Re: [PATCH] pinctrl: single: Fix PIN_CONFIG_BIAS_DISABLE handling

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Tue, Mar 19, 2024 at 12:07 PM Matthijs Kooijman <matthijs@xxxxxxxx> wrote:

> The pinctrl-single driver handles pin_config_set by looking up the
> requested setting in a DT-defined lookup table, which defines what bits
> correspond to each setting. There is no way to add
> PIN_CONFIG_BIAS_DISABLE entries to the table, since there is instead
> code to disable the bias by applying the disable values of both the
> pullup and pulldown entries in the table.
>
> However, this code is inside the table-lookup loop, so it would only
> execute if there is an entry for PIN_CONFIG_BIAS_DISABLE in the table,
> which can never exist, so this code never runs.
>
> This commit lifts the offending code out of the loop, so it just
> executes directly whenever PIN_CONFIG_BIAS_DISABLE is requested,
> skippipng the table lookup loop.
>
> This also introduces a new `param` variable to make the code slightly
> more readable.
>
> This bug seems to have existed when this code was first merged in commit
> 9dddb4df90d13 ("pinctrl: single: support generic pinconf"). Earlier
> versions of this patch did have an entry for PIN_CONFIG_BIAS_DISABLE in
> the lookup table, but that was removed, which is probably how this bug
> was introduced.
>
> Signed-off-by: Matthijs Kooijman <matthijs@xxxxxxxx>

This looks reasonable to me, but I need Tony to review it before applying.

Yours,
Linus Walleij