[PATCH 1/4] gpio: add gpiod_toggle_active_low()

[Michał Mirosław <mirq-linux@xxxxxxxxxxxx>]

Add possibility to toggle active-low flag of a gpio descriptor. This is
useful for compatibility code, where defaults are inverted vs DT gpio
flags or the active-low flag is taken from elsewhere.

Signed-off-by: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>
---
 drivers/gpio/gpiolib.c        | 11 +++++++++++
 include/linux/gpio/consumer.h |  7 +++++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 9913886ede90..6130691e2047 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3363,6 +3363,17 @@ int gpiod_is_active_low(const struct gpio_desc *desc)
 }
 EXPORT_SYMBOL_GPL(gpiod_is_active_low);
 
+/**
+ * gpiod_toggle_active_low - toggle whether a GPIO is active-low or not
+ * @desc: the gpio descriptor to change
+ */
+void gpiod_toggle_active_low(struct gpio_desc *desc)
+{
+	VALIDATE_DESC_VOID(desc);
+	change_bit(FLAG_ACTIVE_LOW, &desc->flags);
+}
+EXPORT_SYMBOL_GPL(gpiod_toggle_active_low);
+
 /* I/O calls are only valid after configuration completed; the relevant
  * "is this a valid GPIO" error checks should already have been done.
  *
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 5215fdba6b9a..bf2d017dd7b7 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -158,6 +158,7 @@ int gpiod_set_raw_array_value_cansleep(unsigned int array_size,
 
 int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
 int gpiod_set_transitory(struct gpio_desc *desc, bool transitory);
+void gpiod_toggle_active_low(struct gpio_desc *desc);
 
 int gpiod_is_active_low(const struct gpio_desc *desc);
 int gpiod_cansleep(const struct gpio_desc *desc);
@@ -483,6 +484,12 @@ static inline int gpiod_set_transitory(struct gpio_desc *desc, bool transitory)
 	return -ENOSYS;
 }
 
+static inline void gpiod_toggle_active_low(struct gpio_desc *desc)
+{
+	/* GPIO can never have been requested */
+	WARN_ON(desc);
+}
+
 static inline int gpiod_is_active_low(const struct gpio_desc *desc)
 {
 	/* GPIO can never have been requested */
-- 
2.20.1