+/*
+ * Check the status of the Electro Mechanical Interlock (EMI)
+ */
+static int get_lock_status(struct hotplug_slot *hotplug_slot, u8 *value)
+{
+ struct slot *slot = hotplug_slot->private;
+ return (slot->hpc_ops->get_emi_status(slot, value));
+}
+
+/*
+ * sysfs interface for the Electro Mechanical Interlock (EMI)
+ * 1 == locked, 0 == unlocked
+ */
+static ssize_t lock_read_file(struct hotplug_slot *slot, char *buf)
+{
+ int retval;
+ u8 value;
+
+ retval = get_lock_status(slot, &value);
+ if (retval)
+ goto lock_read_exit;
+ retval = sprintf (buf, "%d\n", value);
+
+lock_read_exit:
+ return retval;
+}
+
+/*
+ * Change the status of the Electro Mechanical Interlock (EMI)
+ * This is a toggle - in addition there must be at least 1 second
+ * in between toggles.
+ */
+static int set_lock_status(struct hotplug_slot *hotplug_slot, u8 status)
+{
+ struct slot *slot = hotplug_slot->private;
+ int retval;
+ u8 value;
+
+ mutex_lock(&slot->ctrl->crit_sect);
+
+ /* has it been >1 sec since our last toggle? */
+ if ((get_seconds() - slot->last_emi_toggle) < 1)
+ return -EINVAL;
+
+ /* see what our current state is */
+ retval = get_lock_status(hotplug_slot, &value);
+ if (retval || (value == status))
+ goto set_lock_exit;
+
+ slot->hpc_ops->toggle_emi(slot);
+set_lock_exit:
+ mutex_unlock(&slot->ctrl->crit_sect);
+ return 0;
+}
+
+/*
+ * sysfs interface which allows the user to toggle the Electro Mechanical
+ * Interlock. Valid values are either 0 or 1. 0 == unlock, 1 == lock
+ */
+static ssize_t lock_write_file(struct hotplug_slot *slot, const char *buf,
+ size_t count)
+{
+ unsigned long llock;
+ u8 lock;
+ int retval = 0;
+
+ llock = simple_strtoul(buf, NULL, 10);
+ lock = (u8)(llock & 0xff);
+
+ switch (lock) {
+ case 0:
+ case 1:
+ retval = set_lock_status(slot, lock);
+ break;
+ default:
+ err ("%d is an invalid lock value\n", lock);
+ retval = -EINVAL;
+ }
+ if (retval)
+ return retval;
+ return count;
+}
+
+static struct hotplug_slot_attribute hotplug_slot_attr_lock = {
+ .attr = {.name = "lock", .mode = S_IFREG | S_IRUGO | S_IWUSR},
+ .show = lock_read_file,
+ .store = lock_write_file
+};
+