[PATCH RFC 3/3] media: uvcvideo: reimplement privacy GPIO as a separate subdevice
From: Yunke Cao
Date: Wed Jan 11 2023 - 03:53:24 EST
Reimplement privacy GPIO as a v4l2 subdev with a volatile privacy control.
A v4l2 control event is sent in irq when privacy control value changes.
The behavior matches the original implementation, except that the
control is of a separate subdevice.
V4L2 control kAPI is used for simplicity.
Signed-off-by: Yunke Cao <yunkec@xxxxxxxxxxxx>
---
drivers/media/usb/uvc/uvc_driver.c | 44 +++-------------------
drivers/media/usb/uvc/uvc_entity.c | 76 ++++++++++++++++++++++++++++++++++++++
drivers/media/usb/uvc/uvcvideo.h | 19 +++++++---
3 files changed, 94 insertions(+), 45 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index e4bcb5011360..25848f4dbce0 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -1209,43 +1209,6 @@ static int uvc_parse_control(struct uvc_device *dev)
* Privacy GPIO
*/
-static void uvc_gpio_event(struct uvc_device *dev)
-{
- struct uvc_entity *unit = dev->gpio_unit;
- struct uvc_video_chain *chain;
- u8 new_val;
-
- if (!unit)
- return;
-
- new_val = gpiod_get_value_cansleep(unit->gpio.gpio_privacy);
-
- /* GPIO entities are always on the first chain. */
- chain = list_first_entry(&dev->chains, struct uvc_video_chain, list);
- uvc_ctrl_status_event(chain, unit->controls, &new_val);
-}
-
-static int uvc_gpio_get_cur(struct uvc_device *dev, struct uvc_entity *entity,
- u8 cs, void *data, u16 size)
-{
- if (cs != UVC_CT_PRIVACY_CONTROL || size < 1)
- return -EINVAL;
-
- *(u8 *)data = gpiod_get_value_cansleep(entity->gpio.gpio_privacy);
-
- return 0;
-}
-
-static int uvc_gpio_get_info(struct uvc_device *dev, struct uvc_entity *entity,
- u8 cs, u8 *caps)
-{
- if (cs != UVC_CT_PRIVACY_CONTROL)
- return -EINVAL;
-
- *caps = UVC_CONTROL_CAP_GET | UVC_CONTROL_CAP_AUTOUPDATE;
- return 0;
-}
-
static irqreturn_t uvc_gpio_irq(int irq, void *data)
{
struct uvc_device *dev = data;
@@ -1279,8 +1242,6 @@ static int uvc_gpio_parse(struct uvc_device *dev)
unit->gpio.bControlSize = 1;
unit->gpio.bmControls = (u8 *)unit + sizeof(*unit);
unit->gpio.bmControls[0] = 1;
- unit->get_cur = uvc_gpio_get_cur;
- unit->get_info = uvc_gpio_get_info;
strscpy(unit->name, "GPIO", sizeof(unit->name));
list_add_tail(&unit->list, &dev->entities);
@@ -2202,6 +2163,11 @@ static int uvc_probe(struct usb_interface *intf,
if (media_device_register(&dev->mdev) < 0)
goto error;
#endif
+
+ /* Expose all subdev's nodes*/
+ if (v4l2_device_register_subdev_nodes(&dev->vdev) < 0)
+ goto error;
+
/* Save our data pointer in the interface data. */
usb_set_intfdata(intf, dev);
diff --git a/drivers/media/usb/uvc/uvc_entity.c b/drivers/media/usb/uvc/uvc_entity.c
index 7c4d2f93d351..c8e41b42ffd8 100644
--- a/drivers/media/usb/uvc/uvc_entity.c
+++ b/drivers/media/usb/uvc/uvc_entity.c
@@ -56,17 +56,90 @@ static int uvc_mc_create_links(struct uvc_video_chain *chain,
return 0;
}
+static const struct v4l2_subdev_core_ops uvc_subdev_core_ops = {
+ .subscribe_event = v4l2_ctrl_subdev_subscribe_event,
+ .unsubscribe_event = v4l2_event_subdev_unsubscribe,
+};
+
static const struct v4l2_subdev_ops uvc_subdev_ops = {
+ .core = &uvc_subdev_core_ops,
};
void uvc_mc_cleanup_entity(struct uvc_entity *entity)
{
+ if (UVC_ENTITY_TYPE(entity) == UVC_EXT_GPIO_UNIT)
+ v4l2_ctrl_handler_free(&entity->gpio.hdl);
+
if (UVC_ENTITY_TYPE(entity) != UVC_TT_STREAMING)
media_entity_cleanup(&entity->subdev.entity);
else if (entity->vdev != NULL)
media_entity_cleanup(&entity->vdev->entity);
}
+static int uvc_gpio_g_volatile_ctrl(struct v4l2_ctrl *ctrl)
+{
+ struct uvc_gpio *gpio =
+ container_of(ctrl->handler, struct uvc_gpio, hdl);
+
+ ctrl->cur.val = gpiod_get_value_cansleep(gpio->gpio_privacy);
+
+ return 0;
+}
+
+static const struct v4l2_ctrl_ops uvc_gpio_ctrl_ops = {
+ .g_volatile_ctrl = uvc_gpio_g_volatile_ctrl,
+};
+
+void uvc_gpio_event(struct uvc_device *dev)
+{
+ struct uvc_entity *unit = dev->gpio_unit;
+ struct v4l2_ctrl *ctrl;
+ struct v4l2_event ev;
+ s32 old_val;
+ int ret;
+
+ if (!unit)
+ return;
+
+ ctrl = unit->gpio.privacy_ctrl;
+ old_val = ctrl->cur.val;
+
+ v4l2_ctrl_lock(ctrl);
+
+ ret = uvc_gpio_g_volatile_ctrl(ctrl);
+ if (ret < 0 || old_val == ctrl->cur.val) {
+ v4l2_ctrl_unlock(ctrl);
+ return;
+ }
+
+ v4l2_ctrl_fill_event(&ev, ctrl, V4L2_EVENT_CTRL_CH_VALUE);
+ v4l2_ctrl_unlock(ctrl);
+
+ v4l2_event_queue(unit->subdev.devnode, &ev);
+}
+
+static void uvc_gpio_init_ctrl(struct uvc_entity *entity)
+{
+ struct v4l2_ctrl *ctrl;
+ struct v4l2_ctrl_handler *hdl = &entity->gpio.hdl;
+
+ entity->subdev.flags = V4L2_SUBDEV_FL_HAS_DEVNODE |
+ V4L2_SUBDEV_FL_HAS_EVENTS;
+
+ v4l2_ctrl_handler_init(hdl, 1);
+ entity->subdev.ctrl_handler = hdl;
+ ctrl = v4l2_ctrl_new_std(hdl, &uvc_gpio_ctrl_ops, V4L2_CID_PRIVACY,
+ 0, 1, 1, 0);
+ if (ctrl)
+ ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE |
+ V4L2_CTRL_FLAG_READ_ONLY;
+
+ /* Read GPIO value to initialize the control. */
+ uvc_gpio_g_volatile_ctrl(ctrl);
+
+ entity->gpio.privacy_ctrl = ctrl;
+}
+
static int uvc_mc_init_entity(struct uvc_video_chain *chain,
struct uvc_entity *entity)
{
@@ -113,6 +186,9 @@ static int uvc_mc_init_entity(struct uvc_video_chain *chain,
entity->subdev.entity.function = function;
+ if (UVC_ENTITY_TYPE(entity) == UVC_EXT_GPIO_UNIT)
+ uvc_gpio_init_ctrl(entity);
+
ret = media_entity_pads_init(&entity->subdev.entity,
entity->num_pads, entity->pads);
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index df93db259312..19ca2896c398 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -15,6 +15,7 @@
#include <linux/videodev2.h>
#include <linux/workqueue.h>
#include <media/media-device.h>
+#include <media/v4l2-ctrls.h>
#include <media/v4l2-device.h>
#include <media/v4l2-event.h>
#include <media/v4l2-fh.h>
@@ -163,6 +164,15 @@ struct uvc_control {
#define UVC_ENTITY_FLAG_DEFAULT (1 << 0)
+struct uvc_gpio {
+ u8 bControlSize;
+ u8 *bmControls;
+ struct gpio_desc *gpio_privacy;
+ int irq;
+ struct v4l2_ctrl_handler hdl;
+ struct v4l2_ctrl *privacy_ctrl;
+};
+
struct uvc_entity {
struct list_head list; /* Entity as part of a UVC device. */
struct list_head chain; /* Entity as part of a video device chain. */
@@ -221,12 +231,7 @@ struct uvc_entity {
u8 *bmControlsType;
} extension;
- struct {
- u8 bControlSize;
- u8 *bmControls;
- struct gpio_desc *gpio_privacy;
- int irq;
- } gpio;
+ struct uvc_gpio gpio;
};
u8 bNrInPins;
@@ -766,6 +771,8 @@ int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
struct uvc_xu_control_query *xqry);
+void uvc_gpio_event(struct uvc_device *dev);
+
/* Utility functions */
struct usb_host_endpoint *uvc_find_endpoint(struct usb_host_interface *alts,
u8 epaddr);
--
b4 0.11.0-dev-4d321