The current use of platform devices leads to limitations in terms of API and problematic reference counts flagged during the review of sysfs patches.
As suggested by Greg KH, this patch series introduces a 'Master device' and gets rid of platform devices. The code is inspired by GreyBus, e.g. 'gb_hd_driver' is translated for the SoundWire context as 'sdw_md_driver' and likewise 'gb_host_device' is translated as 'sdw_master_device'. There are differences in the way devices are created, using device_register instead of the multiple steps used in GreyBus.
All I know about GreyBus is that it's based on Unipro, so the code updates are based on a first-order analysis, it could very well be I missed concepts while trying to reverse-engineer the code in staging/greybus/. I focused on the concepts mainly and it's also possible that the dual-license for new files or plan-vanilla EXPORT_SYMBOL are not appropriate for all the changes in this series. Please don't take errors as deliberate intent to work-around GPL but rather as an indicator of maturity of the code only developed in the last few days.
These changes make it possible to provide new callbacks, e.g splitting the bus startup from the initializations in probe, which is very much desired on Intel platforms to detect the machine driver as early as possible before the hardware is fully powered/enable. These patches will be provided as a separate RFC later today to illustrate the benefit of these changes.
To make the code more consistent the first series of patches are renames. I did not rename 'sdw_slave' or 'module_sdw_driver' to avoid compatibility issues since there are codec drivers almost ready for integration. I don't have any specific opinion on if/when additional renames should be done, as long as there is a means to clearly identify what is specific to a SoundWire Master I am fine.
Feedback and reviews welcome.
Bard Liao (1): soundwire: add device driver to sdw_md_driver
Pierre-Louis Bossart (8): soundwire: renames to prepare support for master drivers/devices soundwire: rename dev_to_sdw_dev macro soundwire: rename drv_to_sdw_slave_driver macro soundwire: bus_type: rename sdw_drv_ to sdw_slave_drv soundwire: intel: rename res field as link_res soundwire: add support for sdw_slave_type soundwire: add initial definitions for sdw_master_device soundwire: intel: remove platform devices and provide new interface
drivers/base/regmap/regmap-sdw.c | 4 +- drivers/soundwire/Makefile | 2 +- drivers/soundwire/bus.c | 2 +- drivers/soundwire/bus_type.c | 60 +++--- drivers/soundwire/intel.c | 117 ++++++----- drivers/soundwire/intel.h | 22 +-- drivers/soundwire/intel_init.c | 293 +++++++++++++++++++--------- drivers/soundwire/master.c | 80 ++++++++ drivers/soundwire/slave.c | 9 +- include/linux/soundwire/sdw.h | 39 +++- include/linux/soundwire/sdw_intel.h | 86 +++++++- include/linux/soundwire/sdw_type.h | 34 +++- 12 files changed, 551 insertions(+), 197 deletions(-) create mode 100644 drivers/soundwire/master.c