[PATCH RFC v2 2/3] media: added managed v4l2 control initialization

Andrzej Hajda
2013-05-13T08:35:07Z

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

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@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