uboot一般不会要求开启rtc，，不过还是支持rtc以备特殊需求的。底层驱动移植前面两篇已经介绍，这里介绍顶层的调用过程。顶层在uboot/common/cmd_date.c
/* * (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 */
/* * RTC, Date & Time support: get and set date & time */
include include include include ifdef CONFIG_RELOC_FIXUP_WORKSdefine RELOC(a) aelsedefine RELOC(a) ((typeof(a))((unsigned long)(a) + gd->reloc_off))endif
int mk_date (char , struct rtc_time );
int do_date (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) { struct rtc_time tm; int rcode = 0; int old_bus;
/* switch to correct I2C bus */old_bus = I2C_GET_BUS();I2C_SET_BUS(CONFIG_SYS_RTC_BUS_NUM);switch (argc) {case 2:/* set date & time */if (strcmp(argv[1],”reset”) == 0) {puts (“Reset RTC…\n”);rtc_reset ();} else {/* initialize tm with current time */rcode = rtc_get (&tm);if(!rcode) {/* insert new date & time */if (mk_date (argv[1], &tm) != 0) {puts (“## Bad date format\n”);break;}/* and write to RTC */rcode = rtc_set (&tm);if(rcode)puts(“## Set date failed\n”);} else {puts(“## Get date failed\n”);}}/* FALL TROUGH */case 1:/* get date & time */rcode = rtc_get (&tm);if (rcode) {puts(“## Get date failed\n”);break;}printf (“Date: %4d-%02d-%02d (%sday) Time: %2d:%02d:%02d\n”,tm.tm_year, tm.tm_mon, tm.tm_mday,(tm.tm_wday<0 || tm.tm_wday>6) ?”unknown ” : RELOC(weekdays[tm.tm_wday]),tm.tm_hour, tm.tm_min, tm.tm_sec);break;default:cmd_usage(cmdtp);rcode = 1;}/* switch back to original I2C bus */I2C_SET_BUS(old_bus);return rcode;
}
/* * simple conversion of two-digit string with error checking */ static int cnvrt2 (char *str, int *valp) { int val;
if ((*str < ‘0’) || (*str > ‘9’))return (-1);val = *str – ‘0’;++str;if ((*str < ‘0’) || (*str > ‘9’))return (-1);*valp = 10 * val + (*str – ‘0’);return (0);
}
/* * Convert date string: MMDDhhmm[[CC]YY][.ss] * * Some basic checking for valid values is done, but this will not catch * all possible error conditions. */ int mk_date (char *datestr, struct rtc_time *tmp) { int len, val; char *ptr;
ptr = strchr (datestr,’.’);len = strlen (datestr);/* Set seconds */if (ptr) {int sec;*ptr++ = ‘\0’;if ((len – (ptr – datestr)) != 2)return (-1);len = strlen (datestr);if (cnvrt2 (ptr, &sec))return (-1);tmp->tm_sec = sec;} else {tmp->tm_sec = 0;}if (len == 12) {/* MMDDhhmmCCYY */int year, century;if (cnvrt2 (datestr+ 8, ¢ury) ||cnvrt2 (datestr+10, &year) ) {return (-1);}tmp->tm_year = 100 * century + year;} else if (len == 10) {/* MMDDhhmmYY */int year, century;century = tmp->tm_year / 100;if (cnvrt2 (datestr+ 8, &year))return (-1);tmp->tm_year = 100 * century + year;}switch (len) {case 8:/* MMDDhhmm *//* fall thru */case 10:/* MMDDhhmmYY *//* fall thru */case 12:/* MMDDhhmmCCYY */if (cnvrt2 (datestr+0, &val) ||val > 12) {break;}tmp->tm_mon = val;if (cnvrt2 (datestr+2, &val) ||val > ((tmp->tm_mon==2) ? 29 : 31)) {break;}tmp->tm_mday = val;if (cnvrt2 (datestr+4, &val) ||val > 23) {break;}tmp->tm_hour = val;if (cnvrt2 (datestr+6, &val) ||val > 59) {break;}tmp->tm_min = val;/* calculate day of week */GregorianDay (tmp);return (0);default:break;}return (-1);
}
/*****************************************/
U_BOOT_CMD( date, 2, 1, do_date, “get/set/reset date & time”, “[MMDDhhmm[[CC]YY][.ss]]\ndate reset\n” ” – without arguments: print date & time\n” ” – with numeric argument: set the system date & time\n” ” – with ‘reset’ argument: reset the RTC” ); 这里反向分析： 第一步是注册 date命令 U_BOOT_CMD( date, 2, 1, do_date, “get/set/reset date & time”, “[MMDDhhmm[[CC]YY][.ss]]\ndate reset\n” ” – without arguments: print date & time\n” ” – with numeric argument: set the system date & time\n” ” – with ‘reset’ argument: reset the RTC” ); 这个命令就是rtc的控制命令了 调用的函数是 do_date int do_date (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) 可以看到这命令是调用了rtc里面注册的rtc_reset、rtc_get、rtc_set 分为case1 ：获取当年的时间 case2 设置时间； 时间转换函数mk_date 可以将我们输入的字符串转化成为时间的年月日 供rtc_set 配置下去去
生活中若没有朋友，就像生活中没有阳光一样
