Correct the ad7191 documentation to match the datasheet:
- Fix inverted CLKSEL pin logic: device should use external clock when low,
  internal CMOS/crystal when high.
- Correct CMOS-compatible clock pin from MCLK2 to MCLK1.

Signed-off-by: Ammar Mustafa <ammarmustafa34@gmail.com>
---
 Documentation/iio/ad7191.rst | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Documentation/iio/ad7191.rst b/Documentation/iio/ad7191.rst
index 977d4fea14b0..bb8a1efcfb98 100644
--- a/Documentation/iio/ad7191.rst
+++ b/Documentation/iio/ad7191.rst
@@ -63,12 +63,12 @@ Clock Configuration
 
 The AD7191 supports both internal and external clock sources:
 
-- When CLKSEL pin is tied LOW: Uses internal 4.92MHz clock (no clock property
-  needed)
-- When CLKSEL pin is tied HIGH: Requires external clock source
+- When CLKSEL pin is tied LOW: Requires external clock source
   - Can be a crystal between MCLK1 and MCLK2 pins
-  - Or a CMOS-compatible clock driving MCLK2 pin
+  - Or a CMOS-compatible clock driving MCLK1 pin and MCLK2 left unconnected
   - Must specify the "clocks" property in device tree when using external clock
+- When CLKSEL pin is tied HIGH: Uses internal 4.92MHz clock (no clock property
+  needed)
 
 SPI Interface Requirements
 --------------------------
-- 
2.43.0

On Fri, Feb 27, 2026 at 10:37:41AM -0500, Ammar Mustafa wrote:
> Correct the ad7191 documentation to match the datasheet:
> - Fix inverted CLKSEL pin logic: device should use external clock when low,
>   internal CMOS/crystal when high.
> - Correct CMOS-compatible clock pin from MCLK2 to MCLK1.

...

> -- When CLKSEL pin is tied LOW: Uses internal 4.92MHz clock (no clock property
> -  needed)
> -- When CLKSEL pin is tied HIGH: Requires external clock source
> +- When CLKSEL pin is tied LOW: Requires external clock source
>    - Can be a crystal between MCLK1 and MCLK2 pins
> -  - Or a CMOS-compatible clock driving MCLK2 pin
> +  - Or a CMOS-compatible clock driving MCLK1 pin and MCLK2 left unconnected
>    - Must specify the "clocks" property in device tree when using external clock
> +- When CLKSEL pin is tied HIGH: Uses internal 4.92MHz clock (no clock property
> +  needed)

Is it active-low or active-high pin?

...

When I see such a confusion in the documentation I propose to replace HIGH/LOW
to active/inactive or asserted/deasserted.

And no need to swap the entries.

-- 
With Best Regards,
Andy Shevchenko

On Fri, Feb 27, 2026 at 06:06:09PM +0200, Andy Shevchenko wrote:
> On Fri, Feb 27, 2026 at 10:37:41AM -0500, Ammar Mustafa wrote:
> > Correct the ad7191 documentation to match the datasheet:
> > - Fix inverted CLKSEL pin logic: device should use external clock when low,
> >   internal CMOS/crystal when high.
> > - Correct CMOS-compatible clock pin from MCLK2 to MCLK1.
> 
> ...
> 
> > -- When CLKSEL pin is tied LOW: Uses internal 4.92MHz clock (no clock property
> > -  needed)
> > -- When CLKSEL pin is tied HIGH: Requires external clock source
> > +- When CLKSEL pin is tied LOW: Requires external clock source
> >    - Can be a crystal between MCLK1 and MCLK2 pins
> > -  - Or a CMOS-compatible clock driving MCLK2 pin
> > +  - Or a CMOS-compatible clock driving MCLK1 pin and MCLK2 left unconnected
> >    - Must specify the "clocks" property in device tree when using external clock
> > +- When CLKSEL pin is tied HIGH: Uses internal 4.92MHz clock (no clock property
> > +  needed)
> 
> Is it active-low or active-high pin?
> 
> ...
> 
> When I see such a confusion in the documentation I propose to replace HIGH/LOW
> to active/inactive or asserted/deasserted.
> 
> And no need to swap the entries.
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
>

I haven't seen anything in the documentation to believe clksel is
active-low. I agree that assert/deassert would remove this confusion. I
can resend the patch with this change and without the swapped entries.

Thanks,

Ammar Mustafa

On Fri, Feb 27, 2026 at 12:31:51PM -0500, Ammar Mustafa wrote:
> On Fri, Feb 27, 2026 at 06:06:09PM +0200, Andy Shevchenko wrote:
> > On Fri, Feb 27, 2026 at 10:37:41AM -0500, Ammar Mustafa wrote:

...

> > When I see such a confusion in the documentation I propose to replace HIGH/LOW
> > to active/inactive or asserted/deasserted.
> > 
> > And no need to swap the entries.
> 
> I haven't seen anything in the documentation to believe clksel is
> active-low. I agree that assert/deassert would remove this confusion. I
> can resend the patch with this change and without the swapped entries.

Please, do.

-- 
With Best Regards,
Andy Shevchenko