Commit 710abda5 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

gpio: shared: call gpio_chip::of_xlate() if set 



OF-based GPIO controller drivers may provide a translation function that
calculates the real chip offset from whatever devicetree sources
provide. We need to take this into account in the shared GPIO management
and call of_xlate() if it's provided and adjust the entry->offset we
initially set when scanning the tree.

To that end: modify the shared GPIO API to take the GPIO chip as
argument on setup (to avoid having to rcu_dereference() it from the GPIO
device) and protect the access to entry->offset with the existing lock.

Fixes: a060b8c5 ("gpiolib: implement low-level, shared GPIO support")
Reported-by: default avatarJon Hunter <jonathanh@nvidia.com>
Closes: https://lore.kernel.org/all/921ba8ce-b18e-4a99-966d-c763d22081e2@nvidia.com/


Reviewed-by: default avatarLinus Walleij <linusw@kernel.org>
Tested-by: default avatarJon Hunter <jonathanh@nvidia.com>
Acked-by: default avatarJon Hunter <jonathanh@nvidia.com>
Link: https://patch.msgid.link/20260318-gpio-shared-xlate-v2-1-0ce34c707e81@oss.qualcomm.com


Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
parent 09c8ef62

drivers/gpio/gpiolib-shared.c

+26 −1
Original line number Diff line number Diff line
@@ -506,8 +506,9 @@ static void gpio_shared_remove_adev(struct auxiliary_device *adev) 
	auxiliary_device_uninit(adev);

}



int gpio_device_setup_shared(struct gpio_device *gdev)

int gpiochip_setup_shared(struct gpio_chip *gc)

{

	struct gpio_device *gdev = gc->gpiodev;

	struct gpio_shared_entry *entry;

	struct gpio_shared_ref *ref;

	struct gpio_desc *desc;
@@ -532,12 +533,34 @@ int gpio_device_setup_shared(struct gpio_device *gdev) 
	 * exposing shared pins. Find them and create the proxy devices.

	 */

	list_for_each_entry(entry, &gpio_shared_list, list) {

		guard(mutex)(&entry->lock);



		if (!device_match_fwnode(&gdev->dev, entry->fwnode))

			continue;



		if (list_count_nodes(&entry->refs) <= 1)

			continue;



#if IS_ENABLED(CONFIG_OF)

		if (is_of_node(entry->fwnode) && gc->of_xlate) {

			/*

			 * This is the earliest that we can tranlate the

			 * devicetree offset to the chip offset.

			 */

			struct of_phandle_args gpiospec = { };



			gpiospec.np = to_of_node(entry->fwnode);

			gpiospec.args_count = 2;

			gpiospec.args[0] = entry->offset;



			ret = gc->of_xlate(gc, &gpiospec, NULL);

			if (ret < 0)

				return ret;



			entry->offset = ret;

		}

#endif /* CONFIG_OF */



		desc = &gdev->descs[entry->offset];



		__set_bit(GPIOD_FLAG_SHARED, &desc->flags);
@@ -575,6 +598,8 @@ void gpio_device_teardown_shared(struct gpio_device *gdev) 
	struct gpio_shared_ref *ref;



	list_for_each_entry(entry, &gpio_shared_list, list) {

		guard(mutex)(&entry->lock);



		if (!device_match_fwnode(&gdev->dev, entry->fwnode))

			continue;

drivers/gpio/gpiolib-shared.h

+2 −2
Original line number Diff line number Diff line
@@ -14,14 +14,14 @@ struct device; 


#if IS_ENABLED(CONFIG_GPIO_SHARED)



int gpio_device_setup_shared(struct gpio_device *gdev);

int gpiochip_setup_shared(struct gpio_chip *gc);

void gpio_device_teardown_shared(struct gpio_device *gdev);

int gpio_shared_add_proxy_lookup(struct device *consumer, const char *con_id,

				 unsigned long lflags);



#else



static inline int gpio_device_setup_shared(struct gpio_device *gdev)

static inline int gpiochip_setup_shared(struct gpio_chip *gc)

{

	return 0;

}

drivers/gpio/gpiolib.c

+1 −1
Original line number Diff line number Diff line
@@ -1211,7 +1211,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, 
	if (ret)

		goto err_remove_irqchip_mask;



	ret = gpio_device_setup_shared(gdev);

	ret = gpiochip_setup_shared(gc);

	if (ret)

		goto err_remove_irqchip;