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.
--
Alejandro Tafalla
