[PATCH v4 1/2] phy: core: add phy_property_present method

[Anvesh Salveru]

In some platforms, we need information of phy properties in
the controller drivers. This patch adds a new phy_property_present()
method which can be used to check if some property exists in PHY
or not.

In case of DesignWare PCIe controller, we need to write into controller
register to specify about ZRX-DC compliance property of the PHY, which
reduces the power consumption during lower power states.

Signed-off-by: Anvesh Salveru <anvesh.s@xxxxxxxxxxx>
Signed-off-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
---
 drivers/phy/phy-core.c  | 26 ++++++++++++++++++++++++++
 include/linux/phy/phy.h |  8 ++++++++
 2 files changed, 34 insertions(+)

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index b04f4fe..0a62eca 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -420,6 +420,32 @@ int phy_calibrate(struct phy *phy)
 EXPORT_SYMBOL_GPL(phy_calibrate);
 
 /**
+ * phy_property_present() - checks if the property is present in PHY
+ * @phy: the phy returned by phy_get()
+ * @property: name of the property to check
+ *
+ * Used to check if the given property is present in PHY. PHY drivers
+ * can implement this callback function to expose PHY properties to
+ * controller drivers.
+ *
+ * Returns: true if property exists, false otherwise
+ */
+bool phy_property_present(struct phy *phy, const char *property)
+{
+	bool ret;
+
+	if (!phy || !phy->ops->property_present)
+		return false;
+
+	mutex_lock(&phy->mutex);
+	ret = phy->ops->property_present(phy, property);
+	mutex_unlock(&phy->mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(phy_property_present);
+
+/**
  * phy_configure() - Changes the phy parameters
  * @phy: the phy returned by phy_get()
  * @opts: New configuration to apply
diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
index 15032f14..3dd8f3c 100644
--- a/include/linux/phy/phy.h
+++ b/include/linux/phy/phy.h
@@ -61,6 +61,7 @@ union phy_configure_opts {
  * @reset: resetting the phy
  * @calibrate: calibrate the phy
  * @release: ops to be performed while the consumer relinquishes the PHY
+ * @property_present: check if some property is present in PHY
  * @owner: the module owner containing the ops
  */
 struct phy_ops {
@@ -103,6 +104,7 @@ struct phy_ops {
 	int	(*reset)(struct phy *phy);
 	int	(*calibrate)(struct phy *phy);
 	void	(*release)(struct phy *phy);
+	bool	(*property_present)(struct phy *phy, const char *property);
 	struct module *owner;
 };
 
@@ -217,6 +219,7 @@ static inline enum phy_mode phy_get_mode(struct phy *phy)
 }
 int phy_reset(struct phy *phy);
 int phy_calibrate(struct phy *phy);
+bool phy_property_present(struct phy *phy, const char *property);
 static inline int phy_get_bus_width(struct phy *phy)
 {
 	return phy->attrs.bus_width;
@@ -354,6 +357,11 @@ static inline int phy_calibrate(struct phy *phy)
 	return -ENOSYS;
 }
 
+static inline bool phy_property_present(struct phy *phy, const char *property)
+{
+	return false;
+}
+
 static inline int phy_configure(struct phy *phy,
 				union phy_configure_opts *opts)
 {
-- 
2.7.4