HID: wacom: generic: Treat serial number and related fields as unsigned

[tomoyo/tomoyo-test1.git] / drivers / hid / wacom.h

diff --git a/drivers/hid/wacom.h b/drivers/hid/wacom.h
index 4a7f8d3..203d27d 100644 (file)
--- a/drivers/hid/wacom.h
+++ b/drivers/hid/wacom.h
@@ -202,6 +202,21 @@ static inline void wacom_schedule_work(struct wacom_wac *wacom_wac,
        }
 }
 
+/*
+ * Convert a signed 32-bit integer to an unsigned n-bit integer. Undoes
+ * the normally-helpful work of 'hid_snto32' for fields that use signed
+ * ranges for questionable reasons.
+ */
+static inline __u32 wacom_s32tou(s32 value, __u8 n)
+{
+       switch (n) {
+       case 8:  return ((__u8)value);
+       case 16: return ((__u16)value);
+       case 32: return ((__u32)value);
+       }
+       return value & (1 << (n - 1)) ? value & (~(~0U << n)) : value;
+}
+
 extern const struct hid_device_id wacom_ids[];
 
 void wacom_wac_irq(struct wacom_wac *wacom_wac, size_t len);