Lines Matching full:rtc

2 Real Time Clock (RTC) Drivers for Linux
16 Linux has two largely-compatible userspace RTC API families you may
19     *	/dev/rtc ... is the RTC provided by PC compatible systems,
23 	supported by a wide variety of RTC chips on all systems.
27 RTCs use the same API to make requests in both RTC frameworks (using
29 same functionality.  For example, not every RTC is hooked up to an
35 Old PC/AT-Compatible driver:  /dev/rtc
57 The interrupts are reported via /dev/rtc (major 10, minor 135, read only
62 /proc/driver/rtc if the /proc filesystem was enabled.  The driver has
63 built in locking so that only one process is allowed to have the /dev/rtc
67 select(2) on /dev/rtc -- either will block/stop the user process until
75 typical 486-33 running a tight read loop on /dev/rtc will start to suffer
85 a different value to /proc/sys/dev/rtc/max-user-freq. Note that the
91 the process of doing this, the kernel briefly turns off RTC periodic 
94 whatever) then the kernel will keep its hands off the RTC, allowing you
97 The alarm and/or interrupt frequency are programmed into the RTC via
98 various ioctl(2) calls as listed in ./include/linux/rtc.h
105 (The original /dev/rtc driver was written by Paul Gortmaker.)
108 New portable "RTC Class" drivers:  /dev/rtcN
112 have more than one RTC style clock, it needed a more portable solution
114 Accordingly, a new "RTC Class" framework has been defined.  It offers
117     *	/dev/rtcN ... much the same as the older /dev/rtc interface
119     *	/sys/class/rtc/rtcN ... sysfs attributes support readonly
120 	access to some RTC attributes.
122     *	/proc/driver/rtc ... the system clock RTC may expose itself
123 	using a procfs interface. If there is no RTC for the system clock,
127 The RTC Class framework supports a wide variety of RTCs, ranging from those
133 The new framework also removes the "one RTC per system" restriction.  For
134 example, maybe the low-power battery-backed RTC is a discrete I2C chip, but
135 a high functionality RTC is integrated into the SOC.  That system might read
136 the system clock from the discrete RTC, but use the integrated one for all
139 Check out tools/testing/selftests/rtc/rtctest.c for an example usage of the