Second attempt at implementing a module that allows reading/writing arbitrary dpcd registers. Changes to this version: - 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.
One thing to notice is that I am not updating the file offset during read or write, which is kind of breaking the filesystem abstraction. But i2c-dev doesn't do it either, so I assumed it's fine.
Rafael Antognolli (3): drm/dp: Keep a list of drm_dp_aux helper. drm/dp: Store the drm_connector device pointer on the helper. drm/dp: Add a drm_aux-dev module for reading/writing dpcd registers.
drivers/gpu/drm/Kconfig | 4 + drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/drm_aux-dev.c | 326 ++++++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/drm_dp_helper.c | 73 +++++++++ drivers/gpu/drm/i915/intel_dp.c | 1 + include/drm/drm_dp_helper.h | 6 + 6 files changed, 411 insertions(+) create mode 100644 drivers/gpu/drm/drm_aux-dev.c