Expose the device's Serial Number (SN) and UUID from EFUSE via two
read-only sysfs attributes, `serial_number` and `uuid`, on the ieee80211
phy device under the `rtw89_usb` attribute group.
This hardware identification information is essential for user-space
applications to uniquely identify, track, and manage specific Wi-Fi
adapters. For example, in automated factory provisioning or device
management systems, user-space tools rely on the EFUSE serial number and
UUID to bind configurations to specific physical adapters. Currently,
standard wireless APIs do not expose this low-level hardware
information, making these sysfs nodes the only viable solution for
user space to extract this data.
The attributes are gated behind a new RTW89_QUIRK_HW_INFO_SYSFS quirk,
enabled only for the VID 0x28de / PID 0x2432 device via the
dev_id_quirks field in rtw89_driver_info.
Example usage from user-space:
$ cat /sys/class/ieee80211/phy0/rtw89_usb/serial_number
3642000123
$ cat /sys/class/ieee80211/phy0/rtw89_usb/uuid
aaec2b7c-0a55-4727-8de0-
b30febccbbaa
Cc: Elliot Saba <sabae@valvesoftware.com>
Cc: Charles Lohr <charlesl@valvesoftware.com>
Signed-off-by: Johnson Tsai <wenjie.tsai@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260529075032.16807-3-pkshih@realtek.com
--- /dev/null
+What: /sys/class/ieee80211/phyX/rtw89_usb/serial_number
+Date: May 2026
+Contact: Johnson Tsai <wenjie.tsai@realtek.com>, linux-wireless@vger.kernel.org
+Description: (Read) Serial number burned into EFUSE of the RTL8852CU-based
+ USB Wi-Fi adapter. Only present on devices that set the
+ RTW89_QUIRK_HW_INFO_SYSFS quirk (currently VID 0x28de /
+ PID 0x2432).
+
+ Format: %10phN (5 raw bytes printed as 10 lowercase hex
+ digits, no separators).
+
+ Example: 3642000123
+
+What: /sys/class/ieee80211/phyX/rtw89_usb/uuid
+Date: May 2026
+Contact: Johnson Tsai <wenjie.tsai@realtek.com>, linux-wireless@vger.kernel.org
+Description: (Read) UUID burned into EFUSE of the RTL8852CU-based USB Wi-Fi
+ adapter. Only present on devices that set the
+ RTW89_QUIRK_HW_INFO_SYSFS quirk (currently VID 0x28de /
+ PID 0x2432).
+
+ Format: %pUb (RFC 4122 UUID in lowercase with hyphens).
+
+ Example: aaec2b7c-0a55-4727-8de0-b30febccbbaa
u32 data_tx_cnt_lmt:6;
};
+#define RTW89_EFUSE_SN_LEN 5
+#define RTW89_EFUSE_UUID_LEN 16
+
struct rtw89_efuse {
bool valid;
bool power_k_valid;
u8 adc_td;
u8 bt_setting_2;
u8 bt_setting_3;
+ u8 sn[RTW89_EFUSE_SN_LEN];
+ u8 uuid[RTW89_EFUSE_UUID_LEN];
};
struct rtw89_phy_rate_pattern {
RTW89_QUIRK_PCI_BER,
RTW89_QUIRK_THERMAL_PROT_120C,
RTW89_QUIRK_THERMAL_PROT_110C,
+ RTW89_QUIRK_HW_INFO_SYSFS,
NUM_OF_RTW89_QUIRKS,
};
gain->offset_valid = valid;
}
+static void rtw8852c_efuse_copy_sn_uuid_usb(struct rtw89_dev *rtwdev,
+ const struct rtw8852c_efuse *map)
+{
+ struct rtw89_efuse *efuse = &rtwdev->efuse;
+
+ memcpy(efuse->sn, map->u.sn, sizeof(efuse->sn));
+ memcpy(efuse->uuid, map->u.uuid, sizeof(efuse->uuid));
+}
+
static int rtw8852c_read_efuse(struct rtw89_dev *rtwdev, u8 *log_map,
enum rtw89_efuse_block block)
{
break;
case RTW89_HCI_TYPE_USB:
ether_addr_copy(efuse->addr, map->u.mac_addr);
+ rtw8852c_efuse_copy_sn_uuid_usb(rtwdev, map);
break;
default:
return -ENOTSUPP;
struct rtw8852c_u_efuse {
u8 rsvd[0x88];
u8 mac_addr[ETH_ALEN];
-};
+ u8 rsvd1[8];
+ u8 sn[RTW89_EFUSE_SN_LEN];
+ u8 rsvd2[29];
+ u8 uuid[RTW89_EFUSE_UUID_LEN];
+} __packed;
struct rtw8852c_e_efuse {
u8 mac_addr[ETH_ALEN];
},
};
+static const struct rtw89_driver_info rtw89_8852cu_valve_info = {
+ .chip = &rtw8852c_chip_info,
+ .variant = NULL,
+ .quirks = NULL,
+ .dev_id_quirks = BIT(RTW89_QUIRK_HW_INFO_SYSFS),
+ .bus = {
+ .usb = &rtw8852c_usb_info,
+ },
+};
+
static const struct usb_device_id rtw_8852cu_id_table[] = {
{ USB_DEVICE_AND_INTERFACE_INFO(0x0411, 0x03a6, 0xff, 0xff, 0xff),
.driver_info = (kernel_ulong_t)&rtw89_8852cu_info },
{ USB_DEVICE_AND_INTERFACE_INFO(0x0db0, 0x991d, 0xff, 0xff, 0xff),
.driver_info = (kernel_ulong_t)&rtw89_8852cu_info },
{ USB_DEVICE_AND_INTERFACE_INFO(0x28de, 0x2432, 0xff, 0xff, 0xff),
- .driver_info = (kernel_ulong_t)&rtw89_8852cu_info },
+ .driver_info = (kernel_ulong_t)&rtw89_8852cu_valve_info },
{ USB_DEVICE_AND_INTERFACE_INFO(0x2c7c, 0x8206, 0xff, 0xff, 0xff),
.driver_info = (kernel_ulong_t)&rtw89_8852cu_info },
{ USB_DEVICE_AND_INTERFACE_INFO(0x35b2, 0x0502, 0xff, 0xff, 0xff),
return rtw89_usb_switch_mode_be(rtwdev);
}
+static ssize_t serial_number_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct wiphy *wiphy = container_of(dev, struct wiphy, dev);
+ struct ieee80211_hw *hw = wiphy_to_ieee80211_hw(wiphy);
+ struct rtw89_dev *rtwdev = hw->priv;
+ struct rtw89_efuse *efuse = &rtwdev->efuse;
+
+ return sysfs_emit(buf, "%*phN\n",
+ (int)sizeof(efuse->sn), efuse->sn);
+}
+static DEVICE_ATTR_RO(serial_number);
+
+static ssize_t uuid_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct wiphy *wiphy = container_of(dev, struct wiphy, dev);
+ struct ieee80211_hw *hw = wiphy_to_ieee80211_hw(wiphy);
+ struct rtw89_dev *rtwdev = hw->priv;
+ struct rtw89_efuse *efuse = &rtwdev->efuse;
+
+ return sysfs_emit(buf, "%pUb\n", efuse->uuid);
+}
+static DEVICE_ATTR_RO(uuid);
+
+static struct attribute *rtw89_usb_attrs[] = {
+ &dev_attr_serial_number.attr,
+ &dev_attr_uuid.attr,
+ NULL,
+};
+
+static bool rtw89_usb_group_visible(struct kobject *kobj)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct wiphy *wiphy = container_of(dev, struct wiphy, dev);
+ struct ieee80211_hw *hw = wiphy_to_ieee80211_hw(wiphy);
+ struct rtw89_dev *rtwdev = hw->priv;
+
+ return test_bit(RTW89_QUIRK_HW_INFO_SYSFS, rtwdev->quirks);
+}
+
+DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE(rtw89_usb);
+
+static const struct attribute_group rtw89_usb_group = {
+ .name = "rtw89_usb",
+ .attrs = rtw89_usb_attrs,
+ .is_visible = SYSFS_GROUP_VISIBLE(rtw89_usb),
+};
+__ATTRIBUTE_GROUPS(rtw89_usb);
+
int rtw89_usb_probe(struct usb_interface *intf,
const struct usb_device_id *id)
{
rtwusb->rtwdev = rtwdev;
rtwusb->info = info->bus.usb;
+ rtwdev->hw->wiphy->dev.groups = rtw89_usb_groups;
+
rtwdev->hci.ops = &rtw89_usb_ops;
rtwdev->hci.type = RTW89_HCI_TYPE_USB;
rtwdev->hci.tx_rpt_enabled = true;