pinctrl: bcm2835: Return pins to inputs when freed

When dynamically unloading overlays, it is important that freed pins are
restored to being inputs to prevent functions from being enabled in
multiple places at once.

Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: NPhil Elwell <phil@raspberrypi.org>
Acked-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/bcm/pinctrl-bcm2835.c

@@ -844,6 +844,16 @@ static const struct pinctrl_ops bcm2835_pctl_ops = {
 	.dt_free_map = bcm2835_pctl_dt_free_map,
 };
 
+static int bcm2835_pmx_free(struct pinctrl_dev *pctldev,
+		unsigned offset)
+{
+	struct bcm2835_pinctrl *pc = pinctrl_dev_get_drvdata(pctldev);
+
+	/* disable by setting to GPIO_IN */
+	bcm2835_pinctrl_fsel_set(pc, offset, BCM2835_FSEL_GPIO_IN);
+	return 0;
+}
+
 static int bcm2835_pmx_get_functions_count(struct pinctrl_dev *pctldev)
 {
 	return BCM2835_FSEL_COUNT;
@@ -903,6 +913,7 @@ static int bcm2835_pmx_gpio_set_direction(struct pinctrl_dev *pctldev,
 }
 
 static const struct pinmux_ops bcm2835_pmx_ops = {
+	.free = bcm2835_pmx_free,
 	.get_functions_count = bcm2835_pmx_get_functions_count,
 	.get_function_name = bcm2835_pmx_get_function_name,
 	.get_function_groups = bcm2835_pmx_get_function_groups,