[src/trunk]: src/sys/dev/ic Add note about time-of-day and interval timer pro...

[pk <pk%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/edf8abe7fe5f
branches:  trunk
changeset: 499103:edf8abe7fe5f
user:      pk <pk%NetBSD.org@localhost>
date:      Sat Nov 11 11:18:07 2000 +0000

description:
Add note about time-of-day and interval timer programming on this chip
are combined into the same (write-only!) control register.

diffstat:

 sys/dev/ic/intersil7170.h |  11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diffs (32 lines):

diff -r b334503a584b -r edf8abe7fe5f sys/dev/ic/intersil7170.h
--- a/sys/dev/ic/intersil7170.h Sat Nov 11 11:03:31 2000 +0000
+++ b/sys/dev/ic/intersil7170.h Sat Nov 11 11:18:07 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: intersil7170.h,v 1.3 2000/11/03 05:23:07 tsutsui Exp $ */
+/*     $NetBSD: intersil7170.h,v 1.4 2000/11/11 11:18:07 pk Exp $      */
 
 /*-
  * Copyright (c) 1996 The NetBSD Foundation, Inc.
@@ -45,6 +45,13 @@
  *
  * Derived from: datasheet "ICM7170 a uP-Compatible Real-Time Clock"
  *                          document #301680-005, Dec 85
+ *
+ * Note that this device provides both time-of-day and interval timer
+ * functionality. Both functions use the same control registers. On top
+ * of that, the command control register is write-only. Currently, this
+ * driver assumes that the interval timer is to be enabled, and hence
+ * always sets/restores the INTERSIL_CMD_IENABLE control bit when
+ * manipulating the TOD.
  */
 
 struct intersil_dt {                  /* from p. 7 of 10 */
@@ -96,7 +103,7 @@
 #define INTERSIL_CMD_TEST_MODE      0x20
 #define INTERSIL_CMD_NORMAL_MODE    0x0
 
-/* bit assignments for interrupt register r/w, p 7 of 10*/
+/* bit assignments for interrupt register r/w, p 7 of 10 */
 
 #define INTERSIL_INTER_ALARM       0x1 /* r/w */
 #define INTERSIL_INTER_CSECONDS    0x2 /* r/w */