phy: core: Add consumer device link support

In order to enforce suspend/resume ordering, this commit creates link
between phy consumers and phy devices. This link avoids to suspend phy
before phy consumers.
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>
[jonathanh@nvidia.com: Fix an abort when of_phy_get() returns error]
Signed-off-by: Jonathan Hunter <jonathanh@nvidia.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/phy-core.c

@@ -29,7 +29,7 @@ static void devm_phy_release(struct device *dev, void *res)
 {
 	struct phy *phy = *(struct phy **)res;
 
-	phy_put(phy);
+	phy_put(dev, phy);
 }
 
 static void devm_phy_provider_release(struct device *dev, void *res)
@@ -566,12 +566,12 @@ struct phy *of_phy_get(struct device_node *np, const char *con_id)
 EXPORT_SYMBOL_GPL(of_phy_get);
 
 /**
- * phy_put() - release the PHY
- * @phy: the phy returned by phy_get()
+ * of_phy_put() - release the PHY
+ * @phy: the phy returned by of_phy_get()
  *
- * Releases a refcount the caller received from phy_get().
+ * Releases a refcount the caller received from of_phy_get().
  */
-void phy_put(struct phy *phy)
+void of_phy_put(struct phy *phy)
 {
 	if (!phy || IS_ERR(phy))
 		return;
@@ -584,6 +584,20 @@ void phy_put(struct phy *phy)
 	module_put(phy->ops->owner);
 	put_device(&phy->dev);
 }
+EXPORT_SYMBOL_GPL(of_phy_put);
+
+/**
+ * phy_put() - release the PHY
+ * @dev: device that wants to release this phy
+ * @phy: the phy returned by phy_get()
+ *
+ * Releases a refcount the caller received from phy_get().
+ */
+void phy_put(struct device *dev, struct phy *phy)
+{
+	device_link_remove(dev, &phy->dev);
+	of_phy_put(phy);
+}
 EXPORT_SYMBOL_GPL(phy_put);
 
 /**
@@ -651,6 +665,7 @@ struct phy *phy_get(struct device *dev, const char *string)
 {
 	int index = 0;
 	struct phy *phy;
+	struct device_link *link;
 
 	if (string == NULL) {
 		dev_WARN(dev, "missing string\n");
@@ -672,6 +687,13 @@ struct phy *phy_get(struct device *dev, const char *string)
 
 	get_device(&phy->dev);
 
+	link = device_link_add(dev, &phy->dev, DL_FLAG_STATELESS);
+	if (!link) {
+		dev_err(dev, "failed to create device link to %s\n",
+			dev_name(phy->dev.parent));
+		return ERR_PTR(-EINVAL);
+	}
+
 	return phy;
 }
 EXPORT_SYMBOL_GPL(phy_get);
@@ -765,6 +787,7 @@ struct phy *devm_of_phy_get(struct device *dev, struct device_node *np,
 			    const char *con_id)
 {
 	struct phy **ptr, *phy;
+	struct device_link *link;
 
 	ptr = devres_alloc(devm_phy_release, sizeof(*ptr), GFP_KERNEL);
 	if (!ptr)
@@ -776,6 +799,14 @@ struct phy *devm_of_phy_get(struct device *dev, struct device_node *np,
 		devres_add(dev, ptr);
 	} else {
 		devres_free(ptr);
+		return phy;
+	}
+
+	link = device_link_add(dev, &phy->dev, DL_FLAG_STATELESS);
+	if (!link) {
+		dev_err(dev, "failed to create device link to %s\n",
+			dev_name(phy->dev.parent));
+		return ERR_PTR(-EINVAL);
 	}
 
 	return phy;
@@ -798,6 +829,7 @@ struct phy *devm_of_phy_get_by_index(struct device *dev, struct device_node *np,
 				     int index)
 {
 	struct phy **ptr, *phy;
+	struct device_link *link;
 
 	ptr = devres_alloc(devm_phy_release, sizeof(*ptr), GFP_KERNEL);
 	if (!ptr)
@@ -819,6 +851,13 @@ struct phy *devm_of_phy_get_by_index(struct device *dev, struct device_node *np,
 	*ptr = phy;
 	devres_add(dev, ptr);
 
+	link = device_link_add(dev, &phy->dev, DL_FLAG_STATELESS);
+	if (!link) {
+		dev_err(dev, "failed to create device link to %s\n",
+			dev_name(phy->dev.parent));
+		return ERR_PTR(-EINVAL);
+	}
+
 	return phy;
 }
 EXPORT_SYMBOL_GPL(devm_of_phy_get_by_index);

drivers/usb/renesas_usbhs/rcar2.c

@@ -34,7 +34,7 @@ static int usbhs_rcar2_hardware_exit(struct platform_device *pdev)
 	struct usbhs_priv *priv = usbhs_pdev_to_priv(pdev);
 
 	if (priv->phy) {
-		phy_put(priv->phy);
+		phy_put(&pdev->dev, priv->phy);
 		priv->phy = NULL;
 	}
 

drivers/usb/renesas_usbhs/rza2.c

@@ -29,7 +29,7 @@ static int usbhs_rza2_hardware_exit(struct platform_device *pdev)
 {
 	struct usbhs_priv *priv = usbhs_pdev_to_priv(pdev);
 
-	phy_put(priv->phy);
+	phy_put(&pdev->dev, priv->phy);
 	priv->phy = NULL;
 
 	return 0;

include/linux/phy/phy.h

@@ -234,7 +234,8 @@ struct phy *devm_of_phy_get(struct device *dev, struct device_node *np,
 			    const char *con_id);
 struct phy *devm_of_phy_get_by_index(struct device *dev, struct device_node *np,
 				     int index);
-void phy_put(struct phy *phy);
+void of_phy_put(struct phy *phy);
+void phy_put(struct device *dev, struct phy *phy);
 void devm_phy_put(struct device *dev, struct phy *phy);
 struct phy *of_phy_get(struct device_node *np, const char *con_id);
 struct phy *of_phy_simple_xlate(struct device *dev,
@@ -419,7 +420,11 @@ static inline struct phy *devm_of_phy_get_by_index(struct device *dev,
 	return ERR_PTR(-ENOSYS);
 }
 
-static inline void phy_put(struct phy *phy)
+static inline void of_phy_put(struct phy *phy)
+{
+}
+
+static inline void phy_put(struct device *dev, struct phy *phy)
 {
 }