[PATCH] reset: add reset_control_status helper function

[<dinguyen@opensource.altera.com>]

From: Dinh Nguyen <dinguyen@opensource.altera.com>

There are cases where a system will want to read a reset status bit before
doing any other toggling. Add a reset_control_status helper function to the
reset controller API.

Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>
---
 drivers/reset/core.c             | 13 +++++++++++++
 include/linux/reset-controller.h |  1 +
 include/linux/reset.h            |  7 +++++++
 3 files changed, 21 insertions(+)

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index baeaf82..06387a4 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -126,6 +126,19 @@ int reset_control_deassert(struct reset_control *rstc)
 EXPORT_SYMBOL_GPL(reset_control_deassert);
 
 /**
+ * reset_control_status - returns a status of a reset bit
+ * @rstc: reset controller
+ */
+unsigned int reset_control_status(struct reset_control *rstc)
+{
+	if (rstc->rcdev->ops->status)
+		return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
+
+	return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(reset_control_status);
+
+/**
  * of_reset_control_get - Lookup and obtain a reference to a reset controller.
  * @node: device to be reset by the controller
  * @id: reset line name
diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h
index 41a4695..8e659d5 100644
--- a/include/linux/reset-controller.h
+++ b/include/linux/reset-controller.h
@@ -17,6 +17,7 @@ struct reset_control_ops {
 	int (*reset)(struct reset_controller_dev *rcdev, unsigned long id);
 	int (*assert)(struct reset_controller_dev *rcdev, unsigned long id);
 	int (*deassert)(struct reset_controller_dev *rcdev, unsigned long id);
+	unsigned int (*status)(struct reset_controller_dev *rcdev, unsigned long id);
 };
 
 struct module;
diff --git a/include/linux/reset.h b/include/linux/reset.h
index 349f150..09233ee 100644
--- a/include/linux/reset.h
+++ b/include/linux/reset.h
@@ -10,6 +10,7 @@ struct reset_control;
 int reset_control_reset(struct reset_control *rstc);
 int reset_control_assert(struct reset_control *rstc);
 int reset_control_deassert(struct reset_control *rstc);
+unsigned int reset_control_status(struct reset_control *rstc);
 
 struct reset_control *reset_control_get(struct device *dev, const char *id);
 void reset_control_put(struct reset_control *rstc);
@@ -57,6 +58,12 @@ static inline int reset_control_deassert(struct reset_control *rstc)
 	return 0;
 }
 
+static inline unsigned int reset_control_status(struct reset_control *rstc)
+{
+	WARN_ON(1);
+	return 0;
+}
+
 static inline void reset_control_put(struct reset_control *rstc)
 {
 	WARN_ON(1);
-- 
2.0.3