Message ID | 20180927114850.24565-1-jagan@amarulasolutions.com (mailing list archive) |
---|---|
Headers | show |
Series | drm/sun4i: Allwinner A64 MIPI-DSI support | expand |
On Thu, Sep 27, 2018 at 10:28 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote: > > On Thu, Sep 27, 2018 at 05:18:45PM +0530, Jagan Teki wrote: > > TCON DRQ set bits for non-burst DSI mode can computed via > > horizontal front porch instead of front porch + sync timings. > > > > Since there no documentation for TCON_DRQ_REG(0x7c) register > > this change is taken as reference from BPI-M64-bsp. > > Detailing more what the issue is would be great. > > > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> > > --- > > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > index 599284971ab6..9918fdb990ff 100644 > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > @@ -367,9 +367,9 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi, > > struct mipi_dsi_device *device = dsi->device; > > u32 val = 0; > > The computation here is in the A64 driver: > > if ((panel->lcd_ht - panel->lcd_x - panel->lcd_hbp) < 21) { > dsi_dev[sel]->dsi_tcon_drq.bits.drq_mode = 0; > } else { > dsi_dev[sel]->dsi_tcon_drq.bits.drq_set = > (panel->lcd_ht-panel->lcd_x-panel->lcd_hbp-20) * > dsi_pixel_bits[panel->lcd_dsi_format]/(8*4); > } > > It is testing that the sync + front porch is smaller than 21, and > otherwise sets the drq. > > > - if ((mode->hsync_end - mode->hdisplay) > 20) { > > My code here is testing that the difference between hsync_end and > hdisplay is superior to 20, and sets the DRQ if true. The condition is > reversed, but otherwise, that difference is the front porch plus the > sync length. True, I understand this, but does drq setting here is specific to SoC? I thought of finding DRQ in A31 BSP but I couldn't find the code. do you have bsp somewhere in github? > > > + if ((mode->hsync_start - mode->hdisplay) > 20) { > > However, you are testing for just the front porch, unlike what your > commit log is saying, and unlike what allwinner's code is saying. So > this deserves some explanation. but A64 is doing this, do you think it's completely A64 specific or testing panel with front porch drq?
On Thu, Sep 27, 2018 at 11:15:50PM +0530, Jagan Teki wrote: > On Thu, Sep 27, 2018 at 10:28 PM Maxime Ripard > <maxime.ripard@bootlin.com> wrote: > > > > On Thu, Sep 27, 2018 at 05:18:45PM +0530, Jagan Teki wrote: > > > TCON DRQ set bits for non-burst DSI mode can computed via > > > horizontal front porch instead of front porch + sync timings. > > > > > > Since there no documentation for TCON_DRQ_REG(0x7c) register > > > this change is taken as reference from BPI-M64-bsp. > > > > Detailing more what the issue is would be great. > > > > > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> > > > --- > > > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > index 599284971ab6..9918fdb990ff 100644 > > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > @@ -367,9 +367,9 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi, > > > struct mipi_dsi_device *device = dsi->device; > > > u32 val = 0; > > > > The computation here is in the A64 driver: > > > > if ((panel->lcd_ht - panel->lcd_x - panel->lcd_hbp) < 21) { > > dsi_dev[sel]->dsi_tcon_drq.bits.drq_mode = 0; > > } else { > > dsi_dev[sel]->dsi_tcon_drq.bits.drq_set = > > (panel->lcd_ht-panel->lcd_x-panel->lcd_hbp-20) * > > dsi_pixel_bits[panel->lcd_dsi_format]/(8*4); > > } > > > > It is testing that the sync + front porch is smaller than 21, and > > otherwise sets the drq. > > > > > - if ((mode->hsync_end - mode->hdisplay) > 20) { > > > > My code here is testing that the difference between hsync_end and > > hdisplay is superior to 20, and sets the DRQ if true. The condition is > > reversed, but otherwise, that difference is the front porch plus the > > sync length. > > True, I understand this, but does drq setting here is specific to SoC? > I thought of finding DRQ in A31 BSP but I couldn't find the code. do > you have bsp somewhere in github? > > > > > > + if ((mode->hsync_start - mode->hdisplay) > 20) { > > > > However, you are testing for just the front porch, unlike what your > > commit log is saying, and unlike what allwinner's code is saying. So > > this deserves some explanation. > > but A64 is doing this, do you think it's completely A64 specific or > testing panel with front porch drq? See the above code excerpt: panel->lcd_ht - panel->lcd_x - panel->lcd_hbp This is hsync + front porch. Not the sole front porch. So no, it's not doing this. Maxime
On Tuesday 02 October 2018 06:50 PM, Maxime Ripard wrote: > On Thu, Sep 27, 2018 at 11:15:50PM +0530, Jagan Teki wrote: >> On Thu, Sep 27, 2018 at 10:28 PM Maxime Ripard >> <maxime.ripard@bootlin.com> wrote: >>> >>> On Thu, Sep 27, 2018 at 05:18:45PM +0530, Jagan Teki wrote: >>>> TCON DRQ set bits for non-burst DSI mode can computed via >>>> horizontal front porch instead of front porch + sync timings. >>>> >>>> Since there no documentation for TCON_DRQ_REG(0x7c) register >>>> this change is taken as reference from BPI-M64-bsp. >>> >>> Detailing more what the issue is would be great. >>> >>>> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> >>>> --- >>>> drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c >>>> index 599284971ab6..9918fdb990ff 100644 >>>> --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c >>>> +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c >>>> @@ -367,9 +367,9 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi, >>>> struct mipi_dsi_device *device = dsi->device; >>>> u32 val = 0; >>> >>> The computation here is in the A64 driver: >>> >>> if ((panel->lcd_ht - panel->lcd_x - panel->lcd_hbp) < 21) { >>> dsi_dev[sel]->dsi_tcon_drq.bits.drq_mode = 0; >>> } else { >>> dsi_dev[sel]->dsi_tcon_drq.bits.drq_set = >>> (panel->lcd_ht-panel->lcd_x-panel->lcd_hbp-20) * >>> dsi_pixel_bits[panel->lcd_dsi_format]/(8*4); >>> } >>> >>> It is testing that the sync + front porch is smaller than 21, and >>> otherwise sets the drq. >>> >>>> - if ((mode->hsync_end - mode->hdisplay) > 20) { >>> >>> My code here is testing that the difference between hsync_end and >>> hdisplay is superior to 20, and sets the DRQ if true. The condition is >>> reversed, but otherwise, that difference is the front porch plus the >>> sync length. >> >> True, I understand this, but does drq setting here is specific to SoC? >> I thought of finding DRQ in A31 BSP but I couldn't find the code. do >> you have bsp somewhere in github? >> >>> >>>> + if ((mode->hsync_start - mode->hdisplay) > 20) { >>> >>> However, you are testing for just the front porch, unlike what your >>> commit log is saying, and unlike what allwinner's code is saying. So >>> this deserves some explanation. >> >> but A64 is doing this, do you think it's completely A64 specific or >> testing panel with front porch drq? > > See the above code excerpt: > panel->lcd_ht - panel->lcd_x - panel->lcd_hbp > > This is hsync + front porch. Not the sole front porch. So no, it's not > doing this. => panel->lcd_ht - panel->lcd_x - panel->lcd_hbp from drivers/video/sunxi/disp2/disp/de/disp_lcd.c timmings->hor_front_porch= panel_info->lcd_ht-panel_info->lcd_hbp - panel_info->lcd_x; => (timmings->hor_front_porch + panel->lcd_hbp + panel->lcd_x) - panel->lcd_x - panel->hbp => timmings->hor_front_porch => mode->hsync_start - mode->hdisplay This is simply a front porch.
On Wed, Oct 03, 2018 at 08:52:06AM +0530, Jagan Teki wrote: > On Tuesday 02 October 2018 06:50 PM, Maxime Ripard wrote: > > On Thu, Sep 27, 2018 at 11:15:50PM +0530, Jagan Teki wrote: > > > On Thu, Sep 27, 2018 at 10:28 PM Maxime Ripard > > > <maxime.ripard@bootlin.com> wrote: > > > > > > > > On Thu, Sep 27, 2018 at 05:18:45PM +0530, Jagan Teki wrote: > > > > > TCON DRQ set bits for non-burst DSI mode can computed via > > > > > horizontal front porch instead of front porch + sync timings. > > > > > > > > > > Since there no documentation for TCON_DRQ_REG(0x7c) register > > > > > this change is taken as reference from BPI-M64-bsp. > > > > > > > > Detailing more what the issue is would be great. > > > > > > > > > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> > > > > > --- > > > > > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++-- > > > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > > > index 599284971ab6..9918fdb990ff 100644 > > > > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > > > @@ -367,9 +367,9 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi, > > > > > struct mipi_dsi_device *device = dsi->device; > > > > > u32 val = 0; > > > > > > > > The computation here is in the A64 driver: > > > > > > > > if ((panel->lcd_ht - panel->lcd_x - panel->lcd_hbp) < 21) { > > > > dsi_dev[sel]->dsi_tcon_drq.bits.drq_mode = 0; > > > > } else { > > > > dsi_dev[sel]->dsi_tcon_drq.bits.drq_set = > > > > (panel->lcd_ht-panel->lcd_x-panel->lcd_hbp-20) * > > > > dsi_pixel_bits[panel->lcd_dsi_format]/(8*4); > > > > } > > > > > > > > It is testing that the sync + front porch is smaller than 21, and > > > > otherwise sets the drq. > > > > > > > > > - if ((mode->hsync_end - mode->hdisplay) > 20) { > > > > > > > > My code here is testing that the difference between hsync_end and > > > > hdisplay is superior to 20, and sets the DRQ if true. The condition is > > > > reversed, but otherwise, that difference is the front porch plus the > > > > sync length. > > > > > > True, I understand this, but does drq setting here is specific to SoC? > > > I thought of finding DRQ in A31 BSP but I couldn't find the code. do > > > you have bsp somewhere in github? > > > > > > > > > > > > + if ((mode->hsync_start - mode->hdisplay) > 20) { > > > > > > > > However, you are testing for just the front porch, unlike what your > > > > commit log is saying, and unlike what allwinner's code is saying. So > > > > this deserves some explanation. > > > > > > but A64 is doing this, do you think it's completely A64 specific or > > > testing panel with front porch drq? > > > > See the above code excerpt: > > panel->lcd_ht - panel->lcd_x - panel->lcd_hbp > > > > This is hsync + front porch. Not the sole front porch. So no, it's not > > doing this. > > => panel->lcd_ht - panel->lcd_x - panel->lcd_hbp > > from drivers/video/sunxi/disp2/disp/de/disp_lcd.c > timmings->hor_front_porch= panel_info->lcd_ht-panel_info->lcd_hbp - > panel_info->lcd_x; > > => (timmings->hor_front_porch + panel->lcd_hbp + panel->lcd_x) - > panel->lcd_x - panel->hbp > => timmings->hor_front_porch > => mode->hsync_start - mode->hdisplay > > This is simply a front porch. And this should be in your commit log as well. Maxime