Use flags the device exposes for UVC controls.
This allows the device to define which property flags are set.
Since some cameras offer auto-adjustments for properties (e.g. auto-gain),
the values of other properties (e.g. gain) can change in the camera.
Examining the flags ensures that the driver is aware of such properties.
Signed-off-by: Edgar Thier <i...@edgarthier.net>
---
drivers/media/usb/uvc/uvc_ctrl.c | 65 ++++++++++++++++++++++++++++++----------
1 file changed, 50 insertions(+), 15 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index 20397ab..7fbfeef 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1630,12 +1630,47 @@ static void uvc_ctrl_fixup_xu_info(struct uvc_device
*dev,
}
/*
+ * Retrieve flags for a given control
+ */
+static int uvc_ctrl_get_flags(struct uvc_device *dev, const struct uvc_control
*ctrl,
+ const struct uvc_control_info *info)
+{
+ u8 *data;
+ int ret = 0;
+ int flags = 0;
+
+ data = kmalloc(2, GFP_KERNEL);
+ if (data == NULL)
+ return -ENOMEM;
+
+ ret = uvc_query_ctrl(dev, UVC_GET_INFO, ctrl->entity->id, dev->intfnum,
+ info->selector, data, 1);
+ if (ret < 0) {
+ uvc_trace(UVC_TRACE_CONTROL,
+ "GET_INFO failed on control %pUl/%u (%d).\n",
+ info->entity, info->selector, ret);
+ } else {
+ flags = UVC_CTRL_FLAG_GET_MIN | UVC_CTRL_FLAG_GET_MAX
+ | UVC_CTRL_FLAG_GET_RES | UVC_CTRL_FLAG_GET_DEF
+ | (data[0] & UVC_CONTROL_CAP_GET ?
+ UVC_CTRL_FLAG_GET_CUR : 0)
+ | (data[0] & UVC_CONTROL_CAP_SET ?
+ UVC_CTRL_FLAG_SET_CUR : 0)
+ | (data[0] & UVC_CONTROL_CAP_AUTOUPDATE ?
+ UVC_CTRL_FLAG_AUTO_UPDATE : 0);
+ }
+ kfree(data);
+ return flags;
+}
+
+/*
* Query control information (size and flags) for XU controls.
*/
static int uvc_ctrl_fill_xu_info(struct uvc_device *dev,
const struct uvc_control *ctrl, struct uvc_control_info *info)
{
u8 *data;
+ int flags;
int ret;
data = kmalloc(2, GFP_KERNEL);
@@ -1659,24 +1694,14 @@ static int uvc_ctrl_fill_xu_info(struct uvc_device *dev,
info->size = le16_to_cpup((__le16 *)data);
- /* Query the control information (GET_INFO) */
- ret = uvc_query_ctrl(dev, UVC_GET_INFO, ctrl->entity->id, dev->intfnum,
- info->selector, data, 1);
- if (ret < 0) {
+ flags = uvc_ctrl_get_flags(dev, ctrl, info);
+
+ if (flags < 0) {
uvc_trace(UVC_TRACE_CONTROL,
- "GET_INFO failed on control %pUl/%u (%d).\n",
- info->entity, info->selector, ret);
+ "Failed to retrieve flags (%d).\n", ret);
goto done;
}
-
- info->flags = UVC_CTRL_FLAG_GET_MIN | UVC_CTRL_FLAG_GET_MAX
- | UVC_CTRL_FLAG_GET_RES | UVC_CTRL_FLAG_GET_DEF
- | (data[0] & UVC_CONTROL_CAP_GET ?
- UVC_CTRL_FLAG_GET_CUR : 0)
- | (data[0] & UVC_CONTROL_CAP_SET ?
- UVC_CTRL_FLAG_SET_CUR : 0)
- | (data[0] & UVC_CONTROL_CAP_AUTOUPDATE ?
- UVC_CTRL_FLAG_AUTO_UPDATE : 0);
+ info->flags = flags;
uvc_ctrl_fixup_xu_info(dev, ctrl, info);
@@ -1890,6 +1915,7 @@ static int uvc_ctrl_add_info(struct uvc_device *dev,
struct uvc_control *ctrl,
const struct uvc_control_info *info)
{
int ret = 0;
+ int flags = 0;
ctrl->info = *info;
INIT_LIST_HEAD(&ctrl->info.mappings);
@@ -1902,6 +1928,15 @@ static int uvc_ctrl_add_info(struct uvc_device *dev,
struct uvc_control *ctrl,
goto done;
}
+ flags = uvc_ctrl_get_flags(dev, ctrl, info);
+
+ if (flags < 0) {
+ uvc_trace(UVC_TRACE_CONTROL,
+ "Failed to retrieve flags (%d).\n", ret);
+ }
+
+ ctrl->info.flags = flags;
+
ctrl->initialized = 1;
uvc_trace(UVC_TRACE_CONTROL, "Added control %pUl/%u to device %s "
--
2.7.4
