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authorLinus Torvalds <torvalds@linux-foundation.org>2011-03-15 18:59:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-15 18:59:21 -0700
commit21a32816b2e13eafb6d8a4589a84c6e629adc392 (patch)
tree8cfd2b8ffd355ef0954d6fef36aaffbc6fd53215 /Documentation
parent420c1c572d4ceaa2f37b6311b7017ac6cf049fe2 (diff)
parentea04683f592e6200b52e191b7e2842aedcfd88b6 (diff)
Merge branch 'timers-rtc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-rtc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: RTC: Fix up rtc.txt documentation to reflect changes to generic rtc layer RTC: sa1100: Update the sa1100 RTC driver. RTC: Fix the cross interrupt issue on rtc-test. RTC: Remove UIE and PIE information from the sa1100 driver proc. RTC: Include information about UIE and PIE in RTC driver proc. RTC: Clean out UIE icotl implementations RTC: Cleanup rtc_class_ops->update_irq_enable() RTC: Cleanup rtc_class_ops->irq_set_freq() RTC: Cleanup rtc_class_ops->irq_set_state RTC: Initialize kernel state from RTC
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/rtc.txt29
1 files changed, 10 insertions, 19 deletions
diff --git a/Documentation/rtc.txt b/Documentation/rtc.txt
index 9104c1062084..250160469d83 100644
--- a/Documentation/rtc.txt
+++ b/Documentation/rtc.txt
@@ -178,38 +178,29 @@ RTC class framework, but can't be supported by the older driver.
setting the longer alarm time and enabling its IRQ using a single
request (using the same model as EFI firmware).
- * RTC_UIE_ON, RTC_UIE_OFF ... if the RTC offers IRQs, it probably
- also offers update IRQs whenever the "seconds" counter changes.
- If needed, the RTC framework can emulate this mechanism.
+ * RTC_UIE_ON, RTC_UIE_OFF ... if the RTC offers IRQs, the RTC framework
+ will emulate this mechanism.
- * RTC_PIE_ON, RTC_PIE_OFF, RTC_IRQP_SET, RTC_IRQP_READ ... another
- feature often accessible with an IRQ line is a periodic IRQ, issued
- at settable frequencies (usually 2^N Hz).
+ * RTC_PIE_ON, RTC_PIE_OFF, RTC_IRQP_SET, RTC_IRQP_READ ... these icotls
+ are emulated via a kernel hrtimer.
In many cases, the RTC alarm can be a system wake event, used to force
Linux out of a low power sleep state (or hibernation) back to a fully
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:
+Note that many of these ioctls are handled by the common rtc-dev interface.
+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.
+ * RTC_ALM_SET, RTC_ALM_READ, RTC_WKALM_SET, RTC_WKALM_RD: gets or sets
+ the alarm rtc_timer. May call the set_alarm driver function.
- * 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. Your driver needs to initialize the irq_freq member during
- init. Make sure you check the requested frequency is in range of your
- hardware in the irq_set_freq function. If it isn't, return -EINVAL. If
- you cannot actually change the frequency, do not define irq_set_freq.
+ * RTC_IRQP_SET, RTC_IRQP_READ: These are emulated by the generic code.
- * RTC_PIE_ON, RTC_PIE_OFF: the irq_set_state function will be called.
+ * RTC_PIE_ON, RTC_PIE_OFF: These are also emulated by the generic code.
If all else fails, check out the rtc-test.c driver!