Re: [PATCH v8 0/3] drm: Add support for Cadence MHDP DPI/DP bridge and J721E wrapper.

[Guido Günther]

Hi,
On Thu, Aug 06, 2020 at 01:34:29PM +0200, Swapnil Jakhade wrote:
> This patch series adds new DRM bridge driver for Cadence MHDP DPI/DP
> bridge. The Cadence Display Port IP is also referred as MHDP (Mobile High
> Definition Link, High-Definition Multimedia Interface, Display Port).
> Cadence Display Port complies with VESA DisplayPort (DP) and embedded
> Display Port (eDP) standards.

Is there any relation to the cadence mhdp ip core used inthe imx8mq:

    https://lore.kernel.org/dri-devel/cover.1590982881.git.Sandor.yu@xxxxxxx/

It looks very similar in several places so should that use the same driver?
Cheers,
 -- Guido

> 
> The MHDP bridge driver currently implements Single Stream Transport (SST)
> mode. It also adds Texas Instruments j721e SoC specific wrapper and adds
> the device tree bindings in YAML format.
> 
> Some of the features that will be added later on include (but are not
> limited to):
> - Power Management (PM) support: We will implement the PM functions in
>   next stage once there will be a stable driver in upstream
> - Audio and MST support
> 
> The patch series has three patches in the below sequence:
> 1. 0001-dt-bindings-drm-bridge-Document-Cadence-MHDP-brid.patch
> Documents the bindings in yaml format.
> 2. 0002-drm-bridge-Add-support-for-Cadence-MHDP-DPI-DP-br.patch
> This patch adds new DRM bridge driver for Cadence MHDP Display Port.
> The patch implements support for single stream transport mode.
> 3. 0003-drm-bridge-cdns-mhdp-Add-j721e-wrapper.patch
> Adds Texas Instruments (TI) j721e wrapper for MHDP. The wrapper configures
> MHDP clocks and muxes as required by SoC.
> 
> This patch series is dependent on PHY patch series [1] to add new PHY APIs
> to get/set PHY attributes which is under review and not merged yet.
> 
> [1] https://lkml.org/lkml/2020/7/17/158
> 
> Version History:
> 
> v8:
> 
> In 1/3
> - Fix error reported by dt_binding_check
> - Fix indent in the example
> - Fix other comments given for v7 patches.
> 
> In 2/3:
> - Implement bridge connector operations .get_edid() and .detect().
> - Make connector creation optional based on DRM_BRIDGE_ATTACH_NO_CONNECTOR
>   flag.
> - Fix other comments given for v7 patches.
> 
> In 3/3
> - Fix comments given for v7 patches.
> 
> v7:
> 
> In 1/3
> - No change
> 
> In 2/3
> - Switch to atomic versions of bridge operations
> - Implement atomic_check() handler to perform all validation checks
> - Add struct cdns_mhdp_bridge_state with subclassed bridge state
> - Use PHY API[1] to get PHY attributes instead of reading from PHY DT node
> - Updated HPD handling and link configuration in IRQ handler
> - Add "link_mutex" protecting the access to all the link parameters
> - Add support to check and print FW version information
> - Add separate function to initialize host parameters to simplify probe
> - Use waitqueue instead of manual loop in cdns_mhdp_remove
> - Add forward declarations and header files in cdns-mhdp-core.h file
> - Use bool instead of single bit values in struct cdns_mhdp_device
> - Fix for other minor comments given for v6 patches
> 
> In 3/3
> - Use of_device_is_compatible() to set compatible string specific values
> - Move mhdp_ti_j721e_ops structure to cdns-mhdp-j721e.c
> - Remove duplicate Copyright message
> - Remove CONFIG_DRM_CDNS_MHDP_J721E check
> - Add Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> 
> v6:
> - Added minor fixes in YAML file.
> - Added Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>   to the YAML patch.
> - Removed all the FIXME comments which are invalid in drm driver.
> - Reduced the mailbox timeout from 5s to 2s.
> - Added Reviewed-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
>   to the 003-drm-mhdp-add-j721e-wrapper patch.
> - Added Signed-off all the module authors.
> - Fixed the compiler error Reported-by: kbuild test robot <lkp@xxxxxxxxx>.
> 
> v5:
> - Added Signed-off-by: Jyri Sarha <jsarha@xxxxxx> tag to
>   the code patches.
> 
> v4:
> - Added SPDX dual license tag to YAML bindings.
> - Corrected indentation of the child node properties.
> - Removed the maxItems in the conditional statement.
> - Add Reviewed-by: Rob Herring <robh@xxxxxxxxxx> tag to the
>   Document Cadence MHDP bridge bindings patch.
> - Renamed the DRM driver executable name from mhdp8546 to cdns-mhdp in
>   Makefile.
> - Renamed the DRM driver and header file from cdns-mhdp to cdns-mhdp-core.
> 
> v3:
> - Added if / then clause to validate that the reg length is proper
>   based on the value of the compatible property.
> - Updated phy property description in YAML to a generic one.
> - Renamed num_lanes and max_bit_rate property strings to cdns,num-lanes
>   and cdns,max-bit-rate.
> 
> v2:
> - Use enum in compatible property of YAML file.
> - Add reg-names property to YAML file
> - Add minItems and maxItems to reg property in YAML.
> - Remove cdns_mhdp_link_probe function to remove
>   duplication of reading dpcd capabilities.
> 
> Swapnil Jakhade (2):
>   drm: bridge: Add support for Cadence MHDP DPI/DP bridge
>   drm: bridge: cdns-mhdp: Add j721e wrapper
> 
> Yuti Amonkar (1):
>   dt-bindings: drm/bridge: Document Cadence MHDP bridge bindings
> 
>  .../bindings/display/bridge/cdns,mhdp.yaml    |  139 +
>  drivers/gpu/drm/bridge/Kconfig                |   24 +
>  drivers/gpu/drm/bridge/Makefile               |    4 +
>  drivers/gpu/drm/bridge/cdns-mhdp-core.c       | 2562 +++++++++++++++++
>  drivers/gpu/drm/bridge/cdns-mhdp-core.h       |  397 +++
>  drivers/gpu/drm/bridge/cdns-mhdp-j721e.c      |   72 +
>  drivers/gpu/drm/bridge/cdns-mhdp-j721e.h      |   19 +
>  7 files changed, 3217 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/cdns,mhdp.yaml
>  create mode 100644 drivers/gpu/drm/bridge/cdns-mhdp-core.c
>  create mode 100644 drivers/gpu/drm/bridge/cdns-mhdp-core.h
>  create mode 100644 drivers/gpu/drm/bridge/cdns-mhdp-j721e.c
>  create mode 100644 drivers/gpu/drm/bridge/cdns-mhdp-j721e.h
> 
> -- 
> 2.26.1
> 
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