Add optional reset-gpios pin control. If present, de-assert the
specified reset gpio pin to bring the chip out of reset.

Signed-off-by: Steve Longerbeam <redacted>
Cc: Linus Walleij <redacted>
Cc: Alexandre Courbot <redacted>
Cc: linux-gpio@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

---

v2:
- documented optional reset-gpios property in
  Documentation/devicetree/bindings/gpio/gpio-pca953x.txt.
---
 Documentation/devicetree/bindings/gpio/gpio-pca953x.txt |  4 ++++
 drivers/gpio/gpio-pca953x.c                             | 17 +++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
index 08dd15f..da54f4c 100644
--- a/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio-pca953x.txt

@@ -29,6 +29,10 @@ Required properties:
 	onsemi,pca9654
 	exar,xra1202
 
+Optional properties:
+ - reset-gpios: GPIO specification for the RESET input
+
+
 Example:
 
 

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index d5d72d8..d1c0bd5 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c

@@ -22,6 +22,7 @@
 #include <linux/of_platform.h>
 #include <linux/acpi.h>
 #include <linux/regulator/consumer.h>
+#include <linux/gpio/consumer.h>
 
 #define PCA953X_INPUT		0
 #define PCA953X_OUTPUT		1

@@ -133,6 +134,7 @@ struct pca953x_chip {
 	const char *const *names;
 	unsigned long driver_data;
 	struct regulator *regulator;
+	struct gpio_desc *reset_gpio;
 
 	const struct pca953x_reg_config *regs;
 

@@ -756,6 +758,21 @@ static int pca953x_probe(struct i2c_client *client,
 	} else {
 		chip->gpio_start = -1;
 		irq_base = 0;
+
+		/* see if we need to de-assert a reset pin */
+		chip->reset_gpio = devm_gpiod_get_optional(&client->dev,
+							   "reset",
+							   GPIOD_OUT_LOW);