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authorFrancesco Dolcini <francesco.dolcini@toradex.com>2023-04-27 17:29:30 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-07-19 17:21:15 +0300
commit2545a8d06ad8c38428e86a41ab02bfd3eebba5d2 (patch)
tree1f9f3a13412a8b0348939ab93ed1db3ee7633dea /drivers/gpu
parent587ba0805e4f4e57691041748427bb081e6a2dd6 (diff)
downloadlinux-2545a8d06ad8c38428e86a41ab02bfd3eebba5d2.tar.xz
drm/bridge: tc358768: fix TCLK_TRAILCNT computation
[ Upstream commit ee18698e212b1659dd0850d7e2ae0f22e16ed3d3 ] Correct computation of TCLK_TRAILCNT register. The driver does not implement non-continuous clock mode, so the actual value doesn't make a practical difference yet. However this change also ensures that the value does not write to reserved registers bits in case of under/overflow. This register must be set to a value that ensures that TCLK-TRAIL > 60ns and TEOT <= (105 ns + 12 x UI) with the actual value of TCLK-TRAIL being (TCLK_TRAILCNT + (1 to 2)) xHSByteClkCycle + (2 + (1 to 2)) * 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/20230427142934.55435-2-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-3-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-4-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-5-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-2-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-3-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-4-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-5-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-2-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-3-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-4-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-5-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-2-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-3-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-4-francesco@dolcini.it Link: https://patchwork.freedesktop.org/patch/msgid/20230427142934.55435-5-francesco@dolcini.it Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/bridge/tc358768.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 8f7efb14ebdc..822de6e356a2 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -10,6 +10,7 @@
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/media-bus-format.h>
+#include <linux/minmax.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
@@ -640,6 +641,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
struct mipi_dsi_device *dsi_dev = priv->output.dev;
unsigned long mode_flags = dsi_dev->mode_flags;
u32 val, val2, lptxcnt, hact, data_type;
+ s32 raw_val;
const struct drm_display_mode *mode;
u32 dsibclk_nsk, dsiclk_nsk, ui_nsk, phy_delay_nsk;
u32 dsiclk, dsibclk, video_start;
@@ -751,9 +753,9 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
dev_dbg(priv->dev, "TCLK_HEADERCNT: 0x%x\n", val);
tc358768_write(priv, TC358768_TCLK_HEADERCNT, val);
- /* TCLK_TRAIL > 60ns + 3*UI */
- val = 60 + tc358768_to_ns(3 * ui_nsk);
- val = tc358768_ns_to_cnt(val, dsibclk_nsk) - 5;
+ /* TCLK_TRAIL > 60ns AND TEOT <= 105 ns + 12*UI */
+ raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(2 * ui_nsk), dsibclk_nsk) - 5;
+ val = clamp(raw_val, 0, 127);
dev_dbg(priv->dev, "TCLK_TRAILCNT: 0x%x\n", val);
tc358768_write(priv, TC358768_TCLK_TRAILCNT, val);