On 09/04/2013 03:11 PM, Mark Rutland wrote: > Hi Lee, > > On Wed, Sep 04, 2013 at 10:31:43AM +0100, Lee Jones wrote: >> The power to some of the sensors are controlled by regulators. In most >> cases these are 'always on', but if not they will fail to work until >> the regulator is enabled using the relevant APIs. >> >> Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx> >> --- >> drivers/iio/pressure/st_pressure_core.c | 13 +++++++++++++ >> include/linux/iio/common/st_sensors.h | 3 +++ >> 2 files changed, 16 insertions(+) >> >> diff --git a/drivers/iio/pressure/st_pressure_core.c b/drivers/iio/pressure/st_pressure_core.c >> index f452417..7beed89 100644 >> --- a/drivers/iio/pressure/st_pressure_core.c >> +++ b/drivers/iio/pressure/st_pressure_core.c >> @@ -23,6 +23,7 @@ >> #include <linux/iio/sysfs.h> >> #include <linux/iio/trigger.h> >> #include <linux/iio/buffer.h> >> +#include <linux/regulator/consumer.h> >> #include <asm/unaligned.h> >> >> #include <linux/iio/common/st_sensors.h> >> @@ -315,6 +316,15 @@ int st_press_common_probe(struct iio_dev *indio_dev) >> indio_dev->modes = INDIO_DIRECT_MODE; >> indio_dev->info = &press_info; >> >> + /* Regulator not mandatory, but if requested we should enable it. */ >> + pdata->regulator = regulator_get(&indio_dev->dev, "vdd"); >> + if (!IS_ERR_OR_NULL(pdata->regulator)) { > > Can regulator_get return NULL? As far as I can see, it either returns a > valid reulator pointer or an ERR_PTR value. > > When you say "if requested", do you mean "if described in the dt"? If > so, the above doesn't distunguish between a regulator not being listed > and one failing to be got (e.g. if we got EPROBE_DEFER from > regulator_get). > > I think this would be better handled with something like Mark Brown's > suggested regulator_get_optional [1,2]. It can return NULL, but NULL is actually a valid regulator in that case, so the check should only be IS_ERR. And yes regulator_get_optional is what should be used here. - Lars -- 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