This series adds support for very late atomic transfers to the I2C subsystem. It finally reached a state which I think is ready-to-apply. This is mainly because of two things: a) we decided to respect the current locking scheme and to not give atomic transfers a priority. The code needed for that would have been either incomplete or very invasive. And we cannot guarantee successful transfers anyhow. See [1] for the discussion and other write-ups for design choices. b) thanks to a discussion with Peter Zijlstra[2], the conditions when to allow atomic transfers became much clearer. The new helper i2c_in_atomic_xfer_mode() adds readability, too. In detail, changes since RFC v2: * dropped coding style patch because already applied * added new patch 1 to drop in_atomic() and have better conditions when to enter the atomic path * added support to the mux-core * simplified omap conversion a little * added new conversions for ocores, stu300, and algo-bit/gpio * typo corrections found by Simon and Stefan * added tags to drivers * dropped tags from core patches because that part changed too much All tested on a Renesas Lager board (R-Car H2). Sadly, the i2c-sh_mobile driver cannot be converted now because of other work needed first. I tested with the i2c-gpio driver, though. The other driver patches are build tested. A branch can be found here: git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git renesas/i2c/atomic_xfer I am happy for reviews and comments. Please note if you review (especially the core parts), I'd like to have a short summary of your review even if there is no proposed change. Like what you did, what you think about it, etc. Some stuff in here is subtle, so if you went through the effort to double check my assumptions you should name it :) Finally, a big thank you and credit to Renesas for funding this work, of course! Happy hacking, Wolfram [1] https://lkml.org/lkml/2019/3/2/76 [2] http://patchwork.ozlabs.org/patch/1067437/ Wolfram Sang (12): i2c: remove use of in_atomic() i2c: core: use I2C locking behaviour also for SMBUS i2c: core: introduce callbacks for atomic transfers i2c: mux: populate the new *_atomic callbacks i2c: demux: handle the new atomic callbacks i2c: omap: Add the master_xfer_irqless hook i2c: tegra-bpmp: convert to use new atomic callbacks i2c: ocores: refactor setup for polling i2c: ocores: enable atomic xfers i2c: stu300: use xfer_atomic callback to bail out early i2c: algo: bit: add flag to whitelist atomic transfers i2c: gpio: flag atomic capability if possible drivers/i2c/algos/i2c-algo-bit.c | 22 +++++++++- drivers/i2c/busses/i2c-gpio.c | 2 + drivers/i2c/busses/i2c-ocores.c | 16 +++----- drivers/i2c/busses/i2c-omap.c | 76 +++++++++++++++++++++++++++++------ drivers/i2c/busses/i2c-stu300.c | 25 +++++------- drivers/i2c/busses/i2c-tegra-bpmp.c | 25 +++++++++--- drivers/i2c/i2c-core-base.c | 17 ++++---- drivers/i2c/i2c-core-smbus.c | 25 +++++++++--- drivers/i2c/i2c-core.h | 25 ++++++++++++ drivers/i2c/i2c-mux.c | 6 +++ drivers/i2c/muxes/i2c-demux-pinctrl.c | 2 + include/linux/i2c-algo-bit.h | 1 + include/linux/i2c.h | 15 +++++-- 13 files changed, 194 insertions(+), 63 deletions(-) -- 2.11.0
