dm: gpio: Enhance gpio command to show only active GPIOs

The GPIO list is very long in many cases and most of them are not used.
By default, show only the GPIOs that are in use, and provide a flag to show
all of them. This makes the 'gpio status' command much more pleasant.

In order to do this, driver model now exposes a method for obtaining the
'function' of a GPIO, which describes whether it is an input or output, for
example. Implementation of this method is optional.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 13 insertions, 2 deletions

diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index a6e52a0de6..60539d8a9d 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -79,11 +79,15 @@ int gpio_get_value(unsigned gpio);
  */
 int gpio_set_value(unsigned gpio, int value);
 
-/* State of a GPIO, as reported by get_state() */
+/* State of a GPIO, as reported by get_function() */
 enum {
 	GPIOF_INPUT = 0,
 	GPIOF_OUTPUT,
-	GPIOF_UNKNOWN,
+	GPIOF_UNUSED,		/* Not claimed */
+	GPIOF_UNKNOWN,		/* Not known */
+	GPIOF_FUNC,		/* Not used as a GPIO */
+
+	GPIOF_COUNT,
 };
 
 struct udevice;
@@ -123,6 +127,13 @@ struct dm_gpio_ops {
 				int value);
 	int (*get_value)(struct udevice *dev, unsigned offset);
 	int (*set_value)(struct udevice *dev, unsigned offset, int value);
+	/**
+	 * get_function() Get the GPIO function
+	 *
+	 * @dev:     Device to check
+	 * @offset:  GPIO offset within that device
+	 * @return current function - GPIOF_...
+	 */
 	int (*get_function)(struct udevice *dev, unsigned offset);
 	int (*get_state)(struct udevice *dev, unsigned offset, char *state,
 			 int maxlen);