[U-Boot] [PATCH v3 1/5] dm: gpio: Add get_alt_function ops

[Patrice Chotard <patrice.chotard@st.com>]

From: Patrick Delaunay <patrick.delaunay@st.com>

When a pin is not configured as a GPIO, it could
have several alternate function.

To be able to identify the alternate function,
add ops get_alt_function() to request the pin
alternate function index from the driver when pin is
not used as gpio.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
---

Changes in v3:
   - Rename get_alternate_function to get_alt_function
     in include/asm-generic/gpio.h

Changes in v2:
   - Rename get_function_number to get_alternate_function
     in include/asm-generic/gpio.h

 drivers/gpio/gpio-uclass.c |  6 ++++++
 include/asm-generic/gpio.h | 13 +++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/gpio/gpio-uclass.c b/drivers/gpio/gpio-uclass.c
index da5e9ba6e524..27010a1ebf22 100644
--- a/drivers/gpio/gpio-uclass.c
+++ b/drivers/gpio/gpio-uclass.c
@@ -568,6 +568,12 @@ int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize)
 			 label ? label : "");
 	}
 
+	if (func == GPIOF_FUNC && ops->get_alt_function) {
+		ret = ops->get_alt_function(dev, offset);
+		if (ret >= 0)
+			snprintf(str + len, buffsize - len, ": %d", ret);
+	}
+
 	return 0;
 }
 
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index d03602696f6d..dd3d77fafa98 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -266,6 +266,19 @@ struct dm_gpio_ops {
 	int (*get_function)(struct udevice *dev, unsigned offset);
 
 	/**
+	 * get_alt_function() Get the pins alternate function
+	 *
+	 * When a pin is not configured as GPIO, this pin can have several
+	 * alternate function. get_alt_function indicate the current
+	 * pin's alternate function index
+	 *
+	 * @dev:     Device to check
+	 * @offset:  GPIO offset within that device
+	 * @return current alternate function index
+	 */
+	int (*get_alt_function)(struct udevice *dev, unsigned int offset);
+
+	/**
 	 * xlate() - Translate phandle arguments into a GPIO description
 	 *
 	 * This function should set up the fields in desc according to the
-- 
1.9.1