[PATCH wireless-next] wifi: cfg80211: add fw_version device attribute for sysfs

[Rory Little <roryl@candelatech.com>]

The firmware version is already exposed via ethtool, but is not
accessible without an attached interface to create a netdev. Expose this
info in sysfs to allow users to query it without the use of ethtool.

Signed-off-by: Rory Little <roryl@candelatech.com>
---
 Documentation/ABI/testing/sysfs-class-ieee80211 |  7 +++++++
 MAINTAINERS                                     |  1 +
 net/wireless/sysfs.c                            | 14 ++++++++++++++
 3 files changed, 22 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-ieee80211

diff --git a/Documentation/ABI/testing/sysfs-class-ieee80211 b/Documentation/ABI/testing/sysfs-class-ieee80211
new file mode 100644
index 000000000000..caaf4f3fd4b4
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-ieee80211
@@ -0,0 +1,7 @@
+What:		/sys/class/ieee80211/<phyname>/fw_version
+Date:		July 2026
+Contact:	linux-wireless@vger.kernel.org
+Description:	Read-only firmware version string provided by the driver for
+		this wireless device. The read data will match the information
+		provided by ethtool get_drvinfo. As drivers are not required to
+		provide this information, reading may yield no data.
diff --git a/MAINTAINERS b/MAINTAINERS
index 2d420d40782e..56181edb718f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -117,6 +117,7 @@ W:	https://wireless.wiki.kernel.org/
 Q:	https://patchwork.kernel.org/project/linux-wireless/list/
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless.git
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next.git
+F:	Documentation/ABI/testing/sysfs-class-ieee80211
 F:	Documentation/driver-api/80211/cfg80211.rst
 F:	Documentation/networking/regulatory.rst
 F:	include/linux/ieee80211.h
diff --git a/net/wireless/sysfs.c b/net/wireless/sysfs.c
index 3ec25d3f004e..e63b6d1fa411 100644
--- a/net/wireless/sysfs.c
+++ b/net/wireless/sysfs.c
@@ -65,12 +65,26 @@ static ssize_t addresses_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(addresses);
 
+static ssize_t fw_version_show(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	struct wiphy *wiphy = &dev_to_rdev(dev)->wiphy;
+
+	if (!wiphy->fw_version[0])
+		return 0;
+
+	return sysfs_emit(buf, "%s\n", wiphy->fw_version);
+}
+static DEVICE_ATTR_RO(fw_version);
+
 static struct attribute *ieee80211_attrs[] = {
 	&dev_attr_index.attr,
 	&dev_attr_macaddress.attr,
 	&dev_attr_address_mask.attr,
 	&dev_attr_addresses.attr,
 	&dev_attr_name.attr,
+	&dev_attr_fw_version.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(ieee80211);
-- 
2.52.0