linux-kernel - RE: [PATCH] drm/bridge: adv7533: Reset DSI receiver logic

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Message-ID:
 <TY3PR01MB11346035EA645C5069C78C5B486252@TY3PR01MB11346.jpnprd01.prod.outlook.com>
Date: Sat, 16 Nov 2024 12:19:53 +0000
From: Biju Das <biju.das.jz@...renesas.com>
To: Stefan Ekenberg <stefan.ekenberg@...s.com>, Dmitry Baryshkov
	<dmitry.baryshkov@...aro.org>
CC: Andrzej Hajda <andrzej.hajda@...el.com>, Neil Armstrong
	<neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, laurent.pinchart
	<laurent.pinchart@...asonboard.com>, Jonas Karlman <jonas@...boo.se>, Jernej
 Skrabec <jernej.skrabec@...il.com>, Maarten Lankhorst
	<maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>, "dri-devel@...ts.freedesktop.org"
	<dri-devel@...ts.freedesktop.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "kernel@...s.com" <kernel@...s.com>
Subject: RE: [PATCH] drm/bridge: adv7533: Reset DSI receiver logic

Hi Stefan Ekenberg <stefan.ekenberg@...s.com>,

> -----Original Message-----
> From: dri-devel <dri-devel-bounces@...ts.freedesktop.org> On Behalf Of Stefan Ekenberg
> Sent: 15 November 2024 09:02
> Subject: Re: [PATCH] drm/bridge: adv7533: Reset DSI receiver logic
> 
> On 11/15/24 09:10, Dmitry Baryshkov wrote:
> > On Wed, Nov 13, 2024 at 08:40:15AM +0100, Stefan Ekenberg wrote:
> >> Reset DSI receiver logic during power on. The need for this change
> >> was discovered when investigating issue with ADV7535. The symptom of
> >> the problem was that ADV7535 continuously outputs a black image. This
> >> happened for about 10% of the times that ADV7535 was powered on. The
> >> rest of the times the image was as expected.
> >>
> >> The solution in this patch (placement of reset and sleep time of
> >> 200ms) is implemented as outlined by the Analog Devices support team.
> >
> > Is this reset sequence specific only to adv7535? Is it applicable to
> > adv7533? adv7511?
> 
> I know that it is not applicable for ADV7511 (that chip doesn't have any MIPI DSI receiver). It might
> be applicable for ADV7533 but unfortunately I don't know. I have only used AD7535 and therefore never
> tested anything on ADV7533.
> 
> >
> >>
> >> Signed-off-by: Stefan Ekenberg <stefan.ekenberg@...s.com>

With and without the patch, display works on Renesas RZ/V2L SMARC board which is connected to ADV7535 device.

Tested-by: Biju Das <biju.das.jz@...renesas.com>

Cheers,
Biju

> >> ---
> >>   drivers/gpu/drm/bridge/adv7511/adv7533.c | 9 +++++++++
> >>   1 file changed, 9 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7533.c b/drivers/gpu/drm/bridge/adv7511/adv7533.c
> >> index 4481489aaf5ebf164313c86cbf3447d2d7914ab9..93085c2b872ed98f4ee394236dc66c568c0e5ccf 100644
> >> --- a/drivers/gpu/drm/bridge/adv7511/adv7533.c
> >> +++ b/drivers/gpu/drm/bridge/adv7511/adv7533.c
> >> @@ -67,6 +67,15 @@ void adv7533_dsi_power_on(struct adv7511 *adv)
> >>   {
> >>   	struct mipi_dsi_device *dsi = adv->dsi;
> >>
> >> +	/*
> >> +	 * Reset DSI receiver block logic to avoid ADV7535 startup problem.
> >> +	 * Without this reset it sometimes continuously fails to receive
> >> +	 * incoming DSI packets and outputs black image.
> >> +	 */
> >> +	regmap_write(adv->regmap_cec, 0x26, 0x18);
> >> +	msleep(200);
> >> +	regmap_write(adv->regmap_cec, 0x26, 0x38);
> >> +
> >>   	if (adv->use_timing_gen)
> >>   		adv7511_dsi_config_timing_gen(adv);
> >>
> >>
> >> ---
> >> base-commit: 59b723cd2adbac2a34fc8e12c74ae26ae45bf230
> >> change-id: 20241108-adv7533-dsi-reset-488c6fbb5e42
> >>
> >> Best regards,
> >> --
> >> Stefan Ekenberg <stefan.ekenberg@...s.com>
> >>
> >