4ef666f ("gpio: Access `gpio_bus_type` in
gpiochip_setup_dev()") moved the bus type assignment from
gpiochip_add_data_with_key() to gpiochip_setup_dev().

This change introduced a bug where dev_printk() and friends might access
the bus name after gpiochip_add_data_with_key() but before
gpiochip_setup_dev() has run.  In this window, the bus type is not yet
initialized, leading to empty bus names in logs.

Move the bus type assignment back to gpiochip_add_data_with_key() to
ensure the bus name is available before any potential users like
dev_printk().

Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Closes: https://lore.kernel.org/all/CAMuHMdU0Xb=Moca5LUex+VxyHQa2-uYJgYf4hzHiSEjDCQQT=Q@xxxxxxxxxxxxxx/
Signed-off-by: Tzung-Bi Shih <tzungbi@xxxxxxxxxx>
---
Geert: I hadn't seen the revert patch, so I've sent out a version.

Bart: In any case, please feel free to pick this patch.

 drivers/gpio/gpiolib.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index bbb96e52197c..c1290ba20eac 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -903,8 +903,6 @@ static int gpiochip_setup_dev(struct gpio_chip *gc)
 	struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev);
 	int ret;
 
-	gdev->dev.bus = &gpio_bus_type;
-
 	/*
 	 * If fwnode doesn't belong to another device, it's safe to clear its
 	 * initialized flag.
@@ -1095,6 +1093,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	 * then make sure they get free():ed there.
 	 */
 	gdev->dev.type = &gpio_dev_type;
+	gdev->dev.bus = &gpio_bus_type;
 	gdev->dev.parent = gc->parent;
 	device_set_node(&gdev->dev, gpiochip_choose_fwnode(gc));
 
@@ -1232,8 +1231,8 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	 * we get a device node entry in sysfs under
 	 * /sys/bus/gpio/devices/gpiochipN/dev that can be used for
 	 * coldplug of device nodes and other udev business.
-	 * We can do this only if gpiolib has been initialized
-	 * (i.e., `gpio_bus_type` is ready).  Otherwise, defer until later.
+	 * We can do this only if gpiolib has been initialized.
+	 * Otherwise, defer until later.
 	 */
 	if (gpiolib_initialized) {
 		ret = gpiochip_setup_dev(gc);
-- 
2.53.0.851.ga537e3e6e9-goog