On Tue, 7 Jan 2025 17:40:53 -0600
David Lechner <dlechner@xxxxxxxxxxxx> wrote:
> On 1/7/25 9:25 AM, Jonathan Santos wrote:
> > From: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx>
> >
> > Depending on the controller, the default state of a gpio can vary. This
> > change excludes the probability that the dafult state of the ADC reset
> > gpio will be HIGH if it will be passed as reference in the deivcetree.
devicetree
> >
> > Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx>
> > ---
> > drivers/iio/adc/ad7768-1.c | 13 +++++++++++++
> > 1 file changed, 13 insertions(+)
> >
> > diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
> > index 881446462ff5..f73b9aec8b0f 100644
> > --- a/drivers/iio/adc/ad7768-1.c
> > +++ b/drivers/iio/adc/ad7768-1.c
> > @@ -161,6 +161,7 @@ struct ad7768_state {
> > struct completion completion;
> > struct iio_trigger *trig;
> > struct gpio_desc *gpio_sync_in;
> > + struct gpio_desc *gpio_reset;
> > const char *labels[ARRAY_SIZE(ad7768_channels)];
> > /*
> > * DMA (thus cache coherency maintenance) may require the
> > @@ -441,6 +442,18 @@ static int ad7768_setup(struct ad7768_state *st)
> > {
> > int ret;
> >
> > + st->gpio_reset = devm_gpiod_get_optional(&st->spi->dev, "reset",
> > + GPIOD_OUT_LOW);
>
> Could be simplified by setting this to GPIOD_OUT_HIGH and drop
>
> gpiod_direction_output(st->gpio_reset, 1);
>
> > + if (IS_ERR(st->gpio_reset))
> > + return PTR_ERR(st->gpio_reset);
> > +
> > + if (st->gpio_reset) {
> > + gpiod_direction_output(st->gpio_reset, 1);
It's an output already, gpiod_set_value() should work I think?
Possibly even then sleep allowing variants
> > + usleep_range(10, 15);
> > + gpiod_direction_output(st->gpio_reset, 0);
> > + usleep_range(10, 15);
>
> prefer fsleep()
>
> > + }
> > +
>
> We can move the code below in an else since we don't need to do 2 resets.
>
> > /*
> > * Two writes to the SPI_RESET[1:0] bits are required to initiate
> > * a software reset. The bits must first be set to 11, and then
>
