From 5f0e659d2a2ac6172d495915f2775fa592c7ab17 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Tue, 25 Oct 2022 21:42:21 +0300 Subject: [PATCH] media: uvcvideo: Factor out usb_string() calls When parsing UVC descriptors to instantiate entities, 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 Reviewed-by: Guenter Roeck --- 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 1de17db..5f6e0da 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -794,6 +794,27 @@ 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) @@ -860,9 +881,7 @@ 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; @@ -880,6 +899,7 @@ 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]) { @@ -985,15 +1005,14 @@ 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; @@ -1026,9 +1045,7 @@ 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; @@ -1049,9 +1066,7 @@ 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; @@ -1080,9 +1095,7 @@ 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; @@ -1109,9 +1122,7 @@ 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; -- 2.7.4