[PATCH 5.17 484/772] gpiolib: of: Introduce hook for missing gpio-ranges

Greg Kroah-Hartman
2022-06-07T21:21:33Z

From: Stefan Wahren <stefan.wahren@i2se.com>

[ Upstream commit 3550bba25d5587a701e6edf20e20984d2ee72c78 ]

Since commit 2ab73c6d8323 ("gpio: Support GPIO controllers without pin-ranges")
the device tree nodes of GPIO controller need the gpio-ranges property to
handle gpio-hogs. Unfortunately it's impossible to guarantee that every new
kernel is shipped with an updated device tree binary.

In order to provide backward compatibility with those older DTB, we need a
callback within of_gpiochip_add_pin_range() so the relevant platform driver
can handle this case.

Fixes: 2ab73c6d8323 ("gpio: Support GPIO controllers without pin-ranges")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Bartosz Golaszewski <brgl@bgdev.pl>
Link: https://lore.kernel.org/r/20220409095129.45786-2-stefan.wahren@i2se.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpio/gpiolib-of.c | 5 +++++
include/linux/gpio/driver.h | 12 ++++++++++++
2 files changed, 17 insertions(+)

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 775a7dadf9a3..1fcb759062c4 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -933,6 +933,11 @@ static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
if (!np)
return 0;

+ if (!of_property_read_bool(np, "gpio-ranges") &&
+ chip->of_gpio_ranges_fallback) {
+ return chip->of_gpio_ranges_fallback(chip, np);
+ }
+
group_names = of_find_property(np, group_names_propname, NULL);

for (;; index++) {
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index f8996b46f430..9f0408222f40 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -498,6 +498,18 @@ struct gpio_chip {
*/
int (*of_xlate)(struct gpio_chip *gc,
const struct of_phandle_args *gpiospec, u32 *flags);
+
+ /**
+ * @of_gpio_ranges_fallback:
+ *
+ * Optional hook for the case that no gpio-ranges property is defined
+ * within the device tree node "np" (usually DT before introduction
+ * of gpio-ranges). So this callback is helpful to provide the
+ * necessary backward compatibility for the pin ranges.
+ */
+ int (*of_gpio_ranges_fallback)(struct gpio_chip *gc,
+ struct device_node *np);
+
#endif /* CONFIG_OF_GPIO */
};

--
2.35.1