netdev - Re: [PATCHv2 0/2] net: fec: Reset ethernet PHY whenever the enet

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Date:	Tue, 12 Jan 2016 17:04:44 +0100
From:	Lothar Waßmann <LW@...O-electronics.de>
To:	Russell King - ARM Linux <linux@....linux.org.uk>
Cc:	Andrew Lunn <andrew@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Fabio Estevam <fabio.estevam@...escale.com>,
	Greg Ungerer <gerg@...inux.org>,
	Kevin Hao <haokexin@...il.com>,
	Lucas Stach <l.stach@...gutronix.de>,
	Nimrod Andy <B38611@...escale.com>,
	Philippe Reynes <tremyfr@...il.com>,
	Richard Cochran <richardcochran@...il.com>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Stefan Agner <stefan@...er.ch>, linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org, Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Mark Rutland <mark.rutland@....com>,
	Pawel Moll <pawel.moll@....com>,
	Rob Herring <robh+dt@...nel.org>,
	Sascha Hauer <kernel@...gutronix.de>,
	Shawn Guo <shawnguo@...nel.org>, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCHv2 0/2] net: fec: Reset ethernet PHY whenever the
 enet_out clock is being enabled

Hi,

> On Tue, Jan 12, 2016 at 04:17:54PM +0100, Lothar Waßmann wrote:
> > This patchset fixes a regression introduced by
> > commit e8fcfcd5684a ("net: fec: optimize the clock management to save power")
> > for ethernet PHYs that are using ENET_OUT as reference clock (on i.MX6 or i.MX28)
> > 
> > Changes vs. v1:
> > - fixed reference to the commit that introduced the regression.
> > - dropped patch to use gpiod framework. This should be added later,
> >   after the affected DTBs have been updated to specify the correct
> >   gpio_flags.
> > 
> > Patch overview:
> > 1. cleanup patch to remove redundant NULL checks
> > 2. call fec_reset_phy() after the ENET_OUT clock has been enabled
> 
> I definitely want to test these on my SolidRun boards before these get
> merged: the AR8035 on there is configured via pin-straps, and then
> further tweaked with PHY quirks.  Resetting with the iMX6 in the
> wrong state may result in the AR8035 being reconfigured (even jumping
> to a different MDIO address) and certainly would need the PHY quirks
> re-running.
> 
As far as I can tell, all SolidRun boards do not specify the enet_out
clock in the dtb, so the PHY reset behaviour should be unaffected by
this patch on those boards, since the additional fec_reset_phy() call is
framed by:
if (fep->clk_enet_out) {
	...
}

But verifying this explicitly is of course a good idea.


Lothar Waßmann