[PATCH 2/2] reset: implement reset_control_bulk_get()

[Sascha Hauer <s.hauer@pengutronix.de>]

This implements reset_control_bulk_get() to get multiple reset
controllers at once.

This somewhat overlaps with reset_control_array_get(). The difference is
that reset_control_array_get() returns a single reset controller which
internally handles the array of reset controllers whereas
reset_control_bulk_get() allows the consumer to control each reset
controller individually.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/reset/core.c  | 24 ++++++++++++++++++++++++
 include/linux/reset.h | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index 679deee3c1..2431a9374a 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -484,6 +484,30 @@ struct reset_control *reset_control_array_get(struct device *dev)
 	return rstc;
 }
 
+int __reset_control_bulk_get(struct device *dev, int num_rstcs,
+			     struct reset_control_bulk_data *rstcs,
+			     bool optional)
+{
+	int ret, i;
+
+	for (i = 0; i < num_rstcs; i++) {
+		rstcs[i].rstc = __reset_control_get(dev, rstcs[i].id, optional);
+		if (IS_ERR(rstcs[i].rstc)) {
+			ret = PTR_ERR(rstcs[i].rstc);
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	while (i--)
+		reset_control_put(rstcs[i].rstc);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__reset_control_bulk_get);
+
 int device_reset_all(struct device *dev)
 {
 	struct reset_control *rstc;
diff --git a/include/linux/reset.h b/include/linux/reset.h
index 183d7d55a0..9469825faf 100644
--- a/include/linux/reset.h
+++ b/include/linux/reset.h
@@ -6,6 +6,21 @@
 struct device;
 struct reset_control;
 
+/**
+ * struct reset_control_bulk_data - Data used for bulk reset control operations.
+ *
+ * @id: reset control consumer ID
+ * @rstc: struct reset_control * to store the associated reset control
+ *
+ * The reset APIs provide a series of reset_control_bulk_*() API calls as
+ * a convenience to consumers which require multiple reset controls.
+ * This structure is used to manage data for these calls.
+ */
+struct reset_control_bulk_data {
+	const char			*id;
+	struct reset_control		*rstc;
+};
+
 #ifdef CONFIG_RESET_CONTROLLER
 
 int reset_control_status(struct reset_control *rstc);
@@ -28,6 +43,10 @@ int reset_control_get_count(struct device *dev);
 
 struct reset_control *reset_control_array_get(struct device *dev);
 
+int __reset_control_bulk_get(struct device *dev, int num_rstcs,
+			     struct reset_control_bulk_data *rstcs,
+			     bool optional);
+
 #else
 
 static inline int reset_control_status(struct reset_control *rstc)
@@ -91,6 +110,14 @@ static inline struct reset_control *reset_control_array_get(struct device *dev)
 	return NULL;
 }
 
+static inline int
+__reset_control_bulk_get(struct device *dev, int num_rstcs,
+			 struct reset_control_bulk_data *rstcs,
+			 bool optional)
+{
+	return optional ? 0 : -EOPNOTSUPP;
+}
+
 #endif /* CONFIG_RESET_CONTROLLER */
 
 static inline struct reset_control *reset_control_get_optional(struct device *dev,
@@ -105,4 +132,21 @@ static inline struct reset_control *reset_control_get(struct device *dev,
 	return __reset_control_get(dev, id, false);
 }
 
+/**
+ * reset_control_bulk_get - Lookup and obtain references to
+ *                                    multiple reset controllers.
+ * @dev: device to be reset by the controller
+ * @num_rstcs: number of entries in rstcs array
+ * @rstcs: array of struct reset_control_bulk_data with reset line names set
+ *
+ * Fills the rstcs array with pointers to reset controls and
+ * returns 0, or an IS_ERR() condition containing errno.
+ */
+static inline int __must_check
+reset_control_bulk_get(struct device *dev, int num_rstcs,
+		       struct reset_control_bulk_data *rstcs)
+{
+	return __reset_control_bulk_get(dev, num_rstcs, rstcs, false);
+}
+
 #endif

-- 
2.39.5