[PATCH v3 1/4] phylib: Add device reset GPIO support

From: Geert Uytterhoeven
Date: Fri Oct 20 2017 - 04:14:45 EST

From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxxx>
Acked-by: Rob Herring <robh@xxxxxxxxxx>
Acked-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
[geert: Propagate actual errors from fwnode_get_named_gpiod()]
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
This has gained a dependency on "[PATCH v2] of_mdio: Fix broken PHY IRQ
in case of probe deferral"
(https://www.spinics.net/lists/linux-renesas-soc/msg19442.html), as v3
needs to propagate errors from of_mdiobus_register_phy() and
of_mdiobus_register_device() [*].

v3:
- Fix fwnode_get_named_gpiod() call due to added parameters (which
allowed to eliminate the gpiod_direction_output() call),
- Undelete one blank line in the AT803x driver,
- Resolve rejects, refresh patch,
- Reword/reformat changelog,
- Take over from Sergei,
- Add Acked-by,
- Remove unneeded gpiod check, as gpiod_set_value() handles NULL fine,
- Handle fwnode_get_named_gpiod() errors correctly:
- -ENOENT is ignored (the GPIO is optional), and turned into NULL,
which allowed to remove all later !IS_ERR() checks,
- Other errors (incl. -EPROBE_DEFER) are propagated [*],

v2:
- Reformat changelog,
- Resolve rejects, refresh patch.
---
Documentation/devicetree/bindings/net/phy.txt | 2 ++
drivers/net/phy/at803x.c | 18 +++------------
drivers/net/phy/mdio_bus.c | 4 ++++
drivers/net/phy/mdio_device.c | 26 +++++++++++++++++++--
drivers/net/phy/phy_device.c | 33 +++++++++++++++++++++++++--
drivers/of/of_mdio.c | 23 +++++++++++++++++++
include/linux/mdio.h | 3 +++
include/linux/phy.h | 5 ++++
8 files changed, 95 insertions(+), 19 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt
index 77d0b2a61ffa96fc..c05479f5ac7cc837 100644
--- a/Documentation/devicetree/bindings/net/phy.txt
+++ b/Documentation/devicetree/bindings/net/phy.txt
@@ -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 {
diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
index 5f93e6add56394f2..15b4560aeb5de759 100644
--- a/drivers/net/phy/at803x.c
+++ b/drivers/net/phy/at803x.c
@@ -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);
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 2df7b62c1a36811e..da6e5366d641a416 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -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>

@@ -420,6 +421,9 @@ 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);
}
diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c
index e24f28924af8953d..6926db11ae888174 100644
--- a/drivers/net/phy/mdio_device.c
+++ b/drivers/net/phy/mdio_device.c
@@ -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 +116,12 @@ void mdio_device_remove(struct mdio_device *mdiodev)
}
EXPORT_SYMBOL(mdio_device_remove);

+void mdio_device_reset(struct mdio_device *mdiodev, int value)
+{
+ gpiod_set_value(mdiodev->reset, value);
+}
+EXPORT_SYMBOL(mdio_device_reset);
+
/**
* mdio_probe - probe an MDIO device
* @dev: device to probe
@@ -128,9 +136,16 @@ 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);

+ /* Assert the reset signal */
+ mdio_device_reset(mdiodev, 1);
+ }
+
return err;
}

@@ -140,9 +155,16 @@ 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) {
+ /* Deassert the reset signal */
+ mdio_device_reset(mdiodev, 0);
+
mdiodrv->remove(mdiodev);

+ /* Assert the reset signal */
+ mdio_device_reset(mdiodev, 1);
+ }
+
return 0;
}

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 67f25ac29025c539..e694b0ecf780d096 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -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) {
@@ -647,9 +650,15 @@ int phy_device_register(struct phy_device *phydev)
goto out;
}

+ /* Assert the reset signal */
+ phy_device_reset(phydev, 1);
+
return 0;

out:
+ /* Assert the reset signal */
+ phy_device_reset(phydev, 1);
+
mdiobus_unregister_device(&phydev->mdio);
return err;
}
@@ -849,6 +858,9 @@ 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 +1138,9 @@ 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);

@@ -1811,9 +1826,16 @@ 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);

+ /* Assert the reset signal */
+ phy_device_reset(phydev, 1);
+ }
+
mutex_unlock(&phydev->lock);

return err;
@@ -1829,8 +1851,15 @@ 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) {
+ /* Deassert the reset signal */
+ phy_device_reset(phydev, 0);
+
phydev->drv->remove(phydev);
+
+ /* Assert the reset signal */
+ phy_device_reset(phydev, 1);
+ }
phydev->drv = NULL;

return 0;
diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
index 98258583abb0b405..3d044119c032d176 100644
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -47,6 +47,7 @@ static int of_get_phy_id(struct device_node *device, u32 *phy_id)
static int of_mdiobus_register_phy(struct mii_bus *mdio,
struct device_node *child, u32 addr)
{
+ struct gpio_desc *gpiod;
struct phy_device *phy;
bool is_c45;
int rc;
@@ -55,10 +56,22 @@ static int of_mdiobus_register_phy(struct mii_bus *mdio,
is_c45 = of_device_is_compatible(child,
"ethernet-phy-ieee802.3-c45");

+ /* Deassert the optional reset signal */
+ gpiod = fwnode_get_named_gpiod(&child->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);
+
if (!is_c45 && !of_get_phy_id(child, &phy_id))
phy = phy_device_create(mdio, addr, phy_id, 0, NULL);
else
phy = get_phy_device(mdio, addr, is_c45);
+
+ /* Assert the reset signal again */
+ gpiod_set_value(gpiod, 1);
+
if (IS_ERR(phy))
return PTR_ERR(phy);

@@ -81,6 +94,7 @@ static int of_mdiobus_register_phy(struct mii_bus *mdio,
* can be looked up later */
of_node_get(child);
phy->mdio.dev.of_node = child;
+ phy->mdio.reset = gpiod;

/* All data is now stored in the phy struct;
* register it */
@@ -100,6 +114,7 @@ static int of_mdiobus_register_device(struct mii_bus *mdio,
struct device_node *child, u32 addr)
{
struct mdio_device *mdiodev;
+ struct gpio_desc *gpiod;
int rc;

mdiodev = mdio_device_create(mdio, addr);
@@ -112,6 +127,14 @@ static int of_mdiobus_register_device(struct mii_bus *mdio,
of_node_get(child);
mdiodev->dev.of_node = child;

+ gpiod = fwnode_get_named_gpiod(&child->fwnode, "reset-gpios", 0,
+ GPIOD_ASIS, "PHY reset");
+ if (PTR_ERR(gpiod) == -ENOENT)
+ gpiod = NULL;
+ else if (IS_ERR(gpiod))
+ return PTR_ERR(gpiod);
+ mdiodev->reset = gpiod;
+
/* All data is now stored in the mdiodev struct; register it. */
rc = mdio_device_register(mdiodev);
if (rc) {
diff --git a/include/linux/mdio.h b/include/linux/mdio.h
index ca08ab16ecdc9b78..92d4e55ffe675637 100644
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -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);
diff --git a/include/linux/phy.h b/include/linux/phy.h
index d78cd01ea5131018..175f3a6a61abcf0f 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -847,6 +847,11 @@ static inline int phy_read_status(struct phy_device *phydev)
return phydev->drv->read_status(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)

--
2.7.4