From 69226896ad636b94f6d2e55d75ff21a29c4de83b Mon Sep 17 00:00:00 2001 From: Roger Quadros Date: Fri, 21 Apr 2017 16:15:38 +0300 Subject: 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 --- drivers/of/of_mdio.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers/of') 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) -- cgit v1.2.3-73-gaa49b