linux-kernel - Re: [RFC 2/2] phy: exynos5-usbdrd: remove disable and enable of phy clk

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Date:   Mon, 9 Oct 2017 18:59:20 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Anand Moon <linux.amoon@...il.com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Russell King <linux@...linux.org.uk>,
        Kukjin Kim <kgene@...nel.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Lee Jones <lee.jones@...aro.org>,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Vivek Gautam <vivek.gautam@...eaurora.org>,
        Andrzej Pietrasiewicz <andrzej.p@...sung.com>,
        devicetree <devicetree@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        "linux-samsung-soc@...r.kernel.org" 
        <linux-samsung-soc@...r.kernel.org>,
        Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [RFC 2/2] phy: exynos5-usbdrd: remove disable and enable of phy
 clk

On Mon, Oct 09, 2017 at 08:46:48PM +0530, Anand Moon wrote:
> hi Krzysztof,
> 
> On 9 October 2017 at 02:37, Anand Moon <linux.amoon@...il.com> wrote:
> > Hi Krzysztof,
> >
> > On 8 October 2017 at 21:20, Krzysztof Kozlowski <krzk@...nel.org> wrote:
> >> On Sun, Oct 08, 2017 at 06:11:12PM +0530, Anand Moon wrote:
> >>> Hi Krzysztof,
> >>>
> >>> On 6 October 2017 at 12:12, Krzysztof Kozlowski <krzk@...nel.org> wrote:
> >>> > On Fri, Oct 6, 2017 at 6:36 AM, Anand Moon <linux.amoon@...il.com> wrote:
> >>> >> remove the disable and enable of phy clk.
> >>> >> phy clk is needed to tune the phy controller.
> >>> >
> >>> > Drivers should in general enable and disable the clocks they use. Just
> >>> > like in patch #1 please describe why you are doing this, what kind of
> >>> > problem are you trying to solve and what exactly are you trying to do
> >>> > here.
> >>> >
> >>> > BR,
> >>> > Krzysztof
> >>> >
> >>>
> >>> [snip]
> >>>
> >>> Usually we would disable the clk on error patch and return with failed.
> >>> but in the current code we disable the clk in init routine and
> >>> enable the clk in disable routine which seem incorrect.
> >>
> 
> disable of clk could affect the PMU used to control the phy driver.

Disabling device's clock affects the device but the PMU rather not...
but I might misunderstood you cause this sounds quite unprecise.

Best regards,
Krzysztof