[Intel-gfx] [PATCH v6 0/2] Add drm_dp_aux chardev support.

[Rafael Antognolli]

This series implement support to a drm_dp_aux chardev that allows reading and
writing an arbitrary amount of bytes to arbitrary dpcd register addresses using
regular read, write and lseek operations.

v2:
 - lseek is used to select the register to read/write
 - read/write are used instead of ioctl
 - no blocking_notifier is used, just a direct callback

v3:
 - use drm_dp_aux_dev prefix for public functions
 - chardev is named drm_dp_auxN
 - read/write don't allocate a buffer anymore, and transfer up to 16 bytes a
   time
 - remove notifier list from the implementation
 - option on menuconfig is now a boolean
 - add inline stub functions to avoid breakage when this option is disabled

v4:
 - fix build system changes - actually disable this module when not selected.

v5:
 - Use kref to avoid device closing while still in use 
 - Don't use list, use an idr for storing aux_dev
 - Remove "connector" attribute
 - set aux.dev to the connector drm_connector device, instead of
   drm_device

v6:
 - Use atomic_t for usage count
 - Use a mutex instead of spinlock for idr lock
 - Destroy chardev immediately on unregister
 - other minor suggestions from Ville

Rafael Antognolli (2):
  drm/dp: Add a drm_aux-dev module for reading/writing dpcd registers.
  drm/dp: Set aux.dev to the drm_connector device, instead of
    drm_device.

 drivers/gpu/drm/Kconfig          |   8 +
 drivers/gpu/drm/Makefile         |   1 +
 drivers/gpu/drm/drm_dp_aux_dev.c | 381 +++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_dp_helper.c  |   5 +
 drivers/gpu/drm/i915/intel_dp.c  |  19 +-
 include/drm/drm_dp_aux_dev.h     |  50 +++++
 6 files changed, 447 insertions(+), 17 deletions(-)
 create mode 100644 drivers/gpu/drm/drm_dp_aux_dev.c
 create mode 100644 include/drm/drm_dp_aux_dev.h

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2.4.3