Linux Drivers: RTC subsystem

1. Description

   
   

   This paper analyzes code based on 3.10 kernel, hardware platform for embedded arm platform.
   

2. RTC Subsystem Related files

drivers/rtc/class.cdrivers/rtc/interface.cdrivers/rtc/rtc-core.hdrivers/rtc/rtc-dev.cdrivers/rtc/ Rtc-lib.cdrivers/rtc/rtc-proc.cdrivers/rtc/rtc-sysfs.cdrivers/rtc/hctosys.cdrivers/rtc/rtc-xxx.c

CLASS.C: Managing the RTC SYS class;

INTERFACE.C: The main function is the indirect RTC drive interface;

RTC-DEV.C:RTC device user interface;

RTC-LIB.C:RTC auxiliary function, mainly used for RTC time conversion, calculation;

RTC-PROC:RTC proc FS (user) interface;

RTC-SYSFS:RTC SYS FS (user) interface;

HCTOSYS.C: Used to read time from RTC at system startup and set to system time;

RTC-XXX.C:RTC hardware chip driver, such as rtc-wm8350.c,rtc-hym8563.c.

3. RTC Subsystem Block Diagram

650) this.width=650; "src=" Https://s4.51cto.com/wyfs02/M00/97/FC/wKioL1k2EYuwmCfUAABNGCkC9gw392.gif "title=" Rtc-hie.gif "alt=" Wkiol1k2eyuwmcfuaabngckc9gw392.gif "/>

is based on the new RTC Subsystem Framework, which can better adapt to the embedded development environment, the embedded environment may have multiple RTC cores

Chip.

The old RTC Drive is a simple character device driver that is adapted to the PC platform and should have a/DEV/RTC device file.

Under the new RTC Subsystem Framework, the application accesses the RTC chip via the/DEV/RTC[0-N] device. These accesses are

The interface provided by the RTC-DEV.C provides indirect access to the RTC chip driver provided by the RTC-XXX.C. Common operations have read/set time operations,

This each RTC chip must support the operation.

Of course, access to the/dev/rtc[0-n] device files is not the only way to access the RTC chip, and the Proc,sys FS provided by RTC

Interface to access the RTC.

4. System Time Source: RTC Device Development

Device Drivers--->

[*] Real Time Clock--->

(rtc0) RTC used to set system time

...

RTC Interfaces * * *

...

i²c RTC Drivers * * *

...

SPI RTC Drivers * * *

...

on-cpu RTC Drivers * * *

...

Note: The red typeface is the RTC device specified as the source of the system time.

This article is from the "Jimokuangxiangqu" blog, make sure to keep this source http://4594296.blog.51cto.com/4584296/1932659

Linux Drivers: RTC subsystem