[PATCH v8 05/15] drm/sun4i: dsi: Get tcon0_div at runtime

[Jagan Teki <jagan-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org>]

tcon0 divider is used while computing drq edge0 for burst mode
devices, currently driver is using default macro value 4 via
SUN6I_DSI_TCON_DIV.

Unfortunately not all the panel devices are working with this
default divider value 4, so to make future changes on this divider
value get the divider from tcon dot clock at runtime.

Signed-off-by: Jagan Teki <jagan-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org>
Tested-by: Merlijn Wajer <merlijn-tF0PIh4TN3odnm+yROfE0A@public.gmane.org>
---
 drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 8 +++++++-
 drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h | 2 --
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index a8d3df0ea8f5..388e1161974c 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -392,9 +392,15 @@ static u16 sun6i_dsi_get_drq_edge0(struct sun6i_dsi *dsi,
 				   struct drm_display_mode *mode,
 				   u16 line_num, u16 edge1)
 {
+	struct sun4i_tcon *tcon = dsi->tcon;
+	unsigned long dclk_rate, dclk_parent_rate, tcon0_div;
 	u16 edge0 = edge1;
 
-	edge0 += (mode->hdisplay + 40) * SUN6I_DSI_TCON_DIV / 8;
+	dclk_rate = clk_get_rate(tcon->dclk);
+	dclk_parent_rate = clk_get_rate(clk_get_parent(tcon->dclk));
+	tcon0_div = dclk_parent_rate / dclk_rate;
+
+	edge0 += (mode->hdisplay + 40) * tcon0_div / 8;
 
 	if (edge0 > line_num)
 		return edge0 - line_num;
diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h
index 20516f7ab179..747c451a9a20 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h
@@ -13,8 +13,6 @@
 #include <drm/drm_encoder.h>
 #include <drm/drm_mipi_dsi.h>
 
-#define SUN6I_DSI_TCON_DIV	4
-
 struct sun6i_dsi {
 	struct drm_connector	connector;
 	struct drm_encoder	encoder;
-- 
2.18.0.321.gffc6fa0e3