> From: Antti Keränen <detegr@rbx.email> > Sent: Tuesday, July 6, 2021 11:29 AM > To: linux-iio@xxxxxxxxxxxxxxx > Cc: Antti Keränen <detegr@rbx.email>; Hannu Hartikainen > <hannu@xxxxxxx>; Lars-Peter Clausen <lars@xxxxxxxxxx>; Hennerich, > Michael <Michael.Hennerich@xxxxxxxxxx>; Sa, Nuno > <Nuno.Sa@xxxxxxxxxx>; Jonathan Cameron <jic23@xxxxxxxxxx> > Subject: [RESEND PATCH] iio: adis: set GPIO reset pin direction > > Use GPIOD_OUT_LOW instead of GPIOD_ASIS as the reset pin needs > to be an > active low output pin. > > Suggested-by: Hannu Hartikainen <hannu@xxxxxxx> > Signed-off-by: Antti Keränen <detegr@rbx.email> > --- > The documentation of GPIO consumer interface states: > > Be aware that there is no default direction for GPIOs. Therefore, > **using a GPIO without setting its direction first is illegal and will > result in undefined behavior!** > > Therefore the direction of the reset GPIO pin should be set as output. > > drivers/iio/imu/adis.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c > index 319b64b2fd88..7f13b3763732 100644 > --- a/drivers/iio/imu/adis.c > +++ b/drivers/iio/imu/adis.c > @@ -415,7 +415,7 @@ int __adis_initial_startup(struct adis *adis) > int ret; > > /* check if the device has rst pin low */ > - gpio = devm_gpiod_get_optional(&adis->spi->dev, "reset", > GPIOD_ASIS); > + gpio = devm_gpiod_get_optional(&adis->spi->dev, "reset", > GPIOD_OUT_LOW); > if (IS_ERR(gpio)) > return PTR_ERR(gpio); > Hi, Thanks for the patch. Forcing the device reset was intentional (thus the GPIO_ASIS). But what Lars is suggesting is a good idea and a neat improvement here. - Nuno Sá
