[PATCH 0/2] Documentation: rtc: move ioctl to ABI

[PATCH 0/2] Documentation: rtc: move ioctl to ABI

[Aishwarya Pant]

Two documentation changes in rtc:
1) Minor change to add file permissions to sysfs interface
2) Move ioctl interface to Documentation/ABI

Aishwarya Pant (2):
  Documentation: rtc: add sysfs file permissions
  Documentation: rtc: move iotcl interface documentation to ABI

 Documentation/ABI/testing/rtc-cdev        | 42 ++++++++++++++++++++++++++
 Documentation/ABI/testing/sysfs-class-rtc | 44 ++++++++++++++-------------
 Documentation/rtc.txt                     | 49 ++-----------------------------
 3 files changed, 67 insertions(+), 68 deletions(-)
 create mode 100644 Documentation/ABI/testing/rtc-cdev

-- 
2.15.1

[PATCH 1/2] Documentation: rtc: add sysfs file permissions

[Aishwarya Pant]

Annotate the sysfs interface of rtc with file specific permissions
(RO/RW).

Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
---
 Documentation/ABI/testing/sysfs-class-rtc | 44 ++++++++++++++++---------------
 1 file changed, 23 insertions(+), 21 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-class-rtc b/Documentation/ABI/testing/sysfs-class-rtc
index df2eca7e2e77..5083841b03d4 100644
--- a/Documentation/ABI/testing/sysfs-class-rtc
+++ b/Documentation/ABI/testing/sysfs-class-rtc
@@ -18,14 +18,14 @@ Date:		March 2006
 KernelVersion:	2.6.17
 Contact:	linux-rtc@vger.kernel.org
 Description:
-		RTC-provided date in YYYY-MM-DD format
+		(RO) RTC-provided date in YYYY-MM-DD format
 
 What:		/sys/class/rtc/rtcX/hctosys
 Date:		September 2009
 KernelVersion:	2.6.32
 Contact:	linux-rtc@vger.kernel.org
 Description:
-		1 if the RTC provided the system time at boot via the
+		(RO) 1 if the RTC provided the system time at boot via the
 		CONFIG_RTC_HCTOSYS kernel option, 0 otherwise
 
 What:		/sys/class/rtc/rtcX/max_user_freq
@@ -33,7 +33,7 @@ Date:		October 2007
 KernelVersion:	2.6.24
 Contact:	linux-rtc@vger.kernel.org
 Description:
-		The maximum interrupt rate an unprivileged user may request
+		(RW) The maximum interrupt rate an unprivileged user may request
 		from this RTC.
 
 What:		/sys/class/rtc/rtcX/name
@@ -41,58 +41,60 @@ Date:		March 2006
 KernelVersion:	2.6.17
 Contact:	linux-rtc@vger.kernel.org
 Description:
-		The name of the RTC corresponding to this sysfs directory
+		(RO) The name of the RTC corresponding to this sysfs directory
 
 What:		/sys/class/rtc/rtcX/range
 Date:		January 2018
 KernelVersion:	4.16
 Contact:	linux-rtc@vger.kernel.org
 Description:
-		Valid time range for the RTC, as seconds from epoch, formatted
-		as [min, max]
+		(RO) Valid time range for the RTC, as seconds from epoch,
+		formatted as [min, max]
 
 What:		/sys/class/rtc/rtcX/since_epoch
 Date:		March 2006
 KernelVersion:	2.6.17
 Contact:	linux-rtc@vger.kernel.org
 Description:
-		RTC-provided time as the number of seconds since the epoch
+		(RO) RTC-provided time as the number of seconds since the epoch
 
 What:		/sys/class/rtc/rtcX/time
 Date:		March 2006
 KernelVersion:	2.6.17
 Contact:	linux-rtc@vger.kernel.org
 Description:
-		RTC-provided time in 24-hour notation (hh:mm:ss)
+		(RO) RTC-provided time in 24-hour notation (hh:mm:ss)
 
 What:		/sys/class/rtc/rtcX/*/nvmem
 Date:		February 2016
 KernelVersion:	4.6
 Contact:	linux-rtc@vger.kernel.org
 Description:
-		The non volatile storage exported as a raw file, as described in
-		Documentation/nvmem/nvmem.txt
+		(RW) The non volatile storage exported as a raw file, as
+		described in Documentation/nvmem/nvmem.txt
 
 What:		/sys/class/rtc/rtcX/offset
 Date:		February 2016
 KernelVersion:	4.6
 Contact:	linux-rtc@vger.kernel.org
 Description:
-		The amount which the rtc clock has been adjusted in firmware.
-		Visible only if the driver supports clock offset adjustment.
-		The unit is parts per billion, i.e. The number of clock ticks
-		which are added to or removed from the rtc's base clock per
-		billion ticks. A positive value makes a day pass more slowly,
-		longer, and a negative value makes a day pass more quickly.
+		(RW) The amount which the rtc clock has been adjusted in
+		firmware. Visible only if the driver supports clock offset
+		adjustment. The unit is parts per billion, i.e. The number of
+		clock ticks which are added to or removed from the rtc's base
+		clock per billion ticks. A positive value makes a day pass more
+		slowly, longer, and a negative value makes a day pass more
+		quickly.
 
 What:		/sys/class/rtc/rtcX/wakealarm
 Date:		February 2007
 KernelVersion:	2.6.20
 Contact:	linux-rtc@vger.kernel.org
 Description:
-		The time at which the clock will generate a system wakeup event.
-		This is a one shot wakeup event, so must be reset after wake if
-		a daily wakeup is required. Format is seconds since the epoch by
-		default, or if there's a leading +, seconds in the future, or if
-		there is a leading +=, seconds ahead of the current alarm.
+		(RW) The time at which the clock will generate a system wakeup
+		event. This is a one shot wakeup event, so must be reset after
+		wake if a daily wakeup is required. Format is seconds since the
+		epoch by default, or if there's a leading +, seconds in the
+		future, or if there is a leading +=, seconds ahead of the
+		current alarm.
 
-- 
2.15.1

[PATCH 2/2] Documentation: rtc: move iotcl interface documentation to ABI

[Aishwarya Pant]

The ioctl interface should be in Documentation/ABI along with the rest
of the interfaces.

Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
---
 Documentation/ABI/testing/rtc-cdev | 42 ++++++++++++++++++++++++++++++++
 Documentation/rtc.txt              | 49 ++------------------------------------
 2 files changed, 44 insertions(+), 47 deletions(-)
 create mode 100644 Documentation/ABI/testing/rtc-cdev

diff --git a/Documentation/ABI/testing/rtc-cdev b/Documentation/ABI/testing/rtc-cdev
new file mode 100644
index 000000000000..97447283f13b
--- /dev/null
+++ b/Documentation/ABI/testing/rtc-cdev
@@ -0,0 +1,42 @@
+What:		/dev/rtcX
+Date:		April 2005
+KernelVersion:	2.6.12
+Contact:	linux-rtc@vger.kernel.org
+Description:
+		The ioctl interface to drivers for real-time clocks (RTCs).
+		Following actions are supported:
+
+		* RTC_RD_TIME, RTC_SET_TIME: Read or set the RTC time. Time
+		  format is a Gregorian calendar date and 24 hour wall clock
+		  time.
+
+		* RTC_AIE_ON, RTC_AIE_OFF: Enable or disable the alarm interrupt
+		  for RTCs that support alarms
+
+		* RTC_ALM_READ, RTC_ALM_SET: Read or set the alarm time for
+		  RTCs that support alarms. Can be set upto 24 hours in the
+		  future. Requires a separate RTC_AIE_ON call to enable the
+		  alarm interrupt. (Prefer to use RTC_WKALM_*)
+
+		* RTC_WKALM_RD, RTC_WKALM_SET: For RTCs that support a more
+		  powerful interface, which can issue alarms beyond 24 hours and
+		  enable IRQs in the same request.
+
+		* RTC_PIE_ON, RTC_PIE_OFF: Enable or disable the periodic
+		  interrupt for RTCs that support periodic interrupts.
+
+		* RTC_UIE_ON, RTC_UIE_OFF: Enable or disable the update
+		  interrupt for RTCs that support it.
+
+		* RTC_IRQP_READ, RTC_IRQP_SET: Read or set the frequency for
+		  periodic interrupts for RTCs that support periodic interrupts.
+		  Requires a separate RTC_PIE_ON call to enable the periodic
+		  interrupts.
+
+		The ioctl() calls supported by the older /dev/rtc interface are
+		also supported by the newer RTC class framework. However,
+		because the chips and systems are not standardized, some PC/AT
+		functionality might not be provided. And in the same way, some
+		newer features -- including those enabled by ACPI -- are exposed
+		by the RTC class framework, but can't be supported by the older
+		driver.
diff --git a/Documentation/rtc.txt b/Documentation/rtc.txt
index f521262cdc85..a129acf38537 100644
--- a/Documentation/rtc.txt
+++ b/Documentation/rtc.txt
@@ -136,50 +136,5 @@ a high functionality RTC is integrated into the SOC.  That system might read
 the system clock from the discrete RTC, but use the integrated one for all
 other tasks, because of its greater functionality.
 
-IOCTL interface
----------------
-
-The ioctl() calls supported by /dev/rtc are also supported by the RTC class
-framework.  However, because the chips and systems are not standardized,
-some PC/AT functionality might not be provided.  And in the same way, some
-newer features -- including those enabled by ACPI -- are exposed by the
-RTC class framework, but can't be supported by the older driver.
-
-    *	RTC_RD_TIME, RTC_SET_TIME ... every RTC supports at least reading
-	time, returning the result as a Gregorian calendar date and 24 hour
-	wall clock time.  To be most useful, this time may also be updated.
-
-    *	RTC_AIE_ON, RTC_AIE_OFF, RTC_ALM_SET, RTC_ALM_READ ... when the RTC
-	is connected to an IRQ line, it can often issue an alarm IRQ up to
-	24 hours in the future.  (Use RTC_WKALM_* by preference.)
-
-    *	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).
-
-    *	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 ... 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 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: gets or sets
-	the alarm rtc_timer. May call the set_alarm driver function.
-
-    *	RTC_IRQP_SET, RTC_IRQP_READ: These are emulated by the generic code.
-
-    *	RTC_PIE_ON, RTC_PIE_OFF: These are also emulated by the generic code.
-
-If all else fails, check out the tools/testing/selftests/timers/rtctest.c test!
+Check out tools/testing/selftests/timers/rtctest.c for an example usage of the
+ioctl interface.
-- 
2.15.1

Re: [PATCH 0/2] Documentation: rtc: move ioctl to ABI

[Alexandre Belloni]

On 01/01/2018 at 23:00:02 +0530, Aishwarya Pant wrote:
> Two documentation changes in rtc:
> 1) Minor change to add file permissions to sysfs interface
> 2) Move ioctl interface to Documentation/ABI
> 
> Aishwarya Pant (2):
>   Documentation: rtc: add sysfs file permissions
>   Documentation: rtc: move iotcl interface documentation to ABI
> 

Applied, thanks.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com