[Intel-gfx] [PATCH v2 00/59] Add support for KeemBay DRM driver

Wed Jul 15 15:05:49 UTC 2020

Hi Anitha

On Tue, Jul 14, 2020 at 01:56:46PM -0700, Anitha Chrisanthus wrote:
> This is a new DRM driver for Intel's KeemBay SOC.
> The SoC couples an ARM Cortex A53 CPU with an Intel
> Movidius VPU.
> 
> This driver is tested with the KMB EVM board which is the refernce baord
> for Keem Bay SOC. The SOC's display pipeline is as follows
> 
> +--------------+    +---------+    +-----------------------+
> |LCD controller| -> |Mipi DSI | -> |Mipi to HDMI Converter |
> +--------------+    +---------+    +-----------------------+
> 
> LCD controller and Mipi DSI transmitter are part of the SOC and
> mipi to HDMI converter is ADV7535 for KMB EVM board.
> 
> The DRM driver is a basic KMS atomic modesetting display driver and
> has no 2D or 3D graphics.It calls into the ADV bridge driver at
> the connector level.
> 
> Only 1080p resolution and single plane is supported at this time.
> The usecase is for debugging video and camera outputs.
> 
> Device tree patches are under review here
> https://lore.kernel.org/linux-arm-kernel/20200708175020.194436-1-daniele.alessandrelli@linux.intel.com/T/

Cool, new driver, thanks a lot for submitting.

> Changes since v1:
> - Removed redundant license text, updated license
> - Rearranged include blocks
> - renamed global vars and removed extern in c
> - Used upclassing for dev_private
> - Used drm_dev_init in drm device create (will be updated to use
>   devm_drm_dev_alloc() in a separate patch later as kmb driver is currently
>   developed on 5.4 kernel)

drm moves fairly quickly, please develop the upstream submission on top of
linux-next or similar. We constantly add new helpers to simplify drivers,
and we expect new driver submissions to be up to date with all that.

Another thing: From your description it sounds like it's a very simple
driver, just a single plane/crtc, nothing fancy, plus adv bridge output.
Is the driver already using simple display pipeline helpers? I think that
would be an ideal fit and probably greatly simplifies the code.

> - minor cleanups

The patch series looks like it contains the entire development history, or
at least large chunks of it. That's useful for you, but for upstreaming
the main focues (especially for smaller drivers) is whether your driver
uses all the available helpers and integrations correctly. And for that
it's much easier if the history is cleaned up, and all intermediate steps
removed.

I think once that's done I can do a quick pass and drop suggestions for
cleanup and stuff like that, and then we should (usually at least) be able
to pull in the driver fairly quickly.

Another thing to consider is where/how this driver will be maintained.
Preferred option is as part of drm-misc so that we have redudancy and all
that in a fairly big group. Works with commit rights, so maybe check out
some of our docs about that too.

https://drm.pages.freedesktop.org/maintainer-tools/drm-misc.html

The committer model comes with a full set of scripts and docs to avoid
oopsies in maintainership. Generally works really well.

Cheers, Daniel

> 
> Anitha Chrisanthus (52):
>   drm/kmb: Add support for KeemBay Display
>   drm/kmb: Added id to kmb_plane
>   drm/kmb: Set correct values in the LAYERn_CFG register
>   drm/kmb: Use biwise operators for register definitions
>   drm/kmb: Updated kmb_plane_atomic_check
>   drm/kmb: Initial check-in for Mipi DSI
>   drm/kmb: Set OUT_FORMAT_CFG register
>   drm/kmb: Added mipi_dsi_host initialization
>   drm/kmb: Part 1 of Mipi Tx Initialization
>   drm/kmb: Part 2 of Mipi Tx Initialization
>   drm/kmb: Use correct mmio offset from data book
>   drm/kmb: Part3 of Mipi Tx initialization
>   drm/kmb: Part4 of Mipi Tx Initialization
>   drm/kmb: Correct address offsets for mipi registers
>   drm/kmb: Part5 of Mipi Tx Intitialization
>   drm/kmb: Part6 of Mipi Tx Initialization
>   drm/kmb: Part7 of Mipi Tx Initialization
>   drm/kmb: Part8 of Mipi Tx Initialization
>   drm/kmb: Added ioremap/iounmap for register access
>   drm/kmb: Register IRQ for LCD
>   drm/kmb: IRQ handlers for LCD and mipi dsi
>   drm/kmb: Set hardcoded values to LCD_VSYNC_START
>   drm/kmb: Additional register programming to update_plane
>   drm/kmb: Add ADV7535 bridge
>   drm/kmb: Display clock enable/disable
>   drm/kmb: rebase to newer kernel version
>   drm/kmb: minor name change to match device tree
>   drm/kmb: Changed MMIO size
>   drm/kmb: Defer Probe
>   drm/kmb: call bridge init in the very beginning
>   drm/kmb: Enable MSS_CAM_CLK_CTRL for LCD and MIPI
>   drm/kmb: Set MSS_CAM_RSTN_CTRL along with enable
>   drm/kmb: Mipi DPHY initialization changes
>   drm/kmb: Fixed driver unload
>   drm/kmb: Added LCD_TEST config
>   drm/kmb: Changes for LCD to Mipi
>   drm/kmb: Update LCD programming to match MIPI
>   drm/kmb: Changed name of driver to kmb-drm
>   drm/kmb: Mipi settings from input timings
>   drm/kmb: Enable LCD interrupts
>   drm/kmb: Enable LCD interrupts during modeset
>   drm/kmb: Don’t inadvertantly disable LCD controller
>   drm/kmb: SWAP R and B LCD Layer order
>   drm/kmb: Disable ping pong mode
>   drm/kmb: Do the layer initializations only once
>   drm/kmb: disable the LCD layer in EOF irq handler
>   drm/kmb: Initialize uninitialized variables
>   drm/kmb: Added useful messages in LCD ISR
>   kmb/drm: Prune unsupported modes
>   drm/kmb: workaround for dma undeflow issue
>   drm/kmb: Get System Clock from SCMI
>   drm/kmb: work around for planar formats
> 
> Edmund Dea (7):
>   drm/kmb: Cleanup probe functions
>   drm/kmb: Revert dsi_host back to a static variable
>   drm/kmb: Initialize clocks for clk_msscam, clk_mipi_ecfg, &
>     clk_mipi_cfg.
>   drm/kmb: Remove declaration of irq_lcd/irq_mipi
>   drm/kmb: Enable MIPI TX HS Test Pattern Generation
>   drm/kmb: Write to LCD_LAYERn_CFG only once
>   drm/kmb: Cleaned up code
> 
>  drivers/gpu/drm/Kconfig         |    2 +
>  drivers/gpu/drm/Makefile        |    1 +
>  drivers/gpu/drm/kmb/Kconfig     |   12 +
>  drivers/gpu/drm/kmb/Makefile    |    2 +
>  drivers/gpu/drm/kmb/kmb_crtc.c  |  226 +++++
>  drivers/gpu/drm/kmb/kmb_crtc.h  |   41 +
>  drivers/gpu/drm/kmb/kmb_drv.c   |  809 ++++++++++++++++
>  drivers/gpu/drm/kmb/kmb_drv.h   |  176 ++++
>  drivers/gpu/drm/kmb/kmb_dsi.c   | 1927 +++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/kmb/kmb_dsi.h   |  370 ++++++++
>  drivers/gpu/drm/kmb/kmb_plane.c |  518 +++++++++++
>  drivers/gpu/drm/kmb/kmb_plane.h |  124 +++
>  drivers/gpu/drm/kmb/kmb_regs.h  |  738 +++++++++++++++
>  13 files changed, 4946 insertions(+)
>  create mode 100644 drivers/gpu/drm/kmb/Kconfig
>  create mode 100644 drivers/gpu/drm/kmb/Makefile
>  create mode 100644 drivers/gpu/drm/kmb/kmb_crtc.c
>  create mode 100644 drivers/gpu/drm/kmb/kmb_crtc.h
>  create mode 100644 drivers/gpu/drm/kmb/kmb_drv.c
>  create mode 100644 drivers/gpu/drm/kmb/kmb_drv.h
>  create mode 100644 drivers/gpu/drm/kmb/kmb_dsi.c
>  create mode 100644 drivers/gpu/drm/kmb/kmb_dsi.h
>  create mode 100644 drivers/gpu/drm/kmb/kmb_plane.c
>  create mode 100644 drivers/gpu/drm/kmb/kmb_plane.h
>  create mode 100644 drivers/gpu/drm/kmb/kmb_regs.h
> 
> -- 
> 2.7.4
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch