Message-ID: <3d96a5be6c6f0140b738a302befc25b5@codeaurora.org>
Date:   Mon, 10 May 2021 17:46:26 +0530
From:   sbillaka@...eaurora.org
To:     Rob Clark <robdclark@...il.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc:     "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <dri-devel@...ts.freedesktop.org>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <linux-arm-msm@...r.kernel.org>,
        freedreno <freedreno@...ts.freedesktop.org>,
        open list <linux-kernel@...r.kernel.org>,
        Sean Paul <seanpaul@...omium.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Kalyan Thota <kalyan_t@...eaurora.org>,
        Abhinav Kumar <abhinavk@...eaurora.org>,
        Douglas Anderson <dianders@...omium.org>,
        Kuogee Hsieh <khsieh@...eaurora.org>,
        Krishna Manikandan <mkrishn@...eaurora.org>
Subject: Re: [PATCH v1 0/3] Add support for next gen eDP driver on SnapDragon

On 2021-05-06 20:32, Rob Clark wrote:
> On Wed, May 5, 2021 at 11:47 PM <sbillaka@...eaurora.org> wrote:
>> 
>> On 2021-05-05 15:31, Dmitry Baryshkov wrote:
>> > Hi,
>> >
>> > On Wed, 5 May 2021 at 11:17, Sankeerth Billakanti
>> > <sbillaka@...eaurora.org> wrote:
>> >>
>> >> These patches add support for the next generation eDP driver on
>> >> SnapDragon
>> >> with dpu support. The existing eDP driver cannot support the new eDP
>> >> hardware. So, to maintain backward compatibility, the older eDP driver
>> >> is
>> >> moved to v200 folder and the new generation eDP driver is added in
>> >> the v510 folder.
>> >
>> > What exactly does this version correspond to?
>> > I assume that v510 corresponds to sdmshrike/sc8180x. Is it right?
>> [Sankeerth] This is for sc7280.
>> 
>> > Is it really so specific, or just v2/v5 would be enough? Not to
>> > mention that this is the MDP/ version, while other blocks tend to use
>> > block-specific versions/ids.
>> [Sankeerth] I can rename it as edp-v1 and edp-v2. Edp v1 is very old
>> chip and there is considerable HW delta between v1 and v2. So, we want
>> to separate the driver. We followed similar model for DPU driver 
>> where,
>> MDP4, MDP5 and DPU have separate folders. EDP v1 belongs to MDP4
>> generation.
> 
> Bjorn brought up the idea of just dropping the existing drm/msm/edp..
> since the efforts to upstream the platform it worked on (8084?)
> fizzled out, I don't think there is any device which uses it.
> 
> But it does sound like edp is a subset of the the newer dp driver, so
> seems sort of like the better approach would be to add edp support to
> dp.  I believe Bjorn has something based on this approach which is
> working for sc8280 (although not sure if it is in shape to post
> patches yet)
> 
> BR,
> -R
Hi Rob,
I will explore to integrate native eDP driver as part of DP driver. Will 
follow up with new patchsets.

Hi Dmitry,
I will move the eDP phy to qmp drivers folder in the new patchsets so 
that it can reuse the dp core driver.

Sankeerth

> 
>> >
>> > Also, how much does it differ from the current DP core supported via
>> > drivers/gpu/drm/msm/dp ?
>> [Sankeerth] eDP is a native controller like DP but does not have 
>> audio,
>> content protection and interoperability requirement. Upstream already
>> supports eDP as a new interface driver found here:
>> drivers/gpu/drm/msm/edp.
>> I wanted to add the new controller driver as part of that folder.
>> 
>> >
>> > First two patches did not make it to the linux-msm, so I can not
>> > comment on each of the lines.
>> [Sankeerth] I am also not sure why they did not make it to patchwork. 
>> I
>> will repost them.
>> 
>> > However just my few cents (other reviewers might disagree though):
>> >
>> > - I see little benefit in renaming the folders just for the sake of
>> > renaming. You can put your code in drivers/gpu/drm/msm/edp-v510, if
>> > you really insist on that. Note that for all other (even incompatible)
>> > hardware types we still use single level of folders.
>> >
>> > - Also I see that significant parts of code (e.g. AUX, bridge,
>> > connector, maybe more) are just c&p of old edp code pieces. Please
>> > share the code instead of duplicating it.
>> [Sankeerth] It is a baseline driver. As we add more features, it will
>> considerably deviate a lot. The effort seems to be very high to 
>> maintain
>> the common portion of code as I expect a lot of deviation.
>> >
>> > - Please consider updating register definitions in xml form and then
>> > providing both changed xml files (to mesa project (?)) and generated
>> > headers into the kernel.
>> [Sankeerth] I followed what was done in the DP driver at
>> /drivers/gpu/drm/msm/dp. I need to explore the xml approach to 
>> generate
>> the register definitions.
>> >
>> > - Please consider using clk_bulk_* functions instead of using
>> > dss_module_power. I'm going to send a patchset reworking current users
>> > to use the generic clk_bulk_* function family.
>> [Sankeerth] I will explore and rebase after your patch is available.
>> >
>> > - In generic, this eDP clock handling seems to match closely DP clocks
>> > handling (with all the name comparison, etc). Consider moving this to
>> > a generic piece of code
>> >
>> > - PHY seems to be a version of QMP PHY. Please use it, like it was
>> > done for the DP itself. There is support for combined USB+DP PHYs
>> > (both v3 and v4), so it should be possible to extend that for eDP.
>> [Sankeerth] The DP phy is a combophy which supports both usb and dp 
>> phy
>> concurrently, unlike eDP phy which is specific to only the eDP
>> controller in sc7280. So, I implemented the edp phy sequences in the
>> same folder.
>> >
>> >
>> >> These are baseline changes with which we can enable display. The new
>> >> eDP
>> >> controller can also support additional features such as backlight
>> >> control,
>> >> PSR etc. which will be enabled in subsequent patch series.
>> >>
>> >> Summary of changes:
>> >> DPU driver interface to the new eDP v510 display driver.
>> >> New generation eDP controller and phy driver implementation.
>> >> A common interface to choose enable the required eDP driver.
>> >>
>> >> Sankeerth Billakanti (3):
>> >>   drm/msm/edp: support multiple generations of edp hardware
>> >>   drm/msm/edp: add support for next gen edp
>> >>   drm/msm/disp/dpu1: add support for edp encoder
>> >>
>> >>  drivers/gpu/drm/msm/Makefile                      |   19 +-
>> >>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c       |    7 +-
>> >>  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c           |   33 +
>> >>  drivers/gpu/drm/msm/edp/edp.c                     |  198 ---
>> >>  drivers/gpu/drm/msm/edp/edp.h                     |   78 -
>> >>  drivers/gpu/drm/msm/edp/edp.xml.h                 |  380 -----
>> >>  drivers/gpu/drm/msm/edp/edp_aux.c                 |  264 ----
>> >>  drivers/gpu/drm/msm/edp/edp_bridge.c              |  111 --
>> >>  drivers/gpu/drm/msm/edp/edp_common.c              |   38 +
>> >>  drivers/gpu/drm/msm/edp/edp_common.h              |   47 +
>> >>  drivers/gpu/drm/msm/edp/edp_connector.c           |  132 --
>> >>  drivers/gpu/drm/msm/edp/edp_ctrl.c                | 1375
>> >> ------------------
>> >>  drivers/gpu/drm/msm/edp/edp_phy.c                 |   98 --
>> >>  drivers/gpu/drm/msm/edp/v200/edp.xml.h            |  380 +++++
>> >>  drivers/gpu/drm/msm/edp/v200/edp_v200.c           |  210 +++
>> >>  drivers/gpu/drm/msm/edp/v200/edp_v200.h           |   70 +
>> >>  drivers/gpu/drm/msm/edp/v200/edp_v200_aux.c       |  264 ++++
>> >>  drivers/gpu/drm/msm/edp/v200/edp_v200_bridge.c    |  111 ++
>> >>  drivers/gpu/drm/msm/edp/v200/edp_v200_connector.c |  132 ++
>> >>  drivers/gpu/drm/msm/edp/v200/edp_v200_ctrl.c      | 1375
>> >> ++++++++++++++++++
>> >>  drivers/gpu/drm/msm/edp/v200/edp_v200_phy.c       |   98 ++
>> >>  drivers/gpu/drm/msm/edp/v510/edp_v510.c           |  220 +++
>> >>  drivers/gpu/drm/msm/edp/v510/edp_v510.h           |  151 ++
>> >>  drivers/gpu/drm/msm/edp/v510/edp_v510_aux.c       |  268 ++++
>> >>  drivers/gpu/drm/msm/edp/v510/edp_v510_bridge.c    |  111 ++
>> >>  drivers/gpu/drm/msm/edp/v510/edp_v510_connector.c |  117 ++
>> >>  drivers/gpu/drm/msm/edp/v510/edp_v510_ctrl.c      | 1583
>> >> +++++++++++++++++++++
>> >>  drivers/gpu/drm/msm/edp/v510/edp_v510_phy.c       |  641 +++++++++
>> >>  drivers/gpu/drm/msm/edp/v510/edp_v510_reg.h       |  339 +++++
>> >>  29 files changed, 6207 insertions(+), 2643 deletions(-)
>> >>  delete mode 100644 drivers/gpu/drm/msm/edp/edp.c
>> >>  delete mode 100644 drivers/gpu/drm/msm/edp/edp.h
>> >>  delete mode 100644 drivers/gpu/drm/msm/edp/edp.xml.h
>> >>  delete mode 100644 drivers/gpu/drm/msm/edp/edp_aux.c
>> >>  delete mode 100644 drivers/gpu/drm/msm/edp/edp_bridge.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/edp_common.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/edp_common.h
>> >>  delete mode 100644 drivers/gpu/drm/msm/edp/edp_connector.c
>> >>  delete mode 100644 drivers/gpu/drm/msm/edp/edp_ctrl.c
>> >>  delete mode 100644 drivers/gpu/drm/msm/edp/edp_phy.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v200/edp.xml.h
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v200/edp_v200.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v200/edp_v200.h
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v200/edp_v200_aux.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v200/edp_v200_bridge.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v200/edp_v200_connector.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v200/edp_v200_ctrl.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v200/edp_v200_phy.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v510/edp_v510.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v510/edp_v510.h
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v510/edp_v510_aux.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v510/edp_v510_bridge.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v510/edp_v510_connector.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v510/edp_v510_ctrl.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v510/edp_v510_phy.c
>> >>  create mode 100644 drivers/gpu/drm/msm/edp/v510/edp_v510_reg.h
>> >>
>> >> --
>> >> The Qualcomm Innovatin Center, Inc. is a member of the Code Aurora
>> >> Forum, a Linux Foundation Collaborative Project
>> >>
>> >
>> >
>> > --
>> > With best wishes
>> > Dmitry

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