rtc: imxdi: add some background info about the states the machine can be in

	struct work_struct work;

	struct work_struct work;

};

};

/* Some background:

 *

 * The DryIce unit is a complex security/tamper monitor device. To be able do

 * its job in a useful manner it runs a bigger statemachine to bring it into

 * security/tamper failure state and once again to bring it out of this state.

 *

 * This unit can be in one of three states:

 *

 * - "NON-VALID STATE"

 *   always after the battery power was removed

 * - "FAILURE STATE"

 *   if one of the enabled security events has happened

 * - "VALID STATE"

 *   if the unit works as expected

 *

 * Everything stops when the unit enters the failure state including the RTC

 * counter (to be able to detect the time the security event happened).

 *

 * The following events (when enabled) let the DryIce unit enter the failure

 * state:

 *

 * - wire-mesh-tamper detect

 * - external tamper B detect

 * - external tamper A detect

 * - temperature tamper detect

 * - clock tamper detect

 * - voltage tamper detect

 * - RTC counter overflow

 * - monotonic counter overflow

 * - external boot

 *

 * If we find the DryIce unit in "FAILURE STATE" and the TDCHL cleared, we

 * can only detect this state. In this case the unit is completely locked and

 * must force a second "SYSTEM POR" to bring the DryIce into the

 * "NON-VALID STATE" + "FAILURE STATE" where a recovery is possible.

 * If the TDCHL is set in the "FAILURE STATE" we are out of luck. In this case

 * a battery power cycle is required.

 *

 * In the "NON-VALID STATE" + "FAILURE STATE" we can clear the "FAILURE STATE"

 * and recover the DryIce unit. By clearing the "NON-VALID STATE" as the last

 * task, we bring back this unit into life.

 */

/*

/*

 * enable a dryice interrupt

 * enable a dryice interrupt

 */

 */