On Sun, 2017-06-11 at 11:46 +0100, Jonathan Cameron wrote: > On Sat, 10 Jun 2017 21:58:41 +0300 > Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > > > While using GPIO library API we might get into troubles in the > > future, > > because we can't rely on label name in the driver since vendor > > firmware > > might provide any GPIO pin there, e.g. "reset", and even mark it in > > _DSD > > (in which case the request will fail). > > > > To avoid inconsistency and potential issues we have two options: > > a) generate GPIO ACPI mapping table and supply it via > > acpi_dev_add_driver_gpios(), or > > b) just pass NULL as connection ID. > > > > The b) approach is much simpler and would work since the driver > > relies > > on GPIO indices only. Moreover, the _CRS fallback mechanism, when > > requesting GPIO, is going to be stricter, and supplying non-NULL > > connection ID when neither _DSD, nor GPIO ACPI mapping is present, > > will > > make request fail. > > > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > > Hi Andy, > > A bit of googling suggests that this is one of a number of similar > patches. > I'd have appreciated some cross references in here as otherwise it > seems > to have come out of nowhere. I think the best is to read a documentation portion patch from here: https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git/co mmit/?h=for-next&id=ed7fcf1ed5ea4ea01243995ae085757a77cf0f3e > > Also, I'd be happier with an Ack from Linus Walleij on a change like > this to confirm the method (a reference to him saying it was fine > elsewhere would be fine as well!) > > Anyhow I've cc'd Linus in the meantime. Sure. > > Thanks, > > Jonathan > > --- > > drivers/iio/accel/mma9551.c | 4 +--- > > 1 file changed, 1 insertion(+), 3 deletions(-) > > > > diff --git a/drivers/iio/accel/mma9551.c > > b/drivers/iio/accel/mma9551.c > > index bf2704435629..1f53f08476f5 100644 > > --- a/drivers/iio/accel/mma9551.c > > +++ b/drivers/iio/accel/mma9551.c > > @@ -27,7 +27,6 @@ > > > > #define MMA9551_DRV_NAME "mma9551" > > #define MMA9551_IRQ_NAME "mma9551_event" > > -#define MMA9551_GPIO_NAME "mma9551_int" > > #define MMA9551_GPIO_COUNT 4 > > > > /* Tilt application (inclination in IIO terms). */ > > @@ -418,8 +417,7 @@ static int mma9551_gpio_probe(struct iio_dev > > *indio_dev) > > struct device *dev = &data->client->dev; > > > > for (i = 0; i < MMA9551_GPIO_COUNT; i++) { > > - gpio = devm_gpiod_get_index(dev, MMA9551_GPIO_NAME, > > i, > > - GPIOD_IN); > > + gpio = devm_gpiod_get_index(dev, NULL, i, > > GPIOD_IN); > > if (IS_ERR(gpio)) { > > dev_err(dev, "acpi gpio get index > > failed\n"); > > return PTR_ERR(gpio); > > -- Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
