Re: [PATCH v1 1/2] drm/panel: simple: add Multi-Innotechnology MI1010AIT-1CP1

From: Oleksij Rempel <o.rempel@pengutronix.de>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: "Thierry Reding" <thierry.reding@gmail.com>,
	"David Airlie" <airlied@linux.ie>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Pengutronix Kernel Team" <kernel@pengutronix.de>,
	"Ulrich Ölmann" <u.oelmann@pengutronix.de>,
	"Sam Ravnborg" <sam@ravnborg.org>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v1 1/2] drm/panel: simple: add Multi-Innotechnology MI1010AIT-1CP1
Date: Thu, 5 Aug 2021 12:08:14 +0200	[thread overview]
Message-ID: <20210805100814.zdulbeqbrbq2omks@pengutronix.de> (raw)
In-Reply-To: <1462f001-a01f-9634-744c-8981f72663f6@pengutronix.de>

On Thu, Aug 05, 2021 at 07:52:24AM +0200, Ahmad Fatoum wrote:
> Hello Oleksij,
> 
> On 05.08.21 06:37, Oleksij Rempel wrote:
> > From: Sam Ravnborg <sam@ravnborg.org>
> > 
> > The Multi Innotechnology is a 10.1" 1280x800 panel.
> > 
> > The datasheet did not specify specific values for sync, back, front porch.
> > The values are a best guess based on values for similar panels.
> > 
> > Co-Developed-by: Sam Ravnborg <sam@ravnborg.org>
> > Co-Developed-by: Ulrich Ölmann <u.oelmann@pengutronix.de>
> > Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> > Signed-off-by: Ulrich Ölmann <u.oelmann@pengutronix.de>
> > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> > ---
> >  drivers/gpu/drm/panel/panel-simple.c | 34 ++++++++++++++++++++++++++++
> >  1 file changed, 34 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
> > index 21939d4352cf..fda79a986d12 100644
> > --- a/drivers/gpu/drm/panel/panel-simple.c
> > +++ b/drivers/gpu/drm/panel/panel-simple.c
> > @@ -3033,6 +3033,37 @@ static const struct panel_desc mitsubishi_aa070mc01 = {
> >  	.bus_flags = DRM_BUS_FLAG_DE_HIGH,
> >  };
> >  
> > +static const struct display_timing multi_inno_mi1010ait_1cp_timing = {
> > +	.pixelclock = { 68900000, 70000000, 73400000 },
> > +	.hactive = { 1280, 1280, 1280 },
> > +	.hfront_porch = { 30, 60, 71 },
> > +	.hback_porch = { 30, 60, 71 },
> > +	.hsync_len = { 10, 10, 48 },
> > +	.vactive = { 800, 800, 800 },
> > +	.vfront_porch = { 5, 10, 10 },
> > +	.vback_porch = { 5, 10, 10 },
> > +	.vsync_len = { 5, 6, 13 },
> > +	.flags = DISPLAY_FLAGS_HSYNC_LOW | DISPLAY_FLAGS_VSYNC_LOW |
> > +		 DISPLAY_FLAGS_DE_HIGH,
> > +};
> 
> Here you specify DISPLAY_FLAGS_DE_HIGH.
> 
> > +
> > +static const struct panel_desc multi_inno_mi1010ait_1cp = {
> > +	.timings = &multi_inno_mi1010ait_1cp_timing,
> > +	.num_timings = 1,
> > +	.bpc = 8,
> > +	.size = {
> > +		.width = 217,
> > +		.height = 136,
> > +	},
> > +	.delay = {
> > +		.enable = 50,
> > +		.disable = 50,
> > +	},
> > +	.bus_format = MEDIA_BUS_FMT_RGB888_1X7X4_SPWG,
> > +	.bus_flags = DRM_BUS_FLAG_DE_HIGH,
> 
> And here DRM_BUS_FLAG_DE_HIGH. I see that some other panels do this too
> and some only specify one of them. Do you know if they are redundant
> or one of them is ignored?

Hmm... there is a drm_bus_flags_from_videomode():
        if (vm->flags & DISPLAY_FLAGS_DE_HIGH)
                *bus_flags |= DRM_BUS_FLAG_DE_HIGH;

It looks like for DPI panel it would be set automatically. This
function is not execute in case of LVDS panel.

Regards,
Oleksij
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