| Message ID | 04a18f4115539752429da55fb857834cea0944e5.1630632805.git.atafalla@dnyon.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add reset-gpios handling for max98927 | expand |
On Fri, Sep 3, 2021 at 4:51 AM Alejandro <atafalla@dnyon.com> wrote: > > From: Alejandro Tafalla <atafalla@dnyon.com> > > Drive the reset gpio if defined in the DTS node. ... > + reset_gpio > + = devm_gpiod_get_optional(&i2c->dev, "reset", GPIOD_OUT_LOW); > + if (IS_ERR(reset_gpio)) { > + ret = PTR_ERR(reset_gpio); > + return dev_err_probe(&i2c->dev, ret, "failed to request GPIO reset pin"); Not sure why my comments have been ignored here. > + } -- With Best Regards, Andy Shevchenko
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, ®); >
On viernes, 3 de septiembre de 2021 10:18:14 (CEST) Andy Shevchenko wrote: > On Fri, Sep 3, 2021 at 4:51 AM Alejandro <atafalla@dnyon.com> wrote: > > From: Alejandro Tafalla <atafalla@dnyon.com> > > > > Drive the reset gpio if defined in the DTS node. > > ... > > > + reset_gpio > > + = devm_gpiod_get_optional(&i2c->dev, "reset", > > GPIOD_OUT_LOW); + if (IS_ERR(reset_gpio)) { > > + ret = PTR_ERR(reset_gpio); > > + return dev_err_probe(&i2c->dev, ret, "failed to request > > GPIO reset pin"); > Not sure why my comments have been ignored here. > > > + } > > -- > With Best Regards, > Andy Shevchenko Sorry, I misread your suggestion and didn't notice PTR_ERR was also in the same line.
On 3/9/21 11:20 Péter Ujfalusi wrote: > > 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 I'll change it to be consistent in the next version. Thank you for the explanation. > > + 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. Okay, thanks.
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 (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); + } + /* Check Revision ID */ ret = regmap_read(max98927->regmap, MAX98927_R01FF_REV_ID, ®);