[PATCH v5] media: v4l2-ctrl: add a helper function to add standard control with driver specific menu

From: Prabhakar
Date: Mon Sep 24 2012 - 08:54:00 EST


From: Lad, Prabhakar <prabhakar.lad@xxxxxx>

Add helper function v4l2_ctrl_new_std_menu_items(), which adds
a standard menu control, with driver specific menu.

Signed-off-by: Lad, Prabhakar <prabhakar.lad@xxxxxx>
Signed-off-by: Manjunath Hadli <manjunath.hadli@xxxxxx>
Cc: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Cc: Sakari Ailus <sakari.ailus@xxxxxx>
Cc: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxx>
Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
Cc: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
Cc: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
Cc: Rob Landley <rob@xxxxxxxxxxx>
---
Changes for v5:
1: Fixed some grammatical issues pointed by Hans.

Changes for v4:
1: Rather then adding a function to modify the menu, added a helper
function, that creates a new standard control with user specific
menu.

Changes for v3:
1: Fixed style/grammer issues as pointed by Hans.
Thanks Hans for providing the description.

Changes for v2:
1: Fixed review comments from Hans, to have return type as
void, add WARN_ON() for fail conditions, allow this fucntion
to modify the menu of custom controls.

Documentation/video4linux/v4l2-controls.txt | 24 +++++++++++++++++++++
drivers/media/v4l2-core/v4l2-ctrls.c | 30 +++++++++++++++++++++++++++
include/media/v4l2-ctrls.h | 23 ++++++++++++++++++++
3 files changed, 77 insertions(+), 0 deletions(-)

diff --git a/Documentation/video4linux/v4l2-controls.txt b/Documentation/video4linux/v4l2-controls.txt
index 43da22b..b0cb0b8 100644
--- a/Documentation/video4linux/v4l2-controls.txt
+++ b/Documentation/video4linux/v4l2-controls.txt
@@ -136,11 +136,25 @@ Or alternatively for integer menu controls, by calling v4l2_ctrl_new_int_menu:
const struct v4l2_ctrl_ops *ops,
u32 id, s32 max, s32 def, const s64 *qmenu_int);

+Standard menu controls with a driver specific menu are added by calling
+v4l2_ctrl_new_std_menu_items:
+
+ struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(
+ struct v4l2_ctrl_handler *hdl,
+ const struct v4l2_ctrl_ops *ops, u32 id, s32 max,
+ s32 skip_mask, s32 def, const char * const *qmenu);
+
These functions are typically called right after the v4l2_ctrl_handler_init:

static const s64 exp_bias_qmenu[] = {
-2, -1, 0, 1, 2
};
+ static const char * const test_pattern[] = {
+ "Disabled",
+ "Vertical Bars",
+ "Solid Black",
+ "Solid White",
+ };

v4l2_ctrl_handler_init(&foo->ctrl_handler, nr_of_controls);
v4l2_ctrl_new_std(&foo->ctrl_handler, &foo_ctrl_ops,
@@ -156,6 +170,9 @@ These functions are typically called right after the v4l2_ctrl_handler_init:
ARRAY_SIZE(exp_bias_qmenu) - 1,
ARRAY_SIZE(exp_bias_qmenu) / 2 - 1,
exp_bias_qmenu);
+ v4l2_ctrl_new_std_menu_items(&foo->ctrl_handler, &foo_ctrl_ops,
+ V4L2_CID_TEST_PATTERN, ARRAY_SIZE(test_pattern) - 1, 0,
+ 0, test_pattern);
...
if (foo->ctrl_handler.error) {
int err = foo->ctrl_handler.error;
@@ -185,6 +202,13 @@ v4l2_ctrl_new_std_menu in that it doesn't have the mask argument and takes
as the last argument an array of signed 64-bit integers that form an exact
menu item list.

+The v4l2_ctrl_new_std_menu_items function is very similar to
+v4l2_ctrl_new_std_menu but takes an extra parameter qmenu, which is the driver
+specific menu for an otherwise standard menu control. A good example for this
+control is the test pattern control for capture/display/sensors devices that
+have the capability to generate test patterns. These test patterns are hardware
+specific, so the contents of the menu will vary from device to device.
+
Note that if something fails, the function will return NULL or an error and
set ctrl_handler->error to the error code. If ctrl_handler->error was already
set, then it will just return and do nothing. This is also true for
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 41b7732..96c5e73 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1643,6 +1643,36 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
}
EXPORT_SYMBOL(v4l2_ctrl_new_std_menu);

+/* Helper function for standard menu controls with driver defined menu */
+struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
+ const struct v4l2_ctrl_ops *ops, u32 id, s32 max,
+ s32 mask, s32 def, const char * const *qmenu)
+{
+ enum v4l2_ctrl_type type;
+ const char *name;
+ u32 flags;
+ s32 step;
+ s32 min;
+
+ /* v4l2_ctrl_new_std_menu_items() should only be called for
+ * standard controls without a standard menu.
+ */
+ if (v4l2_ctrl_get_menu(id)) {
+ handler_set_err(hdl, -EINVAL);
+ return NULL;
+ }
+
+ v4l2_ctrl_fill(id, &name, &type, &min, &max, &step, &def, &flags);
+ if (type != V4L2_CTRL_TYPE_MENU || qmenu == NULL) {
+ handler_set_err(hdl, -EINVAL);
+ return NULL;
+ }
+ return v4l2_ctrl_new(hdl, ops, id, name, type, 0, max, mask, def,
+ flags, qmenu, NULL, NULL);
+
+}
+EXPORT_SYMBOL(v4l2_ctrl_new_std_menu_items);
+
/* Helper function for standard integer menu controls */
struct v4l2_ctrl *v4l2_ctrl_new_int_menu(struct v4l2_ctrl_handler *hdl,
const struct v4l2_ctrl_ops *ops,
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index 776605f..8db9dbe 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -351,6 +351,29 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
const struct v4l2_ctrl_ops *ops,
u32 id, s32 max, s32 mask, s32 def);

+/** v4l2_ctrl_new_std_menu_items() - Create a new standard V4L2 menu control
+ * with driver specific menu.
+ * @hdl: The control handler.
+ * @ops: The control ops.
+ * @id: The control ID.
+ * @max: The control's maximum value.
+ * @mask: The control's skip mask for menu controls. This makes it
+ * easy to skip menu items that are not valid. If bit X is set,
+ * then menu item X is skipped. Of course, this only works for
+ * menus with <= 32 menu items. There are no menus that come
+ * close to that number, so this is OK. Should we ever need more,
+ * then this will have to be extended to a u64 or a bit array.
+ * @def: The control's default value.
+ * @qmenu: The new menu.
+ *
+ * Same as v4l2_ctrl_new_std_menu(), but @qmenu will be the driver specific
+ * menu of this control.
+ *
+ */
+struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
+ const struct v4l2_ctrl_ops *ops, u32 id, s32 max,
+ s32 mask, s32 def, const char * const *qmenu);
+
/** v4l2_ctrl_new_int_menu() - Create a new standard V4L2 integer menu control.
* @hdl: The control handler.
* @ops: The control ops.
--
1.7.4.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/