Re: [PATCH v11 05/10] drm/mediatek: Add MT8195 Embedded DisplayPort driver

On Mon, 2022-06-20 at 11:19 +0800, CK Hu wrote:

On Mon, 2022-06-20 at 11:12 +0800, CK Hu wrote:

quoted

On Fri, 2022-06-10 at 18:55 +0800, Bo-Chen Chen wrote:

quoted

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 [off-list ref]

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Signed-off-by: Guillaume Ranquet <redacted>
[Bo-Chen: Cleanup the drivers and modify comments from reviewers]
Signed-off-by: Bo-Chen Chen <redacted>
---

[snip]

quoted

+
+static void mtk_dp_calculate_pixrate(struct mtk_dp *mtk_dp)
+{
+	u8 target_frame_rate = 60;
+	u32 target_pixel_clk;
+	struct drm_display_mode mode;
+	struct mtk_dp_timings *timings = &mtk_dp->info.timings;
+
+	drm_display_mode_from_videomode(&timings->vm, &mode);
+
+	if (mtk_dp->info.timings.frame_rate > 0) {
+		target_frame_rate = mtk_dp->info.timings.frame_rate;
+		target_pixel_clk = mode.htotal * mode.vtotal *
+				   target_frame_rate;
+	} else if (mtk_dp->info.timings.pix_rate_khz > 0) {
+		target_pixel_clk = mtk_dp->info.timings.pix_rate_khz *
1000;
+	} else {
+		target_pixel_clk = mode.htotal * mode.vtotal *
+				   target_frame_rate;
+	}
+
+	mtk_dp->info.timings.pix_rate_khz = target_pixel_clk / 1000;

It seems that pix_rate_khz is used only here and does not used in
another place, so pix_rate_khz is useless, remove it.

It seems that frame_rate is also redundant, so remove it.

Regards,
CK

I think we do use this variable in mtk_dp_parse_drm_mode_timings()
We use this variable to get target framerate.

BRs,
Bo-Chen

quoted

Regards,
CK

quoted

+}
+