From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756753AbdLGRUO (ORCPT ); Thu, 7 Dec 2017 12:20:14 -0500 Received: from mail-lf0-f68.google.com ([209.85.215.68]:39558 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756665AbdLGRUK (ORCPT ); Thu, 7 Dec 2017 12:20:10 -0500 X-Google-Smtp-Source: AGs4zMZl4oEgCpqg5+c/uBfiL6omIwsVCug5Ac/Sitls9MMxnh9TSQ9y2mYWZYRUy66RYPyRxvQccg== Subject: Re: [PATCH v4.1] 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 , Richard Leitner , netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org References: <1512383692-14009-2-git-send-email-geert+renesas@glider.be> <1512390905-28094-1-git-send-email-geert+renesas@glider.be> From: Sergei Shtylyov Organization: Cogent Embedded Message-ID: <69fe9a6d-4039-6f80-b80d-7dc0de31e5bf@cogentembedded.com> Date: Thu, 7 Dec 2017 20:20:05 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <1512390905-28094-1-git-send-email-geert+renesas@glider.be> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-MW Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! On 12/04/2017 03:35 PM, 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 > [geert: Propagate actual errors from fwnode_get_named_gpiod()] > [geert: Avoid destroying initial setup] > [geert: Consolidate GPIO descriptor acquiring code] > Signed-off-by: Geert Uytterhoeven [...] > diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c > index 2df7b62c1a36811e..8f8b7747c54bc478 100644 > --- a/drivers/net/phy/mdio_bus.c > +++ b/drivers/net/phy/mdio_bus.c [...] > @@ -48,9 +49,26 @@ > > int mdiobus_register_device(struct mdio_device *mdiodev) > { > + struct gpio_desc *gpiod = NULL; > + > if (mdiodev->bus->mdio_map[mdiodev->addr]) > return -EBUSY; > > + /* Deassert the optional reset signal */ Umm, but why deassert it here for such a short time? > + if (mdiodev->dev.of_node) > + gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode, > + "reset-gpios", 0, GPIOD_OUT_LOW, > + "PHY reset"); > + if (PTR_ERR(gpiod) == -ENOENT) > + gpiod = NULL; > + else if (IS_ERR(gpiod)) > + return PTR_ERR(gpiod); Hm, returning on error with reset deasserted? > + > + mdiodev->reset = gpiod; > + > + /* Assert the reset signal again */ > + mdio_device_reset(mdiodev, 1); > + > mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev; > > return 0; [...] MBR, Sergei