This patch adds managed versions of initialization
and cleanup functions for v4l2 control handler.

Signed-off-by: Andrzej Hajda <a.ha...@samsung.com>
Reviewed-by: Sylwester Nawrocki <s.nawro...@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.p...@samsung.com>
---
v2:
        - added missing struct device forward declaration,
        - corrected few comments
---
 drivers/media/v4l2-core/v4l2-ctrls.c |   48 ++++++++++++++++++++++++++++++++++
 include/media/v4l2-ctrls.h           |   31 ++++++++++++++++++++++
 2 files changed, 79 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c 
b/drivers/media/v4l2-core/v4l2-ctrls.c
index ebb8e48..69c9b95 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1421,6 +1421,54 @@ void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler 
*hdl)
 }
 EXPORT_SYMBOL(v4l2_ctrl_handler_free);
 
+static void devm_v4l2_ctrl_handler_release(struct device *dev, void *res)
+{
+       struct v4l2_ctrl_handler **hdl = res;
+
+       v4l2_ctrl_handler_free(*hdl);
+}
+
+int devm_v4l2_ctrl_handler_init(struct device *dev,
+                               struct v4l2_ctrl_handler *hdl,
+                               unsigned nr_of_controls_hint)
+{
+       struct v4l2_ctrl_handler **dr;
+       int rc;
+
+       dr = devres_alloc(devm_v4l2_ctrl_handler_release, sizeof(*dr),
+                         GFP_KERNEL);
+       if (!dr)
+               return -ENOMEM;
+
+       rc = v4l2_ctrl_handler_init(hdl, nr_of_controls_hint);
+       if (rc) {
+               devres_free(dr);
+               return rc;
+       }
+
+       *dr = hdl;
+       devres_add(dev, dr);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(devm_v4l2_ctrl_handler_init);
+
+static int devm_v4l2_ctrl_handler_match(struct device *dev, void *res,
+                                       void *data)
+{
+       struct v4l2_ctrl_handler **this = res, **hdl = data;
+
+       return *this == *hdl;
+}
+
+void devm_v4l2_ctrl_handler_free(struct device *dev,
+                                struct v4l2_ctrl_handler *hdl)
+{
+       WARN_ON(devres_release(dev, devm_v4l2_ctrl_handler_release,
+                              devm_v4l2_ctrl_handler_match, &hdl));
+}
+EXPORT_SYMBOL_GPL(devm_v4l2_ctrl_handler_free);
+
 /* For backwards compatibility: V4L2_CID_PRIVATE_BASE should no longer
    be used except in G_CTRL, S_CTRL, QUERYCTRL and QUERYMENU when dealing
    with applications that do not use the NEXT_CTRL flag.
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index 7343a27..1986b90 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -25,6 +25,7 @@
 #include <linux/videodev2.h>
 
 /* forward references */
+struct device;
 struct file;
 struct v4l2_ctrl_handler;
 struct v4l2_ctrl_helper;
@@ -306,6 +307,36 @@ int v4l2_ctrl_handler_init_class(struct v4l2_ctrl_handler 
*hdl,
   */
 void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);
 
+/*
+ * devm_v4l2_ctrl_handler_init - managed control handler initialization
+ *
+ * @dev: Device the @hdl belongs to.
+ * @hdl:       The control handler.
+ * @nr_of_controls_hint: A hint of how many controls this handler is
+ *             expected to refer to.
+ *
+ * This is a managed version of v4l2_ctrl_handler_init. Handler initialized 
with
+ * this function will be automatically cleaned up on driver detach.
+ *
+ * If an handler initialized with this function needs to be cleaned up
+ * separately, devm_v4l2_ctrl_handler_free() must be used.
+ */
+int devm_v4l2_ctrl_handler_init(struct device *dev,
+                               struct v4l2_ctrl_handler *hdl,
+                               unsigned nr_of_controls_hint);
+
+/**
+ * devm_v4l2_ctrl_handler_free - managed control handler free
+ *
+ * @dev: Device the @hdl belongs to.
+ * @hdl: Handler to be cleaned up.
+ *
+ * This function should be used to manual free of an control handler
+ * initialized with devm_v4l2_ctrl_handler_init().
+ */
+void devm_v4l2_ctrl_handler_free(struct device *dev,
+                                struct v4l2_ctrl_handler *hdl);
+
 /** v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
   * to the handler to initialize the hardware to the current control values.
   * @hdl:      The control handler.
-- 
1.7.10.4

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