linux-kernel - Re: [PATCH v12 3/4] drm/bridge: anx7625: add MIPI DPI input feature

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CAG3jFysvDa2FS3NS6f2sXAid_TmrXyb9vCADN87v=mJ-txGp0A@mail.gmail.com>
Date:   Mon, 28 Mar 2022 11:54:12 +0200
From:   Robert Foss <robert.foss@...aro.org>
To:     Xin Ji <xji@...logixsemi.com>
Cc:     Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Nícolas F. R. A. Prado 
        <nfraprado@...labora.com>, a.hajda@...sung.com,
        narmstrong@...libre.com, dan.carpenter@...cle.com, jonas@...boo.se,
        jernej.skrabec@...il.com, airlied@...ux.ie, daniel@...ll.ch,
        sam@...nborg.org, pihsun@...omium.org, tzungbi@...gle.com,
        maxime@...no.tech, drinkcat@...gle.com, hsinyi@...omium.org,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        bliang@...logixsemi.com, qwen@...logixsemi.com, robh+dt@...nel.org,
        devicetree@...r.kernel.org, Chen-Yu Tsai <wenst@...omium.org>
Subject: Re: [PATCH v12 3/4] drm/bridge: anx7625: add MIPI DPI input feature

> > > > > > -   DRM_DEV_DEBUG_DRIVER(dev, "found dsi host node.\n");
> > > > > > +   bus_type = V4L2_FWNODE_BUS_TYPE_PARALLEL;
> > > > > > +   mipi_lanes = MAX_LANES_SUPPORT;
> > > > > > +   ep0 = of_graph_get_endpoint_by_regs(np, 0, 0);
> > > > > > +   if (ep0) {
> > > > > > +           if (of_property_read_u32(ep0, "bus-type", &bus_type))
> > > > > > +                   bus_type = 0;
> > > > > > +
> > > > > > +           mipi_lanes = of_property_count_u32_elems(ep0, "data-lanes");
> > > > > > +   }
> > > > > > +
> > > > > > +   if (bus_type == V4L2_FWNODE_BUS_TYPE_PARALLEL) /* bus type is Parallel(DSI) */
> > > > >
> > > > > This is not correct *at all*. V4L2_FWNODE_BUS_TYPE_PARALLEL has nothing
> > > > > to do with DSI. DSI stands for Digital *Serial* Interface. If anything,
> > > > > the V4L2_FWNODE_BUS_TYPE_PARALLEL type would map better to DPI, even if
> > > > > it's not an exact match.
> > > > >
> > > > > This patch has landed in v5.17-rc1, along with the corresponding
> > > > > bindings. As DT bindings are an ABI, we should really fix this before
> > > > > v5.17 is released. There is no DSI bus types defined in DT, and adding
> > > > > one as a fix so late in the v5.17-rc cycle seems a bit of a stretch to
> > > > > me (unless Rob disagrees).
> > > > >
> > > > > It would seem best to revert this series and the corresponding bindings,
> > > > > and retry in v5.18.
> > > >
> > > > There is a DT patch using this property that is already queued up for 5.17
> > > > in the soc tree:
> > > >
> > > > https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F20220214200507.2500693-1-nfraprado%40collabora.com%2F&amp;data=04%7C01%7Cxji%40analogixsemi.com%7C69542695a9cd42cff5a508da00ea7baa%7Cb099b0b4f26c4cf59a0fd5be9acab205%7C0%7C0%7C637823304343387964%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=KbitBhnvGWfpHu6PNLUmrgdqcoZbXaA3hGwq9iAjQfI%3D&amp;reserved=0
> > > >
> > > > merged here:
> > > >
> > > > https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fgit.kernel.org%2Fsoc%2Fsoc%2Fc%2F32568ae37596b529628ac09b875f4874e614f63f&amp;data=04%7C01%7Cxji%40analogixsemi.com%7C69542695a9cd42cff5a508da00ea7baa%7Cb099b0b4f26c4cf59a0fd5be9acab205%7C0%7C0%7C637823304343387964%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=YJAs0IPxR0hrHpGR7K00itcTIF9cnz4L4ta%2B9ACQdSk%3D&amp;reserved=0
> > > >
> > > > We will need to revert that one as well.
> > >
> > > I just submitted a series reverting the dt-binding change + the
> > > related commit to "mt8183: jacuzzi".
> > > Can I get a quick r-b/a-b in order to get this into v5.17.
> > >
> > > https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F20220307154558.2505734-3-robert.foss%40linaro.org%2F&amp;data=04%7C01%7Cxji%40analogixsemi.com%7C69542695a9cd42cff5a508da00ea7baa%7Cb099b0b4f26c4cf59a0fd5be9acab205%7C0%7C0%7C637823304343387964%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=S5ScH2jid3ZRobvO%2Fl2nVgdOvFHNj1nWafTQYG3L9d0%3D&amp;reserved=0
> > >
> >
> > v2 of revert submitted.
> >
> > https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F20220308094911.2680291-1-robert.foss%40linaro.org%2F&amp;data=04%7C01%7Cxji%40analogixsemi.com%7C69542695a9cd42cff5a508da00ea7baa%7Cb099b0b4f26c4cf59a0fd5be9acab205%7C0%7C0%7C637823304343387964%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=D6ulS16g4v4x0u23OtYRrSeitTqllWwDzPiT%2BxMcQQg%3D&amp;reserved=0
> >
> > Xin: Will you spin a series that adds DPI support and re-enables DPI
> > for anx7625? Additionally, "mt8183: jacuzzi" will have to have DPI
> > re-enabled.
> Hi Robert Foss, I'm little confused, do I need resend this serial or
> send a patch based on currently define(V4L2_FWNODE_BUS_TYPE_PARALLEL)?
>
> And use V4L2_FWNODE_BUS_TYPE_PARALLEL for DPI, other value for DSI
> setup?

V4L2_FWNODE_BUS_TYPE_PARALLEL is not meant to be used for DPI, but
rather is used to represtent CPI. So another enum (something along the
lines of V4L2_FWNODE_BUS_TYPE_DPI) needs to be defined, and then this
series needs to use this new enum.

I'd like to see the following:
 - Introduction of V4L2_FWNODE_BUS_TYPE_DPI
 - Reworking this series to use V4L2_FWNODE_BUS_TYPE_DPI
 - Reworking "mt8183: jacuzzi" to use V4L2_FWNODE_BUS_TYPE_DPI

Does that make sense?


Rob.