[RFC PATCH v2 1/7] of: base: Add of_device_is_fail

[Chen-Yu Tsai <wenst@chromium.org>]

In some cases we want to check that a device is not only unavailable,
but specifically marked as "fail".

This will be used in a following change in the hardware prober driver.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
 drivers/of/base.c  | 20 ++++++++++++++++++++
 include/linux/of.h |  6 ++++++
 2 files changed, 26 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 8d93cb6ea9cd..2726e5dce1bf 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -486,6 +486,26 @@ static bool __of_device_is_fail(const struct device_node *device)
 	return !strcmp(status, "fail") || !strncmp(status, "fail-", 5);
 }
 
+/**
+ *  of_device_is_fail - check if a device has status "fail" or "fail-..."
+ *
+ *  @device: Node to check status for
+ *
+ *  Return: True if the status property is set to "fail" or "fail-..." (for any
+ *  error code suffix), false otherwise
+ */
+bool of_device_is_fail(const struct device_node *device)
+{
+	unsigned long flags;
+	bool res;
+
+	raw_spin_lock_irqsave(&devtree_lock, flags);
+	res = __of_device_is_fail(device);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
+	return res;
+}
+EXPORT_SYMBOL(of_device_is_fail);
+
 /**
  *  of_device_is_big_endian - check if a device has BE registers
  *
diff --git a/include/linux/of.h b/include/linux/of.h
index 6a9ddf20e79a..463fbf0072bd 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -350,6 +350,7 @@ extern int of_device_is_compatible(const struct device_node *device,
 extern int of_device_compatible_match(const struct device_node *device,
 				      const char *const *compat);
 extern bool of_device_is_available(const struct device_node *device);
+extern bool of_device_is_fail(const struct device_node *device);
 extern bool of_device_is_big_endian(const struct device_node *device);
 extern const void *of_get_property(const struct device_node *node,
 				const char *name,
@@ -584,6 +585,11 @@ static inline bool of_device_is_available(const struct device_node *device)
 	return false;
 }
 
+static inline bool of_device_is_fail(const struct device_node *device)
+{
+	return false;
+}
+
 static inline bool of_device_is_big_endian(const struct device_node *device)
 {
 	return false;
-- 
2.42.0.869.gea05f2083d-goog