diff options
| author | Francesco Dolcini <francesco.dolcini@toradex.com> | 2023-04-13 15:45:45 +0200 |
|---|---|---|
| committer | Francesco Dolcini <francesco.dolcini@toradex.com> | 2023-04-28 14:38:29 +0200 |
| commit | 7bc0da5a5b0819d050242595516e61103ca6c436 (patch) | |
| tree | b4045508d8906ddc5b8c4e5bd6bdec694eb13698 | |
| parent | 540c31b9bcec0223fba0330e90ce3399b3ec42cf (diff) | |
drm/bridge: tc358768: fix TCLK_ZEROCNT computation
Correct computation of TCLK_ZEROCNT register.
This register must be set to a value that ensure that
(TCLK-PREPARECNT + TCLK-ZERO) > 300ns
with the actual value of (TCLK-PREPARECNT + TCLK-ZERO) being
(1 to 2) + (TCLK_ZEROCNT + 1)) x HSByteClkCycle + (PHY output delay)
with PHY output delay being about
(2 to 3) 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 | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c index 23c855d3c384..4916f2730a3b 100644 --- a/drivers/gpu/drm/bridge/tc358768.c +++ b/drivers/gpu/drm/bridge/tc358768.c @@ -743,10 +743,10 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge) /* 38ns < TCLK_PREPARE < 95ns */ val = tc358768_ns_to_cnt(65, dsibclk_nsk) - 1; - /* TCLK_PREPARE > 300ns */ - val2 = tc358768_ns_to_cnt(300 + tc358768_to_ns(3 * ui_nsk), - dsibclk_nsk); - val |= (val2 - tc358768_to_ns(phy_delay_nsk - dsibclk_nsk)) << 8; + /* TCLK_PREPARE + TCLK_ZERO > 300ns */ + val2 = tc358768_ns_to_cnt(300 - tc358768_to_ns(2 * ui_nsk), + dsibclk_nsk) - 2; + val |= val2 << 8; dev_dbg(priv->dev, "TCLK_HEADERCNT: 0x%x\n", val); tc358768_write(priv, TC358768_TCLK_HEADERCNT, val); |