1 files changed, 73 insertions, 0 deletions

diff --git a/drivers/hid/hid-uclogic-params.c b/drivers/hid/hid-uclogic-params.c
index 34fa991e6267..cd1233d7e253 100644
--- a/drivers/hid/hid-uclogic-params.c
+++ b/drivers/hid/hid-uclogic-params.c
@@ -18,6 +18,7 @@
 #include "usbhid/usbhid.h"
 #include "hid-ids.h"
 #include <linux/ctype.h>
+#include <linux/string.h>
 #include <asm/unaligned.h>
 
 /**
@@ -1212,6 +1213,69 @@ static int uclogic_params_ugee_v2_init_frame_mouse(struct uclogic_params *p)
 }
 
 /**
+ * uclogic_params_ugee_v2_has_battery() - check whether a UGEE v2 device has
+ * battery or not.
+ * @hdev:	The HID device of the tablet interface.
+ *
+ * Returns:
+ *	True if the device has battery, false otherwise.
+ */
+static bool uclogic_params_ugee_v2_has_battery(struct hid_device *hdev)
+{
+	/* The XP-PEN Deco LW vendor, product and version are identical to the
+	 * Deco L. The only difference reported by their firmware is the product
+	 * name. Add a quirk to support battery reporting on the wireless
+	 * version.
+	 */
+	if (hdev->vendor == USB_VENDOR_ID_UGEE &&
+	    hdev->product == USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO_L) {
+		struct usb_device *udev = hid_to_usb_dev(hdev);
+
+		if (strstarts(udev->product, "Deco LW"))
+			return true;
+	}
+
+	return false;
+}
+
+/**
+ * uclogic_params_ugee_v2_init_battery() - initialize UGEE v2 battery reporting.
+ * @hdev:	The HID device of the tablet interface, cannot be NULL.
+ * @p:		Parameters to fill in, cannot be NULL.
+ *
+ * Returns:
+ *	Zero, if successful. A negative errno code on error.
+ */
+static int uclogic_params_ugee_v2_init_battery(struct hid_device *hdev,
+					       struct uclogic_params *p)
+{
+	int rc = 0;
+
+	if (!hdev || !p)
+		return -EINVAL;
+
+	/* Some tablets contain invalid characters in hdev->uniq, throwing a
+	 * "hwmon: '<name>' is not a valid name attribute, please fix" error.
+	 * Use the device vendor and product IDs instead.
+	 */
+	snprintf(hdev->uniq, sizeof(hdev->uniq), "%x-%x", hdev->vendor,
+		 hdev->product);
+
+	rc = uclogic_params_frame_init_with_desc(&p->frame_list[1],
+						 uclogic_rdesc_ugee_v2_battery_template_arr,
+						 uclogic_rdesc_ugee_v2_battery_template_size,
+						 UCLOGIC_RDESC_UGEE_V2_BATTERY_ID);
+	if (rc)
+		return rc;
+
+	p->frame_list[1].suffix = "Battery";
+	p->pen.subreport_list[1].value = 0xf2;
+	p->pen.subreport_list[1].id = UCLOGIC_RDESC_UGEE_V2_BATTERY_ID;
+
+	return rc;
+}
+
+/**
  * uclogic_params_ugee_v2_init() - initialize a UGEE graphics tablets by
  * discovering their parameters.
  *
@@ -1334,6 +1398,15 @@ static int uclogic_params_ugee_v2_init(struct uclogic_params *params,
 	if (rc)
 		goto cleanup;
 
+	/* Initialize the battery interface*/
+	if (uclogic_params_ugee_v2_has_battery(hdev)) {
+		rc = uclogic_params_ugee_v2_init_battery(hdev, &p);
+		if (rc) {
+			hid_err(hdev, "error initializing battery: %d\n", rc);
+			goto cleanup;
+		}
+	}
+
 output:
 	/* Output parameters */
 	memcpy(params, &p, sizeof(*params));