On 03/09/2021 04:49, Alejandro wrote:
From: Alejandro Tafalla atafalla@dnyon.com
Drive the reset gpio if defined in the DTS node.
Signed-off-by: Alejandro Tafalla atafalla@dnyon.com
sound/soc/codecs/max98927.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/sound/soc/codecs/max98927.c b/sound/soc/codecs/max98927.c index 8b206ee77709..daf06b503433 100644 --- a/sound/soc/codecs/max98927.c +++ b/sound/soc/codecs/max98927.c @@ -868,6 +868,7 @@ static int max98927_i2c_probe(struct i2c_client *i2c, int ret = 0, value; int reg = 0; struct max98927_priv *max98927 = NULL;
struct gpio_desc *reset_gpio;
max98927 = devm_kzalloc(&i2c->dev, sizeof(*max98927), GFP_KERNEL);
@@ -898,6 +899,19 @@ static int max98927_i2c_probe(struct i2c_client *i2c, return ret; }
- reset_gpio
= devm_gpiod_get_optional(&i2c->dev, "reset", GPIOD_OUT_LOW);
If this is a 'reset' pin then it's ACTIVE state is when it places the device to _reset_. GPIOD_OUT_LOW == Deasserted state of the GPIO line.
If the reset pin should be pulled low for reset (GPIO_ACTIVE_LOW) and you want the device initially in reset then you need GPIOD_OUT_HIGH, because: GPIOD_OUT_HIGH == Asserted state of the GPIO line.
Same goes for the gpiod_set_value_cansleep(): 0 - deasserted 1 = asserted
and this all depends on how the gpio is defined in DT (GPIO_ACTIVE_LOW/HIGH), which depends on how the documentation refers to the pin...
reset pin: low to keep the device in reset, high to release it from reset: GPIO_ACTIVE_LOW gpiod_set_value_cansleep(0) to enable gpiod_set_value_cansleep(1) to disable
enable pin: high to enable the part, low to disable GPIO_ACTIVE_HIGH gpiod_set_value_cansleep(1) to enable gpiod_set_value_cansleep(0) to disable
In both cases electrical 0: reset/disable electrical 1: enable
- if (IS_ERR(reset_gpio)) {
ret = PTR_ERR(reset_gpio);return dev_err_probe(&i2c->dev, ret, "failed to request GPIO reset pin");- }
- if (reset_gpio) {
usleep_range(8000, 10000);gpiod_set_value_cansleep(reset_gpio, 1);usleep_range(1000, 5000);- }
You might want to put the device to reset on remove at minimum.
/* Check Revision ID */ ret = regmap_read(max98927->regmap, MAX98927_R01FF_REV_ID, ®);