diff options
| author | Francesco Dolcini <francesco.dolcini@toradex.com> | 2023-04-27 16:29:29 +0200 |
|---|---|---|
| committer | Robert Foss <rfoss@kernel.org> | 2023-05-05 20:11:35 +0200 |
| commit | f9cf811374f42fca31ac34aaf59ee2ae72b89879 (patch) | |
| tree | be2d1377984842990c3fb7a6d5ee7fe1ae9a7cdc /drivers/gpu/drm/bridge/tc358768.c | |
| parent | ffd2e4bbea626d565b9817312b0fcfb382fecb88 (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.
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/20230427142934.55435-5-francesco@dolcini.it
Diffstat (limited to 'drivers/gpu/drm/bridge/tc358768.c')
| -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 429bd49c53c4..487bfe33edc8 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); |