diff options
| author | Roger Quadros <rogerq@ti.com> | 2017-04-21 16:15:38 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-04-24 12:40:24 -0400 |
| commit | 69226896ad636b94f6d2e55d75ff21a29c4de83b (patch) | |
| tree | f5df9ce46570ffe61c581a9feb68471c9a86cdee /drivers/of | |
| parent | 15769ff8b6d560a358761598aad5fc413ce2251b (diff) | |
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 <rogerq@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/of')
| -rw-r--r-- | drivers/of/of_mdio.c | 7 |
1 files changed, 7 insertions, 0 deletions
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 <linux/of_net.h> #include <linux/module.h> +#define DEFAULT_GPIO_RESET_DELAY 10 /* in microseconds */ + MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>"); 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) |