| Message ID | 20180718142357.120998-1-giulio.benetti@micronovasrl.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Paul, can you give a try to this patch on A13 with VGA DAC? Unfortunately I don't have an A13 board to test it. Thanks in advance. Giulio Il 18/07/2018 16:23, Giulio Benetti ha scritto: > Handle both positive and negative dclk polarity, > according to bus_flags, taking care of this: > > 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. > This patch is a way to avoid quirks all around TCON and DOTCLOCK drivers > for using A33 90° phase divided by 2 and consequently increase code > complexity. > > Check if panel is used. TCON can also handle VGA DAC, then panel could > be empty. > > Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com> > --- > drivers/gpu/drm/sun4i/sun4i_tcon.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c > index 8232b39e16ca..5c7d6ae53111 100644 > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c > @@ -17,6 +17,7 @@ > #include <drm/drm_encoder.h> > #include <drm/drm_modes.h> > #include <drm/drm_of.h> > +#include <drm/drm_panel.h> > > #include <uapi/drm/drm_mode.h> > > @@ -474,6 +475,33 @@ static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon *tcon, > if (mode->flags & DRM_MODE_FLAG_PVSYNC) > val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE; > > + /* > + * 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 (!IS_ERR(tcon->panel)) { > + struct drm_panel *panel = tcon->panel; > + struct drm_connector *connector = panel->connector; > + struct drm_display_info display_info = connector->display_info; > + > + if (display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_POSEDGE) > + clk_set_phase(tcon->dclk, 240); > + > + if (display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_NEGEDGE) > + clk_set_phase(tcon->dclk, 0); > + } > + > regmap_update_bits(tcon->regs, SUN4I_TCON0_IO_POL_REG, > SUN4I_TCON0_IO_POL_HSYNC_POSITIVE | SUN4I_TCON0_IO_POL_VSYNC_POSITIVE, > val); >
On Wed, Jul 18, 2018 at 04:23:57PM +0200, Giulio Benetti wrote: > Handle both positive and negative dclk polarity, > according to bus_flags, taking care of this: > > 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. > This patch is a way to avoid quirks all around TCON and DOTCLOCK drivers > for using A33 90° phase divided by 2 and consequently increase code > complexity. > > Check if panel is used. TCON can also handle VGA DAC, then panel could > be empty. > > Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com> Applied, thanks Maxime
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index 8232b39e16ca..5c7d6ae53111 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -17,6 +17,7 @@ #include <drm/drm_encoder.h> #include <drm/drm_modes.h> #include <drm/drm_of.h> +#include <drm/drm_panel.h> #include <uapi/drm/drm_mode.h> @@ -474,6 +475,33 @@ static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon *tcon, if (mode->flags & DRM_MODE_FLAG_PVSYNC) val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE; + /* + * 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 (!IS_ERR(tcon->panel)) { + struct drm_panel *panel = tcon->panel; + struct drm_connector *connector = panel->connector; + struct drm_display_info display_info = connector->display_info; + + if (display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_POSEDGE) + clk_set_phase(tcon->dclk, 240); + + if (display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_NEGEDGE) + clk_set_phase(tcon->dclk, 0); + } + regmap_update_bits(tcon->regs, SUN4I_TCON0_IO_POL_REG, SUN4I_TCON0_IO_POL_HSYNC_POSITIVE | SUN4I_TCON0_IO_POL_VSYNC_POSITIVE, val);
Handle both positive and negative dclk polarity, according to bus_flags, taking care of this: 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. This patch is a way to avoid quirks all around TCON and DOTCLOCK drivers for using A33 90° phase divided by 2 and consequently increase code complexity. Check if panel is used. TCON can also handle VGA DAC, then panel could be empty. Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com> --- drivers/gpu/drm/sun4i/sun4i_tcon.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)