Thread (17 messages) 17 messages, 3 authors, 2018-01-02

[PATCH v6 4/5] clk: aspeed: Register gated clocks

From: benh@kernel.crashing.org (Benjamin Herrenschmidt)
Date: 2017-12-29 23:20:55
Also in: linux-clk, lkml

On Tue, 2017-12-26 at 17:32 -0800, Stephen Boyd wrote:
quoted
I noticed we do have a few i2c based clock drivers... how are they ever
supposed to work ? i2c bus controllers are allowed to sleep and the i2c
core takes mutexes...
We have clk_prepare()/clk_unprepare() for sleeping suckage. You
can use that, and i2c based clk drivers do that today.
"suckage" ? Hehe ... the suckage should rather be stuff that cannot
sleep. Arbitrary latencies and jitter caused by too much code wanting
to be "atomic" when unnecessary are a bad thing.

In the case of clocks like the aspeed where we have to wait for a
rather long stabilization delay, way too long to legitimately do a non-
sleepable delay with a lock held, do we need to do everything in
prepare() then ?

Ben.
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