linux-kernel - Re: [PATCH 14/15] net: phy: add PHY regulator support

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Message-ID: <CAMpxmJVP9db-4-AA4e1JkEfrajvJ4s0T6zo5+oFzpJHRBcuSsg@mail.gmail.com>
Date:   Tue, 23 Jun 2020 11:46:15 +0200
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     Russell King - ARM Linux admin <linux@...linux.org.uk>
Cc:     Bartosz Golaszewski <brgl@...ev.pl>, Andrew Lunn <andrew@...n.ch>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        devicetree <devicetree@...r.kernel.org>,
        Vladimir Oltean <vladimir.oltean@....com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Fabien Parent <fparent@...libre.com>,
        Iyappan Subramanian <iyappan@...amperecomputing.com>,
        Quan Nguyen <quan@...amperecomputing.com>,
        Frank Rowand <frowand.list@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Andrew Perepech <andrew.perepech@...iatek.com>,
        Stephane Le Provost <stephane.leprovost@...iatek.com>,
        Keyur Chudgar <keyur@...amperecomputing.com>,
        Jassi Brar <jaswinder.singh@...aro.org>,
        Claudiu Manoil <claudiu.manoil@....com>,
        Mark Brown <broonie@...nel.org>,
        "moderated list:ARM/Mediatek SoC..." 
        <linux-mediatek@...ts.infradead.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        netdev <netdev@...r.kernel.org>,
        Ilias Apalodimas <ilias.apalodimas@...aro.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Pedro Tsai <pedro.tsai@...iatek.com>,
        "David S . Miller" <davem@...emloft.net>,
        Heiner Kallweit <hkallweit1@...il.com>
Subject: Re: [PATCH 14/15] net: phy: add PHY regulator support

wt., 23 cze 2020 o 11:43 Russell King - ARM Linux admin
<linux@...linux.org.uk> napisał(a):
>
> On Tue, Jun 23, 2020 at 11:41:11AM +0200, Bartosz Golaszewski wrote:
> > pon., 22 cze 2020 o 15:29 Russell King - ARM Linux admin
> > <linux@...linux.org.uk> napisał(a):
> > >
> >
> > [snip!]
> >
> > >
> > > This is likely to cause issues for some PHY drivers.  Note that we have
> > > some PHY drivers which register a temperature sensor in the probe
> > > function, which means they can be accessed independently of the lifetime
> > > of the PHY bound to the network driver (which may only be while the
> > > network device is "up".)  We certainly do not want hwmon failing just
> > > because the network device is down.
> > >
> > > That's kind of worked around for the reset stuff, because there are two
> > > layers to that: the mdio device layer reset support which knows nothing
> > > of the PHY binding state to the network driver, and the phylib reset
> > > support, but it is not nice.
> > >
> >
> > Regulators are reference counted so if the hwmon driver enables it
> > using mdio_device_power_on() it will stay on even after the PHY driver
> > calls phy_device_power_off(), right? Am I missing something?
>
> If that is true, you will need to audit the PHY drivers to add that.
>

This change doesn't have any effect on devices which don't have a
regulator assigned in DT though. The one I'm adding in the last patch
is the first to use this.

Bart