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Groups > linux.kernel > #1412101

Shared Resets

From Lee Jones <lee.jones@linaro.org>
Newsgroups linux.kernel
Subject Shared Resets
Date 2016-06-02 12:20 +0200
Message-ID <rFxTk-4Ge-23@gated-at.bofh.it> (permalink)
Organization linux.* mail to news gateway

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Philipp, Hans,

After rebasing to the most recent upstream kernel tag (v4.6-rc1), I
witnessed some issues where a couple of USB PHY drivers where having
trouble requesting their reset lines.  After some poking around, I
stumbled across Hans' shared reset patch.  It looks reasonable at
first, but when I came to make the necessary driver changes, I
realised that your effectively insisting that drivers have platform
specific knowledge.

The way I see it, drivers should request, deassert and assert their
reset lines.  Just as clock users, request, enable and disable their
clocks.  Whether the reset lines (or clocks) are left on after an
assert (disable) because there are other users, should be of no
concern to the consumer, right?

I would like to see (and am happy to author) a different approach,
where knowledge of whether a reset line is shared or not is contained
in the framework, as it is in the clock case.

What are your thoughts?

Kind regards,
Lee

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

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Shared Resets Lee Jones <lee.jones@linaro.org> - 2016-06-02 12:20 +0200
  Re: Shared Resets Hans de Goede <hdegoede@redhat.com> - 2016-06-02 13:00 +0200

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