+/*
+ * TLV callback for mixer volume controls
+ */
+static int mixer_vol_tlv(struct snd_kcontrol *kcontrol, int op_flag,
+ unsigned int size, unsigned int __user *_tlv)
+{
+ struct usb_mixer_elem_info *cval = kcontrol->private_data;
+ DECLARE_TLV_DB_SCALE(scale, 0, 0, 0);
+
+ if (size < sizeof(scale))
+ return -ENOMEM;
+ /* USB descriptions contain the dB scale in 1/256 dB unit
+ * while ALSA TLV contains in 1/100 dB unit
+ */
+ scale[2] = (convert_signed_value(cval, cval->min) * 100) / 256;
+ scale[3] = (convert_signed_value(cval, cval->res) * 100) / 256;
+ if (copy_to_user(_tlv, scale, sizeof(scale)))
+ return -EFAULT;
+ return 0;
+}