gpio: generic: add get_direction support

Allow to determine the current direction configuration by
reading back from the direction register.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-generic.c

@@ -302,6 +302,14 @@ static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 	return 0;
 }
 
+static int bgpio_get_dir(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct bgpio_chip *bgc = to_bgpio_chip(gc);
+
+	return (bgc->read_reg(bgc->reg_dir) & bgc->pin2mask(bgc, gpio)) ?
+	       GPIOF_DIR_OUT : GPIOF_DIR_IN;
+}
+
 static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 {
 	struct bgpio_chip *bgc = to_bgpio_chip(gc);
@@ -351,6 +359,14 @@ static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
 	return 0;
 }
 
+static int bgpio_get_dir_inv(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct bgpio_chip *bgc = to_bgpio_chip(gc);
+
+	return (bgc->read_reg(bgc->reg_dir) & bgc->pin2mask(bgc, gpio)) ?
+	       GPIOF_DIR_IN : GPIOF_DIR_OUT;
+}
+
 static int bgpio_setup_accessors(struct device *dev,
 				 struct bgpio_chip *bgc,
 				 bool bit_be,
@@ -468,10 +484,12 @@ static int bgpio_setup_direction(struct bgpio_chip *bgc,
 		bgc->reg_dir = dirout;
 		bgc->gc.direction_output = bgpio_dir_out;
 		bgc->gc.direction_input = bgpio_dir_in;
+		bgc->gc.get_direction = bgpio_get_dir;
 	} else if (dirin) {
 		bgc->reg_dir = dirin;
 		bgc->gc.direction_output = bgpio_dir_out_inv;
 		bgc->gc.direction_input = bgpio_dir_in_inv;
+		bgc->gc.get_direction = bgpio_get_dir_inv;
 	} else {
 		bgc->gc.direction_output = bgpio_simple_dir_out;
 		bgc->gc.direction_input = bgpio_simple_dir_in;