[PATCH] omapfb: dss: Fix max fclk divider for omap36xx

From: Adam Ford
Date: Tue Jun 30 2020 - 14:26:51 EST


The drm/omap driver was fixed to correct an issue where using a
divider of 32 breaks the DSS despite the TRM stating 32 is a valid
number. Through experimentation, it appears that 31 works, and
it is consistent with the value used by the drm/omap driver.

This patch fixes the divider for fbdev driver instead of the drm.

Fixes: f76ee892a99e ("omapfb: copy omapdss & displays for omapfb")

Cc: <stable@xxxxxxxxxxxxxxx> #4.9+
Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
---
Linux 4.4 will need a similar patch, but it doesn't apply cleanly.

The DRM version of this same fix is:
e2c4ed148cf3 ("drm/omap: fix max fclk divider for omap36xx")


diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dss.c b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
index 7252d22dd117..bfc5c4c5a26a 100644
--- a/drivers/video/fbdev/omap2/omapfb/dss/dss.c
+++ b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
@@ -833,7 +833,7 @@ static const struct dss_features omap34xx_dss_feats = {
};

static const struct dss_features omap3630_dss_feats = {
- .fck_div_max = 32,
+ .fck_div_max = 31,
.dss_fck_multiplier = 1,
.parent_clk_name = "dpll4_ck",
.dpi_select_source = &dss_dpi_select_source_omap2_omap3,
--
2.25.1