[PATCH v8 02/15] drm/sun4i: tcon: Compute DCLK dividers based on format, lanes

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

pll-video => pll-mipi => tcon0 => tcon0-pixel-clock is the typical
MIPI clock topology in Allwinner DSI controller.

TCON dotclock driver is computing the desired DCLK divider based on
panel pixel clock along with input DCLK min, max divider values from
tcon driver and that would eventually set the pll-mipi clock rate.

The current code allows the TCON clock divider to have a default 4
for min, max ranges that would fail to compute the desired pll-mipi
rate while supporting new panels.

So, add the computation logic 'format/lanes' to dclk min and max dividers
and instead of default 4. This computation logic align with Allwinner A64
BSP, hoping that would work even for A33.

Tested this on 4 different DSI panels.

Signed-off-by: Jagan Teki <jagan-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org>
Tested-by: Merlijn Wajer <merlijn-tF0PIh4TN3odnm+yROfE0A@public.gmane.org>
---
 drivers/gpu/drm/sun4i/sun4i_tcon.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index e75f77ff8e0f..339f9b1f5745 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -341,8 +341,8 @@ static void sun4i_tcon0_mode_set_cpu(struct sun4i_tcon *tcon,
 	u32 block_space, start_delay;
 	u32 tcon_div;
 
-	tcon->dclk_min_div = SUN6I_DSI_TCON_DIV;
-	tcon->dclk_max_div = SUN6I_DSI_TCON_DIV;
+	tcon->dclk_min_div = bpp/lanes;
+	tcon->dclk_max_div = bpp/lanes;
 
 	sun4i_tcon0_mode_set_common(tcon, mode);
 
-- 
2.18.0.321.gffc6fa0e3