On 30.04.2020 11:24, Alexandru Ardelean wrote: > From: Lars-Peter Clausen <lars@xxxxxxxxxx> > > It is clear that we transition to INDIO_DIRECT_MODE when disabling the > buffer(s) and it is also clear that we transition from INDIO_DIRECT_MODE > when enabling the buffer(s). So leaving the currentmode field > INDIO_DIRECT_MODE until after the preenable() callback and updating it to > INDIO_DIRECT_MODE before the postdisable() callback doesn't add additional > value. On the other hand some drivers will need to perform different > actions depending on which mode the device is going to operate in/was > operating in. > > Moving the update of currentmode before preenable() and after postdisable() > enables us to have drivers which perform mode dependent actions in those > callbacks. > > Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> > --- > > This patch is also a V2 of this older patch from a while ago: > https://lore.kernel.org/linux-iio/1431525891-19285-5-git-send-email-lars@xxxxxxxxxx/ > > However, in this recent context, it comes to fix this: > https://lore.kernel.org/linux-iio/b9ab676489de3575984dac5610fcf05fd8742a38.camel@xxxxxxxxxx/T/#mc09284c8f79250b92a52fd5b8d1f541d1c02c0c0 > > At this point, I don't have a clear idea if this approach is good or > not; since the motivation is to fix the at91 adc. > Hence the RFC. > > Some excerpt from the AT91 discussion: > ------------------------------------------------------------------- > I decided to do a bit of shell magic for this: > > get_files() { > git grep -w iio_buffer_setup_ops | grep drivers | cut -d: -f1 | sort | uniq > } > > for file in $(get_files) ; do > if grep -q currentmode $file ; then > echo $file > fi > done > > It finds 4 drivers. > Though, `get_files()` will return 56 files. > > drivers/iio/accel/bmc150-accel-core.c > drivers/iio/adc/at91-sama5d2_adc.c > drivers/iio/adc/stm32-dfsdm-adc.c > drivers/iio/magnetometer/rm3100-core.c > > The rm3100 driver doesn't do any checks in the setup_ops for 'currentmode' as > far as I could see. > > So, Lars' patch could work nicely to fix this current case and not break others. > > Semantically though, it would sound nicer to have a 'nextmode' parameter > somewhere; maybe on the setup_ops(indio_dev, nextmode)? > Though, only those 3 drivers would really ever use it; so doing it like that > sounds like overkill. > > So, we're left with Lars' patch or we could add an 'indio_dev->nextmode' field, > that may be used in just these 3 drivers [which again: sounds overkill at this > point in time]. > > Alternatively, this 'indio_dev->currentmode' could be removed from all these 3 > drivers somehow. But that needs testing and a thorough understanding of all 3 > drivers and what they're doing, to do properly. > ------------------------------------------------------------------- Hi Alex, Thanks for finding this. I will test this with the at91-sama5d2_adc driver on Jonathan's testing branch. I will let you know of the results. Eugen > > drivers/iio/industrialio-buffer.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c > index 30af8af8f312..efcc44b62946 100644 > --- a/drivers/iio/industrialio-buffer.c > +++ b/drivers/iio/industrialio-buffer.c > @@ -989,6 +989,7 @@ static int iio_enable_buffers(struct iio_dev *indio_dev, > indio_dev->active_scan_mask = config->scan_mask; > indio_dev->scan_timestamp = config->scan_timestamp; > indio_dev->scan_bytes = config->scan_bytes; > + indio_dev->currentmode = config->mode; > > iio_update_demux(indio_dev); > > @@ -1024,8 +1025,6 @@ static int iio_enable_buffers(struct iio_dev *indio_dev, > goto err_disable_buffers; > } > > - indio_dev->currentmode = config->mode; > - > if (indio_dev->setup_ops->postenable) { > ret = indio_dev->setup_ops->postenable(indio_dev); > if (ret) { > @@ -1042,10 +1041,10 @@ static int iio_enable_buffers(struct iio_dev *indio_dev, > buffer_list) > iio_buffer_disable(buffer, indio_dev); > err_run_postdisable: > - indio_dev->currentmode = INDIO_DIRECT_MODE; > if (indio_dev->setup_ops->postdisable) > indio_dev->setup_ops->postdisable(indio_dev); > err_undo_config: > + indio_dev->currentmode = INDIO_DIRECT_MODE; > indio_dev->active_scan_mask = NULL; > > return ret; > @@ -1080,8 +1079,6 @@ static int iio_disable_buffers(struct iio_dev *indio_dev) > ret = ret2; > } > > - indio_dev->currentmode = INDIO_DIRECT_MODE; > - > if (indio_dev->setup_ops->postdisable) { > ret2 = indio_dev->setup_ops->postdisable(indio_dev); > if (ret2 && !ret) > @@ -1090,6 +1087,7 @@ static int iio_disable_buffers(struct iio_dev *indio_dev) > > iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask); > indio_dev->active_scan_mask = NULL; > + indio_dev->currentmode = INDIO_DIRECT_MODE; > > return ret; > } > -- > 2.17.1 >
