From 69226896ad636b94f6d2e55d75ff21a29c4de83b Mon Sep 17 00:00:00 2001 From: Roger Quadros Date: Fri, 21 Apr 2017 16:15:38 +0300 Subject: [PATCH] mdio_bus: Issue GPIO RESET to PHYs. 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 Signed-off-by: David S. Miller --- .../devicetree/bindings/net/mdio.txt | 33 +++++++++++++ drivers/net/phy/mdio_bus.c | 47 +++++++++++++++++++ drivers/of/of_mdio.c | 7 +++ include/linux/phy.h | 7 +++ 4 files changed, 94 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 000000000000..4ffbbacebda1 --- /dev/null +++ b/Documentation/devicetree/bindings/net/mdio.txt @@ -0,0 +1,33 @@ +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 in microseconds as per PHY datasheet. + +A list of child nodes, one per device on the bus is expected. These +should follow the generic phy.txt, or a device specific binding document. + +Example : +This example shows these optional properties, plus other properties +required for the TI Davinci MDIO driver. + + davinci_mdio: ethernet@0x5c030000 { + compatible = "ti,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 */ + + ethphy0: ethernet-phy@1 { + reg = <1>; + }; + + ethphy1: ethernet-phy@3 { + reg = <3>; + }; + }; diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index 5a214f3b8671..a898e5c4ef1b 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 @@ -337,6 +340,7 @@ 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) @@ -363,6 +367,35 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner) if (bus->reset) bus->reset(bus); + /* de-assert bus level PHY GPIO resets */ + if (bus->num_reset_gpios > 0) { + bus->reset_gpiod = devm_kcalloc(&bus->dev, + bus->num_reset_gpios, + sizeof(struct gpio_desc *), + GFP_KERNEL); + if (!bus->reset_gpiod) + return -ENOMEM; + } + + 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) { + dev_err(&bus->dev, + "mii_bus %s couldn't get reset GPIO\n", + bus->id); + return err; + } + } else { + bus->reset_gpiod[i] = gpiod; + 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; @@ -390,6 +423,13 @@ error: mdiodev->device_remove(mdiodev); mdiodev->device_free(mdiodev); } + + /* Put PHYs in RESET to save power */ + for (i = 0; i < bus->num_reset_gpios; i++) { + if (bus->reset_gpiod[i]) + gpiod_set_value_cansleep(bus->reset_gpiod[i], 1); + } + device_del(&bus->dev); return err; } @@ -411,6 +451,13 @@ void mdiobus_unregister(struct mii_bus *bus) mdiodev->device_remove(mdiodev); mdiodev->device_free(mdiodev); } + + /* Put PHYs in RESET to save power */ + for (i = 0; i < bus->num_reset_gpios; i++) { + if (bus->reset_gpiod[i]) + gpiod_set_value_cansleep(bus->reset_gpiod[i], 1); + } + device_del(&bus->dev); } EXPORT_SYMBOL(mdiobus_unregister); diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c index 0b2979816dbf..7e4c80f9b6cd 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 624cecf69c28..37ca77d86983 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -217,6 +217,13 @@ struct mii_bus { * matching its address */ int irq[PHY_MAX_ADDR]; + + /* GPIO reset pulse width in microseconds */ + int reset_delay_us; + /* Number of reset GPIOs */ + int num_reset_gpios; + /* Array of RESET GPIO descriptors */ + struct gpio_desc **reset_gpiod; }; #define to_mii_bus(d) container_of(d, struct mii_bus, dev) -- 2.39.2