From: Lad, Prabhakar <[email protected]>

Signed-off-by: Lad, Prabhakar <[email protected]>
Signed-off-by: Manjunath Hadli <[email protected]>
Cc: Hans Verkuil <[email protected]>
Cc: Sakari Ailus <[email protected]>
Cc: Sylwester Nawrocki <[email protected]>
Cc: Laurent Pinchart <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: Hans de Goede <[email protected]>
Cc: Kyungmin Park <[email protected]>
Cc: Rob Landley <[email protected]>
---
 Documentation/video4linux/v4l2-controls.txt |   26 +++++++++++++++++++++++++
 drivers/media/v4l2-core/v4l2-ctrls.c        |   28 +++++++++++++++++++++++++++
 include/media/v4l2-ctrls.h                  |   14 +++++++++++++
 3 files changed, 68 insertions(+), 0 deletions(-)

diff --git a/Documentation/video4linux/v4l2-controls.txt 
b/Documentation/video4linux/v4l2-controls.txt
index 43da22b..54a9539 100644
--- a/Documentation/video4linux/v4l2-controls.txt
+++ b/Documentation/video4linux/v4l2-controls.txt
@@ -196,6 +196,32 @@ the error code at the end. Saves a lot of repetitive error 
checking.
 It is recommended to add controls in ascending control ID order: it will be
 a bit faster that way.
 
+2.1) Changing the menu of a standard control:
+There are suitations when the control is standard but the menu items may be
+device specific, in such cases the framework provides the helper to do that.
+
+struct v4l2_ctrl * v4l2_ctrl_modify_menu(struct v4l2_ctrl *ctrl,
+       const char * const *qmenu, s32 min, s32 max,
+       u32 menu_skip_mask, s32 def);
+
+This helper, function is used to modify the menu, min, max, mask and
+the default value to set.
+Example for usage:
+       static const char * const test_pattern[] = {
+               "Disabled",
+               "Vertical Bars",
+               "Vertical Bars",
+               "Solid Black",
+               "Solid White",
+               NULL
+       };
+       struct v4l2_ctrl *test_pattern_ctrl =
+               v4l2_ctrl_new_std_menu(&foo->ctrl_handler, &foo_ctrl_ops,
+                       V4L2_CID_TEST_PATTERN, V4L2_TEST_PATTERN_DISABLED, 0,
+                       V4L2_TEST_PATTERN_DISABLED);
+
+       v4l2_ctrl_modify_menu(test_pattern_ctrl, test_pattern, 0, 5, 0x3, 0);
+
 3) Optionally force initial control setup:
 
        v4l2_ctrl_handler_setup(&foo->ctrl_handler);
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c 
b/drivers/media/v4l2-core/v4l2-ctrls.c
index d731422..ac0fb28 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -2666,3 +2666,31 @@ unsigned int v4l2_ctrl_poll(struct file *file, struct 
poll_table_struct *wait)
        return 0;
 }
 EXPORT_SYMBOL(v4l2_ctrl_poll);
+
+/* Helper function for standard menu controls to modify the menu */
+struct v4l2_ctrl *v4l2_ctrl_modify_menu(struct v4l2_ctrl *ctrl,
+                                        const char * const *qmenu, s32 min,
+                                        s32 max, u32 menu_skip_mask, s32 def)
+{
+       if (ctrl->type != V4L2_CTRL_TYPE_MENU)
+               return NULL;
+
+       if (qmenu == NULL)
+               return NULL;
+
+       /* Determine if it is standard menu control */
+       if (!v4l2_ctrl_get_menu(ctrl->id))
+               return NULL;
+
+       if ((def > max) || (max < min))
+               return NULL;
+
+       ctrl->qmenu = qmenu;
+       ctrl->minimum = min;
+       ctrl->maximum = max;
+       ctrl->menu_skip_mask = menu_skip_mask;
+       ctrl->cur.val = ctrl->val = ctrl->default_value = def;
+
+       return ctrl;
+}
+EXPORT_SYMBOL(v4l2_ctrl_modify_menu);
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index 776605f..5b0ea04 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -488,6 +488,20 @@ static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
        mutex_unlock(ctrl->handler->lock);
 }
 
+/**
+ * v4l2_ctrl_modify_menu() - Modify the menu. This function is used when the
+ * control is standard but the menu is specific to device.
+ * @ctrl:              The control to change the menu.
+ * @qmenu:             The menu to which control will point to.
+ * @min:               Minimum value of the control.
+ * @max:               Maximum valur of the control.
+ * @menu_skip_mask:    The control's skip mask for menu controls.
+ * @def:               The default value for control.
+ */
+struct v4l2_ctrl *v4l2_ctrl_modify_menu(struct v4l2_ctrl *ctrl,
+                                        const char * const *qmenu, s32 min,
+                                        s32 max, u32 menu_skip_mask, s32 def);
+
 /** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from 
within a driver.
   * @ctrl:     The control.
   *
-- 
1.7.0.4

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