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SubjectRe: [PATCH v12 05/10] drm/mediatek: Add MT8195 Embedded DisplayPort driver
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Hi, Bo-Chen:

On Mon, 2022-06-27 at 16:03 +0800, Bo-Chen Chen wrote:
> From: Markus Schneider-Pargmann <msp@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@mediatek.com>
>
> Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
> Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
> [Bo-Chen: Cleanup the drivers and modify comments from reviewers]
> Signed-off-by: Bo-Chen Chen <rex-bc.chen@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



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