This is a note to let you know that I've just added the patch titled
drm/bridge: tc358768: fix TXTAGOCNT 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-txtagocnt-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 788f47ad64967c3021a44e7d9809619e7164e4c7
Author: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>
Date: Thu Apr 27 16:29:32 2023 +0200
drm/bridge: tc358768: fix TXTAGOCNT computation
[ Upstream commit 3666aad8185af8d0ce164fd3c4974235417d6d0b ]
Correct computation of TXTAGOCNT register.
This register must be set to a value that ensure that the
TTA-GO period = (4 x TLPX)
with the actual value of TTA-GO being
4 x (TXTAGOCNT + 1) x (HSByteClk cycle)
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/20230427142934.55435-8-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 151eecbf6027d..c9c2e15c6f4a2 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -779,7 +779,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
/* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
val = tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk * 4);
- val = tc358768_ns_to_cnt(val, dsibclk_nsk) - 1;
+ val = tc358768_ns_to_cnt(val, dsibclk_nsk) / 4 - 1;
val2 = tc358768_ns_to_cnt(tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk),
dsibclk_nsk) - 2;
val |= val2 << 16;
