[PATCH v14 05/10] drm/mediatek: Add MT8195 Embedded DisplayPort driver

[CK Hu]

Hi, Bo-Chen:

On Tue, 2022-07-12 at 19:12 +0800, Bo-Chen Chen wrote:
> From: Markus Schneider-Pargmann <msp at baylibre.com>
> 
> This patch adds a embedded displayport driver for the MediaTek mt8195
> SoC.
> 
> It supports the MT8195, the embedded DisplayPort units. It offers
> DisplayPort 1.4 with up to 4 lanes.
> 
> The driver creates a child device for the phy. The child device will
> never exist without the parent being active. As they are sharing a
> register range, the parent passes a regmap pointer to the child so
> that
> both can work with the same register range. The phy driver sets
> device
> data that is read by the parent to get the phy device that can be
> used
> to control the phy properties.
> 
> This driver is based on an initial version by
> Jitao shi <jitao.shi at mediatek.com>
> 
> Signed-off-by: Markus Schneider-Pargmann <msp at baylibre.com>
> Signed-off-by: Guillaume Ranquet <granquet at baylibre.com>
> Signed-off-by: Bo-Chen Chen <rex-bc.chen at mediatek.com>
> ---

[snip]

> +
> +static int mtk_dp_training(struct mtk_dp *mtk_dp)
> +{
> +	short max_retry = 50;
> +	int ret;
> +
> +	do {
> +		ret = mtk_dp_train_start(mtk_dp);
> +		if (!ret)
> +			break;
> +		else if (ret != -EAGAIN)
> +			return ret;
> +	} while (--max_retry);

mtk_dp_train_start() would never return -EAGAIN, so drop this while
loop.

Regards,
CK

> 
> +	if (!max_retry)
> +		return -ETIMEDOUT;
> +
> +	ret = mtk_dp_video_config(mtk_dp);
> +	if (ret)
> +		return ret;
> +	mtk_dp_video_enable(mtk_dp, true);
> +
> +	return 0;
> +}
> +