[PATCH v2 1/2] phy: add new phy_notify_pmstate() api

[Peter Griffin]

Add a new phy_notify_pmstate() api that notifies and configures a phy for a
given PM link state transition.

This is intended to be by phy drivers which need to do some runtime
configuration of parameters during the transition that can't be handled by
phy_calibrate() or phy_power_{on|off}().

The first usage of this API is in the Samsung UFS phy that needs to issue
some register writes when entering and exiting the hibernate link state.

Signed-off-by: Peter Griffin <peter.griffin at linaro.org>
---
 drivers/phy/phy-core.c  | 25 +++++++++++++++++++++++++
 include/linux/phy/phy.h | 25 +++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index 04a5a34e7a950ae94fae915673c25d476fc071c1..0b29bc2c709890d7fc27d1480a35cda6a826fd30 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -520,6 +520,31 @@ int phy_notify_disconnect(struct phy *phy, int port)
 }
 EXPORT_SYMBOL_GPL(phy_notify_disconnect);
 
+/**
+ * phy_notify_pmstate() - phy link state notification
+ * @phy: the phy returned by phy_get()
+ * @state: the link state
+ *
+ * Notify the phy of some PM link state transition. Used to notify and
+ * configure the phy accordingly.
+ *
+ * Returns: %0 if successful, a negative error code otherwise
+ */
+int phy_notify_pmstate(struct phy *phy, enum phy_linkstate state)
+{
+	int ret;
+
+	if (!phy || !phy->ops->notify_pmstate)
+		return 0;
+
+	mutex_lock(&phy->mutex);
+	ret = phy->ops->notify_pmstate(phy, state);
+	mutex_unlock(&phy->mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(phy_notify_pmstate);
+
 /**
  * phy_configure() - Changes the phy parameters
  * @phy: the phy returned by phy_get()
diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
index 13add0c2c40721fe9ca3f0350d13c035cd25af45..d904ec4edb7e2be41fcf6ab780d3148c2ee8a950 100644
--- a/include/linux/phy/phy.h
+++ b/include/linux/phy/phy.h
@@ -53,6 +53,11 @@ enum phy_media {
 	PHY_MEDIA_DAC,
 };
 
+enum phy_linkstate {
+	PHY_UFS_HIBERN8_ENTER,
+	PHY_UFS_HIBERN8_EXIT,
+};
+
 /**
  * union phy_configure_opts - Opaque generic phy configuration
  *
@@ -132,6 +137,18 @@ struct phy_ops {
 	int	(*connect)(struct phy *phy, int port);
 	int	(*disconnect)(struct phy *phy, int port);
 
+	/**
+	 * @notify_pmstate:
+	 *
+	 * Optional.
+	 *
+	 * Used to notify and configure the phy for a PM link state
+	 * transition.
+	 *
+	 * Returns: 0 if successful, an negative error code otherwise
+	 */
+	int	(*notify_pmstate)(struct phy *phy, enum phy_linkstate state);
+
 	void	(*release)(struct phy *phy);
 	struct module *owner;
 };
@@ -255,6 +272,7 @@ int phy_reset(struct phy *phy);
 int phy_calibrate(struct phy *phy);
 int phy_notify_connect(struct phy *phy, int port);
 int phy_notify_disconnect(struct phy *phy, int port);
+int phy_notify_pmstate(struct phy *phy, enum phy_linkstate state);
 static inline int phy_get_bus_width(struct phy *phy)
 {
 	return phy->attrs.bus_width;
@@ -412,6 +430,13 @@ static inline int phy_notify_disconnect(struct phy *phy, int index)
 	return -ENOSYS;
 }
 
+static inline int phy_notify_pmstate(struct phy *phy, enum phy_linkstate state)
+{
+	if (!phy)
+		return 0;
+	return -ENOSYS;
+}
+
 static inline int phy_configure(struct phy *phy,
 				union phy_configure_opts *opts)
 {

-- 
2.50.0.727.gbf7dc18ff4-goog