[PATCH v3 0/4] drm/dp: Introduce AUX channel infrastructure

Alex Deucher alexdeucher at gmail.com
Tue Jan 14 07:54:45 PST 2014


On Tue, Jan 14, 2014 at 9:55 AM, Thierry Reding
<thierry.reding at gmail.com> wrote:
> Hi,
>
> This small series introduces some infrastructure to support AUX channels
> in a generic way. Drivers make use of it by embedding and filling in a
> struct drm_dp_aux. Various helpers can then be used to for example read
> from or write to the DPCD.
>
> Patch 1 adds the basic infrastructure as well as a couple of helpers to
> access the DPCD.
>
> The helper introduced in patch 2 can be used to obtain the link status
> as expected by various existing DP helpers.
>
> More convenience helpers are added in patch 3, which can come in handy
> during DP initialization.
>
> An AUX channel can also be used to implement I2C-over-AUX and patch 4
> implements an I2C adapter that can be used with the DRM EDID helpers.
>
> Changes in v3:
> - address comments by Jani Nikula:
>   - keep debug and error messages in AUX helpers
>   - read/write back-to-back registers in chunks
>   - separate link power up and configuration
>   - do not power up for DPCD prior to 1.1
>   - sleep after power up as per the spec
>   - return number of bytes transferred
>   - factor out some common code
>   - reorder function arguments
>   - fix typo in comment
> - address comments by Daniel Vetter:
>   - embed i2c_adapter within struct drm_dp_aux
>   - describe error codes
>
> Changes in v2:
> - reimplement I2C-over-AUX functionality to get rid of the additional
>   layer
> - extract retry logic from existing drivers
> - add more kerneldoc comments
>

Just one small spelling fix in patch 3, with that fixed,

Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

Thanks for doing this!

Alex

> Thierry
>
> Thierry Reding (4):
>   drm/dp: Add AUX channel infrastructure
>   drm/dp: Add drm_dp_dpcd_read_link_status()
>   drm/dp: Add DisplayPort link helpers
>   drm/dp: Allow registering AUX channels as I2C busses
>
>  drivers/gpu/drm/drm_dp_helper.c | 403 ++++++++++++++++++++++++++++++++++++++++
>  include/drm/drm_dp_helper.h     |  92 +++++++++
>  2 files changed, 495 insertions(+)
>
> --
> 1.8.4.2
>
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