Re: [PATCH v5 0/9] phy: Add configuration interface for MIPI D-PHY devices

Kishon Vijay Abraham I
2019-02-04T10:05:25Z

On 21/01/19 9:15 PM, Maxime Ripard wrote:
> Hi,
>
> Here is a set of patches to allow the phy framework consumers to test and
> apply runtime configurations.
>
> This is needed to support more phy classes that require tuning based on
> parameters depending on the current use case of the device, in addition to
> the power state management already provided by the current functions.
>
> A first test bed for that API are the MIPI D-PHY devices. There's a number
> of solutions that have been used so far to support these phy, most of the
> time being an ad-hoc driver in the consumer.
>
> That approach has a big shortcoming though, which is that this is quite
> difficult to deal with consumers integrated with multiple variants of phy,
> of multiple consumers integrated with the same phy.
>
> The latter case can be found in the Cadence DSI bridge, and the CSI
> transceiver and receivers. All of them are integrated with the same phy, or
> can be integrated with different phy, depending on the implementation.
>
> I've looked at all the MIPI DSI drivers I could find, and gathered all the
> parameters I could find. The interface should be complete, and most of the
> drivers can be converted in the future. The current set converts two of
> them: the above mentionned Cadence DSI driver so that the v4l2 drivers can
> use them, and the Allwinner MIPI-DSI driver.

Can the PHY changes go independently of the consumer drivers? or else I'll need
ACKs from the GPU MAINTAINER.

Thanks
Kishon

>
> Let me know what you think,
> Maxime
>
> Changes from v4:
> - Removed regression on the variable calculation
> - Fixed the wakeup unit
> - Collected Sean Acked-by on the last patch
> - Collected Sakari Reviewed-by on the first patch
>
> Changes from v3
> - Rebased on 5.0-rc1
> - Added the fixes suggested by Sakari
>
> Changes from v2:
> - Rebased on next
> - Changed the interface to accomodate for the new submodes
> - Changed the timings units from nanoseconds to picoseconds
> - Added minimum and maximum boundaries to the documentation
> - Moved the clock enabling to phy_power_on in the Cadence DPHY driver
> - Exported the phy_configure and phy_validate symbols
> - Rework the phy pll divider computation in the cadence dphy driver
>
> Changes from v1:
> - Rebased on top of 4.20-rc1
> - Removed the bus mode and timings parameters from the MIPI D-PHY
> parameters, since that shouldn't have any impact on the PHY itself.
> - Reworked the Cadence DSI and D-PHY drivers to take this into account.
> - Remove the mode parameter from phy_configure
> - Added phy_configure and phy_validate stubs
> - Return -EOPNOTSUPP in phy_configure and phy_validate when the operation
> is not implemented
>
> Maxime Ripard (9):
> phy: dphy: Remove unused header
> phy: dphy: Change units of wakeup and init parameters
> phy: dphy: Clarify lanes parameter documentation
> sun6i: dsi: Convert to generic phy handling
> phy: Move Allwinner A31 D-PHY driver to drivers/phy/
> drm/bridge: cdns: Separate DSI and D-PHY configuration
> dt-bindings: phy: Move the Cadence D-PHY bindings
> phy: Add Cadence D-PHY support
> drm/bridge: cdns: Convert to phy framework
>
> Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt | 21 +-
> Documentation/devicetree/bindings/phy/cdns,dphy.txt | 20 +-
> drivers/gpu/drm/bridge/Kconfig | 1 +-
> drivers/gpu/drm/bridge/cdns-dsi.c | 538 +------
> drivers/gpu/drm/sun4i/Kconfig | 3 +-
> drivers/gpu/drm/sun4i/Makefile | 5 +-
> drivers/gpu/drm/sun4i/sun6i_mipi_dphy.c | 292 +----
> drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 31 +-
> drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h | 17 +-
> drivers/phy/allwinner/Kconfig | 12 +-
> drivers/phy/allwinner/Makefile | 1 +-
> drivers/phy/allwinner/phy-sun6i-mipi-dphy.c | 318 ++++-
> drivers/phy/cadence/Kconfig | 13 +-
> drivers/phy/cadence/Makefile | 1 +-
> drivers/phy/cadence/cdns-dphy.c | 389 +++++-
> drivers/phy/phy-core-mipi-dphy.c | 8 +-
> include/linux/phy/phy-mipi-dphy.h | 13 +-
> 17 files changed, 894 insertions(+), 789 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/phy/cdns,dphy.txt
> delete mode 100644 drivers/gpu/drm/sun4i/sun6i_mipi_dphy.c
> create mode 100644 drivers/phy/allwinner/phy-sun6i-mipi-dphy.c
> create mode 100644 drivers/phy/cadence/cdns-dphy.c
>
> base-commit: bfeffd155283772bbe78c6a05dec7c0128ee500c