[PATCH v4 3/3] usb: misc: ljca: add firmware version sysfs attribute

[Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>]

For diagnostics purpose read firmware version during probe and add
sysfs attribute to make that information available.

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
---
v3->v4: use sysfs attribute to provide firmware version,
	drop tags from Hans since the code changed
v2->v3: use dev_dbg() for printing the firmware version
v1->v2: fix 80-chars line wrap

 .../ABI/testing/sysfs-bus-usb-devices-ljca    |  9 ++++
 drivers/usb/misc/usb-ljca.c                   | 53 +++++++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-usb-devices-ljca

diff --git a/Documentation/ABI/testing/sysfs-bus-usb-devices-ljca b/Documentation/ABI/testing/sysfs-bus-usb-devices-ljca
new file mode 100644
index 000000000000..f5eb38bf99a8
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-usb-devices-ljca
@@ -0,0 +1,9 @@
+What:		/sys/bus/usb/devices/.../ljca_version
+Date:		November 2024
+KernelVersion:	6.13
+Contact:	Sakari Ailus <sakari.ailus@linux.intel.com>
+Description:
+		Provides the firmware version of LJCA device.
+		The format is Major.Minor.Patch.Build, where
+		Major, Minor, Patch, and Build are decimal numbers.
+		For example: 1.0.0.256
diff --git a/drivers/usb/misc/usb-ljca.c b/drivers/usb/misc/usb-ljca.c
index d9c21f783055..4b5bd5b27b2a 100644
--- a/drivers/usb/misc/usb-ljca.c
+++ b/drivers/usb/misc/usb-ljca.c
@@ -43,6 +43,7 @@ enum ljca_client_type {
 
 /* MNG client commands */
 enum ljca_mng_cmd {
+	LJCA_MNG_GET_VERSION = 1,
 	LJCA_MNG_RESET = 2,
 	LJCA_MNG_ENUM_GPIO = 4,
 	LJCA_MNG_ENUM_I2C = 5,
@@ -68,6 +69,13 @@ struct ljca_msg {
 	u8 data[] __counted_by(len);
 } __packed;
 
+struct ljca_fw_version {
+	u8 major;
+	u8 minor;
+	__le16 patch;
+	__le16 build;
+} __packed;
+
 struct ljca_i2c_ctr_info {
 	u8 id;
 	u8 capacity;
@@ -152,8 +160,10 @@ struct ljca_adapter {
 	struct mutex mutex;
 
 	struct list_head client_list;
+	struct ljca_fw_version fw_version;
 
 	bool disconnect;
+	bool fw_version_valid;
 
 	u32 reset_id;
 };
@@ -740,6 +750,24 @@ static int ljca_enumerate_clients(struct ljca_adapter *adap)
 	return ret;
 }
 
+static void ljca_read_fw_version(struct ljca_adapter *adap)
+{
+	struct ljca_fw_version version;
+	int ret;
+
+	ret = ljca_send(adap, LJCA_CLIENT_MNG, LJCA_MNG_GET_VERSION, NULL, 0,
+			(u8 *)&version, sizeof(version), true,
+			LJCA_WRITE_ACK_TIMEOUT_MS);
+
+	if (ret != sizeof(version)) {
+		dev_err(adap->dev, "Get version failed, ret: %d\n", ret);
+		return;
+	}
+
+	adap->fw_version = version;
+	adap->fw_version_valid = true;
+}
+
 static int ljca_probe(struct usb_interface *interface,
 		      const struct usb_device_id *id)
 {
@@ -811,6 +839,8 @@ static int ljca_probe(struct usb_interface *interface,
 	if (ret)
 		goto err_free;
 
+	ljca_read_fw_version(adap);
+
 	/*
 	 * This works around problems with ov2740 initialization on some
 	 * Lenovo platforms. The autosuspend delay, has to be smaller than
@@ -874,6 +904,28 @@ static int ljca_resume(struct usb_interface *interface)
 	return usb_submit_urb(adap->rx_urb, GFP_KERNEL);
 }
 
+static ssize_t ljca_version_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct ljca_adapter *adap = usb_get_intfdata(intf);
+	struct ljca_fw_version ver = adap->fw_version;
+
+	if (!adap->fw_version_valid)
+		return -ENODATA;
+
+	return sysfs_emit(buf, "%d.%d.%d.%d\n", ver.major, ver.minor,
+			  le16_to_cpu(ver.patch), le16_to_cpu(ver.build));
+}
+
+static DEVICE_ATTR_RO(ljca_version);
+
+static struct attribute *ljca_attrs[] = {
+	&dev_attr_ljca_version.attr,
+};
+
+ATTRIBUTE_GROUPS(ljca);
+
 static const struct usb_device_id ljca_table[] = {
 	{ USB_DEVICE(0x8086, 0x0b63) },
 	{ /* sentinel */ }
@@ -888,6 +940,7 @@ static struct usb_driver ljca_driver = {
 	.suspend = ljca_suspend,
 	.resume = ljca_resume,
 	.supports_autosuspend = 1,
+	.dev_groups = ljca_groups,
 };
 module_usb_driver(ljca_driver);
 
-- 
2.34.1