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

Daniel Vetter
2019-02-05T08:46:33Z

On Mon, Feb 04, 2019 at 03:33:31PM +0530, Kishon Vijay Abraham I wrote:
>
>
> 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.

Maxime is a gpu maintainer, so you're all good :-)
-Daniel

>
> 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
> >
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--
Daniel Vetter
Software Engineer, Intel Corporation