Commit e2c4ed14 authored by Tomi Valkeinen's avatar Tomi Valkeinen
Browse files

drm/omap: fix max fclk divider for omap36xx



The OMAP36xx and AM/DM37x TRMs say that the maximum divider for DSS fclk
(in CM_CLKSEL_DSS) is 32. Experimentation shows that this is not
correct, and using divider of 32 breaks DSS with a flood or underflows
and sync losts. Dividers up to 31 seem to work fine.

There is another patch to the DT files to limit the divider correctly,
but as the DSS driver also needs to know the maximum divider to be able
to iteratively find good rates, we also need to do the fix in the DSS
driver.
Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Adam Ford <aford173@gmail.com>
Cc: stable@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/20191002122542.8449-1-tomi.valkeinen@ti.com

Tested-by: default avatarAdam Ford <aford173@gmail.com>
Reviewed-by: default avatarJyri Sarha <jsarha@ti.com>
parent a0ecd6fd
......@@ -1090,7 +1090,7 @@ static const struct dss_features omap34xx_dss_feats = {
static const struct dss_features omap3630_dss_feats = {
.model = DSS_MODEL_OMAP3,
.fck_div_max = 32,
.fck_div_max = 31,
.fck_freq_max = 173000000,
.dss_fck_multiplier = 1,
.parent_clk_name = "dpll4_ck",
......
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