This is a note to let you know that I've just added the patch titled
drm/bridge: tc358768: fix PLL parameters computation
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-bridge-tc358768-fix-pll-parameters-computation.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 507ef3091a4136a9a8d6a62917c5a4cde29ecdcf
Author: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>
Date: Thu Apr 27 16:29:27 2023 +0200
drm/bridge: tc358768: fix PLL parameters computation
[ Upstream commit 6a4020b4c63911977aaf8047f904a300d15de739 ]
According to Toshiba documentation the PLL input clock after the divider
should be not less than 4MHz, fix the PLL parameters computation
accordingly.
Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
Signed-off-by: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>
Reviewed-by: Robert Foss <rfoss@xxxxxxxxxx>
Signed-off-by: Robert Foss <rfoss@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-3-francesco@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 8de7d9764ba88..e09e007a2749c 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -329,13 +329,17 @@ static int tc358768_calc_pll(struct tc358768_priv *priv,
u32 fbd;
for (fbd = 0; fbd < 512; ++fbd) {
- u32 pll, diff;
+ u32 pll, diff, pll_in;
pll = (u32)div_u64((u64)refclk * (fbd + 1), divisor);
if (pll >= max_pll || pll < min_pll)
continue;
+ pll_in = (u32)div_u64((u64)refclk, prd + 1);
+ if (pll_in < 4000000)
+ continue;
+
diff = max(pll, target_pll) - min(pll, target_pll);
if (diff < best_diff) {
