Hi Miquel On Tue, Sep 10, 2024 at 12:13 PM Miquel Raynal <miquel.ray...@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 mich...@amarulasolutions.com __________________________________ Amarula Solutions BV Joop Geesinkweg 125, 1114 AB, Amsterdam, NL T. +31 (0)85 111 9172 i...@amarulasolutions.com www.amarulasolutions.com
