When parsing UVC descriptors to instantiate entity, the driver calls
usb_string() to retrieve the entity name from the device, and falls back
to a default name if the string can't be retrieved. This code pattern
occurs multiple times. Factor it out to a separate helper function.
Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---
Ricardo, Guenter, this applies on top of "media: uvcvideo: Handle errors
from calls to usb_string". Any opinion ?
---
drivers/media/usb/uvc/uvc_driver.c | 59 ++++++++++++++++++------------
1 file changed, 35 insertions(+), 24 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index bd3716a359b0..6eb011f452e5 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -813,6 +813,27 @@ static struct uvc_entity *uvc_alloc_entity(u16 type, u16 id,
return entity;
}
+static void uvc_entity_set_name(struct uvc_device *dev, struct uvc_entity *entity,
+ const char *type_name, u8 string_id)
+{
+ int ret;
+
+ /*
+ * First attempt to read the entity name from the device. If the entity
+ * has no associated string, or if reading the string fails (most
+ * likely due to a buggy firmware), fall back to default names based on
+ * the entity type.
+ */
+ if (string_id) {
+ ret = usb_string(dev->udev, string_id, entity->name,
+ sizeof(entity->name));
+ if (!ret)
+ return;
+ }
+
+ sprintf(entity->name, "%s %u", type_name, entity->id);
+}
+
/* Parse vendor-specific extensions. */
static int uvc_parse_vendor_control(struct uvc_device *dev,
const unsigned char *buffer, int buflen)
@@ -879,9 +900,7 @@ static int uvc_parse_vendor_control(struct uvc_device *dev,
+ n;
memcpy(unit->extension.bmControls, &buffer[23+p], 2*n);
- if (buffer[24+p+2*n] == 0 ||
- usb_string(udev, buffer[24+p+2*n], unit->name, sizeof(unit->name)) < 0)
- sprintf(unit->name, "Extension %u", buffer[3]);
+ uvc_entity_set_name(dev, unit, "Extension", buffer[24+p+2*n]);
list_add_tail(&unit->list, &dev->entities);
handled = 1;
@@ -899,6 +918,7 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
struct usb_interface *intf;
struct usb_host_interface *alts = dev->intf->cur_altsetting;
unsigned int i, n, p, len;
+ const char *type_name;
u16 type;
switch (buffer[2]) {
@@ -1004,15 +1024,14 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
memcpy(term->media.bmTransportModes, &buffer[10+n], p);
}
- if (buffer[7] == 0 ||
- usb_string(udev, buffer[7], term->name, sizeof(term->name)) < 0) {
- if (UVC_ENTITY_TYPE(term) == UVC_ITT_CAMERA)
- sprintf(term->name, "Camera %u", buffer[3]);
- if (UVC_ENTITY_TYPE(term) == UVC_ITT_MEDIA_TRANSPORT_INPUT)
- sprintf(term->name, "Media %u", buffer[3]);
- else
- sprintf(term->name, "Input %u", buffer[3]);
- }
+ if (UVC_ENTITY_TYPE(term) == UVC_ITT_CAMERA)
+ type_name = "Camera";
+ else if (UVC_ENTITY_TYPE(term) == UVC_ITT_MEDIA_TRANSPORT_INPUT)
+ type_name = "Media";
+ else
+ type_name = "Input";
+
+ uvc_entity_set_name(dev, term, type_name, buffer[7]);
list_add_tail(&term->list, &dev->entities);
break;
@@ -1045,9 +1064,7 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
memcpy(term->baSourceID, &buffer[7], 1);
- if (buffer[8] == 0 ||
- usb_string(udev, buffer[8], term->name, sizeof(term->name)) < 0)
- sprintf(term->name, "Output %u", buffer[3]);
+ uvc_entity_set_name(dev, term, "Output", buffer[8]);
list_add_tail(&term->list, &dev->entities);
break;
@@ -1068,9 +1085,7 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
memcpy(unit->baSourceID, &buffer[5], p);
- if (buffer[5+p] == 0 ||
- usb_string(udev, buffer[5+p], unit->name, sizeof(unit->name)) < 0)
- sprintf(unit->name, "Selector %u", buffer[3]);
+ uvc_entity_set_name(dev, unit, "Selector", buffer[5+p]);
list_add_tail(&unit->list, &dev->entities);
break;
@@ -1099,9 +1114,7 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
if (dev->uvc_version >= 0x0110)
unit->processing.bmVideoStandards = buffer[9+n];
- if (buffer[8+n] == 0 ||
- usb_string(udev, buffer[8+n], unit->name, sizeof(unit->name)) < 0)
- sprintf(unit->name, "Processing %u", buffer[3]);
+ uvc_entity_set_name(dev, unit, "Processing", buffer[8+n]);
list_add_tail(&unit->list, &dev->entities);
break;
@@ -1128,9 +1141,7 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
unit->extension.bmControls = (u8 *)unit + sizeof(*unit);
memcpy(unit->extension.bmControls, &buffer[23+p], n);
- if (buffer[23+p+n] == 0 ||
- usb_string(udev, buffer[23+p+n], unit->name, sizeof(unit->name)) < 0)
- sprintf(unit->name, "Extension %u", buffer[3]);
+ uvc_entity_set_name(dev, unit, "Extension", buffer[23+p+n]);
list_add_tail(&unit->list, &dev->entities);
break;
--
Regards,
Laurent Pinchart
