gpiolib: add gpio get direction callback support

Add .get_direction callback to gpio_chip. This allows gpiolib
to check the current direction of a gpio.
Used to show the correct gpio direction in sysfs and debug entries.

If callback is not set then gpiolib will work as previously;
e.g. guessing everything is input until a direction is set.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index a9432fc6b8ba..eb70ca295971 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -56,6 +56,8 @@ struct device_node;
  *      enabling module power and clock; may sleep
  * @free: optional hook for chip-specific deactivation, such as
  *      disabling module power and clock; may sleep
+ * @get_direction: returns direction for signal "offset", 0=out, 1=in,
+ *      (same as GPIOF_DIR_XXX), or negative error
  * @direction_input: configures signal "offset" as input, or returns error
  * @get: returns value for signal "offset"; for output signals this
  *      returns either the value actually sensed, or zero
@@ -100,7 +102,8 @@ struct gpio_chip {
                                                 unsigned offset);
         void                    (*free)(struct gpio_chip *chip,
                                                 unsigned offset);
-
+        int                     (*get_direction)(struct gpio_chip *chip,
+                                                unsigned offset);
         int                     (*direction_input)(struct gpio_chip *chip,
                                                 unsigned offset);
         int                     (*get)(struct gpio_chip *chip,