[PATCH v7 04/12] drm: panel: sitronix-st7701: Enable prepare_prev_first for ts8550b

[Jagan Teki <jagan@amarulasolutions.com>]

Enable the drm panel prepare_prev_first flag for ts8550b panel so-that
the previous controller should be prepared first before the prepare for
the panel is called.
           
This makes sure that the previous controller(sun6i-mipi-dsi), likely to
be a DSI host controller should be initialized to LP-11 before the panel
is powered up.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
Changes for v7:
- new patch

 drivers/gpu/drm/panel/panel-sitronix-st7701.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-sitronix-st7701.c b/drivers/gpu/drm/panel/panel-sitronix-st7701.c
index 7eae83aa0ea1..dc7677412023 100644
--- a/drivers/gpu/drm/panel/panel-sitronix-st7701.c
+++ b/drivers/gpu/drm/panel/panel-sitronix-st7701.c
@@ -105,6 +105,7 @@ struct st7701_panel_desc {
 	unsigned int lanes;
 	enum mipi_dsi_pixel_format format;
 	unsigned int panel_sleep_delay;
+	bool prepare_prev_first;
 
 	/* TFT matrix driver configuration, panel specific. */
 	const u8	pv_gamma[16];	/* Positive voltage gamma control */
@@ -564,6 +565,7 @@ static const struct st7701_panel_desc ts8550b_desc = {
 	.lanes = 2,
 	.format = MIPI_DSI_FMT_RGB888,
 	.panel_sleep_delay = 80, /* panel need extra 80ms for sleep out cmd */
+	.prepare_prev_first = true,
 
 	.pv_gamma = {
 		CFIELD_PREP(DSI_CMD2_BK0_GAMCTRL_AJ_MASK, 0) |
@@ -875,6 +877,7 @@ static int st7701_dsi_probe(struct mipi_dsi_device *dsi)
 
 	drm_panel_init(&st7701->panel, &dsi->dev, &st7701_funcs,
 		       DRM_MODE_CONNECTOR_DSI);
+	st7701->panel.prepare_prev_first = desc->prepare_prev_first;
 
 	/**
 	 * Once sleep out has been issued, ST7701 IC required to wait 120ms
-- 
2.25.1