[media] v4l2-ctrls: add support for setting string controls

Rather than always having to use a v4l2_ext_control struct to set
a control value from within a driver, switch to just setting the
new value. This is faster and it makes it possible to set more
complex types such as a string control as is added by this
patch.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 004e7e82e1e033a1615ebfbc96f83a3cac83d387..5db038525f99fa8e9cbc0a840d58e656af31bd8f 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -3121,26 +3121,22 @@ static int set_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl,
        struct v4l2_ctrl *master = ctrl->cluster[0];
        int i;
 
-       /* Compound controls are not supported. The user_to_new() and
-        * cur_to_user() calls below would need to be modified not to access
-        * userspace memory when called from set_ctrl().
-        */
-       if (ctrl->is_ptr)
-               return -EINVAL;
-
        /* Reset the 'is_new' flags of the cluster */
        for (i = 0; i < master->ncontrols; i++)
                if (master->cluster[i])
                        master->cluster[i]->is_new = 0;
 
+       if (c)
+               user_to_new(c, ctrl);
+
        /* For autoclusters with volatiles that are switched from auto to
           manual mode we have to update the current volatile values since
           those will become the initial manual values after such a switch. */
        if (master->is_auto && master->has_volatiles && ctrl == master &&
-           !is_cur_manual(master) && c->value == master->manual_mode_value)
+           !is_cur_manual(master) && ctrl->val == master->manual_mode_value)
                update_from_auto_cluster(master);
 
-       user_to_new(c, ctrl);
+       ctrl->is_new = 1;
        return try_or_set_cluster(fh, master, true, ch_flags);
 }
 
@@ -3188,40 +3184,37 @@ EXPORT_SYMBOL(v4l2_subdev_s_ctrl);
 
 int __v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val)
 {
-       struct v4l2_ext_control c;
-       int rval;
-
        lockdep_assert_held(ctrl->handler->lock);
 
        /* It's a driver bug if this happens. */
        WARN_ON(!ctrl->is_int);
-       c.value = val;
-       rval = set_ctrl(NULL, ctrl, &c, 0);
-       if (!rval)
-               cur_to_user(&c, ctrl);
-
-       return rval;
+       ctrl->val = val;
+       return set_ctrl(NULL, ctrl, NULL, 0);
 }
 EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl);
 
 int __v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
 {
-       struct v4l2_ext_control c;
-       int rval;
-
        lockdep_assert_held(ctrl->handler->lock);
 
        /* It's a driver bug if this happens. */
        WARN_ON(ctrl->is_ptr || ctrl->type != V4L2_CTRL_TYPE_INTEGER64);
-       c.value64 = val;
-       rval = set_ctrl(NULL, ctrl, &c, 0);
-       if (!rval)
-               cur_to_user(&c, ctrl);
-
-       return rval;
+       *ctrl->p_new.p_s64 = val;
+       return set_ctrl(NULL, ctrl, NULL, 0);
 }
 EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl_int64);
 
+int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
+{
+       lockdep_assert_held(ctrl->handler->lock);
+
+       /* It's a driver bug if this happens. */
+       WARN_ON(ctrl->type != V4L2_CTRL_TYPE_STRING);
+       strlcpy(ctrl->p_new.p_char, s, ctrl->maximum + 1);
+       return set_ctrl(NULL, ctrl, NULL, 0);
+}
+EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl_string);
+
 void v4l2_ctrl_notify(struct v4l2_ctrl *ctrl, v4l2_ctrl_notify_fnc notify, void *priv)
 {
        if (ctrl == NULL)

diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index 8c4edd69fa4b5c33a68a2ac20f6042b26408883f..d6540d2017642686c853c657cfabdc309630fff1 100644 (file)
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -737,6 +737,30 @@ static inline int v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
        return rval;
 }
 
+/** __v4l2_ctrl_s_ctrl_string() - Unlocked variant of v4l2_ctrl_s_ctrl_string(). */
+int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s);
+
+/** v4l2_ctrl_s_ctrl_string() - Helper function to set a control's string value from within a driver.
+  * @ctrl:     The control.
+  * @s:                The new string.
+  *
+  * This set the control's new string 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 string type controls only.
+  */
+static inline int v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
+{
+       int rval;
+
+       v4l2_ctrl_lock(ctrl);
+       rval = __v4l2_ctrl_s_ctrl_string(ctrl, s);
+       v4l2_ctrl_unlock(ctrl);
+
+       return rval;
+}
+
 /* Internal helper functions that deal with control events. */
 extern const struct v4l2_subscribed_event_ops v4l2_ctrl_sub_ev_ops;
 void v4l2_ctrl_replace(struct v4l2_event *old, const struct v4l2_event *new);