[PATCH v3 2/4] gpio: Add a valid_mask getter

[Matti Vaittinen]

The valid_mask member of the struct gpio_chip is unconditionally written
by the GPIO core at driver registration. It shouldn't be directly
populated by drivers. This can be prevented by moving it from the struct
gpio_chip to struct gpio_device, which is internal to the GPIO core.

As a preparatory step, provide a getter function which can be used by
those drivers which need the valid_mask information.

Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
Revision history:
v2 => v3:
 - Rebase to gpio/for-next
v1 => v2:
  - New patch
  (spin-off from discussion to v1:
   https://lore.kernel.org/all/Z71qphikHPGB0Yuv@mva-rohm/)
---
 drivers/gpio/gpiolib.c      | 16 ++++++++++++++++
 include/linux/gpio/driver.h |  1 +
 2 files changed, 17 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index b5f472beb3bd..4c15a70d4d80 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -723,6 +723,22 @@ static int gpiochip_add_pin_ranges(struct gpio_chip *gc)
 	return 0;
 }
 
+/**
+ * gpiochip_query_valid_mask - return the GPIO validity information
+ * @gc:	gpio chip which validity information is queried
+ *
+ * Returns: bitmap representing valid GPIOs or NULL if all GPIOs are valid
+ *
+ * Some GPIO chips may support configurations where some of the pins aren't
+ * available. These chips can have valid_mask set to represent the valid
+ * GPIOs. This function can be used to retrieve this information.
+ */
+const unsigned long *gpiochip_query_valid_mask(const struct gpio_chip *gc)
+{
+	return gc->valid_mask;
+}
+EXPORT_SYMBOL_GPL(gpiochip_query_valid_mask);
+
 bool gpiochip_line_is_valid(const struct gpio_chip *gc,
 				unsigned int offset)
 {
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 83e0a7e86962..e3b59fda62e0 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -720,6 +720,7 @@ bool gpiochip_line_is_open_source(struct gpio_chip *gc, unsigned int offset);
 /* Sleep persistence inquiry for drivers */
 bool gpiochip_line_is_persistent(struct gpio_chip *gc, unsigned int offset);
 bool gpiochip_line_is_valid(const struct gpio_chip *gc, unsigned int offset);
+const unsigned long *gpiochip_query_valid_mask(const struct gpio_chip *gc);
 
 /* get driver data */
 void *gpiochip_get_data(struct gpio_chip *gc);
-- 
2.48.1

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