| Message ID | 20230427142934.55435-6-francesco@dolcini.it (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/bridge: tc358768: various fixes on PLL calculation and DSI timings | expand |
On Thu, Apr 27, 2023 at 4:35 PM Francesco Dolcini <francesco@dolcini.it> wrote: > > From: Francesco Dolcini <francesco.dolcini@toradex.com> > > 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> > --- > drivers/gpu/drm/bridge/tc358768.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c > index aff400c36066..360c7c65f8c4 100644 > --- a/drivers/gpu/drm/bridge/tc358768.c > +++ b/drivers/gpu/drm/bridge/tc358768.c > @@ -9,6 +9,7 @@ > #include <linux/gpio/consumer.h> > #include <linux/i2c.h> > #include <linux/kernel.h> > +#include <linux/minmax.h> > #include <linux/module.h> > #include <linux/regmap.h> > #include <linux/regulator/consumer.h> > @@ -638,6 +639,7 @@ 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; > @@ -749,9 +751,9 @@ 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); > > -- > 2.25.1 > Reviewed-by: Robert Foss <rfoss@kernel.org>
diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c index aff400c36066..360c7c65f8c4 100644 --- a/drivers/gpu/drm/bridge/tc358768.c +++ b/drivers/gpu/drm/bridge/tc358768.c @@ -9,6 +9,7 @@ #include <linux/gpio/consumer.h> #include <linux/i2c.h> #include <linux/kernel.h> +#include <linux/minmax.h> #include <linux/module.h> #include <linux/regmap.h> #include <linux/regulator/consumer.h> @@ -638,6 +639,7 @@ 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; @@ -749,9 +751,9 @@ 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);