diff options
| author | Francesco Dolcini <francesco.dolcini@toradex.com> | 2023-04-27 17:29:33 +0300 |
|---|---|---|
| committer | Robert Foss <rfoss@kernel.org> | 2023-05-05 21:11:49 +0300 |
| commit | bac7842cd179572e8e0fc2d7b5254e40c6e9e057 (patch) | |
| tree | 56f693997d7dce2b67f984db63730eeec4d374ef /drivers/gpu/drm | |
| parent | 3666aad8185af8d0ce164fd3c4974235417d6d0b (diff) | |
| download | linux-bac7842cd179572e8e0fc2d7b5254e40c6e9e057.tar.xz | |
drm/bridge: tc358768: fix THS_TRAILCNT computation
Correct computation of THS_TRAILCNT register.
This register must be set to a value that ensure that
THS_TRAIL > 60 ns + 4 x UI
and
THS_TRAIL > 8 x UI
and
THS_TRAIL < TEOT
with
TEOT = 105 ns + (12 x UI)
with the actual value of THS_TRAIL being
(1 + THS_TRAILCNT) x ByteClk cycle + ((1 to 2) + 2) xHSBYTECLK cycle +
- (PHY output delay)
with PHY output delay being about
(8 + (5 to 6)) x MIPIBitClk cycle in the BitClk conversion.
Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-9-francesco@dolcini.it
Diffstat (limited to 'drivers/gpu/drm')
| -rw-r--r-- | drivers/gpu/drm/bridge/tc358768.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c index d8209433d5f4..966a25cb0b10 100644 --- a/drivers/gpu/drm/bridge/tc358768.c +++ b/drivers/gpu/drm/bridge/tc358768.c @@ -780,9 +780,10 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge) dev_dbg(priv->dev, "TCLK_POSTCNT: 0x%x\n", val); tc358768_write(priv, TC358768_TCLK_POSTCNT, val); - /* 60ns + 4*UI < THS_PREPARE < 105ns + 12*UI */ - val = tc358768_ns_to_cnt(60 + tc358768_to_ns(15 * ui_nsk), - dsibclk_nsk) - 5; + /* max(60ns + 4*UI, 8*UI) < THS_TRAILCNT < 105ns + 12*UI */ + raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(18 * ui_nsk), + dsibclk_nsk) - 4; + val = clamp(raw_val, 0, 15); dev_dbg(priv->dev, "THS_TRAILCNT: 0x%x\n", val); tc358768_write(priv, TC358768_THS_TRAILCNT, val); |