[PATCH 1/4] PCI: of: Add of_pci_clkreq_present()

[Shawn Lin <shawn.lin@rock-chips.com>]

of_pci_clkreq_present() is used by host drivers to decide whether the clkreq#
is properly connected and could enable L1.1/L1.2 support.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
---
 drivers/pci/of.c  | 18 ++++++++++++++++++
 drivers/pci/pci.h |  6 ++++++
 2 files changed, 24 insertions(+)

diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 3579265f1198..52c6d365083b 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -1010,3 +1010,21 @@ int of_pci_get_equalization_presets(struct device *dev,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_pci_get_equalization_presets);
+
+/**
+ * of_pci_clkreq_present() - Check if the "supports-clkreq" is present
+ * @np: Device tree node
+ *
+ * If the property is present, it means CLKREQ# is properly connected
+ * and the hardware is ready to support L1.1/L1.2
+ *
+ * Return: true if the property is available, false otherwise.
+ */
+bool of_pci_clkreq_present(struct device_node *np)
+{
+	if (!np)
+		return false;
+
+	return of_property_present(np, "supports-clkreq");
+}
+EXPORT_SYMBOL_GPL(of_pci_clkreq_present);
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 4492b809094b..2421e39e6e48 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -1061,6 +1061,7 @@ bool of_pci_supply_present(struct device_node *np);
 int of_pci_get_equalization_presets(struct device *dev,
 				    struct pci_eq_presets *presets,
 				    int num_lanes);
+bool of_pci_clkreq_present(struct device_node *np);
 #else
 static inline int
 of_get_pci_domain_nr(struct device_node *node)
@@ -1106,6 +1107,11 @@ static inline bool of_pci_supply_present(struct device_node *np)
 	return false;
 }
 
+static inline bool of_pci_clkreq_present(struct device_node *np)
+{
+	return false;
+}
+
 static inline int of_pci_get_equalization_presets(struct device *dev,
 						  struct pci_eq_presets *presets,
 						  int num_lanes)
-- 
2.43.0