Re: [PATCH 3/4] iio: adc: xilinx-ams: Fixed wrong sequencer register settings

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 26 Jan 2022 10:12:50 +0100
Michael Tretter <m.tretter@pengutronix.de> wrote:

> On Tue, 25 Jan 2022 16:15:05 +0000, Robert Hancock wrote:
> > On Tue, 2022-01-25 at 09:21 +0100, Michael Tretter wrote:  
> > > On Wed, 19 Jan 2022 19:02:45 -0600, Robert Hancock wrote:  
> > > > Register settings used for the sequencer configuration register
> > > > were incorrect, causing some inputs to not be read properly.
> > > > 
> > > > Fixes: d5c70627a794 ("iio: adc: Add Xilinx AMS driver")
> > > > Signed-off-by: Robert Hancock <robert.hancock@calian.com>
> > > > ---
> > > >  drivers/iio/adc/xilinx-ams.c | 4 ++--
> > > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > > 
> > > > diff --git a/drivers/iio/adc/xilinx-ams.c b/drivers/iio/adc/xilinx-ams.c
> > > > index b93864362dac..199027c93cdc 100644
> > > > --- a/drivers/iio/adc/xilinx-ams.c
> > > > +++ b/drivers/iio/adc/xilinx-ams.c
> > > > @@ -91,8 +91,8 @@
> > > >  
> > > >  #define AMS_CONF1_SEQ_MASK		GENMASK(15, 12)
> > > >  #define AMS_CONF1_SEQ_DEFAULT		FIELD_PREP(AMS_CONF1_SEQ_MASK,
> > > > 0)
> > > > -#define AMS_CONF1_SEQ_CONTINUOUS	FIELD_PREP(AMS_CONF1_SEQ_MASK, 1)
> > > > -#define AMS_CONF1_SEQ_SINGLE_CHANNEL	FIELD_PREP(AMS_CONF1_SEQ_MASK,
> > > > 2)
> > > > +#define AMS_CONF1_SEQ_CONTINUOUS	FIELD_PREP(AMS_CONF1_SEQ_MASK, 2)
> > > > +#define AMS_CONF1_SEQ_SINGLE_CHANNEL	FIELD_PREP(AMS_CONF1_SEQ_MASK,
> > > > 3)  
> > > 
> > > The TRM states that Continuous Loop Mode is 2, but Single Pass Sequence Mode
> > > is 1, not 3. Is there a reason, why you need to set both bits?  
> > 
> > Single pass sequence mode (1) just runs the same sequence only once. To read
> > these values it needs to switch to single channel mode (3).
> > 
> > The register bits are defined in Table 3-8 of 
> > https://www.xilinx.com/support/documentation/user_guides/ug580-ultrascale-sysmon.pdf
> >  .  
> 
> Thanks for the clarification.
> 
> Reviewed-by: Michael Tretter <m.tretter@pengutronix.de>

Applied to the fixes-togreg branch of iio.git

Thanks,

Jonathan