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phylib: Add device reset GPIO support 

The PHY devices sometimes do have their reset signal (maybe even power
supply?) tied to some GPIO and sometimes it also does happen that a boot
loader does not leave it deasserted. So far this issue has been attacked
from (as I believe) a wrong angle: by teaching the MAC driver to manipulate
the GPIO in question; that solution, when applied to the device trees, led
to adding the PHY reset GPIO properties to the MAC device node, with one
exception: Cadence MACB driver which could handle the "reset-gpios" prop
in a PHY device subnode. I believe that the correct approach is to teach
the 'phylib' to get the MDIO device reset GPIO from the device tree node
corresponding to this device -- which this patch is doing...

Note that I had to modify the AT803x PHY driver as it would stop working
otherwise -- it made use of the reset GPIO for its own purposes...

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Acked-by: Rob Herring <robh@kernel.org>
[geert: Propagate actual errors from fwnode_get_named_gpiod()]
[geert: Avoid destroying initial setup]
[geert: Consolidate GPIO descriptor acquiring code]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Richard Leitner <richard.leitner@skidata.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Sergei Shtylyov 2017-12-04 13:35:05 +01:00 committed by David S. Miller
parent 62b32379fd
commit bafbdd527d
7 changed files with 87 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/devicetree/bindings/net/phy.txt
View File

@ -53,6 +53,8 @@ Optional Properties:
to ensure the integrated PHY is used. The absence of this property indicates
the muxers should be configured so that the external PHY is used.
- reset-gpios: The GPIO phandle and specifier for the PHY reset signal.
Example:
ethernet-phy@0 {

18
drivers/net/phy/at803x.c
View File

@ -71,7 +71,6 @@ MODULE_LICENSE("GPL");
struct at803x_priv {
bool phy_reset:1;
struct gpio_desc *gpiod_reset;
};
struct at803x_context {
@ -254,22 +253,11 @@ static int at803x_probe(struct phy_device *phydev)
{
struct device *dev = &phydev->mdio.dev;
struct at803x_priv *priv;
struct gpio_desc *gpiod_reset;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
if (phydev->drv->phy_id != ATH8030_PHY_ID)
goto does_not_require_reset_workaround;
gpiod_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
if (IS_ERR(gpiod_reset))
return PTR_ERR(gpiod_reset);
priv->gpiod_reset = gpiod_reset;
does_not_require_reset_workaround:
phydev->priv = priv;
return 0;
@ -343,14 +331,14 @@ static void at803x_link_change_notify(struct phy_device *phydev)
* cannot recover from by software.
*/
if (phydev->state == PHY_NOLINK) {
if (priv->gpiod_reset && !priv->phy_reset) {
if (phydev->mdio.reset && !priv->phy_reset) {
struct at803x_context context;
at803x_context_save(phydev, &context);
gpiod_set_value(priv->gpiod_reset, 1);
phy_device_reset(phydev, 1);
msleep(1);
gpiod_set_value(priv->gpiod_reset, 0);
phy_device_reset(phydev, 0);
msleep(1);
at803x_context_restore(phydev, &context);

21
drivers/net/phy/mdio_bus.c
View File

@ -38,6 +38,7 @@
#include <linux/phy.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/gpio/consumer.h>
#include <asm/irq.h>
@ -48,9 +49,26 @@
int mdiobus_register_device(struct mdio_device *mdiodev)
{
struct gpio_desc *gpiod = NULL;
if (mdiodev->bus->mdio_map[mdiodev->addr])
return -EBUSY;
/* Deassert the optional reset signal */
if (mdiodev->dev.of_node)
gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
"reset-gpios", 0, GPIOD_OUT_LOW,
"PHY reset");
if (PTR_ERR(gpiod) == -ENOENT)
gpiod = NULL;
else if (IS_ERR(gpiod))
return PTR_ERR(gpiod);
mdiodev->reset = gpiod;
/* Assert the reset signal again */
mdio_device_reset(mdiodev, 1);
mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
return 0;
@ -420,6 +438,9 @@ void mdiobus_unregister(struct mii_bus *bus)
if (!mdiodev)
continue;
if (mdiodev->reset)
gpiod_put(mdiodev->reset);
mdiodev->device_remove(mdiodev);
mdiodev->device_free(mdiodev);
}

25
drivers/net/phy/mdio_device.c
View File

@ -12,6 +12,8 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/errno.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
@ -114,6 +116,13 @@ void mdio_device_remove(struct mdio_device *mdiodev)
}
EXPORT_SYMBOL(mdio_device_remove);
void mdio_device_reset(struct mdio_device *mdiodev, int value)
{
if (mdiodev->reset)
gpiod_set_value(mdiodev->reset, value);
}
EXPORT_SYMBOL(mdio_device_reset);
/**
* mdio_probe - probe an MDIO device
* @dev: device to probe
@ -128,8 +137,16 @@ static int mdio_probe(struct device *dev)
struct mdio_driver *mdiodrv = to_mdio_driver(drv);
int err = 0;
if (mdiodrv->probe)
if (mdiodrv->probe) {
/* Deassert the reset signal */
mdio_device_reset(mdiodev, 0);
err = mdiodrv->probe(mdiodev);
if (err) {
/* Assert the reset signal */
mdio_device_reset(mdiodev, 1);
}
}
return err;
}
@ -140,9 +157,13 @@ static int mdio_remove(struct device *dev)
struct device_driver *drv = mdiodev->dev.driver;
struct mdio_driver *mdiodrv = to_mdio_driver(drv);
if (mdiodrv->remove)
if (mdiodrv->remove) {
mdiodrv->remove(mdiodev);
/* Assert the reset signal */
mdio_device_reset(mdiodev, 1);
}
return 0;
}

32
drivers/net/phy/phy_device.c
View File

@ -632,6 +632,9 @@ int phy_device_register(struct phy_device *phydev)
if (err)
return err;
/* Deassert the reset signal */
phy_device_reset(phydev, 0);
/* Run all of the fixups for this PHY */
err = phy_scan_fixups(phydev);
if (err) {
@ -650,6 +653,9 @@ int phy_device_register(struct phy_device *phydev)
return 0;
out:
/* Assert the reset signal */
phy_device_reset(phydev, 1);
mdiobus_unregister_device(&phydev->mdio);
return err;
}
@ -666,6 +672,10 @@ EXPORT_SYMBOL(phy_device_register);
void phy_device_remove(struct phy_device *phydev)
{
device_del(&phydev->mdio.dev);
/* Assert the reset signal */
phy_device_reset(phydev, 1);
mdiobus_unregister_device(&phydev->mdio);
}
EXPORT_SYMBOL(phy_device_remove);
@ -849,6 +859,9 @@ int phy_init_hw(struct phy_device *phydev)
{
int ret = 0;
/* Deassert the reset signal */
phy_device_reset(phydev, 0);
if (!phydev->drv || !phydev->drv->config_init)
return 0;
@ -1126,6 +1139,9 @@ void phy_detach(struct phy_device *phydev)
put_device(&phydev->mdio.dev);
if (ndev_owner != bus->owner)
module_put(bus->owner);
/* Assert the reset signal */
phy_device_reset(phydev, 1);
}
EXPORT_SYMBOL(phy_detach);
@ -1811,8 +1827,16 @@ static int phy_probe(struct device *dev)
/* Set the state to READY by default */
phydev->state = PHY_READY;
if (phydev->drv->probe)
if (phydev->drv->probe) {
/* Deassert the reset signal */
phy_device_reset(phydev, 0);
err = phydev->drv->probe(phydev);
if (err) {
/* Assert the reset signal */
phy_device_reset(phydev, 1);
}
}
mutex_unlock(&phydev->lock);
@ -1829,8 +1853,12 @@ static int phy_remove(struct device *dev)
phydev->state = PHY_DOWN;
mutex_unlock(&phydev->lock);
if (phydev->drv && phydev->drv->remove)
if (phydev->drv && phydev->drv->remove) {
phydev->drv->remove(phydev);
/* Assert the reset signal */
phy_device_reset(phydev, 1);
}
phydev->drv = NULL;
return 0;

3
include/linux/mdio.h
View File

@ -12,6 +12,7 @@
#include <uapi/linux/mdio.h>
#include <linux/mod_devicetable.h>
struct gpio_desc;
struct mii_bus;
/* Multiple levels of nesting are possible. However typically this is
@ -39,6 +40,7 @@ struct mdio_device {
/* Bus address of the MDIO device (0-31) */
int addr;
int flags;
struct gpio_desc *reset;
};
#define to_mdio_device(d) container_of(d, struct mdio_device, dev)
@ -71,6 +73,7 @@ void mdio_device_free(struct mdio_device *mdiodev);
struct mdio_device *mdio_device_create(struct mii_bus *bus, int addr);
int mdio_device_register(struct mdio_device *mdiodev);
void mdio_device_remove(struct mdio_device *mdiodev);
void mdio_device_reset(struct mdio_device *mdiodev, int value);
int mdio_driver_register(struct mdio_driver *drv);
void mdio_driver_unregister(struct mdio_driver *drv);
int mdio_device_bus_match(struct device *dev, struct device_driver *drv);

5
include/linux/phy.h
View File

@ -854,6 +854,11 @@ int phy_aneg_done(struct phy_device *phydev);
int phy_stop_interrupts(struct phy_device *phydev);
int phy_restart_aneg(struct phy_device *phydev);
static inline void phy_device_reset(struct phy_device *phydev, int value)
{
mdio_device_reset(&phydev->mdio, value);
}
#define phydev_err(_phydev, format, args...) \
dev_err(&_phydev->mdio.dev, format, ##args)