From: Giulio Benetti giulio.benetti@micronovasrl.com
During commit 88bc4178568b ("drm: Use new DRM_BUS_FLAG_*_(DRIVE|SAMPLE)_(POS|NEG)EDGE flags") DRM_BUS_FLAG_* macros have been changed to avoid ambiguity but just because of this ambiguity previous DRM_BUS_FLAG_PIXDATA_(POS/NEG)EDGE were used meaning _SAMPLE_ not _DRIVE_. This leads to DLCK inversion and need to fix but instead of swapping phase values, let's adopt an easier approach Maxime suggested: It turned out that bit 26 of SUN4I_TCON0_IO_POL_REG is dedicated to invert DCLK polarity and this makes things really easier than before. So let's handle DCLK polarity by adding SUN4I_TCON0_IO_POL_DCLK_DRIVE_NEGEDGE as bit 26 and activating according to bus_flags the same way it is done for all the other signals polarity.
Fixes: 88bc4178568b ("drm: Use new DRM_BUS_FLAG_*_(DRIVE|SAMPLE)_(POS|NEG)EDGE flags") Suggested-by: Maxime Ripard maxime@cerno.tech Signed-off-by: Giulio Benetti giulio.benetti@micronovasrl.com --- V2->V3: - squash 2 patches into 1 V3->V4: - add SUN4I_TCON0_IO_POL_DCLK_POSITIVE to regmap_update_bits() as suggested by Maxime V4->V5: polarity is still wrong so: - let's use SUN4I_TCON0_IO_POL_DCLK_DRIVE_NEGEDGE macro instead of _DCLK_POSITIVE(that would make sense only in realtion with DCLK) - invert condition using _NEGEDGE instead of _POSEDGE and then matching with register bit SUN4I_TCON0_IO_POL_DCLK_DRIVE_NEGEDGE - correct commit log according to V4->V5 changes V5->V6: - fix typo in SUN4I_TCON0_IO_POL_DCLK_DRIVE_NEGEDGE as suggested by Marjan --- drivers/gpu/drm/sun4i/sun4i_tcon.c | 21 ++------------------- drivers/gpu/drm/sun4i/sun4i_tcon.h | 1 + 2 files changed, 3 insertions(+), 19 deletions(-)
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index eaaf5d70e352..6b9af4c08cd6 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -569,30 +569,13 @@ static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon *tcon, if (info->bus_flags & DRM_BUS_FLAG_DE_LOW) val |= SUN4I_TCON0_IO_POL_DE_NEGATIVE;
- /* - * On A20 and similar SoCs, the only way to achieve Positive Edge - * (Rising Edge), is setting dclk clock phase to 2/3(240°). - * By default TCON works in Negative Edge(Falling Edge), - * this is why phase is set to 0 in that case. - * Unfortunately there's no way to logically invert dclk through - * IO_POL register. - * The only acceptable way to work, triple checked with scope, - * is using clock phase set to 0° for Negative Edge and set to 240° - * for Positive Edge. - * On A33 and similar SoCs there would be a 90° phase option, - * but it divides also dclk by 2. - * Following code is a way to avoid quirks all around TCON - * and DOTCLOCK drivers. - */ - if (info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE) - clk_set_phase(tcon->dclk, 240); - if (info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE) - clk_set_phase(tcon->dclk, 0); + val |= SUN4I_TCON0_IO_POL_DCLK_DRIVE_NEGEDGE;
regmap_update_bits(tcon->regs, SUN4I_TCON0_IO_POL_REG, SUN4I_TCON0_IO_POL_HSYNC_POSITIVE | SUN4I_TCON0_IO_POL_VSYNC_POSITIVE | + SUN4I_TCON0_IO_POL_DCLK_DRIVE_NEGEDGE | SUN4I_TCON0_IO_POL_DE_NEGATIVE, val);
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h b/drivers/gpu/drm/sun4i/sun4i_tcon.h index cfbf4e6c1679..c5ac1b02482c 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.h +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.h @@ -113,6 +113,7 @@ #define SUN4I_TCON0_IO_POL_REG 0x88 #define SUN4I_TCON0_IO_POL_DCLK_PHASE(phase) ((phase & 3) << 28) #define SUN4I_TCON0_IO_POL_DE_NEGATIVE BIT(27) +#define SUN4I_TCON0_IO_POL_DCLK_DRIVE_NEGEDGE BIT(26) #define SUN4I_TCON0_IO_POL_HSYNC_POSITIVE BIT(25) #define SUN4I_TCON0_IO_POL_VSYNC_POSITIVE BIT(24)