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

[Robert Hancock]

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 at 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
 .

> 
> Michael
> 
> >  
> >  #define AMS_REG_SEQ0_MASK		GENMASK(15, 0)
> >  #define AMS_REG_SEQ2_MASK		GENMASK(21, 16)
> > -- 
> > 2.31.1
> > 
> > 
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel at lists.infradead.org
> > https://urldefense.com/v3/__http://lists.infradead.org/mailman/listinfo/linux-arm-kernel__;!!IOGos0k!yGFEjSC1BL20lwurby914len0HCLXyzarwxKJP9Jx30qv_qrERSkRJUiVo_2MdusMVA$ 
> > 
-- 
Robert Hancock
Senior Hardware Designer, Calian Advanced Technologies
www.calian.com