[PATCH v6] drm: bridge/dw_hdmi: add dw hdmi i2c bus adapter support

[Vladimir Zapolskiy]

Hi Philipp,

On 09/16/2016 06:21 PM, Philipp Zabel wrote:
> Hi Vladimir,
>
> Am Mittwoch, den 14.09.2016, 21:46 +0300 schrieb Vladimir Zapolskiy:
>> Hi Philipp,
>>
>> On 08/29/2016 06:50 PM, Rob Herring wrote:
>>> On Wed, Aug 24, 2016 at 08:46:37AM +0300, Vladimir Zapolskiy wrote:
>>>> The change adds support of internal HDMI I2C master controller, this
>>>> subdevice is used by default, if "ddc-i2c-bus" DT property is omitted.
>>>>
>>>> The main purpose of this functionality is to support reading EDID from
>>>> an HDMI monitor on boards, which don't have an I2C bus connected to
>>>> DDC pins.
>>>>
>>>> The current implementation does not support "I2C Master Interface
>>>> Extended Read Mode" to read data addressed by non-zero segment
>>>> pointer, this means that if EDID has more than 1 extension blocks,
>>>> EDID reading operation won't succeed, in my practice all tested HDMI
>>>> monitors have at maximum one extension block.
>>>>
>>>> Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy at mentor.com>
>>>> ---
>>>> The change is based on top of v4.8.0-rc1 and a fix in DW HDMI driver
>>>> https://patchwork.kernel.org/patch/9284717/
>>>>
>>>> Changes from v5 to v6:
>>>> * rebased on top of v4.8.0-rc1
>>>> * fixed one improper resource deallocation on error path of dw_hdmi_bind()
>>>> * added a comment describing a mutex asked by checkpatch.pl --strict
>>>>
>>>> Link to version v5: https://patchwork.kernel.org/patch/7279831/
>>>>
>>>> Changes from v4 to v5:
>>>> * do I2C bus controller initialization only once in bind() as it was done
>>>>   in v1-v3 of the change.
>>>>
>>>> Changes from v3 to v4, thanks to Doug and Philipp for review:
>>>> * set speed mode after software reset in dw_hdmi_i2c_init()
>>>> * by default set standard speed mode instead of fast speed mode, on iMX6Q
>>>>   this configures SCL to 100 KHz, which is compliant with HDMI 1.3a spec
>>>> * do I2C bus controller reinitialization on every data transfer,
>>>>   this change hopefully solves some observed problems on RK3288 platform
>>>> * added short functional change description to dw_hdmi.txt
>>>>
>>>> v3 of the change was
>>>>
>>>>   Tested-by: Philipp Zabel <p.zabel at pengutronix.de>
>>>>
>>>> Changes from v2 to v3, thanks to Russell:
>>>> * moved register field value definitions to dw_hdmi.h
>>>> * made completions uninterruptible to avoid transfer retries if interrupted
>>>> * use one completion for both read and write transfers as in v1,
>>>>   operation_reg is removed
>>>> * redundant i2c->stat = 0 is removed from dw_hdmi_i2c_read/write()
>>>> * struct i2c_algorithm dw_hdmi_algorithm is qualified as const
>>>> * dw_hdmi_i2c_adapter() does not modify struct dw_hdmi on error path
>>>> * dw_hdmi_i2c_irq() does not modify hdmi->i2c->stat, if interrupt is
>>>>   not for I2CM
>>>> * spin lock is removed from dw_hdmi_i2c_irq()
>>>> * removed spin lock from dw_hdmi_i2c_xfer() around write to
>>>>   HDMI_IH_MUTE_I2CM_STAT0 register
>>>> * split loop over message array in dw_hdmi_i2c_xfer() to validation
>>>>   and transfer parts
>>>> * added a mutex to serialize I2C transfer requests, i2c->lock is
>>>>   completely removed
>>>> * removed if(len) check from dw_hdmi_i2c_write(), hardware supports
>>>>   only len>0 transfers
>>>> * described extension blocks <= 1 limitation in the commit message
>>>> * a number of minor clean ups
>>>>
>>>> Changes from v1 to v2:
>>>> * fixed a devm_kfree() signature
>>>> * split completions for read and write operations
>>>>
>>>>  .../devicetree/bindings/display/bridge/dw_hdmi.txt |   4 +-
>>>
>>> Acked-by: Rob Herring <robh at kernel.org>
>>>
>>>>  drivers/gpu/drm/bridge/dw-hdmi.c                   | 265 ++++++++++++++++++++-
>>>>  drivers/gpu/drm/bridge/dw-hdmi.h                   |  19 ++
>>>>  3 files changed, 281 insertions(+), 7 deletions(-)
>>
>> as far as I know David accepts pull requests from you, can you please
>> create and send a pull request for v4.9 containing these changes?
>>
>>     https://patchwork.kernel.org/patch/9284717/ -- with Russell's ack
>
> Is that a forward looking statement? I don't see Russell's ack.

Here it is: http://www.spinics.net/lists/dri-devel/msg115880.html

Please don't bother about two other commits from that series, at least
there are official maintainers for the changes. And by the way please
consider to add youself as a maintainer of DW HDMI.

>>     https://patchwork.kernel.org/patch/9296883/ -- with Rob's ack and yours tested-by
>>
>> Some users anticipate this change, for example see https://lkml.org/lkml/2016/9/14/55
>
> Those I see. I can re-test and prepare a pull request.
>

Thank you in advance!

--
With best wishes,
Vladimir