[PATCH v6 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>
---
Changes w.r.t v5:
 - Added check for NULL pointer

 drivers/phy/phy-core.c  | 20 ++++++++++++++++++++
 include/linux/phy/phy.h |  6 ++++++
 2 files changed, 26 insertions(+)

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index b04f4fe..16b19aa 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -420,6 +420,26 @@ 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.
+ * Searches for the given property in the phy device tree
+ * node.
+ *
+ * Returns: true if property exists, false otherwise
+ */
+bool phy_property_present(struct phy *phy, const char *property)
+{
+	if (!phy)
+		return false;
+
+	return of_property_read_bool(phy->dev.of_node, property);
+}
+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 56d3a10..9d8240d 100644
--- a/include/linux/phy/phy.h
+++ b/include/linux/phy/phy.h
@@ -218,6 +218,7 @@ 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;
@@ -355,6 +356,11 @@ 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