Re: [PATCH v4 04/11] drm/bridge: it6505: fix aux command write to aux operaction register

[AngeloGioacchino Del Regno]

Il 26/09/24 09:47, Hermes Wu ha scritto:
> From: Hermes Wu <Hermes.wu@xxxxxxxxxx>
>
> The aux control register command is 4 bits LSB only, adding a MACRO to get
> correct operaction command.
>
> Fixes: b5c84a9edcd4 ("drm/bridge: add it6505 driver")
> Signed-off-by: Hermes Wu <Hermes.wu@xxxxxxxxxx>
> ---
>   drivers/gpu/drm/bridge/ite-it6505.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
> index 0583abdca75f..d1f5220e04a6 100644
> --- a/drivers/gpu/drm/bridge/ite-it6505.c
> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
> @@ -329,6 +329,8 @@ enum aux_cmd_type {
>   	CMD_AUX_GET_KSV_LIST = 0x10,
>   };
>   
> +#define GET_AUX_CONTROL_CODE(cmd) ((cmd) & 0x0F)

Just (cmd & 0xf) as the leading zero is meaningless.

As a out-of-scope consideration, though, this driver would really benefit from
a conversion to use bitfield macros... would be a nice cleanup.

Cheers,
Angelo

> +
>   enum aux_cmd_reply {
>   	REPLY_ACK,
>   	REPLY_NACK,
> @@ -1000,7 +1002,7 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
>   				  size);
>   
>   	/* Aux Fire */
> -	it6505_write(it6505, REG_AUX_CMD_REQ, cmd);
> +	it6505_write(it6505, REG_AUX_CMD_REQ, GET_AUX_CONTROL_CODE(cmd));
>   
>   	ret = it6505_aux_wait(it6505);
>   	if (ret < 0)