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+/*
+ V4L2 controls support header.
+
+ Copyright (C) 2010 Hans Verkuil <hverkuil@xs4all.nl>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _V4L2_CTRLS_H
+#define _V4L2_CTRLS_H
+
+#include <linux/list.h>
+#include <linux/device.h>
+
+/* forward references */
+struct v4l2_ctrl_handler;
+struct v4l2_ctrl;
+struct video_device;
+struct v4l2_subdev;
+
+/** struct v4l2_ctrl_ops - The control operations that the driver has to provide.
+ * @g_volatile_ctrl: Get a new value for this control. Generally only relevant
+ * for volatile (and usually read-only) controls such as a control
+ * that returns the current signal strength which changes
+ * continuously.
+ * If not set, then the currently cached value will be returned.
+ * @try_ctrl: Test whether the control's value is valid. Only relevant when
+ * the usual min/max/step checks are not sufficient.
+ * @s_ctrl: Actually set the new control value. s_ctrl is compulsory. The
+ * ctrl->handler->lock is held when these ops are called, so no
+ * one else can access controls owned by that handler.
+ */
+struct v4l2_ctrl_ops {
+ int (*g_volatile_ctrl)(struct v4l2_ctrl *ctrl);
+ int (*try_ctrl)(struct v4l2_ctrl *ctrl);
+ int (*s_ctrl)(struct v4l2_ctrl *ctrl);
+};
+
+/** struct v4l2_ctrl - The control structure.
+ * @node: The list node.
+ * @handler: The handler that owns the control.
+ * @cluster: Point to start of cluster array.
+ * @ncontrols: Number of controls in cluster array.
+ * @has_new: Internal flag: set when there is a valid new value.
+ * @done: Internal flag: set for each processed control.
+ * @is_private: If set, then this control is private to its handler and it
+ * will not be added to any other handlers. Drivers can set
+ * this flag.
+ * @is_volatile: If set, then this control is volatile. This means that the
+ * control's current value cannot be cached and needs to be
+ * retrieved through the g_volatile_ctrl op. Drivers can set
+ * this flag.
+ * @ops: The control ops.
+ * @id: The control ID.
+ * @name: The control name.
+ * @type: The control type.
+ * @minimum: The control's minimum value.
+ * @maximum: The control's maximum value.
+ * @default_value: The control's default value.
+ * @step: The control's step value for non-menu controls.
+ * @menu_skip_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.
+ * @qmenu: A const char * array for all menu items. Array entries that are
+ * empty strings ("") correspond to non-existing menu items (this
+ * is in addition to the menu_skip_mask above). The last entry
+ * must be NULL.
+ * @flags: The control's flags.
+ * @cur: The control's current value.
+ * @val: The control's new s32 value.
+ * @val64: The control's new s64 value.
+ * @string: The control's new string value.
+ * @priv: The control's private pointer. For use by the driver. It is
+ * untouched by the control framework. Note that this pointer is
+ * not freed when the control is deleted. Should this be needed
+ * then a new internal bitfield can be added to tell the framework
+ * to free this pointer.
+ */
+struct v4l2_ctrl {
+ /* Administrative fields */
+ struct list_head node;
+ struct v4l2_ctrl_handler *handler;
+ struct v4l2_ctrl **cluster;
+ unsigned ncontrols;
+ unsigned int has_new:1;
+ unsigned int done:1;
+
+ unsigned int is_private:1;
+ unsigned int is_volatile:1;
+
+ const struct v4l2_ctrl_ops *ops;
+ u32 id;
+ const char *name;
+ enum v4l2_ctrl_type type;
+ s32 minimum, maximum, default_value;
+ union {
+ u32 step;
+ u32 menu_skip_mask;
+ };
+ const char **qmenu;
+ unsigned long flags;
+ union {
+ s32 val;
+ s64 val64;
+ char *string;
+ } cur;
+ union {
+ s32 val;
+ s64 val64;
+ char *string;
+ };
+ void *priv;
+};
+
+/** struct v4l2_ctrl_ref - The control reference.
+ * @node: List node for the sorted list.
+ * @next: Single-link list node for the hash.
+ * @ctrl: The actual control information.
+ *
+ * Each control handler has a list of these refs. The list_head is used to
+ * keep a sorted-by-control-ID list of all controls, while the next pointer
+ * is used to link the control in the hash's bucket.
+ */
+struct v4l2_ctrl_ref {
+ struct list_head node;
+ struct v4l2_ctrl_ref *next;
+ struct v4l2_ctrl *ctrl;
+};
+
+/** struct v4l2_ctrl_handler - The control handler keeps track of all the
+ * controls: both the controls owned by the handler and those inherited
+ * from other handlers.
+ * @lock: Lock to control access to this handler and its controls.
+ * @ctrls: The list of controls owned by this handler.
+ * @ctrl_refs: The list of control references.
+ * @cached: The last found control reference. It is common that the same
+ * control is needed multiple times, so this is a simple
+ * optimization.
+ * @buckets: Buckets for the hashing. Allows for quick control lookup.
+ * @nr_of_buckets: Total number of buckets in the array.
+ * @error: The error code of the first failed control addition.
+ */
+struct v4l2_ctrl_handler {
+ struct mutex lock;
+ struct list_head ctrls;
+ struct list_head ctrl_refs;
+ struct v4l2_ctrl_ref *cached;
+ struct v4l2_ctrl_ref **buckets;
+ u16 nr_of_buckets;
+ int error;
+};
+
+/** struct v4l2_ctrl_config - Control configuration structure.
+ * @ops: The control ops.
+ * @id: The control ID.
+ * @name: The control name.
+ * @type: The control type.
+ * @min: The control's minimum value.
+ * @max: The control's maximum value.
+ * @step: The control's step value for non-menu controls.
+ * @def: The control's default value.
+ * @flags: The control's flags.
+ * @menu_skip_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.
+ * @qmenu: A const char * array for all menu items. Array entries that are
+ * empty strings ("") correspond to non-existing menu items (this
+ * is in addition to the menu_skip_mask above). The last entry
+ * must be NULL.
+ * @is_private: If set, then this control is private to its handler and it
+ * will not be added to any other handlers.
+ * @is_volatile: If set, then this control is volatile. This means that the
+ * control's current value cannot be cached and needs to be
+ * retrieved through the g_volatile_ctrl op.
+ */
+struct v4l2_ctrl_config {
+ const struct v4l2_ctrl_ops *ops;
+ u32 id;
+ const char *name;
+ enum v4l2_ctrl_type type;
+ s32 min;
+ s32 max;
+ u32 step;
+ s32 def;
+ u32 flags;
+ u32 menu_skip_mask;
+ const char **qmenu;
+ unsigned int is_private:1;
+ unsigned int is_volatile:1;
+};
+
+/** v4l2_ctrl_fill() - Fill in the control fields based on the control ID.
+ *
+ * This works for all standard V4L2 controls.
+ * For non-standard controls it will only fill in the given arguments
+ * and @name will be NULL.
+ *
+ * This function will overwrite the contents of @name, @type and @flags.
+ * The contents of @min, @max, @step and @def may be modified depending on
+ * the type.
+ *
+ * Do not use in drivers! It is used internally for backwards compatibility
+ * control handling only. Once all drivers are converted to use the new
+ * control framework this function will no longer be exported.
+ */
+void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
+ s32 *min, s32 *max, s32 *step, s32 *def, u32 *flags);
+
+
+/** v4l2_ctrl_handler_init() - Initialize the control handler.
+ * @hdl: The control handler.
+ * @nr_of_controls_hint: A hint of how many controls this handler is
+ * expected to refer to. This is the total number, so including
+ * any inherited controls. It doesn't have to be precise, but if
+ * it is way off, then you either waste memory (too many buckets
+ * are allocated) or the control lookup becomes slower (not enough
+ * buckets are allocated, so there are more slow list lookups).
+ * It will always work, though.
+ *
+ * Returns an error if the buckets could not be allocated. This error will
+ * also be stored in @hdl->error.
+ */
+int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
+ unsigned nr_of_controls_hint);
+
+/** v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
+ * the control list.
+ * @hdl: The control handler.
+ *
+ * Does nothing if @hdl == NULL.
+ */
+void v4l2_ctrl_handler_free(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.
+ *
+ * Button controls will be skipped, as are read-only controls.
+ *
+ * If @hdl == NULL, then this just returns 0.
+ */
+int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);
+
+/** v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
+ * @hdl: The control handler.
+ * @prefix: The prefix to use when logging the control values. If the
+ * prefix does not end with a space, then ": " will be added
+ * after the prefix. If @prefix == NULL, then no prefix will be
+ * used.
+ *
+ * For use with VIDIOC_LOG_STATUS.
+ *
+ * Does nothing if @hdl == NULL.
+ */
+void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
+ const char *prefix);
+
+/** v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
+ * control.
+ * @hdl: The control handler.
+ * @cfg: The control's configuration data.
+ * @priv: The control's driver-specific private data.
+ *
+ * If the &v4l2_ctrl struct could not be allocated then NULL is returned
+ * and @hdl->error is set to the error code (if it wasn't set already).
+ */
+struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
+ const struct v4l2_ctrl_config *cfg, void *priv);
+
+/** v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu control.
+ * @hdl: The control handler.
+ * @ops: The control ops.
+ * @id: The control ID.
+ * @min: The control's minimum value.
+ * @max: The control's maximum value.
+ * @step: The control's step value
+ * @def: The control's default value.
+ *
+ * If the &v4l2_ctrl struct could not be allocated, or the control
+ * ID is not known, then NULL is returned and @hdl->error is set to the
+ * appropriate error code (if it wasn't set already).
+ *
+ * If @id refers to a menu control, then this function will return NULL.
+ *
+ * Use v4l2_ctrl_new_std_menu() when adding menu controls.
+ */
+struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
+ const struct v4l2_ctrl_ops *ops,
+ u32 id, s32 min, s32 max, u32 step, s32 def);
+
+/** v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2 menu control.
+ * @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.
+ *
+ * Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
+ * determines which menu items are to be skipped.
+ *
+ * If @id refers to a non-menu control, then this function will return NULL.
+ */
+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_add_ctrl() - Add a control from another handler to this handler.
+ * @hdl: The control handler.
+ * @ctrl: The control to add.
+ *
+ * It will return NULL if it was unable to add the control reference.
+ * If the control already belonged to the handler, then it will do
+ * nothing and just return @ctrl.
+ */
+struct v4l2_ctrl *v4l2_ctrl_add_ctrl(struct v4l2_ctrl_handler *hdl,
+ struct v4l2_ctrl *ctrl);
+
+/** v4l2_ctrl_add_handler() - Add all controls from handler @add to
+ * handler @hdl.
+ * @hdl: The control handler.
+ * @add: The control handler whose controls you want to add to
+ * the @hdl control handler.
+ *
+ * Does nothing if either of the two is a NULL pointer.
+ * In case of an error @hdl->error will be set to the error code (if it
+ * wasn't set already).
+ */
+int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
+ struct v4l2_ctrl_handler *add);
+
+
+/** v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging to that cluster.
+ * @ncontrols: The number of controls in this cluster.
+ * @controls: The cluster control array of size @ncontrols.
+ */
+void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);
+
+
+/** v4l2_ctrl_find() - Find a control with the given ID.
+ * @hdl: The control handler.
+ * @id: The control ID to find.
+ *
+ * If @hdl == NULL this will return NULL as well. Will lock the handler so
+ * do not use from inside &v4l2_ctrl_ops.
+ */
+struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);
+
+/** v4l2_ctrl_activate() - Make the control active or inactive.
+ * @ctrl: The control to (de)activate.
+ * @active: True if the control should become active.
+ *
+ * This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
+ * Does nothing if @ctrl == NULL.
+ * This will usually be called from within the s_ctrl op.
+ *
+ * This function can be called regardless of whether the control handler
+ * is locked or not.
+ */
+void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);
+
+/** v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
+ * @ctrl: The control to (de)activate.
+ * @grabbed: True if the control should become grabbed.
+ *
+ * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
+ * Does nothing if @ctrl == NULL.
+ * This will usually be called when starting or stopping streaming in the
+ * driver.
+ *
+ * This function can be called regardless of whether the control handler
+ * is locked or not.
+ */
+void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);
+
+/** v4l2_ctrl_lock() - Helper function to lock the handler
+ * associated with the control.
+ * @ctrl: The control to lock.
+ */
+static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
+{
+ mutex_lock(&ctrl->handler->lock);
+}
+
+/** v4l2_ctrl_lock() - Helper function to unlock the handler
+ * associated with the control.
+ * @ctrl: The control to unlock.
+ */
+static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
+{
+ mutex_unlock(&ctrl->handler->lock);
+}
+
+/** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
+ * @ctrl: The control.
+ *
+ * This returns the control's value safely by going through the control
+ * framework. This function will lock the control's handler, so it cannot be
+ * used from within the &v4l2_ctrl_ops functions.
+ *
+ * This function is for integer type controls only.
+ */
+s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);
+
+/** v4l2_ctrl_s_ctrl() - Helper function to set the control's value from within a driver.
+ * @ctrl: The control.
+ * @val: The new value.
+ *
+ * This set the control's new value safely by going through the control
+ * framework. This function will lock the control's handler, so it cannot be
+ * used from within the &v4l2_ctrl_ops functions.
+ *
+ * This function is for integer type controls only.
+ */
+int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);
+
+
+/* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */
+int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
+int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);
+int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
+int v4l2_s_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
+int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
+int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
+int v4l2_s_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
+
+/* Helpers for subdevices. If the associated ctrl_handler == NULL then they
+ will all return -EINVAL. */
+int v4l2_subdev_queryctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
+int v4l2_subdev_querymenu(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
+int v4l2_subdev_g_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
+int v4l2_subdev_try_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
+int v4l2_subdev_s_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
+int v4l2_subdev_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
+int v4l2_subdev_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
+
+#endif
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