Some devices can implement a physical switch to disable the input of the
camera on demand. Think of it like an elegant privacy sticker.
The system can read the status of the privacy switch via a GPIO.
It is important to know the status of the switch, e.g. to notify the
user when the camera will produce black frames and a videochat
application is used.
Since the uvc device is not aware of this pin (and it should't), we need
to implement a virtual entity that can interact with such pin.
The location of the GPIO is specified via acpi or DT. on the usb device Eg:
Scope (\_SB.PCI0.XHCI.RHUB.HS07)
{
/.../
Name (_CRS, ResourceTemplate () // _CRS: Current Resource Settings
{
GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, IoRestrictionOutputOnly,
"\\_SB.PCI0.GPIO", 0x00, ResourceConsumer, ,
)
{ // Pin list
0x0064
}
})
Name (_DSD, Package (0x02) // _DSD: Device-Specific Data
{
ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301") /* Device Properties for _DSD */,
Package (0x01)
{
Package (0x02)
{
"privacy-gpio",
Package (0x04)
{
\_SB.PCI0.XHCI.RHUB.HS07,
Zero,
Zero,
One
}
}
}
})
}
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
drivers/media/usb/uvc/uvc_ctrl.c | 6 ++
drivers/media/usb/uvc/uvc_driver.c | 106 +++++++++++++++++++++++++++++
drivers/media/usb/uvc/uvcvideo.h | 12 ++++
3 files changed, 124 insertions(+)
diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index 531816762892..53da1d984883 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1302,6 +1302,9 @@ static void uvc_ctrl_status_event_work(struct work_struct *work)
mutex_unlock(&chain->ctrl_mutex);
+ if (!w->urb)
+ return;
+
/* Resubmit the URB. */
w->urb->interval = dev->int_ep->desc.bInterval;
ret = usb_submit_urb(w->urb, GFP_KERNEL);
@@ -2286,6 +2289,9 @@ int uvc_ctrl_init_device(struct uvc_device *dev)
} else if (UVC_ENTITY_TYPE(entity) == UVC_ITT_CAMERA) {
bmControls = entity->camera.bmControls;
bControlSize = entity->camera.bControlSize;
+ } else if (UVC_ENTITY_TYPE(entity) == UVC_EXT_GPIO_UNIT) {
+ bmControls = entity->gpio.bmControls;
+ bControlSize = entity->gpio.bControlSize;
}
/* Remove bogus/blacklisted controls */
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 534629ecd60d..498de09da07e 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -7,6 +7,7 @@
*/
#include <linux/atomic.h>
+#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
@@ -1020,6 +1021,7 @@ static int uvc_parse_streaming(struct uvc_device *dev,
}
static const u8 uvc_camera_guid[16] = UVC_GUID_UVC_CAMERA;
+static const u8 uvc_gpio_guid[16] = UVC_GUID_EXT_GPIO_CONTROLLER;
static const u8 uvc_media_transport_input_guid[16] =
UVC_GUID_UVC_MEDIA_TRANSPORT_INPUT;
static const u8 uvc_processing_guid[16] = UVC_GUID_UVC_PROCESSING;
@@ -1053,6 +1055,9 @@ static struct uvc_entity *uvc_alloc_entity(u16 type, u16 id,
* is initialized by the caller.
*/
switch (type) {
+ case UVC_EXT_GPIO_UNIT:
+ memcpy(entity->guid, uvc_gpio_guid, 16);
+ break;
case UVC_ITT_CAMERA:
memcpy(entity->guid, uvc_camera_guid, 16);
break;
@@ -1466,6 +1471,93 @@ static int uvc_parse_control(struct uvc_device *dev)
return 0;
}
+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;
+
+ *(uint8_t *)data = gpiod_get_value(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_privacy_gpio_irq(int irq, void *data)
+{
+ struct uvc_device *dev = data;
+ struct uvc_video_chain *chain;
+ struct uvc_entity *unit;
+ u8 value;
+
+ /* GPIO entities are always on the first chain */
+ chain = list_first_entry(&dev->chains, struct uvc_video_chain, list);
+ list_for_each_entry(unit, &dev->entities, list) {
+ if (UVC_ENTITY_TYPE(unit) != UVC_EXT_GPIO_UNIT)
+ continue;
+ value = gpiod_get_value(unit->gpio.gpio_privacy);
+ uvc_ctrl_status_event(NULL, chain, unit->controls, &value);
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int uvc_parse_gpio(struct uvc_device *dev)
+{
+ struct uvc_entity *unit;
+ struct gpio_desc *gpio_privacy;
+ int irq;
+ int ret;
+
+ gpio_privacy = devm_gpiod_get_optional(&dev->udev->dev, "privacy",
+ GPIOD_IN);
+ if (IS_ERR(gpio_privacy))
+ return PTR_ERR(gpio_privacy);
+
+ if (!gpio_privacy)
+ return 0;
+
+ unit = uvc_alloc_entity(UVC_EXT_GPIO_UNIT, UVC_EXT_GPIO_UNIT_ID, 0, 1);
+ if (!unit)
+ return -ENOMEM;
+
+ unit->gpio.gpio_privacy = gpio_privacy;
+ 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;
+
+ sprintf(unit->name, "GPIO Unit");
+
+ list_add_tail(&unit->list, &dev->entities);
+
+ irq = gpiod_to_irq(gpio_privacy);
+ if (irq == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+
+ if (irq < 0)
+ return 0;
+
+ ret = devm_request_irq(&dev->udev->dev, irq, uvc_privacy_gpio_irq,
+ IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
+ "uvc_privacy_gpio", dev);
+ if (ret < 0)
+ dev_warn(&dev->udev->dev,
+ "Unable to request uvc_privacy_gpio irq. Continuing\n");
+
+ return 0;
+}
+
/* ------------------------------------------------------------------------
* UVC device scan
*/
@@ -1917,6 +2009,7 @@ static int uvc_scan_device(struct uvc_device *dev)
{
struct uvc_video_chain *chain;
struct uvc_entity *term;
+ struct uvc_entity *unit;
list_for_each_entry(term, &dev->entities, list) {
if (!UVC_ENTITY_IS_OTERM(term))
@@ -1955,6 +2048,13 @@ static int uvc_scan_device(struct uvc_device *dev)
return -1;
}
+ /* Add GPIO entities to the first chain */
+ chain = list_first_entry(&dev->chains, struct uvc_video_chain, list);
+ list_for_each_entry(unit, &dev->entities, list) {
+ if (UVC_ENTITY_TYPE(unit) == UVC_EXT_GPIO_UNIT)
+ list_add_tail(&unit->chain, &chain->entities);
+ }
+
return 0;
}
@@ -2287,6 +2387,12 @@ static int uvc_probe(struct usb_interface *intf,
goto error;
}
+ /* Parse the associated GPIOs */
+ if (uvc_parse_gpio(dev) < 0) {
+ uvc_trace(UVC_TRACE_PROBE, "Unable to parse UVC GPIOs\n");
+ goto error;
+ }
+
uvc_printk(KERN_INFO, "Found UVC %u.%02x device %s (%04x:%04x)\n",
dev->uvc_version >> 8, dev->uvc_version & 0xff,
udev->product ? udev->product : "<unnamed>",
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index ae464ba83f4f..f87d14fb3f56 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -6,6 +6,7 @@
#error "The uvcvideo.h header is deprecated, use linux/uvcvideo.h instead."
#endif /* __KERNEL__ */
+#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/poll.h>
#include <linux/usb.h>
@@ -37,6 +38,8 @@
(UVC_ENTITY_IS_TERM(entity) && \
((entity)->type & 0x8000) == UVC_TERM_OUTPUT)
+#define UVC_EXT_GPIO_UNIT 0x7ffe
+#define UVC_EXT_GPIO_UNIT_ID 0x100
/* ------------------------------------------------------------------------
* GUIDs
@@ -56,6 +59,9 @@
#define UVC_GUID_UVC_SELECTOR \
{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02}
+#define UVC_GUID_EXT_GPIO_CONTROLLER \
+ {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x03}
#define UVC_GUID_FORMAT_MJPEG \
{ 'M', 'J', 'P', 'G', 0x00, 0x00, 0x10, 0x00, \
@@ -348,6 +354,12 @@ struct uvc_entity {
u8 *bmControls;
u8 *bmControlsType;
} extension;
+
+ struct {
+ u8 bControlSize;
+ u8 *bmControls;
+ struct gpio_desc *gpio_privacy;
+ } gpio;
};
u8 bNrInPins;
--
2.29.2.684.gfbc64c5ab5-goog
