[PATCH] gpio: pca953x_gpio: support optional reset-gpios property

[Rasmus Villemoes]

The DT bindings for the pca953x family has an optional reset-gpios
property. If present, ensure that the device is taken out of reset
before attempting to read from it.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes at prevas.dk>
---
 drivers/gpio/pca953x_gpio.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpio/pca953x_gpio.c b/drivers/gpio/pca953x_gpio.c
index b0c66d18317..24b0732f89a 100644
--- a/drivers/gpio/pca953x_gpio.c
+++ b/drivers/gpio/pca953x_gpio.c
@@ -306,6 +306,7 @@ static int pca953x_probe(struct udevice *dev)
 	struct pca953x_info *info = dev_get_plat(dev);
 	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
 	char name[32], label[8], *str;
+	struct gpio_desc reset;
 	int addr;
 	ulong driver_data;
 	int ret;
@@ -321,6 +322,13 @@ static int pca953x_probe(struct udevice *dev)
 
 	driver_data = dev_get_driver_data(dev);
 
+	/* If a reset-gpios property is present, take the device out of reset. */
+	ret = gpio_request_by_name(dev, "reset-gpios", 0, &reset, GPIOD_IS_OUT);
+	if (ret && ret != -ENOENT) {
+		dev_err(dev, "requesting reset-gpios failed: %d\n", ret);
+		return ret;
+	}
+
 	info->gpio_count = driver_data & PCA_GPIO_MASK;
 	if (info->gpio_count > MAX_BANK * BANK_SZ) {
 		dev_err(dev, "Max support %d pins now\n", MAX_BANK * BANK_SZ);
-- 
2.40.1.1.g1c60b9335d