gpio: add ops to get dir flags

Add the ops for GPIO driver get_dir_flags(), allows to get dynamically
the current gpio configuration; it is used by the API function
dm_gpio_get_dir_flags().

When these optional ops are absent, the gpio uclass continues to use
the mandatory ops (direction_output, direction_input, get_value) and
value of desc->flags to manage only the main dir flags:
- GPIOD_IS_IN
- GPIOD_IS_OUT
- GPIOD_IS_OUT_ACTIVE
- GPIOD_ACTIVE_LOW
Signed-off-by: NPatrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

drivers/gpio/gpio-uclass.c

@@ -614,19 +614,36 @@ int dm_gpio_set_dir(struct gpio_desc *desc)
 
 int dm_gpio_get_dir_flags(struct gpio_desc *desc, ulong *flags)
 {
-	int ret;
+	struct udevice *dev = desc->dev;
+	int ret, value;
+	struct dm_gpio_ops *ops = gpio_get_ops(dev);
 	ulong dir_flags;
 
 	ret = check_reserved(desc, "get_dir_flags");
 	if (ret)
 		return ret;
 
-	dir_flags = desc->flags;
-	/* only GPIOD_IS_OUT_ACTIVE is provided by uclass */
-	dir_flags &= ~GPIOD_IS_OUT_ACTIVE;
-	if ((desc->flags & GPIOD_IS_OUT) && _gpio_get_value(desc))
-		dir_flags |= GPIOD_IS_OUT_ACTIVE;
+	/* GPIOD_ are directly provided by driver except GPIOD_ACTIVE_LOW */
+	if (ops->get_dir_flags) {
+		ret = ops->get_dir_flags(dev, desc->offset, &dir_flags);
+		if (ret)
+			return ret;
 
+		/* GPIOD_ACTIVE_LOW is saved in desc->flags */
+		value = dir_flags & GPIOD_IS_OUT_ACTIVE ? 1 : 0;
+		if (desc->flags & GPIOD_ACTIVE_LOW)
+			value = !value;
+		dir_flags &= ~(GPIOD_ACTIVE_LOW | GPIOD_IS_OUT_ACTIVE);
+		dir_flags |= (desc->flags & GPIOD_ACTIVE_LOW);
+		if (value)
+			dir_flags |= GPIOD_IS_OUT_ACTIVE;
+	} else {
+		dir_flags = desc->flags;
+		/* only GPIOD_IS_OUT_ACTIVE is provided by uclass */
+		dir_flags &= ~GPIOD_IS_OUT_ACTIVE;
+		if ((desc->flags & GPIOD_IS_OUT) && _gpio_get_value(desc))
+			dir_flags |= GPIOD_IS_OUT_ACTIVE;
+	}
 	*flags = dir_flags;
 
 	return 0;
@@ -1129,6 +1146,8 @@ static int gpio_post_bind(struct udevice *dev)
 			ops->get_function += gd->reloc_off;
 		if (ops->xlate)
 			ops->xlate += gd->reloc_off;
+		if (ops->get_dir_flags)
+			ops->get_dir_flags += gd->reloc_off;
 
 		reloc_done++;
 	}

include/asm-generic/gpio.h

@@ -297,6 +297,21 @@ struct dm_gpio_ops {
 	 */
 	int (*xlate)(struct udevice *dev, struct gpio_desc *desc,
 		     struct ofnode_phandle_args *args);
+
+	/**
+	 * get_dir_flags() - Get GPIO dir flags
+	 *
+	 * This function return the GPIO direction flags used.
+	 *
+	 * This method is optional.
+	 *
+	 * @dev:	GPIO device
+	 * @offset:	GPIO offset within that device
+	 * @flags:	place to put the used direction flags by GPIO
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*get_dir_flags)(struct udevice *dev, unsigned int offset,
+			     ulong *flags);
 };
 
 /**