From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933559AbdDSLkC (ORCPT ); Wed, 19 Apr 2017 07:40:02 -0400 Received: from vps0.lunn.ch ([178.209.37.122]:34281 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933080AbdDSLkA (ORCPT ); Wed, 19 Apr 2017 07:40:00 -0400 Date: Wed, 19 Apr 2017 13:39:51 +0200 From: Andrew Lunn To: Roger Quadros Cc: davem@davemloft.net, Florian Fainelli , tony@atomide.com, nsekhar@ti.com, jsarha@ti.com, netdev@vger.kernel.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mdio_bus: Issue GPIO RESET to PHYs. Message-ID: <20170419113951.GA31908@lunn.ch> References: <1491381237-24635-1-git-send-email-rogerq@ti.com> <64d6494d-41d2-0faf-a434-057f796637fe@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <64d6494d-41d2-0faf-a434-057f796637fe@ti.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 19, 2017 at 12:24:26PM +0300, Roger Quadros wrote: > Some boards [1] leave the PHYs at an invalid state > during system power-up or reset thus causing unreliability > issues with the PHY which manifests as PHY not being detected > or link not functional. To fix this, these PHYs need to be RESET > via a GPIO connected to the PHY's RESET pin. > > Some boards have a single GPIO controlling the PHY RESET pin of all > PHYs on the bus whereas some others have separate GPIOs controlling > individual PHY RESETs. > > In both cases, the RESET de-assertion cannot be done in the PHY driver > as the PHY will not probe till its reset is de-asserted. > So do the RESET de-assertion in the MDIO bus driver. > > [1] - am572x-idk, am571x-idk, a437x-idk > > Signed-off-by: Roger Quadros > --- > drivers/net/phy/mdio_bus.c | 26 ++++++++++++++++++++++++++ > drivers/of/of_mdio.c | 4 ++++ > include/linux/phy.h | 5 +++++ > 3 files changed, 35 insertions(+) Hi Roger Thanks for making this generic. Please add device tree binding documentation. I think that actually means you have to document MDIO in general, since there currently is not a binding document. > diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c > index fa7d51f..25fda2b 100644 > --- a/drivers/net/phy/mdio_bus.c > +++ b/drivers/net/phy/mdio_bus.c > @@ -22,8 +22,11 @@ > #include > #include > #include > +#include > +#include > #include > #include > +#include > #include > #include > #include > @@ -43,6 +46,8 @@ > > #include "mdio-boardinfo.h" > > +#define DEFAULT_GPIO_RESET_DELAY 10 /* in microseconds */ > + > int mdiobus_register_device(struct mdio_device *mdiodev) > { > if (mdiodev->bus->mdio_map[mdiodev->addr]) > @@ -307,6 +312,7 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner) > { > struct mdio_device *mdiodev; > int i, err; > + struct gpio_desc *gpiod; > > if (NULL == bus || NULL == bus->name || > NULL == bus->read || NULL == bus->write) > @@ -333,6 +339,26 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner) > if (bus->reset) > bus->reset(bus); > > + /* de-assert bus level PHY GPIO resets */ > + for (i = 0; i < bus->num_reset_gpios; i++) { > + gpiod = devm_gpiod_get_index(&bus->dev, "reset", i, > + GPIOD_OUT_LOW); > + if (IS_ERR(gpiod)) { > + err = PTR_ERR(gpiod); > + if (err != -ENOENT) { > + pr_err("mii_bus %s couldn't get reset GPIO\n", > + bus->id); > + return err; > + } > + } else { > + gpiod_set_value_cansleep(gpiod, 1); > + if (!bus->reset_delay_us) > + bus->reset_delay_us = DEFAULT_GPIO_RESET_DELAY; Maybe do this once, where you read the device tree property. > + udelay(bus->reset_delay_us); > + gpiod_set_value_cansleep(gpiod, 0); > + } > + } > + > for (i = 0; i < PHY_MAX_ADDR; i++) { > if ((bus->phy_mask & (1 << i)) == 0) { > struct phy_device *phydev; > diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c > index 0b29798..83a62e4 100644 > --- a/drivers/of/of_mdio.c > +++ b/drivers/of/of_mdio.c > @@ -221,6 +221,10 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np) > > mdio->dev.of_node = np; > > + /* Get bus level PHY reset GPIO details */ > + of_property_read_u32(np, "reset-delay-us", &mdio->reset_delay_us); If the property does not exist, it is guaranteed mdio->reset_delay_us is not changed. So you can set it to the default value before, then do this call. Andrew