Add the compatible string for the SARADC (Successive Approximation
Register ADC) IP block found in the Amlogic Meson S4 SoC.

There are no known differences between the SARADC on S4 and the one
on G12A. Therefore, it uses "amlogic,meson-g12a-saradc" as a proper
specific fallback.

Signed-off-by: Nick Xie <nick@khadas.com>
---
 .../devicetree/bindings/iio/adc/amlogic,meson-saradc.yaml     | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.yaml b/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.yaml
index bb9825e7346dd..70ab4e140e71b 100644
--- a/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.yaml
@@ -27,7 +27,11 @@ properties:
               - amlogic,meson-gxm-saradc
               - amlogic,meson-axg-saradc
               - amlogic,meson-g12a-saradc
+          # Usage of this generic fallback is not allowed for new devices
           - const: amlogic,meson-saradc
+      - items:
+          - const: amlogic,meson-s4-saradc
+          - const: amlogic,meson-g12a-saradc
 
   reg:
     maxItems: 1
-- 
2.34.1

On Mon, Mar 23, 2026 at 09:34:05AM +0800, Nick Xie wrote:
> Add the compatible string for the SARADC (Successive Approximation
> Register ADC) IP block found in the Amlogic Meson S4 SoC.
> 
> There are no known differences between the SARADC on S4 and the one
> on G12A. Therefore, it uses "amlogic,meson-g12a-saradc" as a proper
> specific fallback.

You should explain here why you are adding that comment.

> 
> Signed-off-by: Nick Xie <nick@khadas.com>
> ---
>  .../devicetree/bindings/iio/adc/amlogic,meson-saradc.yaml     | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.yaml b/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.yaml
> index bb9825e7346dd..70ab4e140e71b 100644
> --- a/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.yaml
> @@ -27,7 +27,11 @@ properties:
>                - amlogic,meson-gxm-saradc
>                - amlogic,meson-axg-saradc
>                - amlogic,meson-g12a-saradc
> +          # Usage of this generic fallback is not allowed for new devices

Best regards,
Krzysztof

On Mon, Mar 23, 2026 at 8:53 AM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
> On Mon, Mar 23, 2026 at 09:34:05AM +0800, Nick Xie wrote:
> > Add the compatible string for the SARADC (Successive Approximation
> > Register ADC) IP block found in the Amlogic Meson S4 SoC.
> >
> > There are no known differences between the SARADC on S4 and the one
> > on G12A. Therefore, it uses "amlogic,meson-g12a-saradc" as a proper
> > specific fallback.
>
> You should explain here why you are adding that comment.
What do you think about:
Also add a comment indicating that "amlogic,meson-saradc" must not be
used for new devices. It's a made up compatible string that does not
correspond to a specific hardware generation and is not used to match
any driver. For old devices we keep it as it's part of the ABI.