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authorRoger Quadros <rogerq@ti.com>2017-04-21 16:15:38 +0300
committerDavid S. Miller <davem@davemloft.net>2017-04-24 12:40:24 -0400
commit69226896ad636b94f6d2e55d75ff21a29c4de83b (patch)
treef5df9ce46570ffe61c581a9feb68471c9a86cdee /drivers/net/phy/mdio_bus.c
parent15769ff8b6d560a358761598aad5fc413ce2251b (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/net/phy/mdio_bus.c')
-rw-r--r--drivers/net/phy/mdio_bus.c47
1 files changed, 47 insertions, 0 deletions
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 <linux/init.h>
#include <linux/delay.h>
#include <linux/device.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
#include <linux/of_device.h>
#include <linux/of_mdio.h>
+#include <linux/of_gpio.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
@@ -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);