From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752969AbdJTK4K (ORCPT ); Fri, 20 Oct 2017 06:56:10 -0400 Received: from mail-lf0-f68.google.com ([209.85.215.68]:48218 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752926AbdJTK4H (ORCPT ); Fri, 20 Oct 2017 06:56:07 -0400 X-Google-Smtp-Source: ABhQp+SS2VfVCH7jHvy/1dMW55owjk4FE9lVQrqBqSS0VXLNQyf6KrIEpAVQ4bk3PHHUy4+TMtEp4w== Subject: Re: [PATCH v3 1/4] phylib: Add device reset GPIO support To: Geert Uytterhoeven , "David S . Miller" , Andrew Lunn , Florian Fainelli , Simon Horman , Magnus Damm Cc: Rob Herring , Mark Rutland , Nicolas Ferre , netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org References: <1508487261-18524-1-git-send-email-geert+renesas@glider.be> <1508487261-18524-2-git-send-email-geert+renesas@glider.be> From: Sergei Shtylyov Message-ID: Date: Fri, 20 Oct 2017 13:56:04 +0300 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <1508487261-18524-2-git-send-email-geert+renesas@glider.be> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! On 10/20/2017 11:14 AM, Geert Uytterhoeven wrote: > From: Sergei Shtylyov > > The PHY devices sometimes do have their reset signal (maybe even power > supply?) tied to some GPIO and sometimes it also does happen that a boot > loader does not leave it deasserted. So far this issue has been attacked > from (as I believe) a wrong angle: by teaching the MAC driver to manipulate > the GPIO in question; that solution, when applied to the device trees, led > to adding the PHY reset GPIO properties to the MAC device node, with one > exception: Cadence MACB driver which could handle the "reset-gpios" prop > in a PHY device subnode. I believe that the correct approach is to teach > the 'phylib' to get the MDIO device reset GPIO from the device tree node > corresponding to this device -- which this patch is doing... > > Note that I had to modify the AT803x PHY driver as it would stop working > otherwise -- it made use of the reset GPIO for its own purposes... > > Signed-off-by: Sergei Shtylyov > Acked-by: Rob Herring > Acked-by: Florian Fainelli > [geert: Propagate actual errors from fwnode_get_named_gpiod()] > Signed-off-by: Geert Uytterhoeven [...] > diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c > index e24f28924af8953d..6926db11ae888174 100644 > --- a/drivers/net/phy/mdio_device.c > +++ b/drivers/net/phy/mdio_device.c [...] > @@ -128,9 +136,16 @@ static int mdio_probe(struct device *dev) > struct mdio_driver *mdiodrv = to_mdio_driver(drv); > int err = 0; > > - if (mdiodrv->probe) > + if (mdiodrv->probe) { > + /* Deassert the reset signal */ > + mdio_device_reset(mdiodev, 0); > + > err = mdiodrv->probe(mdiodev); If the probe() method performs some register setup... > + /* Assert the reset signal */ > + mdio_device_reset(mdiodev, 1); ... this reset would kill that setup. Hence we shouldn't drive the reset signal at least when the probe() method succeeds. > + } > + > return err; > } > [...] > diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c > index 67f25ac29025c539..e694b0ecf780d096 100644 > --- a/drivers/net/phy/phy_device.c > +++ b/drivers/net/phy/phy_device.c [...] > @@ -1811,9 +1826,16 @@ static int phy_probe(struct device *dev) > /* Set the state to READY by default */ > phydev->state = PHY_READY; > > - if (phydev->drv->probe) > + if (phydev->drv->probe) { > + /* Deassert the reset signal */ > + phy_device_reset(phydev, 0); > + > err = phydev->drv->probe(phydev); If the probe() method performs some register setup (as does the LXT PHY driver!)... > + /* Assert the reset signal */ > + phy_device_reset(phydev, 1); ... this reset would kill that setup. Hence we shouldn't drive the reset signal at least when the probe() method succeeds. > + } > + > mutex_unlock(&phydev->lock); > > return err; [...] MBR, Sergei