| Message ID | 20210107023032.560182-3-giulio.benetti@benettiengineering.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2,1/2] drm/sun4i: tcon: fix inverted DCLK polarity | expand |
Hi, Thanks for those patches On Thu, Jan 07, 2021 at 03:30:32AM +0100, Giulio Benetti wrote: > From: Giulio Benetti <giulio.benetti@micronovasrl.com> > > It turned out(Maxime suggestion) that bit 26 of SUN4I_TCON0_IO_POL_REG is > dedicated to invert DCLK polarity and this makes thing really easier than > before. So let's handle DCLK polarity by adding > SUN4I_TCON0_IO_POL_DCLK_POSITIVE as bit 26 and activating according to > bus_flags the same way is done for all the other signals. > > Cc: Maxime Ripard <maxime@cerno.tech> Suggested-by would be nice here :) > Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com> > --- > drivers/gpu/drm/sun4i/sun4i_tcon.c | 20 +------------------- > drivers/gpu/drm/sun4i/sun4i_tcon.h | 1 + > 2 files changed, 2 insertions(+), 19 deletions(-) > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c > index 52598bb0fb0b..30171ccd87e5 100644 > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c > @@ -569,26 +569,8 @@ 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, 0); > - > - if (info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE) > - clk_set_phase(tcon->dclk, 240); > + val |= SUN4I_TCON0_IO_POL_DCLK_POSITIVE; I'm not really sure why we need the first patch of this series here? That patch only seem to undo what you did in patch 1 Maxime
Hi, Quote " I'm not really sure why we need the first patch of this series here? That patch only seem to undo what you did in patch 1 " And another question (probably could be a stupid one): in "/[PATCH v2 2/2] drm/sun4i: tcon: improve DCLK polarity handling/" I see you deleted: - clk_set_phase(tcon->dclk, 0); Is safe to assume that phase register will be always set to 0? Or maybe will be safer manually set it to 0 in every condition to avoid surprises (dirt values due to previous condition)? Marjan Il 08/01/2021 10:23, Maxime Ripard ha scritto: > Hi, > > Thanks for those patches > > On Thu, Jan 07, 2021 at 03:30:32AM +0100, Giulio Benetti wrote: >> From: Giulio Benetti <giulio.benetti@micronovasrl.com> >> >> It turned out(Maxime suggestion) that bit 26 of SUN4I_TCON0_IO_POL_REG is >> dedicated to invert DCLK polarity and this makes thing really easier than >> before. So let's handle DCLK polarity by adding >> SUN4I_TCON0_IO_POL_DCLK_POSITIVE as bit 26 and activating according to >> bus_flags the same way is done for all the other signals. >> >> Cc: Maxime Ripard <maxime@cerno.tech> > Suggested-by would be nice here :) > >> Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com> >> --- >> drivers/gpu/drm/sun4i/sun4i_tcon.c | 20 +------------------- >> drivers/gpu/drm/sun4i/sun4i_tcon.h | 1 + >> 2 files changed, 2 insertions(+), 19 deletions(-) >> >> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c >> index 52598bb0fb0b..30171ccd87e5 100644 >> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c >> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c >> @@ -569,26 +569,8 @@ 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, 0); >> - >> - if (info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE) >> - clk_set_phase(tcon->dclk, 240); >> + val |= SUN4I_TCON0_IO_POL_DCLK_POSITIVE; > I'm not really sure why we need the first patch of this series here? > That patch only seem to undo what you did in patch 1 > > Maxime
Hi, On 1/8/21 10:23 AM, Maxime Ripard wrote: > Hi, > > Thanks for those patches > > On Thu, Jan 07, 2021 at 03:30:32AM +0100, Giulio Benetti wrote: >> From: Giulio Benetti <giulio.benetti@micronovasrl.com> >> >> It turned out(Maxime suggestion) that bit 26 of SUN4I_TCON0_IO_POL_REG is >> dedicated to invert DCLK polarity and this makes thing really easier than >> before. So let's handle DCLK polarity by adding >> SUN4I_TCON0_IO_POL_DCLK_POSITIVE as bit 26 and activating according to >> bus_flags the same way is done for all the other signals. >> >> Cc: Maxime Ripard <maxime@cerno.tech> > > Suggested-by would be nice here :) Ok, didn't know about this tag >> Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com> >> --- >> drivers/gpu/drm/sun4i/sun4i_tcon.c | 20 +------------------- >> drivers/gpu/drm/sun4i/sun4i_tcon.h | 1 + >> 2 files changed, 2 insertions(+), 19 deletions(-) >> >> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c >> index 52598bb0fb0b..30171ccd87e5 100644 >> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c >> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c >> @@ -569,26 +569,8 @@ 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, 0); >> - >> - if (info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE) >> - clk_set_phase(tcon->dclk, 240); >> + val |= SUN4I_TCON0_IO_POL_DCLK_POSITIVE; > > I'm not really sure why we need the first patch of this series here? The idea was to have 2 for testing, 1st one is already applicable, while the other must be tested, but I can send only one with no problem. > That patch only seem to undo what you did in patch 1 No, it doesn't, the 2nd one change the way it achieve the same thing, because the 1st swap DCLK phase, while the 2nd uses the IO_POL bit to set IO polarity according to bus_flags. Best Regards
Hi Marjan, On 1/8/21 10:32 AM, Marjan Pascolo wrote: > Hi, please don't top post, answer in-line as we do, and please use plain-test instead of HTML. These are the standards in Mailing Lists(ML). > Quote " > > I'm not really sure why we need the first patch of this series here? > That patch only seem to undo what you did in patch 1 > > " Already answered to Maxime > > And another question (probably could be a stupid one): > > in "/[PATCH v2 2/2] drm/sun4i: tcon: improve DCLK polarity handling/" I > see you deleted: > > - clk_set_phase(tcon->dclk, 0); > > Is safe to assume that phase register will be always set to 0? We always assumed it is set to 0 by default. > > Or maybe will be safer manually set it to 0 in every condition to avoid > surprises (dirt values due to previous condition)? That would be a good idea, so something like this: ''' int phase = 0; if (info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE) phase = 240; clk_set_phase(tcon->dclk, phase); ''' because now DRM_BUS_FLAG_PIXDATA_SAMPLE_ and DRM_BUS_FLAG_PIXDATA_DRIVE_ are exclusive, while before not. But then if bit 26 solution works everything gets easier. Best Regards Giulio > > Marjan > > Il 08/01/2021 10:23, Maxime Ripard ha scritto: >> Hi, >> >> Thanks for those patches >> >> On Thu, Jan 07, 2021 at 03:30:32AM +0100, Giulio Benetti wrote: >>> From: Giulio Benetti<giulio.benetti@micronovasrl.com> >>> >>> It turned out(Maxime suggestion) that bit 26 of SUN4I_TCON0_IO_POL_REG is >>> dedicated to invert DCLK polarity and this makes thing really easier than >>> before. So let's handle DCLK polarity by adding >>> SUN4I_TCON0_IO_POL_DCLK_POSITIVE as bit 26 and activating according to >>> bus_flags the same way is done for all the other signals. >>> >>> Cc: Maxime Ripard<maxime@cerno.tech> >> Suggested-by would be nice here :) >> >>> Signed-off-by: Giulio Benetti<giulio.benetti@micronovasrl.com> >>> --- >>> drivers/gpu/drm/sun4i/sun4i_tcon.c | 20 +------------------- >>> drivers/gpu/drm/sun4i/sun4i_tcon.h | 1 + >>> 2 files changed, 2 insertions(+), 19 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c >>> index 52598bb0fb0b..30171ccd87e5 100644 >>> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c >>> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c >>> @@ -569,26 +569,8 @@ 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, 0); >>> - >>> - if (info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE) >>> - clk_set_phase(tcon->dclk, 240); >>> + val |= SUN4I_TCON0_IO_POL_DCLK_POSITIVE; >> I'm not really sure why we need the first patch of this series here? >> That patch only seem to undo what you did in patch 1 >> >> Maxime
On Fri, Jan 08, 2021 at 03:34:52PM +0100, Giulio Benetti wrote: > Hi, > > On 1/8/21 10:23 AM, Maxime Ripard wrote: > > Hi, > > > > Thanks for those patches > > > > On Thu, Jan 07, 2021 at 03:30:32AM +0100, Giulio Benetti wrote: > > > From: Giulio Benetti <giulio.benetti@micronovasrl.com> > > > > > > It turned out(Maxime suggestion) that bit 26 of SUN4I_TCON0_IO_POL_REG is > > > dedicated to invert DCLK polarity and this makes thing really easier than > > > before. So let's handle DCLK polarity by adding > > > SUN4I_TCON0_IO_POL_DCLK_POSITIVE as bit 26 and activating according to > > > bus_flags the same way is done for all the other signals. > > > > > > Cc: Maxime Ripard <maxime@cerno.tech> > > > > Suggested-by would be nice here :) > > Ok, didn't know about this tag > > > > Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com> > > > --- > > > drivers/gpu/drm/sun4i/sun4i_tcon.c | 20 +------------------- > > > drivers/gpu/drm/sun4i/sun4i_tcon.h | 1 + > > > 2 files changed, 2 insertions(+), 19 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > index 52598bb0fb0b..30171ccd87e5 100644 > > > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > @@ -569,26 +569,8 @@ 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, 0); > > > - > > > - if (info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE) > > > - clk_set_phase(tcon->dclk, 240); > > > + val |= SUN4I_TCON0_IO_POL_DCLK_POSITIVE; > > > > I'm not really sure why we need the first patch of this series here? > > The idea was to have 2 for testing, 1st one is already applicable, while the > other must be tested, but I can send only one with no problem. > > > That patch only seem to undo what you did in patch 1 > > No, it doesn't, the 2nd one change the way it achieve the same thing, > because the 1st swap DCLK phase, while the 2nd uses the IO_POL bit to set IO > polarity according to bus_flags. It makes sense for testing, but I'm not sure we want to carry it into the history. Can you squash them both into the same patch? Thanks! Maxime
On 1/11/21 6:20 PM, Maxime Ripard wrote: > On Fri, Jan 08, 2021 at 03:34:52PM +0100, Giulio Benetti wrote: >> Hi, >> >> On 1/8/21 10:23 AM, Maxime Ripard wrote: >>> Hi, >>> >>> Thanks for those patches >>> >>> On Thu, Jan 07, 2021 at 03:30:32AM +0100, Giulio Benetti wrote: >>>> From: Giulio Benetti <giulio.benetti@micronovasrl.com> >>>> >>>> It turned out(Maxime suggestion) that bit 26 of SUN4I_TCON0_IO_POL_REG is >>>> dedicated to invert DCLK polarity and this makes thing really easier than >>>> before. So let's handle DCLK polarity by adding >>>> SUN4I_TCON0_IO_POL_DCLK_POSITIVE as bit 26 and activating according to >>>> bus_flags the same way is done for all the other signals. >>>> >>>> Cc: Maxime Ripard <maxime@cerno.tech> >>> >>> Suggested-by would be nice here :) >> >> Ok, didn't know about this tag >> >>>> Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com> >>>> --- >>>> drivers/gpu/drm/sun4i/sun4i_tcon.c | 20 +------------------- >>>> drivers/gpu/drm/sun4i/sun4i_tcon.h | 1 + >>>> 2 files changed, 2 insertions(+), 19 deletions(-) >>>> >>>> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c >>>> index 52598bb0fb0b..30171ccd87e5 100644 >>>> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c >>>> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c >>>> @@ -569,26 +569,8 @@ 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, 0); >>>> - >>>> - if (info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE) >>>> - clk_set_phase(tcon->dclk, 240); >>>> + val |= SUN4I_TCON0_IO_POL_DCLK_POSITIVE; >>> >>> I'm not really sure why we need the first patch of this series here? >> >> The idea was to have 2 for testing, 1st one is already applicable, while the >> other must be tested, but I can send only one with no problem. >> >>> That patch only seem to undo what you did in patch 1 >> >> No, it doesn't, the 2nd one change the way it achieve the same thing, >> because the 1st swap DCLK phase, while the 2nd uses the IO_POL bit to set IO >> polarity according to bus_flags. > > It makes sense for testing, but I'm not sure we want to carry it into > the history. Can you squash them both into the same patch? Sure, I'm going to send V3 then. Thank you Best regards
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index 52598bb0fb0b..30171ccd87e5 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -569,26 +569,8 @@ 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, 0); - - if (info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE) - clk_set_phase(tcon->dclk, 240); + val |= SUN4I_TCON0_IO_POL_DCLK_POSITIVE; regmap_update_bits(tcon->regs, SUN4I_TCON0_IO_POL_REG, SUN4I_TCON0_IO_POL_HSYNC_POSITIVE | diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h b/drivers/gpu/drm/sun4i/sun4i_tcon.h index cfbf4e6c1679..0ce71d10a31b 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_POSITIVE BIT(26) #define SUN4I_TCON0_IO_POL_HSYNC_POSITIVE BIT(25) #define SUN4I_TCON0_IO_POL_VSYNC_POSITIVE BIT(24)