+#ifdef CONFIG_RTC_INTF_DEV
+static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+ struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
+ struct rtc_time tm;
+
+ switch (cmd) {
+ case RTC_VL_READ:
+ if (pcf8563->voltage_low)
+ dev_info(dev, "low voltage detected, date/time is not reliable.\n");
+
+ if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
+ sizeof(int)))
+ return -EFAULT;
+ return 0;
+ case RTC_VL_CLR:
+ /*
+ * Clear the VL bit in the seconds register in case
+ * the time has not been set already (which would
+ * have cleared it). This does not really matter
+ * because of the cached voltage_low value but do it
+ * anyway for consistency.
+ */
+ if (pcf8563_get_datetime(to_i2c_client(dev), &tm))
+ pcf8563_set_datetime(to_i2c_client(dev), &tm);
+
+ /* Clear the cached value. */
+ pcf8563->voltage_low = 0;
+
+ return 0;
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+#else
+#define pcf8563_rtc_ioctl NULL
+#endif
+