[Intel-gfx] [PATCH v2 0/4] Enable lspcon support for GEN9 devices

[Shashank Sharma]

LSPCON is essencially a dp++->hdmi adaptor with dual mode of operation.

These modes are:
- Level Shifter mode: In LS mode, this device works as a type2 dp->hdmi
passive dongle, which steps up DP++ output to appropriate HDMI 1.4 signal.
This mode doesn't do any conversion at the protocol level.

- Protocol Converter mode: In PCON mode, this device acts as an
active DP++->HDMI 2.0 dongle, which converts the DP++ output to
compatible HDMI 2.0 output. In PCON mode, lspcon can support 4k at 60
outputs, using DP HBR2 mode.

Many of Intel GEN9 devices come with in-built lspcon card
in motherboartd down mode. This patch series adds support for
lspcon devices in I915 driver.

While unit-testing this code, I was able to see a 4k at 60 modeset with:
- BXT-T board
- Single HDMI 4k at 60 display (ACER S)
- Ubuntu 14.04 desktop

V2: Worked on review comments from Ville
- In general, Ville suggested not to use the dual personality of
  DDI to drive lspcon, so this patch set drives it just as DP++ display.
  There is no separate detection for lspcon (hpd_pulse is good enough), and
  its being driven as a DP display with special initialization and EDID
  read sequence. To be able to do this, we driving lspcon in PCON mode only,
  where it can serve both HDMI1.3/HDMI1.4 sinks as well as 4k at 60 capable
  HDMI 2.0 sinks. So compared to previous series, there is one patch less,
  as we have dropped lspcon detection patch.

Shashank Sharma (4):
  drm: Helper for lspcon in drm_dp_dual_mode
  drm/i915: Add lspcon support for I915 driver
  drm/i915: Parse VBT data for lspcon
  drm/i915: Enable lspcon initialization

 drivers/gpu/drm/drm_dp_dual_mode_helper.c | 103 +++++++++++++++++++++
 drivers/gpu/drm/i915/Makefile             |   1 +
 drivers/gpu/drm/i915/i915_drv.h           |   3 +
 drivers/gpu/drm/i915/intel_bios.c         |  49 ++++++++++
 drivers/gpu/drm/i915/intel_ddi.c          |  29 +++++-
 drivers/gpu/drm/i915/intel_drv.h          |  13 ++-
 drivers/gpu/drm/i915/intel_lspcon.c       | 145 ++++++++++++++++++++++++++++++
 include/drm/drm_dp_dual_mode_helper.h     |  25 ++++++
 8 files changed, 366 insertions(+), 2 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/intel_lspcon.c

-- 
1.9.1