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Message-Id: <20220409095129.45786-2-stefan.wahren@i2se.com>
Date: Sat, 9 Apr 2022 11:51:28 +0200
From: Stefan Wahren <stefan.wahren@...e.com>
To: Linus Walleij <linus.walleij@...aro.org>,
Bartosz Golaszewski <brgl@...ev.pl>,
Florian Fainelli <f.fainelli@...il.com>,
Ray Jui <rjui@...adcom.com>,
Scott Branden <sbranden@...adcom.com>
Cc: bcm-kernel-feedback-list@...adcom.com,
Nicolas Saenz Julienne <nsaenz@...nel.org>,
Phil Elwell <phil@...pberrypi.com>,
Krzysztof Kozlowski <krzk@...nel.org>,
linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-rpi-kernel@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org,
Stefan Wahren <stefan.wahren@...e.com>
Subject: [PATCH 1/2] gpiolib: of: Introduce hook for missing gpio-ranges
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@...e.com>
Reviewed-by: Florian Fainelli <f.fainelli@...il.com>
Tested-by: Florian Fainelli <f.fainelli@...il.com>
Acked-by: Bartosz Golaszewski <brgl@...ev.pl>
---
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 ae1ce319cd78..d9b235c88b54 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -931,6 +931,11 @@ 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 98c93510640e..b5d53decea5a 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -492,6 +492,18 @@ 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 */
};
--
2.25.1
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