[PATCHv2 02/22] drm/bridge: tc358767: reset voltage-swing & pre-emphasis

[Andrzej Hajda]

On 26.03.2019 11:31, Tomi Valkeinen wrote:
> We need to reset DPCD voltage-swing & pre-emphasis before starting the
> link training, as otherwise tc358767 will use the previous values as
> minimums.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
Reviewed-by: Andrzej Hajda <a.hajda at samsung.com>

 --
Regards
Andrzej
> ---
>  drivers/gpu/drm/bridge/tc358767.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> index 7031c4f52c57..11a50f7bb4be 100644
> --- a/drivers/gpu/drm/bridge/tc358767.c
> +++ b/drivers/gpu/drm/bridge/tc358767.c
> @@ -956,6 +956,12 @@ static int tc_main_link_setup(struct tc_data *tc)
>  	if (ret < 0)
>  		goto err_dpcd_write;
>  
> +	// Reset voltage-swing & pre-emphasis
> +	tmp[0] = tmp[1] = DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_0;
> +	ret = drm_dp_dpcd_write(aux, DP_TRAINING_LANE0_SET, tmp, 2);
> +	if (ret < 0)
> +		goto err_dpcd_write;
> +
>  	ret = tc_link_training(tc, DP_TRAINING_PATTERN_1);
>  	if (ret)
>  		goto err;