linux-kernel - Re: [PATCH] usb: remove NULL pointer check for clk_disable

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Date:   Sun, 21 May 2017 04:03:19 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     linux-usb@...r.kernel.org
Cc:     Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Patrice Chotard <patrice.chotard@...com>,
        Alan Stern <stern@...land.harvard.edu>,
        Felipe Balbi <balbi@...nel.org>, linuxppc-dev@...ts.ozlabs.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Li Yang <leoli@...escale.com>,
        Tony Prisk <linux@...sktech.co.nz>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        John Youn <johnyoun@...opsys.com>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        kernel@...inux.com
Subject: Re: [PATCH] usb: remove NULL pointer check for clk_disable_unprepare

2017-05-21 2:52 GMT+09:00 Masahiro Yamada <yamada.masahiro@...ionext.com>:
> After long term efforts of fixing non-common clock implementations,
> clk_disable() is a no-op for a NULL pointer input, and this is now
> tree-wide consistent.
>
> All clock consumers can safely call clk_disable(_unprepare) without
> NULL pointer check.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>


Sorry, I retract this patch.

Krzysztof pointed out
cleanups only for clk_disable_unprepare() will lose the code symmetry.

NULL pointer checks for clk_prepare_enable() should be
removed to keep the code symmetrical.

This is possible for common-clock framework because
clk_prepare_enable() is also a no-op for a NULL clk input.
But it is not necessarily true for non-common clock implementations.



-- 
Best Regards
Masahiro Yamada