[RFC 00/17] clk: Add per-controller locks to fix deadlocks

Hello Krzysztof,

On 08/16/2016 09:34 AM, Krzysztof Kozlowski wrote:

Hi,

RFC, please, do not apply, maybe except patch #1 which is harmless.


Introduction
============
The patchset brings new entity: clock controller representing a hardware
block.  The clock controller comes with its own prepare lock which
is used then in many places.  The idea is to fix the deadlock mentioned
in commit 10ff4c5239a1 ("i2c: exynos5: Fix possible ABBA deadlock by keeping
I2C clock prepared") and commit 34e81ad5f0b6 ("i2c: s3c2410: fix ABBA deadlock
by keeping clock prepared").

I'm not familiar enough with the common clock framework to do a proper review
of this patch-set, but I've tested both on an Exynos5800 Peach Pi Chromebook
and an Exynos5422 Odroid XU4 board and I didn't find any clock regressions.

Also, I confirmed that the possible deadlock in the Odroid XU4 that was fixed
by reverted commit 10ff4c5239a1 doesn't happen anymore with your patches.

Tested-by: Javier Martinez Canillas <redacted>

Best regards,
-- 
Javier Martinez Canillas
Open Source Group
Samsung Research America