From mboxrd@z Thu Jan 1 00:00:00 1970 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Subject: Re: [PATCH] phy: add support for a reset-gpio specification Date: Thu, 12 May 2016 18:14:11 +0200 Message-ID: <20160512161411.GI30822@pengutronix.de> References: <1463047233-18091-1-git-send-email-u.kleine-koenig@pengutronix.de> <57348A2A.8070806@ti.com> <57348D05.905@ti.com> <57349058.6040708@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <57349058.6040708@ti.com> Sender: netdev-owner@vger.kernel.org To: Roger Quadros Cc: Nishanth Menon , netdev@vger.kernel.org, devicetree@vger.kernel.org, Florian Fainelli , kernel@pengutronix.de, "Andrew F . Davis" , Sekhar Nori , Suman Anna List-Id: devicetree@vger.kernel.org Hello, On Thu, May 12, 2016 at 05:16:56PM +0300, Roger Quadros wrote: > On 12/05/16 17:02, Roger Quadros wrote: > > On 12/05/16 16:50, Nishanth Menon wrote: > >> On 05/12/2016 05:00 AM, Uwe Kleine-K=F6nig wrote: > >>> The framework only asserts (for now) that the reset gpio is not a= ctive. > >>> > >>> Signed-off-by: Uwe Kleine-K=F6nig > >>> --- > >>> 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/Docu= mentation/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 = correctly > >>> release the turn around line low at the end of a MDIO transact= ion. > >>> =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_d= evice.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 E= VMs > >> will also benefit with this approach. > >> > >=20 > > Agreed. Although on some of our boards we actually need a RESET pul= se > > to get the PHY in a sane state. I can send a patch on top for that. > >=20 >=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= =2E > e.g. am57xx-idk. > I think the reset needs to be done at MDIO bus level before it enumer= ates > the PHYs so that we know the PHY is in an enumerable state. I have this in the device tree: &davinci_mdio { pinctrl-names =3D "default", "sleep"; pinctrl-0 =3D <&davinci_mdio_default>; pinctrl-1 =3D <&davinci_mdio_sleep>; status =3D "okay"; phy0: ethernet-phy@0 { compatible =3D "ethernet-phy-id2000.a212", "ethernet-ph= y-ieee802.3-c22"; reg =3D <0>; interrupt-parent =3D <&gpio2>; interrupts =3D <2 8>; pinctrl-names =3D "default"; pinctrl-0 =3D <&phy0_pins>; reset-gpios =3D <&gpio2 9 GPIO_ACTIVE_LOW>; }; phy1: ethernet-phy@2 { compatible =3D "ethernet-phy-id2000.a212", "ethernet-ph= y-ieee802.3-c22"; reg =3D <2>; interrupt-parent =3D <&gpio0>; interrupts =3D <2 8>; pinctrl-names =3D "default"; pinctrl-0 =3D <&phy1_pins>; reset-gpios =3D <&gpio2 11 GPIO_ACTIVE_LOW>; }; }; With the phy id values specified in the compatible the mdio bus is only accessed when the reset pin was handled. Best regards Uwe --=20 Pengutronix e.K. | Uwe Kleine-K=F6nig = | Industrial Linux Solutions | http://www.pengutronix.de/= |