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

[Philipp Zabel]

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.

>     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.

regards
Philipp