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SubjectRe: [PATCH 00/12] i2c: core: introduce atomic transfers
On Wed, Apr 03, 2019 at 02:40:07PM +0200, Wolfram Sang wrote:
> 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 :)
>

Thank you!

FWIW,

Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com>

for patches 1-5,12.

Indeed, atomic condition sounds clear now.

>
> 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
>

--
With Best Regards,
Andy Shevchenko


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