diff options
| author | Francesco Dolcini <francesco.dolcini@toradex.com> | 2023-04-17 13:03:09 +0200 |
|---|---|---|
| committer | Francesco Dolcini <francesco.dolcini@toradex.com> | 2023-04-28 14:38:50 +0200 |
| commit | 7292d99b6de959212e12aefd36a4382f7dfc8684 (patch) | |
| tree | d19d57a07078dffc21b7bc224299657779c5590b | |
| parent | 793dea46dc913f2f1c2964622904abd6e9bf96af (diff) | |
drm/bridge: tc358768: fix THS_ZEROCNT computation
Correct computation of THS_ZEROCNT register.
This register must be set to a value that ensure that
THS_PREPARE + THS_ZERO > 145ns + 10*UI
with the actual value of (THS_PREPARE + THS_ZERO) being
((1 to 2) + 1 + (TCLK_ZEROCNT + 1) + (3 to 4)) x ByteClk cycle +
+ HSByteClk x (2 + (1 to 2)) + (PHY delay)
with PHY delay being about
(8 + (5 to 6)) x MIPIBitClk cycle in the BitClk conversion.
Upstream-Status: Submitted [https://lore.kernel.org/all/20230427142934.55435-1-francesco@dolcini.it/]
Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
| -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 259fa3fb5cd1..550f1567c1f8 100644 --- a/drivers/gpu/drm/bridge/tc358768.c +++ b/drivers/gpu/drm/bridge/tc358768.c @@ -761,9 +761,10 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge) /* 40ns + 4*UI < THS_PREPARE < 85ns + 6*UI */ val = 50 + tc358768_to_ns(4 * ui_nsk); val = tc358768_ns_to_cnt(val, dsibclk_nsk) - 1; - /* THS_ZERO > 145ns + 10*UI */ - val2 = tc358768_ns_to_cnt(145 - tc358768_to_ns(ui_nsk), dsibclk_nsk); - val |= (val2 - tc358768_to_ns(phy_delay_nsk)) << 8; + /* THS_PREPARE + THS_ZERO > 145ns + 10*UI */ + raw_val = tc358768_ns_to_cnt(145 - tc358768_to_ns(3 * ui_nsk), dsibclk_nsk) - 10; + val2 = clamp(raw_val, 0, 127); + val |= val2 << 8; dev_dbg(priv->dev, "THS_HEADERCNT: 0x%x\n", val); tc358768_write(priv, TC358768_THS_HEADERCNT, val); |