[PATCH v2 2/6] leds: is31fl319x: Fix shutdown GPIO initial state and remove redundant startup pulse

[Jun Yan]

1. Per IS31FL319x datasheet [1], the hardware shutdown pin (SDB) is
active-low.

Fix incorrect initial GPIO level to properly release the chip from shutdown
state.

2. According to datasheet [1] definition:
  Shutdown mode can either be used as a means of
  reducing power consumption or generating a flashing
  display (repeatedly entering and leaving shutdown
  mode). During shutdown mode all registers retain their
  data.
shutdown mode does NOT perform chip reset.A dedicated software reset is
already implemented in driver by writing 0 to reset chip.

Remove redundant unnecessary toggling of the shutdown GPIO.

[1] https://lumissil.com/assets/pdf/core/IS31FL3193_DS.pdf

Fixes: dddb4e38c6ba ("leds: is31fl319x: Add shutdown pin and generate a 5ms low pulse when startup")
Signed-off-by: Jun Yan <jerrysteve1101 at gmail.com>
---
 drivers/leds/leds-is31fl319x.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/leds/leds-is31fl319x.c b/drivers/leds/leds-is31fl319x.c
index e411cee06dab..41087ed262cb 100644
--- a/drivers/leds/leds-is31fl319x.c
+++ b/drivers/leds/leds-is31fl319x.c
@@ -396,7 +396,10 @@ static int is31fl319x_parse_fw(struct device *dev, struct is31fl319x_chip *is31)
 	int count;
 	int ret;
 
-	is31->shutdown_gpio = devm_gpiod_get_optional(dev, "shutdown", GPIOD_OUT_HIGH);
+	/* Driving this GPIO line low (in fact high) takes the chip out of shutdown,
+	 * as it is flagged as GPIO_ACTIVE_LOW in provider (such as the device tree).
+	 */
+	is31->shutdown_gpio = devm_gpiod_get_optional(dev, "shutdown", GPIOD_OUT_LOW);
 	if (IS_ERR(is31->shutdown_gpio))
 		return dev_err_probe(dev, PTR_ERR(is31->shutdown_gpio),
 				     "Failed to get shutdown gpio\n");
@@ -506,12 +509,6 @@ static int is31fl319x_probe(struct i2c_client *client)
 	if (err)
 		return err;
 
-	if (is31->shutdown_gpio) {
-		gpiod_direction_output(is31->shutdown_gpio, 0);
-		mdelay(5);
-		gpiod_direction_output(is31->shutdown_gpio, 1);
-	}
-
 	is31->client = client;
 	is31->regmap = devm_regmap_init_i2c(client, is31->cdef->is31fl319x_regmap_config);
 	if (IS_ERR(is31->regmap))
-- 
2.54.0