Re: [PATCH v9 0/4] arm64: mediatek: Fix mt8173 mmsys device probing

[CK Hu]

Hi, Enric:

I would like you to modify mmsys binding document. In current document,
mmsys is a clock controller, but I think it's a system controller
including clock control, routing control, and miscellaneous control in
mmsys partition.

Regards,
CK

On Wed, 2020-02-26 at 11:54 +0100, Enric Balletbo i Serra wrote:
> Dear all,
> 
> Those patches are intended to solve an old standing issue on some
> Mediatek devices (mt8173, mt2701 and mt2712).
> 
> Up to now both drivers, clock and drm are probed with the same device tree
> compatible. But only the first driver gets probed, which in effect breaks
> graphics on those devices.
> 
> The MMSYS (Multimedia subsystem) in Mediatek SoCs has some registers to
> control clock gates (which is used in the clk driver) and some registers
> to set the routing and enable the differnet blocks of the display
> and MDP (Media Data Path) subsystem. On this series the clk driver is
> not a pure clock controller but a system controller that can provide
> access to the shared registers between the different drivers that need
> it (mediatek-drm and mediatek-mdp). Hence the MMSYS clk driver was moved
> to drivers/soc/mediatek and is the entry point (parent) which will trigger
> the probe of the corresponding mediatek-drm driver.
> 
> **IMPORTANT** This series only fixes the issue on mt8173 to make it
> simple and as is the only platform I can test. Similar changes should be
> applied for mt2701 and mt2712 to have display working.
> 
> For reference, here are the links to the old discussions:
> * v8: https://patchwork.kernel.org/project/linux-mediatek/list/?series=244891
> * v7: https://patchwork.kernel.org/project/linux-mediatek/list/?series=241217
> * v6: https://patchwork.kernel.org/project/linux-mediatek/list/?series=213219
> * v5: https://patchwork.kernel.org/project/linux-mediatek/list/?series=44063
> * v4:
>   * https://patchwork.kernel.org/patch/10530871/
>   * https://patchwork.kernel.org/patch/10530883/
>   * https://patchwork.kernel.org/patch/10530885/
>   * https://patchwork.kernel.org/patch/10530911/
>   * https://patchwork.kernel.org/patch/10530913/
> * v3:
>   * https://patchwork.kernel.org/patch/10367857/
>   * https://patchwork.kernel.org/patch/10367861/
>   * https://patchwork.kernel.org/patch/10367877/
>   * https://patchwork.kernel.org/patch/10367875/
>   * https://patchwork.kernel.org/patch/10367885/
>   * https://patchwork.kernel.org/patch/10367883/
>   * https://patchwork.kernel.org/patch/10367889/
>   * https://patchwork.kernel.org/patch/10367907/
>   * https://patchwork.kernel.org/patch/10367909/
>   * https://patchwork.kernel.org/patch/10367905/
> * v2: No relevant discussion, see v3
> * v1:
>   * https://patchwork.kernel.org/patch/10016497/
>   * https://patchwork.kernel.org/patch/10016499/
>   * https://patchwork.kernel.org/patch/10016505/
>   * https://patchwork.kernel.org/patch/10016507/
> 
> Best regards,
>  Enric
> 
> Changes in v9:
> - Move mmsys to drivers/soc/mediatek (CK)
> - Do not move the display routing from the drm driver (CK)
> - Removed from this series because are not needed:
>   * [PATCH v8 5/6] drm/mediatek: Move MMSYS configuration to include/linux/platform_data
> - Removed from this series because are applied:
>   * [PATCH v8 3/6] media: mtk-mdp: Check return value of of_clk_get.
> 
> Changes in v8:
> - Select REGMAP and MFD_SYSCON (Randy Dunlap)
> - Be a builtin_platform_driver like other mediatek mmsys drivers.
> - New patch introduced in this series.
> 
> Changes in v7:
> - Add R-by from CK
> - Free clk_data->clks as well
> - Get rid of private data structure
> 
> Enric Balletbo i Serra (1):
>   drm/mediatek: Fix mediatek-drm device probing
> 
> Matthias Brugger (3):
>   drm/mediatek: Use regmap for register access
>   drm/mediatek: Omit warning on probe defers
>   soc: mediatek: Move mt8173 MMSYS to platform driver
> 
>  drivers/clk/mediatek/clk-mt8173.c         | 104 ----------------
>  drivers/gpu/drm/mediatek/Kconfig          |   2 +
>  drivers/gpu/drm/mediatek/mtk_disp_color.c |   5 +-
>  drivers/gpu/drm/mediatek/mtk_disp_ovl.c   |   5 +-
>  drivers/gpu/drm/mediatek/mtk_disp_rdma.c  |   5 +-
>  drivers/gpu/drm/mediatek/mtk_dpi.c        |  12 +-
>  drivers/gpu/drm/mediatek/mtk_drm_crtc.c   |   4 +-
>  drivers/gpu/drm/mediatek/mtk_drm_ddp.c    |  53 ++++----
>  drivers/gpu/drm/mediatek/mtk_drm_ddp.h    |   4 +-
>  drivers/gpu/drm/mediatek/mtk_drm_drv.c    |  45 ++++---
>  drivers/gpu/drm/mediatek/mtk_drm_drv.h    |   2 +-
>  drivers/gpu/drm/mediatek/mtk_dsi.c        |   8 +-
>  drivers/gpu/drm/mediatek/mtk_hdmi.c       |   4 +-
>  drivers/soc/mediatek/Kconfig              |   7 ++
>  drivers/soc/mediatek/Makefile             |   1 +
>  drivers/soc/mediatek/mt8173-mmsys.c       | 143 ++++++++++++++++++++++
>  16 files changed, 233 insertions(+), 171 deletions(-)
>  create mode 100644 drivers/soc/mediatek/mt8173-mmsys.c
>