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

[Dmitry Baryshkov]

On Thu, Sep 26, 2024 at 03:47:54PM GMT, Hermes Wu wrote:
> From: Hermes Wu <Hermes.wu at ite.com.tw>
> 
> The aux control register command is 4 bits LSB only, adding a MACRO to get
> correct operaction command.

Nit: AUX, add (not adding), macro.

What happens if the driver doesn't limit the field? Let me guess, the
KSV reading command is 0x10 (it should have been a part of the commit
message, BTW), so it overrides some other bits? In such a case this
either should be a part of the previous commit, or, at least, come
before it.

> Fixes: b5c84a9edcd4 ("drm/bridge: add it6505 driver")
> Signed-off-by: Hermes Wu <Hermes.wu at ite.com.tw>
> ---
>  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)
> +
>  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)
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry