From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roger Quadros Subject: Re: [PATCH] phy: add support for a reset-gpio specification Date: Thu, 12 May 2016 17:16:56 +0300 Message-ID: <57349058.6040708@ti.com> References: <1463047233-18091-1-git-send-email-u.kleine-koenig@pengutronix.de> <57348A2A.8070806@ti.com> <57348D05.905@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <57348D05.905@ti.com> Sender: netdev-owner@vger.kernel.org To: Nishanth Menon , =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= , netdev@vger.kernel.org, devicetree@vger.kernel.org, Florian Fainelli Cc: kernel@pengutronix.de, "Andrew F . Davis" , Sekhar Nori , Suman Anna List-Id: devicetree@vger.kernel.org On 12/05/16 17:02, Roger Quadros wrote: > Hi, >=20 > On 12/05/16 16:50, Nishanth Menon wrote: >> On 05/12/2016 05:00 AM, Uwe Kleine-K=C3=B6nig wrote: >>> The framework only asserts (for now) that the reset gpio is not act= ive. >>> >>> Signed-off-by: Uwe Kleine-K=C3=B6nig >>> --- >>> Documentation/devicetree/bindings/net/phy.txt | 3 +++ >>> drivers/net/phy/phy_device.c | 8 ++++++++ >>> 2 files changed, 11 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Docume= ntation/devicetree/bindings/net/phy.txt >>> index bc1c3c8bf8fa..c00a9a894547 100644 >>> --- a/Documentation/devicetree/bindings/net/phy.txt >>> +++ b/Documentation/devicetree/bindings/net/phy.txt >>> @@ -35,6 +35,8 @@ Optional Properties: >>> - broken-turn-around: If set, indicates the PHY device does not co= rrectly >>> release the turn around line low at the end of a MDIO transactio= n. >>> =20 >>> +- reset-gpios: Reference to a GPIO used to reset the phy. >>> + >>> Example: >>> =20 >>> ethernet-phy@0 { >>> @@ -42,4 +44,5 @@ ethernet-phy@0 { >>> interrupt-parent =3D <40000>; >>> interrupts =3D <35 1>; >>> reg =3D <0>; >>> + reset-gpios =3D <&gpio1 17 GPIO_ACTIVE_LOW>; >>> }; >>> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_dev= ice.c >>> index e551f3a89cfd..7d666ab47271 100644 >>> --- a/drivers/net/phy/phy_device.c >>> +++ b/drivers/net/phy/phy_device.c >>> @@ -34,6 +34,7 @@ >>> #include >>> #include >>> #include >>> +#include >>> =20 >>> #include >>> =20 >>> @@ -1569,9 +1570,16 @@ static int phy_probe(struct device *dev) >>> struct device_driver *drv =3D phydev->mdio.dev.driver; >>> struct phy_driver *phydrv =3D to_phy_driver(drv); >>> int err =3D 0; >>> + struct gpio_descs *reset_gpios; >>> =20 >>> phydev->drv =3D phydrv; >>> =20 >>> + /* take phy out of reset */ >>> + reset_gpios =3D devm_gpiod_get_array_optional(dev, "reset", >>> + GPIOD_OUT_LOW); >>> + if (IS_ERR(reset_gpios)) >>> + return PTR_ERR(reset_gpios); >>> + >>> /* Disable the interrupt if the PHY doesn't support it >>> * but the interrupt is still a valid one >>> */ >>> >> >> This looks like the right approach to me at least: I see that TI EVM= s >> will also benefit with this approach. >> >=20 > Agreed. Although on some of our boards we actually need a RESET pulse > to get the PHY in a sane state. I can send a patch on top for that. >=20 I think I replied too early. Will phy_probe() be called at all if the PHY is not detected on the MDIO bus? If not then this approach is not sufficient for some of the TI boards. e.g. am57xx-idk. I think the reset needs to be done at MDIO bus level before it enumerat= es the PHYs so that we know the PHY is in an enumerable state. cheers, -roger