Re: [PATCH 00/12] i2c: core: introduce atomic transfers

From: Wolfram Sang
Date: Mon Apr 15 2019 - 08:10:58 EST


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 :)
>
>
> Finally, a big thank you and credit to Renesas for funding this work, of course!

No major critcism voiced here, so applied to for-next! Let's see how
this series does there...

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