[PATCH] some rtc documentation updates
Fix typo when describing RTC_WKALM. Add some helpful pointers to people
developing their own RTC driver. Change a bunch of the error messages in the
test program to be a bit more helpful.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/rtc.txt b/Documentation/rtc.txt
index 7cf1ec5..1ef6bb8 100644
--- a/Documentation/rtc.txt
+++ b/Documentation/rtc.txt
@@ -149,7 +149,7 @@
is connected to an IRQ line, it can often issue an alarm IRQ up to
24 hours in the future.
- * RTC_WKALM_SET, RTC_WKALM_READ ... RTCs that can issue alarms beyond
+ * RTC_WKALM_SET, RTC_WKALM_RD ... RTCs that can issue alarms beyond
the next 24 hours use a slightly more powerful API, which supports
setting the longer alarm time and enabling its IRQ using a single
request (using the same model as EFI firmware).
@@ -167,6 +167,28 @@
operational state. For example, a system could enter a deep power saving
state until it's time to execute some scheduled tasks.
+Note that many of these ioctls need not actually be implemented by your
+driver. The common rtc-dev interface handles many of these nicely if your
+driver returns ENOIOCTLCMD. Some common examples:
+
+ * RTC_RD_TIME, RTC_SET_TIME: the read_time/set_time functions will be
+ called with appropriate values.
+
+ * RTC_ALM_SET, RTC_ALM_READ, RTC_WKALM_SET, RTC_WKALM_RD: the
+ set_alarm/read_alarm functions will be called. To differentiate
+ between the ALM and WKALM, check the larger fields of the rtc_wkalrm
+ struct (like tm_year). These will be set to -1 when using ALM and
+ will be set to proper values when using WKALM.
+
+ * RTC_IRQP_SET, RTC_IRQP_READ: the irq_set_freq function will be called
+ to set the frequency while the framework will handle the read for you
+ since the frequency is stored in the irq_freq member of the rtc_device
+ structure. Also make sure you set the max_user_freq member in your
+ initialization routines so the framework can sanity check the user
+ input for you.
+
+If all else fails, check out the rtc-test.c driver!
+
-------------------- 8< ---------------- 8< -----------------------------
@@ -237,7 +259,7 @@
"\n...Update IRQs not supported.\n");
goto test_READ;
}
- perror("ioctl");
+ perror("RTC_UIE_ON ioctl");
exit(errno);
}
@@ -284,7 +306,7 @@
/* Turn off update interrupts */
retval = ioctl(fd, RTC_UIE_OFF, 0);
if (retval == -1) {
- perror("ioctl");
+ perror("RTC_UIE_OFF ioctl");
exit(errno);
}
@@ -292,7 +314,7 @@
/* Read the RTC time/date */
retval = ioctl(fd, RTC_RD_TIME, &rtc_tm);
if (retval == -1) {
- perror("ioctl");
+ perror("RTC_RD_TIME ioctl");
exit(errno);
}
@@ -320,14 +342,14 @@
"\n...Alarm IRQs not supported.\n");
goto test_PIE;
}
- perror("ioctl");
+ perror("RTC_ALM_SET ioctl");
exit(errno);
}
/* Read the current alarm settings */
retval = ioctl(fd, RTC_ALM_READ, &rtc_tm);
if (retval == -1) {
- perror("ioctl");
+ perror("RTC_ALM_READ ioctl");
exit(errno);
}
@@ -337,7 +359,7 @@
/* Enable alarm interrupts */
retval = ioctl(fd, RTC_AIE_ON, 0);
if (retval == -1) {
- perror("ioctl");
+ perror("RTC_AIE_ON ioctl");
exit(errno);
}
@@ -355,7 +377,7 @@
/* Disable alarm interrupts */
retval = ioctl(fd, RTC_AIE_OFF, 0);
if (retval == -1) {
- perror("ioctl");
+ perror("RTC_AIE_OFF ioctl");
exit(errno);
}
@@ -368,7 +390,7 @@
fprintf(stderr, "\nNo periodic IRQ support\n");
return 0;
}
- perror("ioctl");
+ perror("RTC_IRQP_READ ioctl");
exit(errno);
}
fprintf(stderr, "\nPeriodic IRQ rate is %ldHz.\n", tmp);
@@ -387,7 +409,7 @@
"\n...Periodic IRQ rate is fixed\n");
goto done;
}
- perror("ioctl");
+ perror("RTC_IRQP_SET ioctl");
exit(errno);
}
@@ -397,7 +419,7 @@
/* Enable periodic interrupts */
retval = ioctl(fd, RTC_PIE_ON, 0);
if (retval == -1) {
- perror("ioctl");
+ perror("RTC_PIE_ON ioctl");
exit(errno);
}
@@ -416,7 +438,7 @@
/* Disable periodic interrupts */
retval = ioctl(fd, RTC_PIE_OFF, 0);
if (retval == -1) {
- perror("ioctl");
+ perror("RTC_PIE_OFF ioctl");
exit(errno);
}
}