[PATCH] dt-bindings: pinctrl: mt8195: Use real world values for drive-strength arguments

[PATCH] dt-bindings: pinctrl: mt8195: Use real world values for drive-strength arguments

[Chen-Yu Tsai]

The original binding submission for MT8195 pinctrl described the
possible drive strength values in micro-amps in its description, but
then proceeded to list register values in its device tree binding
constraints.

However, the macros used with the Mediatek pinctrl bindings directly
specify the drive strength in micro-amps, instead of hardware register
values. The current driver implementation in Linux does convert the
value from micro-amps to hardware register values. This implementation
is also used with MT7622 and MT8183, which use real world values in
their device trees.

Given the above, it was likely an oversight to use the raw register
values in the binding. Correct the values in the binding. Also drop
the description since the binding combined with its parent,
pinctrl/pincfg.yaml, the binding is now self-describing.

Fixes: 7f7663899d94 ("dt-bindings: pinctrl: mt8195: add pinctrl file and binding document")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
 .../devicetree/bindings/pinctrl/pinctrl-mt8195.yaml          | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-mt8195.yaml b/Documentation/devicetree/bindings/pinctrl/pinctrl-mt8195.yaml
index 2f12ec59eee5..e17a399e0904 100644
--- a/Documentation/devicetree/bindings/pinctrl/pinctrl-mt8195.yaml
+++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-mt8195.yaml
@@ -80,10 +80,7 @@ patternProperties:
           as macros in dt-bindings/pinctrl/<soc>-pinfunc.h directly.
 
       drive-strength:
-        description: |
-          It can support some arguments which is from 0 to 7. It can only support
-          2/4/6/8/10/12/14/16mA in mt8195.
-        enum: [0, 1, 2, 3, 4, 5, 6, 7]
+        enum: [2, 4, 6, 8, 10, 12, 14, 16]
 
       bias-pull-down: true
 
-- 
2.32.0.432.gabb21c7263-goog

Re: [PATCH] dt-bindings: pinctrl: mt8195: Use real world values for drive-strength arguments

[Rob Herring]

On Mon, 26 Jul 2021 19:19:41 +0800, Chen-Yu Tsai wrote:
> The original binding submission for MT8195 pinctrl described the
> possible drive strength values in micro-amps in its description, but
> then proceeded to list register values in its device tree binding
> constraints.
> 
> However, the macros used with the Mediatek pinctrl bindings directly
> specify the drive strength in micro-amps, instead of hardware register
> values. The current driver implementation in Linux does convert the
> value from micro-amps to hardware register values. This implementation
> is also used with MT7622 and MT8183, which use real world values in
> their device trees.
> 
> Given the above, it was likely an oversight to use the raw register
> values in the binding. Correct the values in the binding. Also drop
> the description since the binding combined with its parent,
> pinctrl/pincfg.yaml, the binding is now self-describing.
> 
> Fixes: 7f7663899d94 ("dt-bindings: pinctrl: mt8195: add pinctrl file and binding document")
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> ---
>  .../devicetree/bindings/pinctrl/pinctrl-mt8195.yaml          | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH] dt-bindings: pinctrl: mt8195: Use real world values for drive-strength arguments

[Linus Walleij]

On Mon, Jul 26, 2021 at 1:19 PM Chen-Yu Tsai <wenst@chromium.org> wrote:

> The original binding submission for MT8195 pinctrl described the
> possible drive strength values in micro-amps in its description, but
> then proceeded to list register values in its device tree binding
> constraints.
>
> However, the macros used with the Mediatek pinctrl bindings directly
> specify the drive strength in micro-amps, instead of hardware register
> values. The current driver implementation in Linux does convert the
> value from micro-amps to hardware register values. This implementation
> is also used with MT7622 and MT8183, which use real world values in
> their device trees.
>
> Given the above, it was likely an oversight to use the raw register
> values in the binding. Correct the values in the binding. Also drop
> the description since the binding combined with its parent,
> pinctrl/pincfg.yaml, the binding is now self-describing.
>
> Fixes: 7f7663899d94 ("dt-bindings: pinctrl: mt8195: add pinctrl file and binding document")
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>

Patch applied.

Yours,
Linus Walleij