On Tue, 17 Aug 2021 16:37:52 +0800 hui.liu <hui.liu@xxxxxxxxxxxx> wrote: > On Sat, 2021-08-14 at 17:10 +0100, Jonathan Cameron wrote: > > On Fri, 13 Aug 2021 11:46:24 +0800 > > hui.liu <hui.liu@xxxxxxxxxxxx> wrote: > > > > > On Thu, 2021-08-12 at 19:07 +0100, Jonathan Cameron wrote: > > > > On Thu, 12 Aug 2021 13:48:43 +0800 > > > > Hui Liu <hui.liu@xxxxxxxxxxxx> wrote: > > > > > > > > > Add support IIO_CHAN_INFO_RAW case. > > > > > > > > Why? > > > > > > > > We almost never support both RAW and PROCESSED as userspace > > > > should be > > > > fine to use either. There are a few reasons we've let drivers do > > > > this but I would like know why it matters to you and it > > > > definitely > > > > needs to be in the patch description. > > > > > > > > > > Hi Jonathan, > > > > > > 1. To support ADC consumers' different types of requirement: some > > > consumers want to call iio_read_channel_raw to get raw data, the > > > others > > > use iio_read_channel_processed to get voltage. > > > > Give an example of the consumer using the raw channel readback > > (without > > acess to any scaling information?) > > > > > > 2. In our origin driver, if consumer call > > > iio_read_channel_processed, > > > read back value is raw data. > > > > > > Could we use SCALE instead of PROCESSED in patch for next version, > > > or > > > what's your suggestion? > > > > That would unfortunately be a userspace ABI change. We can add > > interfaces > > but taking them away is normally a problem :( > > > > Your reasons here are fine, subject to information on what consumer > > cares > > about having _RAW, please resend the patch with this information > > added > > to the description. > > > > Thanks, > > > > Jonathan > > 1. We found afe/iio-rescale.c, dac/dpot-dac.c and multiplexer/iio-mux.c > call iio_read_channel_raw to get raw data. If they use our ADC driver, > I think we should support _RAW case. > If we support _RAW case, we will add more information in v2 > description. iio-rescale has recently gained support for processed. https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git/commit/drivers/iio/afe/iio-rescale.c?h=testing&id=53ebee9499805add3eef630d998c40812e6a1c39 dpot-dac is a rather obscure special case, so I doubt you actually have one of those. If iio-mux is relevant then we should add processed support to that driver as well. I would rather see those users of the interface fixed than us having to tweak lots of drivers to provide _raw when it isn't appropriate for that piece of hardware. Jonathan > > 2. Since we change _PROCESSED readback value from raw data to voltage, > our consumer will make the changes synchronously. > > > > > > > Thanks. > > > > > > > > > > > > > Signed-off-by: Hui Liu <hui.liu@xxxxxxxxxxxx> > > > > > --- > > > > > drivers/iio/adc/mt6577_auxadc.c | 16 +++++++++++++++- > > > > > 1 file changed, 15 insertions(+), 1 deletion(-) > > > > > > > > > > diff --git a/drivers/iio/adc/mt6577_auxadc.c > > > > > b/drivers/iio/adc/mt6577_auxadc.c > > > > > index 79c1dd68b909..e995d43287b2 100644 > > > > > --- a/drivers/iio/adc/mt6577_auxadc.c > > > > > +++ b/drivers/iio/adc/mt6577_auxadc.c > > > > > @@ -60,7 +60,8 @@ static const struct mtk_auxadc_compatible > > > > > mt6765_compat = { > > > > > .type = IIO_VOLTAGE, > > > > > > > > > > \ > > > > > .indexed = 1, > > > > > > > > > > \ > > > > > .channel = (idx), > > > > > \ > > > > > - .info_mask_separate = > > > > > BIT(IIO_CHAN_INFO_PROCESSED), \ > > > > > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | > > > > > > > > > > \ > > > > > + BIT(IIO_CHAN_INFO_PROCESS > > > > > ED), \ > > > > > } > > > > > > > > > > static const struct iio_chan_spec mt6577_auxadc_iio_channels[] > > > > > = { > > > > > @@ -181,6 +182,19 @@ static int mt6577_auxadc_read_raw(struct > > > > > iio_dev *indio_dev, > > > > > struct mt6577_auxadc_device *adc_dev = > > > > > iio_priv(indio_dev); > > > > > > > > > > switch (info) { > > > > > + case IIO_CHAN_INFO_RAW: > > > > > + *val = mt6577_auxadc_read(indio_dev, chan); > > > > > + if (*val < 0) { > > > > > + dev_notice(indio_dev->dev.parent, > > > > > + "failed to sample data on > > > > > channel[%d]\n", > > > > > + chan->channel); > > > > > + return *val; > > > > > + } > > > > > + if (adc_dev->dev_comp->sample_data_cali) > > > > > + *val = mt_auxadc_get_cali_data(*val, > > > > > true); > > > > > + > > > > > + return IIO_VAL_INT; > > > > > + > > > > > case IIO_CHAN_INFO_PROCESSED: > > > > > *val = mt6577_auxadc_read(indio_dev, chan); > > > > > if (*val < 0) { > > > > > > > > > > > >
