phy: add new phy_notify_state() api

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

This is intended to be used by phy drivers which need to do some runtime
configuration of parameters 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@linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20251112-phy-notify-pmstate-v5-1-39df622d8fcb@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index 04a5a34e7a95..60be8af984bf 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -521,6 +521,31 @@ int phy_notify_disconnect(struct phy *phy, int port)
 EXPORT_SYMBOL_GPL(phy_notify_disconnect);
 
 /**
+ * phy_notify_state() - phy state notification
+ * @phy: the PHY returned by phy_get()
+ * @state: the PHY state
+ *
+ * Notify the PHY of a state transition. Used to notify and
+ * configure the PHY accordingly.
+ *
+ * Returns: %0 if successful, a negative error code otherwise
+ */
+int phy_notify_state(struct phy *phy, union phy_notify state)
+{
+	int ret;
+
+	if (!phy || !phy->ops->notify_phystate)
+		return 0;
+
+	mutex_lock(&phy->mutex);
+	ret = phy->ops->notify_phystate(phy, state);
+	mutex_unlock(&phy->mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(phy_notify_state);
+
+/**
  * phy_configure() - Changes the phy parameters
  * @phy: the phy returned by phy_get()
  * @opts: New configuration to apply