Commit Graph

11 Commits

Author SHA1 Message Date
Thierry Reding 88759686c7 drm/dp: Allow registering AUX channels as I2C busses
Implements an I2C-over-AUX I2C adapter on top of the generic drm_dp_aux
infrastructure. It extracts the retry logic from existing drivers, which
should help in porting those drivers to this new helper.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
Changes in v5:
- move comments partially to to header file
- keep MOT set between I2C messages
- return -EPROTO on short reads

Changes in v4:
- fix typo "bitrate" -> "bit rate"

Changes in v3:
- add back DRM_DEBUG_KMS and DRM_ERROR messages
- embed i2c_adapter within struct drm_dp_aux
- fix typo in comment
2014-02-26 17:21:34 +01:00
Thierry Reding 516c0f7c0a drm/dp: Add DisplayPort link helpers
Add a helper to probe a DP link (read out the supported DPCD revision,
maximum rate, link count and capabilities) as well as power up the DP
link and configure it accordingly.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
Changes in v5:
- export helpers

Changes in v4:
- fix a couple of typos in comments as pointed out by Alex Deucher

Changes in v3:
- split into drm_dp_link_power_up() and drm_dp_link_configure()
- do not change sink state for DPCD versions earlier than 1.1
- sleep for 1-2 ms after setting local sink to D0 state
- read and write consecutive registers where possible
- read DPCD revision when link is probed
- remove duplicate kerneldoc
2014-02-26 17:21:34 +01:00
Thierry Reding 8d4adc6a58 drm/dp: Add drm_dp_dpcd_read_link_status()
The function reads the link status (6 bytes starting at offset 0x202)
from the DPCD so that it can be conveniently passed to other DPCD
helpers.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
2014-02-26 17:21:33 +01:00
Thierry Reding c197db75ff drm/dp: Add AUX channel infrastructure
This is a superset of the current i2c_dp_aux bus functionality and can
be used to transfer native AUX in addition to I2C-over-AUX messages.

Helpers are provided to read and write the DPCD, either blockwise or
byte-wise. Many of the existing helpers for DisplayPort take a copy of a
portion of the DPCD and operate on that, without a way to write data
back to the DPCD (e.g. for configuration of the link).

Subsequent patches will build upon this infrastructure to provide common
functionality in a generic way.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
Changes in v5:
- move comments partially to struct drm_dp_aux_msg in header file
- return -EPROTO on short reads in DPCD helpers

Changes in v4:
- fix a typo in a comment

Changes in v3:
- reorder drm_dp_dpcd_writeb() arguments to be more intuitive
- return number of bytes transferred in drm_dp_dpcd_write()
- factor out drm_dp_dpcd_access()
- describe error codes
2014-02-26 17:21:32 +01:00
Jani Nikula 0aec288130 drm/dp: constify DP DPCD helpers
None of the DP DPCD helpers need to modify the DPCD.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-10-01 15:28:57 +10:00
Daniel Vetter 28164fdad8 drm/doc: add new dp helpers into drm DocBook
I didn't bother with documenting the really trivial new "extract
something from dpcd" helpers, but the i2c over aux ch is now
documented a bit.

v2: Clarify the comment for i2c_dp_aux_add_bus a bit.

v3: Fix more spelling fail spotted by Laurent Pinchart.

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2012-11-28 20:26:53 +10:00
Daniel Vetter 3b5c662e8f drm: extract dp link bw helpers
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-10-22 22:34:47 +02:00
Daniel Vetter 1a644cd47c drm: extract dp link train delay functions from radeon
This requires a few changes since that dpcd value is above the
range currently cached by radeon. I've check the dp specs, and
above 0xf there's a big gap and nothing that looks like we should
cache it while a given device is plugged in. It's also the same value
that i915.ko uses.

Hence extend the various dpcd arrays in the radeon driver, use
proper symbolic constants where applicable (one place overallocated
the dpcd array to 25 bytes). Then also drop the rd_interval cache -
radeon_dp_link_train_init re-reads the dpcd block, so the values we'll
consume in train_cr and train_ce will always be fresh.

To avoid needless diff-churn, #define the old size of dpcd as the new
one and keep it around.

v2: Alex Deucher noticed one place where I've forgotten to replace 8
with DP_RECEIVER_CAP_SIZE.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-10-22 22:34:46 +02:00
Daniel Vetter 0f037bdee1 drm: extract helpers to compute new training values from sink request
Safe for the minor difference that the intel versions get an offset
into the link_status as an argument, both are the same again.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-10-22 22:34:45 +02:00
Daniel Vetter 1ffdff134e drm: dp helper: extract drm_dp_channel_eq_ok
radeon and intel use the exact same definition.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-10-22 22:23:36 +02:00
Daniel Vetter 00ae9a456d drm: rename drm_dp_i2c_helper.c to drm_dp_helper.c
I want to move some dp link training helpers into this place, so in
the future this won't be just about i2c any longer.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-10-22 22:20:31 +02:00