drm/panel: samsung-s6e88a0-ams427ap24: Add flip option

The way of implementing a flip option follows the existing
panel-samsung-s6e8aa0.c [1][2][3].

The value to flip the screen is taken from a downstream kernel file of
a similar but older panel [4]. The mipi clock [5] for the new panel
samsung-s6e88a0-ams427ap24 matches 461 MHz and a hardware read-out of the
0xcb values corresponds to revision R01 of that older panel [6]. Although
for samsung-s6e88a0-ams427ap24 that's in non-flipped state while in this
older driver it seems to be the other way around. Further up there is a
hint [7] basically saying for revision R01 to change the first word of the
0xcb command from 0x06 to 0x0e, which is actually setting BIT(3) of that
word. This causes a horizontal flip.

[1] https://github.com/torvalds/linux/blob/v6.11/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c#L103
[2] https://github.com/torvalds/linux/blob/v6.11/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c#L207-L211
[3] https://github.com/torvalds/linux/blob/v6.11/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c#L954-L974
[4] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c
[5] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L2027-L2028
[6] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L137-L151
[7] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L66-L74

Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/1491f275e9956b2da1f1e2580abd54f4e459c7d2.1730070570.git.jahau@rocketmail.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1491f275e9956b2da1f1e2580abd54f4e459c7d2.1730070570.git.jahau@rocketmail.com

diff --git a/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
index 4b8aa088f4458ea70718ba2fd44f5aeaf33bdfa1..e92e95158d1f2a50c1bef77b01103a80210b542f 100644 (file)
--- a/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
+++ b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
@@ -38,6 +38,7 @@ struct s6e88a0_ams427ap24 {
        struct mipi_dsi_device *dsi;
        struct regulator_bulk_data *supplies;
        struct gpio_desc *reset_gpio;
+       bool flip_horizontal;
 };
 
 static const struct regulator_bulk_data s6e88a0_ams427ap24_supplies[] = {
@@ -550,6 +551,10 @@ static int s6e88a0_ams427ap24_on(struct s6e88a0_ams427ap24 *ctx)
        mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xcc, 0x4c); // pixel clock divider pol.
        mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf2, 0x03, 0x0d); // unknown
        mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf1, 0xa5, 0xa5); // level 3 key off
+
+       if (ctx->flip_horizontal)
+               mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xcb, 0x0e); // flip display
+
        mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0xa5, 0xa5); // level 1 key off
        mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0xa5, 0xa5); // level 2 key off
 
@@ -710,6 +715,8 @@ static int s6e88a0_ams427ap24_probe(struct mipi_dsi_device *dsi)
                       DRM_MODE_CONNECTOR_DSI);
        ctx->panel.prepare_prev_first = true;
 
+       ctx->flip_horizontal = device_property_read_bool(dev, "flip-horizontal");
+
        ret = s6e88a0_ams427ap24_register_backlight(ctx);
        if (ret < 0)
                return ret;