[Intel-gfx] [PATCH 0/5] 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 a 
========================== 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

This patch set is a re-spin of old lspcon patch series, with following
design changes / review comments addressed. 

Ville:
1. Use DRM_DP_DUAL_MODE APIs for core lspcon probing, as its
   a dp->hdmi adaptor only. 
2. Move lspcon detection code in drm_dp_dual_mode_helper layer, instead
   of keeping it in i915 layer.

Paulo:
1. Do not create a separate connector for lspcon, re-use the existing ddi
   layer, with special detection sequence (Mutually agreed by Daniel)

Shashank Sharma (5):
  drm: Helper for LSPCON in drm_dp_dual_mode
  drm/i915: Add lspcon support for I915 driver
  drm/i915: lspcon detection
  drm/i915: Parse VBT data for lspcon
  drm/i915: Enable lspcon initialization

 drivers/gpu/drm/drm_dp_dual_mode_helper.c |  85 +++++++++++++++
 drivers/gpu/drm/i915/Makefile             |   1 +
 drivers/gpu/drm/i915/i915_drv.h           |   3 +
 drivers/gpu/drm/i915/intel_bios.c         |  44 ++++++++
 drivers/gpu/drm/i915/intel_ddi.c          |  50 ++++++++-
 drivers/gpu/drm/i915/intel_dp.c           |  12 +++
 drivers/gpu/drm/i915/intel_drv.h          |  17 +++
 drivers/gpu/drm/i915/intel_hdmi.c         |  31 +++++-
 drivers/gpu/drm/i915/intel_lspcon.c       | 165 ++++++++++++++++++++++++++++++
 include/drm/drm_dp_dual_mode_helper.h     |  29 ++++++
 10 files changed, 431 insertions(+), 6 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/intel_lspcon.c

-- 
1.9.1