[PATCH v4 4/5] leds: is31fl32xx: Add powerdown pin to exit hardware shutdown mode

[Jun Yan <jerrysteve1101@gmail.com>]

The IS31FL32XX series features an SDB shutdown pin.
Driving it low (active low) places the chip into hardware shutdown
mode for power saving, while all register contents are preserved
and registers are not reset.

Drive the pin logic low during probe() to exit hardware shutdown
mode.

Signed-off-by: Jun Yan <jerrysteve1101@gmail.com>
---
 drivers/leds/leds-is31fl32xx.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/leds/leds-is31fl32xx.c b/drivers/leds/leds-is31fl32xx.c
index fe07acbb103a..57d779e07a62 100644
--- a/drivers/leds/leds-is31fl32xx.c
+++ b/drivers/leds/leds-is31fl32xx.c
@@ -10,6 +10,7 @@
  */
 
 #include <linux/device.h>
+#include <linux/gpio.h>
 #include <linux/i2c.h>
 #include <linux/kernel.h>
 #include <linux/leds.h>
@@ -60,6 +61,7 @@ struct is31fl32xx_led_data {
 struct is31fl32xx_priv {
 	const struct is31fl32xx_chipdef *cdef;
 	struct i2c_client *client;
+	struct gpio_desc *powerdown_gpio;
 	unsigned int num_leds;
 	struct is31fl32xx_led_data leds[];
 };
@@ -421,6 +423,11 @@ static int is31fl32xx_parse_dt(struct device *dev,
 	const struct is31fl32xx_chipdef *cdef = priv->cdef;
 	int ret = 0;
 
+	priv->powerdown_gpio = devm_gpiod_get_optional(dev, "powerdown", GPIOD_OUT_LOW);
+	if (IS_ERR(priv->powerdown_gpio))
+		return dev_err_probe(dev, PTR_ERR(priv->powerdown_gpio),
+				"Failed to get powerdown gpio\n");
+
 	if ((cdef->output_frequency_setting_reg != IS31FL32XX_REG_NONE) &&
 	    of_property_read_bool(dev_of_node(dev), "issi,22khz-pwm")) {
 
-- 
2.53.0