[PATCH v12 05/10] drm/mediatek: Add MT8195 Embedded DisplayPort driver

[CK Hu]

Hi, Bo-Chen:

On Mon, 2022-06-27 at 16:03 +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>
> [Bo-Chen: Cleanup the drivers and modify comments from reviewers]
> Signed-off-by: Bo-Chen Chen <rex-bc.chen at mediatek.com>
> ---

[snip]

> +
> +static int mtk_dp_training(struct mtk_dp *mtk_dp)
> +{
> +	bool training_done = false;
> +	short max_retry = 50;
> +	int ret = 0;
> +
> +	do {
> +		switch (mtk_dp->train_state) {
> +		case MTK_DP_TRAIN_STATE_TRAINING:
> +			ret = mtk_dp_train_start(mtk_dp);
> +			if (!ret)
> +				mtk_dp->train_state =
> MTK_DP_TRAIN_STATE_NORMAL;
> +			break;
> +		case MTK_DP_TRAIN_STATE_NORMAL:
> +			mtk_dp_video_config(mtk_dp);
> +			mtk_dp_video_enable(mtk_dp, true);
> +			training_done = true;
> +			break;
> +		default:
> +			break;
> +		}
> +
> +		if (ret) {
> +			if (ret == -EAGAIN)
> +				continue;
> +			/*
> +			 * If we get any other error number, it doesn't
> +			 * make any sense to keep iterating.
> +			 */
> +			break;
> +		}
> +	} while (!training_done || --max_retry);
> +
> +	return ret;
> +}

This function could re rewritten as:

static bool mtk_dp_training(struct mtk_dp *mtk_dp)
{
	short max_retry = 50;

	do {
		ret = mtk_dp_train_start(mtk_dp);
		if (!ret)
			break;
		else if (ret != -EAGAIN)
			return false;
	} while (--max_retry);

	if (!max_retry)
		return false;

	mtk_dp_video_config(mtk_dp);
	mtk_dp_video_enable(mtk_dp, true);

	return true;
}

Regards,
CK