drm/panel-edp: Add pre_unprepare delay

In eDP power-off timing specifications, T10 defines the minimum delay
required between the end of valid video data from the source and panel
power-down (main VDD off).

Currently, panel-edp only supports the 'disable' delay, which corresponds
to T9 (backlight off to end of video data) and runs in panel_edp_disable()
while video data is still active. For panels that require a delay after
video data has stopped before cutting power, this delay must occur in
panel_edp_unprepare() before turning off power rails.

Add a 'pre_unprepare' field to struct panel_delay to model T10-min, and
delay for this duration in panel_edp_unprepare() before calling
pm_runtime_put_sync_suspend().

Additionally, adjust the timing entry for TM156VDXP25 to use
delay_200_500_e80_pu100 (enable = 80ms, pre_unprepare = 100ms) to match
its panel specification, replacing the previous delay_200_500_e50_d100.

Fixes: b9e2d5cdaab0 ("drm/panel-edp: Support NV140FHM-N5B and TM156VDXP25")
Signed-off-by: Hsin-Te Yuan <yuanhsinte@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patch.msgid.link/20260803-edp-v1-1-3e92dec1d56c@chromium.org

1 files changed, 22 insertions, 1 deletions

diff --git a/drivers/gpu/drm/panel/panel-edp.c b/drivers/gpu/drm/panel/panel-edp.c
index 3aa51ad21305..2b455369ed70 100644
--- a/drivers/gpu/drm/panel/panel-edp.c
+++ b/drivers/gpu/drm/panel/panel-edp.c
@@ -145,6 +145,16 @@ struct panel_delay {
 	unsigned int disable;
 
 	/**
+	 * @pre_unprepare: Time for the end of video data to power off.
+	 *
+	 * The time (in milliseconds) that it needs to have passed between
+	 * the end of valid video data from source and start powering off.
+	 *
+	 * This is T10-min on eDP timing diagrams. It is not common to set.
+	 */
+	unsigned int pre_unprepare;
+
+	/**
 	 * @unprepare: Time to power down completely.
 	 *
 	 * The time (in milliseconds) that it takes for the panel
@@ -413,8 +423,12 @@ static int panel_edp_suspend(struct device *dev)
 
 static int panel_edp_unprepare(struct drm_panel *panel)
 {
+	struct panel_edp *p = to_panel_edp(panel);
 	int ret;
 
+	if (p->desc->delay.pre_unprepare)
+		msleep(p->desc->delay.pre_unprepare);
+
 	ret = pm_runtime_put_sync_suspend(panel->dev);
 	if (ret < 0)
 		return ret;
@@ -1810,6 +1824,13 @@ static const struct panel_delay delay_80_500_e80_p2e200 = {
 	.prepare_to_enable = 200,
 };
 
+static const struct panel_delay delay_200_500_e80_pu100 = {
+	.hpd_absent = 200,
+	.unprepare = 500,
+	.enable = 80,
+	.pre_unprepare = 100,
+};
+
 static const struct panel_delay delay_100_500_e200 = {
 	.hpd_absent = 100,
 	.unprepare = 500,
@@ -2182,7 +2203,7 @@ static const struct edp_panel_entry edp_panels[] = {
 
 	EDP_PANEL_ENTRY('T', 'M', 'A', 0x0811, &delay_200_500_e80_d50, "TM140VDXP01-04"),
 	EDP_PANEL_ENTRY('T', 'M', 'A', 0x2094, &delay_200_500_e50_d100, "TL140VDMS03-01"),
-	EDP_PANEL_ENTRY('T', 'M', 'A', 0x2139, &delay_200_500_e50_d100, "TM156VDXP25"),
+	EDP_PANEL_ENTRY('T', 'M', 'A', 0x2139, &delay_200_500_e80_pu100, "TM156VDXP25"),
 
 	{ /* sentinal */ }
 };