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

CK Hu
2022-07-13T08:25:08Z

Hi, Bo-Chen:

On Tue, 2022-07-12 at 19:12 +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>
> Signed-off-by: Bo-Chen Chen <rex-bc.chen@mediatek.com>
> ---

[snip]

> +
> +static int mtk_dp_bridge_atomic_check(struct drm_bridge *bridge,
> + struct drm_bridge_state
> *bridge_state,
> + struct drm_crtc_state
> *crtc_state,
> + struct drm_connector_state
> *conn_state)
> +{
> + struct mtk_dp *mtk_dp = mtk_dp_from_bridge(bridge);
> + struct drm_crtc *crtc = conn_state->crtc;
> + unsigned int input_bus_format;
> +
> + input_bus_format = bridge_state->input_bus_cfg.format;
> +
> + dev_dbg(mtk_dp->dev, "input format 0x%04x, output format
> 0x%04x\n",
> + bridge_state->input_bus_cfg.format,
> + bridge_state->output_bus_cfg.format);
> +
> + if (input_bus_format == MEDIA_BUS_FMT_YUYV8_1X16)
> + mtk_dp->info.format = DP_PIXELFORMAT_YUV422;
> + else
> + mtk_dp->info.format = DP_PIXELFORMAT_RGB;
> +
> + if (!crtc) {
> + drm_err(mtk_dp->drm_dev,
> + "Can't enable bridge as connector state doesn't
> have a crtc\n");
> + return -EINVAL;
> + }
> +
> + mtk_dp_parse_drm_mode_timings(mtk_dp, &crtc_state-
> >adjusted_mode);
> + if (mtk_dp_parse_capabilities(mtk_dp)) {

mtk_dp_bridge_atomic_enable() would call mtk_dp_parse_capabilities(),
so this is redundant.

Regards,
CK

> + drm_err(mtk_dp->drm_dev,
> + "Can't enable bridge as nothing is plugged
> in\n");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +