4 files changed, 99 insertions, 11 deletions

diff --git a/Documentation/phy.txt b/Documentation/phy.txt
index 0103e4b15b0e..ebff6ee52441 100644
--- a/Documentation/phy.txt
+++ b/Documentation/phy.txt
@@ -75,14 +75,26 @@ Before the controller can make use of the PHY, it has to get a reference to
 it. This framework provides the following APIs to get a reference to the PHY.
 
 struct phy *phy_get(struct device *dev, const char *string);
+struct phy *phy_optional_get(struct device *dev, const char *string);
 struct phy *devm_phy_get(struct device *dev, const char *string);
-
-phy_get and devm_phy_get can be used to get the PHY. In the case of dt boot,
-the string arguments should contain the phy name as given in the dt data and
-in the case of non-dt boot, it should contain the label of the PHY.
-The only difference between the two APIs is that devm_phy_get associates the
-device with the PHY using devres on successful PHY get. On driver detach,
-release function is invoked on the the devres data and devres data is freed.
+struct phy *devm_phy_optional_get(struct device *dev, const char *string);
+
+phy_get, phy_optional_get, devm_phy_get and devm_phy_optional_get can
+be used to get the PHY. In the case of dt boot, the string arguments
+should contain the phy name as given in the dt data and in the case of
+non-dt boot, it should contain the label of the PHY.  The two
+devm_phy_get associates the device with the PHY using devres on
+successful PHY get. On driver detach, release function is invoked on
+the the devres data and devres data is freed. phy_optional_get and
+devm_phy_optional_get should be used when the phy is optional. These
+two functions will never return -ENODEV, but instead returns NULL when
+the phy cannot be found.
+
+It should be noted that NULL is a valid phy reference. All phy
+consumer calls on the NULL phy become NOPs. That is the release calls,
+the phy_init() and phy_exit() calls, and phy_power_on() and
+phy_power_off() calls are all NOP when applied to a NULL phy. The NULL
+phy is useful in devices for handling optional phy devices.
 
 5. Releasing a reference to the PHY
 
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 20a7517bd339..52b8181ddafd 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -4126,12 +4126,14 @@ static int mv_platform_probe(struct platform_device *pdev)
                         clk_prepare_enable(hpriv->port_clks[port]);
 
                 sprintf(port_number, "port%d", port);
-                hpriv->port_phys[port] = devm_phy_get(&pdev->dev, port_number);
+                hpriv->port_phys[port] = devm_phy_optional_get(&pdev->dev,
+                                                               port_number);
                 if (IS_ERR(hpriv->port_phys[port])) {
                         rc = PTR_ERR(hpriv->port_phys[port]);
                         hpriv->port_phys[port] = NULL;
-                        if ((rc != -EPROBE_DEFER) && (rc != -ENODEV))
-                                dev_warn(&pdev->dev, "error getting phy");
+                        if (rc != -EPROBE_DEFER)
+                                dev_warn(&pdev->dev, "error getting phy %d",
+                                        rc);
                         goto err;
                 } else
                         phy_power_on(hpriv->port_phys[port]);
diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index 645c867c1257..5f5b0f4be5be 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -162,6 +162,9 @@ int phy_init(struct phy *phy)
 {
         int ret;
 
+        if (!phy)
+                return 0;
+
         ret = phy_pm_runtime_get_sync(phy);
         if (ret < 0 && ret != -ENOTSUPP)
                 return ret;
@@ -187,6 +190,9 @@ int phy_exit(struct phy *phy)
 {
         int ret;
 
+        if (!phy)
+                return 0;
+
         ret = phy_pm_runtime_get_sync(phy);
         if (ret < 0 && ret != -ENOTSUPP)
                 return ret;
@@ -212,6 +218,9 @@ int phy_power_on(struct phy *phy)
 {
         int ret;
 
+        if (!phy)
+                return 0;
+
         ret = phy_pm_runtime_get_sync(phy);
         if (ret < 0 && ret != -ENOTSUPP)
                 return ret;
@@ -240,6 +249,9 @@ int phy_power_off(struct phy *phy)
 {
         int ret;
 
+        if (!phy)
+                return 0;
+
         mutex_lock(&phy->mutex);
         if (phy->power_count == 1 && phy->ops->power_off) {
                 ret =  phy->ops->power_off(phy);
@@ -308,7 +320,7 @@ err0:
  */
 void phy_put(struct phy *phy)
 {
-        if (IS_ERR(phy))
+        if (!phy || IS_ERR(phy))
                 return;
 
         module_put(phy->ops->owner);
@@ -328,6 +340,9 @@ void devm_phy_put(struct device *dev, struct phy *phy)
 {
         int r;
 
+        if (!phy)
+                return;
+
         r = devres_destroy(dev, devm_phy_release, devm_phy_match, phy);
         dev_WARN_ONCE(dev, r, "couldn't find PHY resource\n");
 }
@@ -411,6 +426,27 @@ struct phy *phy_get(struct device *dev, const char *string)
 EXPORT_SYMBOL_GPL(phy_get);
 
 /**
+ * phy_optional_get() - lookup and obtain a reference to an optional phy.
+ * @dev: device that requests this phy
+ * @string: the phy name as given in the dt data or the name of the controller
+ * port for non-dt case
+ *
+ * Returns the phy driver, after getting a refcount to it; or
+ * NULL if there is no such phy.  The caller is responsible for
+ * calling phy_put() to release that count.
+ */
+struct phy *phy_optional_get(struct device *dev, const char *string)
+{
+        struct phy *phy = phy_get(dev, string);
+
+        if (PTR_ERR(phy) == -ENODEV)
+                phy = NULL;
+
+        return phy;
+}
+EXPORT_SYMBOL_GPL(phy_optional_get);
+
+/**
  * devm_phy_get() - lookup and obtain a reference to a phy.
  * @dev: device that requests this phy
  * @string: the phy name as given in the dt data or phy device name
@@ -441,6 +477,30 @@ struct phy *devm_phy_get(struct device *dev, const char *string)
 EXPORT_SYMBOL_GPL(devm_phy_get);
 
 /**
+ * devm_phy_optional_get() - lookup and obtain a reference to an optional phy.
+ * @dev: device that requests this phy
+ * @string: the phy name as given in the dt data or phy device name
+ * for non-dt case
+ *
+ * Gets the phy using phy_get(), and associates a device with it using
+ * devres. On driver detach, release function is invoked on the devres
+ * data, then, devres data is freed. This differs to devm_phy_get() in
+ * that if the phy does not exist, it is not considered an error and
+ * -ENODEV will not be returned. Instead the NULL phy is returned,
+ * which can be passed to all other phy consumer calls.
+ */
+struct phy *devm_phy_optional_get(struct device *dev, const char *string)
+{
+        struct phy *phy = devm_phy_get(dev, string);
+
+        if (PTR_ERR(phy) == -ENODEV)
+                phy = NULL;
+
+        return phy;
+}
+EXPORT_SYMBOL_GPL(devm_phy_optional_get);
+
+/**
  * phy_create() - create a new phy
  * @dev: device that is creating the new phy
  * @ops: function pointers for performing phy operations
diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
index e273e5ac19c9..3f83459dbb20 100644
--- a/include/linux/phy/phy.h
+++ b/include/linux/phy/phy.h
@@ -146,7 +146,9 @@ static inline void phy_set_bus_width(struct phy *phy, int bus_width)
         phy->attrs.bus_width = bus_width;
 }
 struct phy *phy_get(struct device *dev, const char *string);
+struct phy *phy_optional_get(struct device *dev, const char *string);
 struct phy *devm_phy_get(struct device *dev, const char *string);
+struct phy *devm_phy_optional_get(struct device *dev, const char *string);
 void phy_put(struct phy *phy);
 void devm_phy_put(struct device *dev, struct phy *phy);
 struct phy *of_phy_simple_xlate(struct device *dev,
@@ -232,11 +234,23 @@ static inline struct phy *phy_get(struct device *dev, const char *string)
         return ERR_PTR(-ENOSYS);
 }
 
+static inline struct phy *phy_optional_get(struct device *dev,
+                                           const char *string)
+{
+        return ERR_PTR(-ENOSYS);
+}
+
 static inline struct phy *devm_phy_get(struct device *dev, const char *string)
 {
         return ERR_PTR(-ENOSYS);
 }
 
+static inline struct phy *devm_phy_optional_get(struct device *dev,
+                                                const char *string)
+{
+        return ERR_PTR(-ENOSYS);
+}
+
 static inline void phy_put(struct phy *phy)
 {
 }