[PATCH 0/8] Add imx8mp video support

[Michael Nazzareno Trimarchi]

Hi Miquel

On Tue, Sep 10, 2024 at 12:13 PM Miquel Raynal
<miquel.raynal at bootlin.com> wrote:
>
> In order to display a boot picture or an error message, the i.MX8MP
> display pipeline must be enabled. The SoC has support for various
> interfaces (LVDS, HDMI, DSI). The one supported in this series is the
> standard 4-lane LVDS output. The minimal setup is thus composed of:
> * An LCD InterFace (LCDIF) with an AXI/APB interface, generating a pixel
>   stream
> * One LVDS Display Bridge (LDB), also named pixel mapper, which receives
>   the pixel stream and route it to one or two (possibly combined) LVDS
>   displays.
> * All necessary clocks and power controls coming from the MEDIAMIX
>   control block.
>
> Patch 1 adds a very useful helper to the core in order to grab devices
> through endpoints instead of being limited to phandles. Video pipelines
> being often described using graphs endpoints, the introduced helper is
> used several times in the serires (there are 3 LCDIF, one of them being
> connected to the LDB, itself having 2 ports).
>
> Patch 2 is a fix which is necessary for this series to work properly,
> but is way broader than just this use case. In practice, when assigned
> clocks are defined in the device tree, the clock uclass tries to assign
> the parents first and then sets them to the correct frequency. This only
> works if the parents have been enabled themselves. Otherwise we end-up
> with a non-clocked parent. I believe this is not the intended behavior
> in general, but more importantly on the i.MX8MP, there are "clock
> slices" which have pre-requisites in order to be modified and selecting
> an ungated parent is one of them.
>
> All the other patches progressively build support for the whole video
> pipeline. Regarding the LCDIF driver, there is already a similar driver
> for older i.MX SoCs but I didn't manage to get it to work. It was
> written more than a decade ago while device-model, clocks and others
> were not yet generically supported. Thus, numerous ad-hoc solutions
> were implemented, which no longer fit today's requirements. I preferred
> to add a new "clean" driver instead of modifying the existing one
> because of the too high risk of breaking these platforms. Once proper
> clocks/power-domain descriptions will be added to them they might be
> converted (and tested) to work with the "new" implementation, but going
> the opposite way felt drawback.
>

Thank you for adding those patches. We are working on mipi support
here and some of the clock patches
are there too. I will try to look and rebase our patchset

https://patchwork.amarulasolutions.com/patch/3401/

Michael


> Thanks,
> Miquèl
>
> Miquel Raynal (8):
>   dm: core: Add a helper to retrieve devices through graph endpoints
>   clk: Ensure the parent clocks are enabled while reparenting
>   clk: imx8mp: Add media related clocks
>   imx: power-domain: Describe the i.MX8 MEDIAMIX domain
>   imx: power-domain: Add support for the MEDIAMIX control block
>   video: imx: Fix Makefile in order to be able to add other imx drivers
>   video: imx: Add LDB driver
>   video: imx: Add LCDIF driver
>
>  drivers/clk/clk-uclass.c                  |   4 +
>  drivers/clk/imx/clk-imx8mp.c              |  35 +++
>  drivers/core/uclass.c                     |  62 +++++
>  drivers/power/domain/Kconfig              |   7 +
>  drivers/power/domain/Makefile             |   1 +
>  drivers/power/domain/imx8m-power-domain.c |  17 ++
>  drivers/power/domain/imx8mp-mediamix.c    | 185 +++++++++++++
>  drivers/video/Makefile                    |   2 +-
>  drivers/video/imx/Kconfig                 |   7 +
>  drivers/video/imx/Makefile                |   4 +-
>  drivers/video/imx/lcdif.c                 | 315 ++++++++++++++++++++++
>  drivers/video/imx/ldb.c                   | 251 +++++++++++++++++
>  include/dm/uclass.h                       |  21 ++
>  13 files changed, 909 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/power/domain/imx8mp-mediamix.c
>  create mode 100644 drivers/video/imx/lcdif.c
>  create mode 100644 drivers/video/imx/ldb.c
>
> --
> 2.43.0
>


-- 
Michael Nazzareno Trimarchi
Co-Founder & Chief Executive Officer
M. +39 347 913 2170
michael at amarulasolutions.com
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