IMX8MM: assign panel to mipi_dsi in a device tree

[Frieder Schrempf]

On 05.03.23 20:45, Patrick Boettcher wrote:
> [Sie erhalten nicht häufig E-Mails von patrick.boettcher at posteo.de. Weitere Informationen, warum dies wichtig ist, finden Sie unter https://aka.ms/LearnAboutSenderIdentification ]
> 
> On Mon, 6 Mar 2023 00:05:03 +0530
> Jagan Teki <jagan at amarulasolutions.com> wrote:
> 
>> On Sun, Mar 5, 2023 at 11:39 PM Patrick Boettcher
>> <patrick.boettcher at posteo.de> wrote:
>>>
>>> Hi list,
>>>
>>> After several days of trying I realize my too small/old brain is
>>> unable to map around how to assign/connect a panel to the
>>> mipi_dsi-node in a device.
>>>
>>> We are using a 'tdo,tl070wsh30' panel connected to the
>>> mipi-dsi-interface of a imx8mm.
>>>
>>> Of all the references I found on the in public repositories none of
>>> them is using this exact panel. Well.
>>>
>>> Looking at other device trees I came up with the following dts-node
>>> add to the mipi_dsi-node:
>>>
>>> &mipi_dsi {
>>>         #address-cells = <1>;
>>>         #size-cells = <0>;
>>>         status = "okay";
>>>
>>>         port at 0 {
>>>                 reg = <0>;
>>>                 mipi_dsi_panel0_out: endpoint {
>>>                         remote-endpoint = <&panel0_in>;
>>>                         attach-bridge;
>>>                 };
>>>         };
>>>
>>>         panel at 0 {
>>>                 compatible = "tdo,tl070wsh30";
>>>                 reg = <0>;
>>>
>>>                 pinctrl-0 = <&pinctrl_mipi_dsi>;
>>>                 pinctrl-names = "default";
>>>                 reset-gpios = <&gpio4 4 GPIO_ACTIVE_LOW>;
>>>                 enable-gpios = <&gpio4 6 GPIO_ACTIVE_LOW>;
>>>
>>>                 backlight = <&panel_gpio_backlight>;
>>>                 power-supply = <&panel_gpio_regulator>;
>>>
>>>                 dsi-lanes = <4>;
>>>
>>>                 video-mode = <0>;
>>>
>>>                 panel-width-mm = <157>;
>>>                 panel-height-mm = <86>;
>>>
>>>                 status = "okay";
>>>
>>>                 port {
>>>                         panel0_in: endpoint {
>>>                                 remote-endpoint
>>> =<&mipi_dsi_panel0_out>; };
>>>                 };
>>>         };
>>> };
>>>
>>>
>>> You'll see that I used the attach-bridge-option, which is maybe not
>>> necessary. I found this during a debug-print-session in the
>>> drm-bridge-driver, it wasn't attaching a bridge. But maybe I don't
>>> need a bridge as the panel-driver contains everything to control the
>>> controllers of the panel. I don't really know.
>>>
>>> However, with this I have the following messages:
>>>
>>> [    0.393985] [drm:drm_bridge_attach] *ERROR* failed to attach
>>> bridge /soc at 0/bus at 32c00000/mipi_dsi at 32e10000 to encoder DSI-34: -19
>>> [    0.405626] imx_sec_dsim_drv 32e10000.mipi_dsi: Failed to attach
>>> bridge: 32e10000.mipi_dsi [    0.413974] imx_sec_dsim_drv
>>> 32e10000.mipi_dsi: failed to bind sec dsim bridge: -517
>>>
>>> The panel driver is never instantiated.
>>>
>>> I'm using 5.15.51 (-imx). mipi_dsi and the panel-driver are built
>>> into the kernel.
>>
>> Please share the source repo link?
> 
> I'm using this one (via yocto's recipe):
> 
>     github.com/nxp-imx/linux-imx.git, branch lf-5.15.y

This is the NXP vendor kernel which differs a lot from mainline,
especially in the graphics/display area. You probably won't get much
support from this list as most people here (including me) would advise
against using the vendor kernel at all.

> 
>> B/W if you may try the mainline
>> code base of imx8mm dsi please check here.
>> https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fopenedev%2Fkernel%2Fcommits%2Fimx8mm-dsi-v16&data=05%7C01%7Cfrieder.schrempf%40kontron.de%7Cecab86504a844ecbe8fb08db1dc80c14%7C8c9d3c973fd941c8a2b1646f3942daf1%7C0%7C0%7C638136517256300234%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=D2Ri4bUaPvkRCiuYWihOgC8PkGC8BGAVG9qnGhlBhEE%3D&reserved=0
> 
> Do you really think this is a kernel version problem not only an
> integration issue? I mean NXP's version is coming with device-tree's
> using panels, and, although I can't test, I believe they are working,
> aren't they?

Probably they are working and probably you can get your setup working,
too, somehow. But you would need to ask for help in the NXP community or
elsewhere. The other option is to switch to mainline (recommended) and
use Jagan's patches for DSIM support that are about to be upstreamed.