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

From: Michael Tretter <[email-masked]>
Date: Wed, 26 Jan 2022 10:12:50 +0100

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 <[email-masked]>
> > > ---
> > >  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 <[email-masked]>

> 
> > 
> > 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
> > > [email-masked]
> > > 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

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