From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S969976AbdDTIjk (ORCPT ); Thu, 20 Apr 2017 04:39:40 -0400 Received: from lelnx193.ext.ti.com ([198.47.27.77]:29504 "EHLO lelnx193.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S968087AbdDTIjg (ORCPT ); Thu, 20 Apr 2017 04:39:36 -0400 Subject: [PATCH v2] mdio_bus: Issue GPIO RESET to PHYs. To: , Andrew Lunn , Florian Fainelli References: <1491381237-24635-1-git-send-email-rogerq@ti.com> <64d6494d-41d2-0faf-a434-057f796637fe@ti.com> CC: , , , , , , From: Roger Quadros Message-ID: Date: Thu, 20 Apr 2017 11:39:20 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <64d6494d-41d2-0faf-a434-057f796637fe@ti.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- v2: - add device tree binding document (mdio.txt) - specify default reset delay in of_mdio.c instead of mdio_bus.c Documentation/devicetree/bindings/net/mdio.txt | 20 ++++++++++++++++++++ drivers/net/phy/mdio_bus.c | 22 ++++++++++++++++++++++ drivers/of/of_mdio.c | 7 +++++++ include/linux/phy.h | 5 +++++ 4 files changed, 54 insertions(+) create mode 100644 Documentation/devicetree/bindings/net/mdio.txt diff --git a/Documentation/devicetree/bindings/net/mdio.txt b/Documentation/devicetree/bindings/net/mdio.txt new file mode 100644 index 0000000..6e703d7 --- /dev/null +++ b/Documentation/devicetree/bindings/net/mdio.txt @@ -0,0 +1,20 @@ +Common MDIO bus properties. + +These are generic properties that can apply to any MDIO bus. + +Optional properties: +- reset-gpios: List of one or more GPIOs that control the RESET lines + of the PHYs on that MDIO bus. +- reset-delay-us: RESET pulse width as per PHY datasheet. + +Example : + + davinci_mdio: ethernet@0x5c030000 { + compatible = "ti,davinci_mdio"; + ti,hwmods = "davinci_mdio"; + reg = <0x5c030000 0x1000>; + #address-cells = <1>; + #size-cells = <0>; + reset-gpios = <&gpio2 5 GPIO_ACTIVE_LOW>; + reset-delay-us = <2>; /* PHY datasheet states 1uS min */ + }; diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index fa7d51f..b353d99 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 @@ -307,6 +310,7 @@ 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 +337,24 @@ 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); + 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..7e4c80f 100644 --- a/drivers/of/of_mdio.c +++ b/drivers/of/of_mdio.c @@ -22,6 +22,8 @@ #include #include +#define DEFAULT_GPIO_RESET_DELAY 10 /* in microseconds */ + MODULE_AUTHOR("Grant Likely "); MODULE_LICENSE("GPL"); @@ -221,6 +223,11 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np) mdio->dev.of_node = np; + /* Get bus level PHY reset GPIO details */ + mdio->reset_delay_us = DEFAULT_GPIO_RESET_DELAY; + of_property_read_u32(np, "reset-delay-us", &mdio->reset_delay_us); + mdio->num_reset_gpios = of_gpio_named_count(np, "reset-gpios"); + /* Register the MDIO bus */ rc = mdiobus_register(mdio); if (rc) diff --git a/include/linux/phy.h b/include/linux/phy.h index 43a7748..80a6574 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -217,6 +217,11 @@ struct mii_bus { * matching its address */ int irq[PHY_MAX_ADDR]; + + /* GPIO reset pulse width in uS */ + int reset_delay_us; + /* Number of reset GPIOs */ + int num_reset_gpios; }; #define to_mii_bus(d) container_of(d, struct mii_bus, dev) -- 2.7.4