netdev - RE: [PATCH/RFC] net: phy: device: Don't deassert the reset when register and probe

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Date:   Wed, 28 Nov 2018 01:10:42 +0000
From:   Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
To:     Andrew Lunn <andrew@...n.ch>
CC:     "f.fainelli@...il.com" <f.fainelli@...il.com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: RE: [PATCH/RFC] net: phy: device: Don't deassert the reset when
 register and probe

Hi Andrew,

> From: Andrew Lunn, Sent: Wednesday, November 28, 2018 1:44 AM
> 
> On Tue, Nov 27, 2018 at 12:18:20PM +0000, Yoshihiro Shimoda wrote:
> > Some PHY device needs edge signal of the reset, but the previous code
> > is impossible to achieve it like following:
> >
> >  1) Kernel boots by using initramfs.
> >  --> No open the nic, so the provious code deasserts the reset by
> >      phy_device_register() and phy_probe().
> >  2) Kernel enters the suspend.
> >  --> So, keep the reset signal as deassert.
> >  --> On R-Car Salvator-XS board, unfortunately, the board power is
> >      turned off.
> >  3) Kernel returns from suspend.
> >  4) ifconfig eth0 up
> >  --> Then, since edge signal of the reset doesn't happen,
> >      it cannot link up.
> 
> Hi Yoshihiro
> 
> It sounds like you should be adding code to the suspend/resume
> handling of phylib, so that it toggle the reset on resume. You cannot
> just delete code like you proposed, it is going to break devices. But
> adding code should be O.K.

Thank you for your comment!
I understood we cannot delete the code, but can add the suspend/resume handling
of phylib. I'll make such a patch.

Best regards,
Yoshihiro Shimoda