uboot中可能会有需求提供rtc的支持目的达到uboot启动也可以进行墙上时间的显示和后面判断。大部分rtc支持的一个必要条件就是已经有i2c的支持。因为很多的rtc是i2c接口控制的，uboot中i2c的移植在前一篇中已经提过。这里就只做rtc的移植。这里选择了常用的一款rtc芯片pcf8653来分析。
第一步开启支持的选项，
uboot/include/configs/mpc5200-common.h这个配置文件中开启了8653这个芯片的支持。
/*
* RTC configuration
*/

define CONFIG_RTC_PCF8563

define CONFIG_SYS_I2C_RTC_ADDR 0x51

这里定义了8653的开启配置和他的i2c的device id
第二步：uboot/drivers/rtc/Makefile
COBJS-$(CONFIG_RTC_PCF8563) += pcf8563.o
确定有这么一条，如果移植里面不存在的你就要自己添加了。
第三步实现pcf8563.c 这个文件，这个就相当于新建立一个命令。但是这个命令还是uboot做了统一的，这样就可以方便使用者了。
/*
* (C) Copyright 2001
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/

/*
* Date & Time support for Philips PCF8563 RTC
*/

/* #define DEBUG */

include

if defined(CONFIG_CMD_DATE)

static uchar rtc_read (uchar reg);
static void rtc_write (uchar reg, uchar val);

/* ————————————————————————- */

int rtc_get (struct rtc_time *tmp)
{
int rel = 0;
uchar sec, min, hour, mday, wday, mon_cent, year;

sec = rtc_read (0x02)-0x80;
min = rtc_read (0x03);
hour    = rtc_read (0x04);
mday    = rtc_read (0x05);
wday    = rtc_read (0x06);
mon_cent= rtc_read (0x07);
year    = rtc_read (0x08);debug ( "Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x ""hr: %02x min: %02x sec: %02x\n",year, mon_cent, mday, wday,hour, min, sec );
debug( "Alarms: wday: %02x day: %02x hour: %02x min: %02x\n",rtc_read (0x0C),rtc_read (0x0B),rtc_read (0x0A),rtc_read (0x09) );

/*
if (sec & 0x80) {
puts (“xu Warning: RTC Low Voltage - date/time not reliable\n”);
rel = -1;
}
*/
tmp->tm_sec = bcd2bin (sec & 0x7F);
tmp->tm_min = bcd2bin (min & 0x7F);
tmp->tm_hour = bcd2bin (hour & 0x3F);
tmp->tm_mday = bcd2bin (mday & 0x3F);
tmp->tm_mon = bcd2bin (mon_cent & 0x1F);
tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900);
tmp->tm_wday = bcd2bin (wday & 0x07);
tmp->tm_yday = 0;
tmp->tm_isdst= 0;

debug( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,tmp->tm_hour, tmp->tm_min, tmp->tm_sec);return rel;

}

int rtc_set (struct rtc_time *tmp)
{
uchar century;

debug ( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,tmp->tm_hour, tmp->tm_min, tmp->tm_sec);rtc_write (0x08, bin2bcd(tmp->tm_year % 100));century = (tmp->tm_year >= 2000) ? 0x80 : 0;
rtc_write (0x07, bin2bcd(tmp->tm_mon) | century);rtc_write (0x06, bin2bcd(tmp->tm_wday));
rtc_write (0x05, bin2bcd(tmp->tm_mday));
rtc_write (0x04, bin2bcd(tmp->tm_hour));
rtc_write (0x03, bin2bcd(tmp->tm_min ));
rtc_write (0x02, bin2bcd(tmp->tm_sec ));return 0;

}

void rtc_reset (void)
{

/* clear all control & status registers */
rtc_write (0x00, 0x00);
rtc_write (0x01, 0x00);
rtc_write (0x0D, 0x00);/* clear Voltage Low bit */
rtc_write (0x02, rtc_read (0x02) & 0x7F);/* reset all alarms */
rtc_write (0x09, 0x00);
rtc_write (0x0A, 0x00);
rtc_write (0x0B, 0x00);
rtc_write (0x0C, 0x00);

}

/* ————————————————————————- */

static uchar rtc_read (uchar reg)
{
return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
}

static void rtc_write (uchar reg, uchar val)
{
i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
}

endif

这俩可以看到
开启CONFIG_CMD_DATE 这个配置
在uboot/include/rtc.h中也是同样对rtc定义了几个标准函数：
int rtc_get (struct rtc_time *);
int rtc_set (struct rtc_time *);
void rtc_reset (void);

void GregorianDay (struct rtc_time *);
void to_tm (int, struct rtc_time *);
unsigned long mktime (unsigned int, unsigned int, unsigned int,
unsigned int, unsigned int, unsigned int);
我们上面的8563文件中也是对应的实现这几个函数。按照标准的参数配置回应标准的数据或者配置。
这里还要关心一个date.c的文件这个文件实现了date命令unsigned long mktime (unsigned int, unsigned int, unsigned int,
unsigned int, unsigned int, unsigned int);

uboot移植rtc相关推荐

uboot移植新手入门实践
版权声明:bug实验室原创 https://blog.csdn.net/weixin_43349284/article/details/82958451 u-boot移植新手入门实践视频前言视频介 ...
嵌入式linux开发环境 cpu,嵌入式Linux开发环境的搭建之：U-Boot移植-嵌入式系统-与非网...
5.2 U-Boot移植 5.2.1 Bootloader介绍 1．概念简单地说,Bootloader就是在操作系统内核运行之前运行的一段程序,它类似于PC机中的BIOS程序.通过这段程序,可以 ...
【u-boot】uboot代码简要分析 (u-boot 移植）
uboot代码简要分析 (u-boot 移植) 2012-12-19 22:46:04 [转] 先来看看源码目录结构,再按照代码的执行顺序简单地分析源码 1.U-boot源码整体框架源码解压以后,我 ...
linux用户环境下进入uboot,嵌入式linux开发uboot移植（一）——uboot项目简介
嵌入式linux开发uboot移植(一)--uboot项目简介一.uboot简介 U-Boot,全称 Universal Boot Loader,是遵循GPL条款的从FADSROM.8xxROM.P ...
[学习资料] Tiny210(S5PV210) u-boot移植
Tiny210(S5PV210) u-boot移植 http://www.microoh.com/bbs/forum.php?mod=viewthread&tid=254&fromui ...
u-boot移植到mini2440，u-boot版本2008.10
这篇文章写于2008.12.28日,主要记录了我移植u-boot-2008.10的过程,并附上了移植好的patch文件.移植好的u-boot-2008.10适用友善公司的mini2440和阳初公司的y ...
U-Boot移植与总结 P2020篇
本文章首发地址:https://www.lgfccl.xyz 随时down 机,转载注明出处谢谢 UBOOT 概述 1 U-Boot简介 U-Boot,全称 Universal Boot Loader ...
X-007 FriendlyARM tiny4412 u-boot移植之内存初始化
<<<<<<<<<<<<<<<<<<<<<<<<< ...
U-Boot移植教程之二：移植
内容来自韦东山<嵌入式Linux应用开发完全手册> 一.U-Boot移植开发板smdk2410的配置适用于大多数S3C2410单板,或是只需要极少的修改即可使用.但是目前U-Boot中 ...

uboot移植rtc

define CONFIG_RTC_PCF8563

define CONFIG_SYS_I2C_RTC_ADDR 0x51

include

include

include

include

if defined(CONFIG_CMD_DATE)

endif

uboot移植rtc相关推荐

最新文章

热门文章