[PATCH v2 rtw-next 2/2] wifi: rtw89: usb: add serial_number and uuid sysfs attributes for 0x28de:0x2432

[Ping-Ke Shih <pkshih@realtek.com>]

From: Johnson Tsai <wenjie.tsai@realtek.com>

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>
---
 .../ABI/testing/sysfs-class-ieee80211-rtw89   | 24 ++++++++
 drivers/net/wireless/realtek/rtw89/core.h     |  6 ++
 drivers/net/wireless/realtek/rtw89/rtw8852c.c | 10 ++++
 drivers/net/wireless/realtek/rtw89/rtw8852c.h |  6 +-
 .../net/wireless/realtek/rtw89/rtw8852cu.c    | 12 +++-
 drivers/net/wireless/realtek/rtw89/usb.c      | 57 +++++++++++++++++++
 6 files changed, 113 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-ieee80211-rtw89

diff --git a/Documentation/ABI/testing/sysfs-class-ieee80211-rtw89 b/Documentation/ABI/testing/sysfs-class-ieee80211-rtw89
new file mode 100644
index 000000000000..7dfdce08a42f
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-ieee80211-rtw89
@@ -0,0 +1,24 @@
+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
diff --git a/drivers/net/wireless/realtek/rtw89/core.h b/drivers/net/wireless/realtek/rtw89/core.h
index e687216da5b6..09f17d958075 100644
--- a/drivers/net/wireless/realtek/rtw89/core.h
+++ b/drivers/net/wireless/realtek/rtw89/core.h
@@ -3615,6 +3615,9 @@ struct rtw89_sta_link {
 	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;
@@ -3625,6 +3628,8 @@ struct rtw89_efuse {
 	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 {
@@ -5373,6 +5378,7 @@ enum rtw89_quirks {
 	RTW89_QUIRK_PCI_BER,
 	RTW89_QUIRK_THERMAL_PROT_120C,
 	RTW89_QUIRK_THERMAL_PROT_110C,
+	RTW89_QUIRK_HW_INFO_SYSFS,
 
 	NUM_OF_RTW89_QUIRKS,
 };
diff --git a/drivers/net/wireless/realtek/rtw89/rtw8852c.c b/drivers/net/wireless/realtek/rtw89/rtw8852c.c
index 7bb1264bcaef..3861cce42b1b 100644
--- a/drivers/net/wireless/realtek/rtw89/rtw8852c.c
+++ b/drivers/net/wireless/realtek/rtw89/rtw8852c.c
@@ -621,6 +621,15 @@ static void rtw8852c_efuse_parsing_gain_offset(struct rtw89_dev *rtwdev,
 	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)
 {
@@ -640,6 +649,7 @@ static int rtw8852c_read_efuse(struct rtw89_dev *rtwdev, u8 *log_map,
 		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;
diff --git a/drivers/net/wireless/realtek/rtw89/rtw8852c.h b/drivers/net/wireless/realtek/rtw89/rtw8852c.h
index 8585921ac6c4..b1d7c354c18e 100644
--- a/drivers/net/wireless/realtek/rtw89/rtw8852c.h
+++ b/drivers/net/wireless/realtek/rtw89/rtw8852c.h
@@ -13,7 +13,11 @@
 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];
diff --git a/drivers/net/wireless/realtek/rtw89/rtw8852cu.c b/drivers/net/wireless/realtek/rtw89/rtw8852cu.c
index 8f89f9a31455..81ee96b0a048 100644
--- a/drivers/net/wireless/realtek/rtw89/rtw8852cu.c
+++ b/drivers/net/wireless/realtek/rtw89/rtw8852cu.c
@@ -39,6 +39,16 @@ static const struct rtw89_driver_info rtw89_8852cu_info = {
 	},
 };
 
+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 },
@@ -53,7 +63,7 @@ static const struct usb_device_id rtw_8852cu_id_table[] = {
 	{ 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),
diff --git a/drivers/net/wireless/realtek/rtw89/usb.c b/drivers/net/wireless/realtek/rtw89/usb.c
index 88d7ec200837..7e23d0a32025 100644
--- a/drivers/net/wireless/realtek/rtw89/usb.c
+++ b/drivers/net/wireless/realtek/rtw89/usb.c
@@ -1059,6 +1059,61 @@ static void rtw89_usb_intf_deinit(struct rtw89_dev *rtwdev,
 	usb_set_intfdata(intf, NULL);
 }
 
+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 const struct attribute_group rtw89_usb_group = {
+	.name = "rtw89_usb",
+	.attrs = rtw89_usb_attrs,
+};
+__ATTRIBUTE_GROUPS(rtw89_usb);
+
+static void rtw89_usb_sysfs_create(struct rtw89_dev *rtwdev)
+{
+	int ret;
+
+	if (!test_bit(RTW89_QUIRK_HW_INFO_SYSFS, rtwdev->quirks))
+		return;
+
+	ret = sysfs_create_groups(&rtwdev->hw->wiphy->dev.kobj,
+				  rtw89_usb_groups);
+	if (ret)
+		rtw89_warn(rtwdev, "failed to create sysfs groups: %d\n", ret);
+}
+
+static void rtw89_usb_sysfs_remove(struct rtw89_dev *rtwdev)
+{
+	sysfs_remove_groups(&rtwdev->hw->wiphy->dev.kobj, rtw89_usb_groups);
+}
+
 int rtw89_usb_probe(struct usb_interface *intf,
 		    const struct usb_device_id *id)
 {
@@ -1123,6 +1178,7 @@ int rtw89_usb_probe(struct usb_interface *intf,
 		goto err_core_deinit;
 	}
 
+	rtw89_usb_sysfs_create(rtwdev);
 	rtw89_usb_start_rx(rtwdev);
 
 	set_bit(RTW89_FLAG_PROBE_DONE, rtwdev->flags);
@@ -1159,6 +1215,7 @@ void rtw89_usb_disconnect(struct usb_interface *intf)
 	rtw89_usb_cancel_rx_bufs(rtwusb);
 	rtw89_usb_cancel_tx_bufs(rtwusb);
 
+	rtw89_usb_sysfs_remove(rtwdev);
 	rtw89_core_unregister(rtwdev);
 	rtw89_core_deinit(rtwdev);
 	rtw89_usb_deinit_rx(rtwdev);
-- 
2.25.1