1 /* 2 * Dallas DS1302 RTC Support 3 * 4 * Copyright (C) 2002 David McCullough 5 * Copyright (C) 2003 - 2007 Paul Mundt 6 * 7 * This file is subject to the terms and conditions of the GNU General Public 8 * License version 2. See the file "COPYING" in the main directory of 9 * this archive for more details. 10 */ 11 12 #include <linux/init.h> 13 #include <linux/module.h> 14 #include <linux/kernel.h> 15 #include <linux/platform_device.h> 16 #include <linux/rtc.h> 17 #include <linux/io.h> 18 #include <linux/bcd.h> 19 #include <asm/rtc.h> 20 21 #define DRV_NAME "rtc-ds1302" 22 #define DRV_VERSION "0.1.1" 23 24 #define RTC_CMD_READ 0x81 /* Read command */ 25 #define RTC_CMD_WRITE 0x80 /* Write command */ 26 27 #define RTC_ADDR_RAM0 0x20 /* Address of RAM0 */ 28 #define RTC_ADDR_TCR 0x08 /* Address of trickle charge register */ 29 #define RTC_ADDR_YEAR 0x06 /* Address of year register */ 30 #define RTC_ADDR_DAY 0x05 /* Address of day of week register */ 31 #define RTC_ADDR_MON 0x04 /* Address of month register */ 32 #define RTC_ADDR_DATE 0x03 /* Address of day of month register */ 33 #define RTC_ADDR_HOUR 0x02 /* Address of hour register */ 34 #define RTC_ADDR_MIN 0x01 /* Address of minute register */ 35 #define RTC_ADDR_SEC 0x00 /* Address of second register */ 36 37 #define RTC_RESET 0x1000 38 #define RTC_IODATA 0x0800 39 #define RTC_SCLK 0x0400 40 41 #ifdef CONFIG_SH_SECUREEDGE5410 42 #include <mach/snapgear.h> 43 #define set_dp(x) SECUREEDGE_WRITE_IOPORT(x, 0x1c00) 44 #define get_dp() SECUREEDGE_READ_IOPORT() 45 #else 46 #error "Add support for your platform" 47 #endif 48 49 static void ds1302_sendbits(unsigned int val) 50 { 51 int i; 52 53 for (i = 8; (i); i--, val >>= 1) { 54 set_dp((get_dp() & ~RTC_IODATA) | ((val & 0x1) ? 55 RTC_IODATA : 0)); 56 set_dp(get_dp() | RTC_SCLK); /* clock high */ 57 set_dp(get_dp() & ~RTC_SCLK); /* clock low */ 58 } 59 } 60 61 static unsigned int ds1302_recvbits(void) 62 { 63 unsigned int val; 64 int i; 65 66 for (i = 0, val = 0; (i < 8); i++) { 67 val |= (((get_dp() & RTC_IODATA) ? 1 : 0) << i); 68 set_dp(get_dp() | RTC_SCLK); /* clock high */ 69 set_dp(get_dp() & ~RTC_SCLK); /* clock low */ 70 } 71 72 return val; 73 } 74 75 static unsigned int ds1302_readbyte(unsigned int addr) 76 { 77 unsigned int val; 78 79 set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); 80 81 set_dp(get_dp() | RTC_RESET); 82 ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ); 83 val = ds1302_recvbits(); 84 set_dp(get_dp() & ~RTC_RESET); 85 86 return val; 87 } 88 89 static void ds1302_writebyte(unsigned int addr, unsigned int val) 90 { 91 set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); 92 set_dp(get_dp() | RTC_RESET); 93 ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE); 94 ds1302_sendbits(val); 95 set_dp(get_dp() & ~RTC_RESET); 96 } 97 98 static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm) 99 { 100 tm->tm_sec = bcd2bin(ds1302_readbyte(RTC_ADDR_SEC)); 101 tm->tm_min = bcd2bin(ds1302_readbyte(RTC_ADDR_MIN)); 102 tm->tm_hour = bcd2bin(ds1302_readbyte(RTC_ADDR_HOUR)); 103 tm->tm_wday = bcd2bin(ds1302_readbyte(RTC_ADDR_DAY)); 104 tm->tm_mday = bcd2bin(ds1302_readbyte(RTC_ADDR_DATE)); 105 tm->tm_mon = bcd2bin(ds1302_readbyte(RTC_ADDR_MON)) - 1; 106 tm->tm_year = bcd2bin(ds1302_readbyte(RTC_ADDR_YEAR)); 107 108 if (tm->tm_year < 70) 109 tm->tm_year += 100; 110 111 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 112 "mday=%d, mon=%d, year=%d, wday=%d\n", 113 __func__, 114 tm->tm_sec, tm->tm_min, tm->tm_hour, 115 tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday); 116 117 return rtc_valid_tm(tm); 118 } 119 120 static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm) 121 { 122 /* Stop RTC */ 123 ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80); 124 125 ds1302_writebyte(RTC_ADDR_SEC, bin2bcd(tm->tm_sec)); 126 ds1302_writebyte(RTC_ADDR_MIN, bin2bcd(tm->tm_min)); 127 ds1302_writebyte(RTC_ADDR_HOUR, bin2bcd(tm->tm_hour)); 128 ds1302_writebyte(RTC_ADDR_DAY, bin2bcd(tm->tm_wday)); 129 ds1302_writebyte(RTC_ADDR_DATE, bin2bcd(tm->tm_mday)); 130 ds1302_writebyte(RTC_ADDR_MON, bin2bcd(tm->tm_mon + 1)); 131 ds1302_writebyte(RTC_ADDR_YEAR, bin2bcd(tm->tm_year % 100)); 132 133 /* Start RTC */ 134 ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80); 135 136 return 0; 137 } 138 139 static int ds1302_rtc_ioctl(struct device *dev, unsigned int cmd, 140 unsigned long arg) 141 { 142 switch (cmd) { 143 #ifdef RTC_SET_CHARGE 144 case RTC_SET_CHARGE: 145 { 146 int tcs_val; 147 148 if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int))) 149 return -EFAULT; 150 151 ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf)); 152 return 0; 153 } 154 #endif 155 } 156 157 return -ENOIOCTLCMD; 158 } 159 160 static struct rtc_class_ops ds1302_rtc_ops = { 161 .read_time = ds1302_rtc_read_time, 162 .set_time = ds1302_rtc_set_time, 163 .ioctl = ds1302_rtc_ioctl, 164 }; 165 166 static int __init ds1302_rtc_probe(struct platform_device *pdev) 167 { 168 struct rtc_device *rtc; 169 170 /* Reset */ 171 set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); 172 173 /* Write a magic value to the DS1302 RAM, and see if it sticks. */ 174 ds1302_writebyte(RTC_ADDR_RAM0, 0x42); 175 if (ds1302_readbyte(RTC_ADDR_RAM0) != 0x42) 176 return -ENODEV; 177 178 rtc = rtc_device_register("ds1302", &pdev->dev, 179 &ds1302_rtc_ops, THIS_MODULE); 180 if (IS_ERR(rtc)) 181 return PTR_ERR(rtc); 182 183 platform_set_drvdata(pdev, rtc); 184 185 return 0; 186 } 187 188 static int __devexit ds1302_rtc_remove(struct platform_device *pdev) 189 { 190 struct rtc_device *rtc = platform_get_drvdata(pdev); 191 192 rtc_device_unregister(rtc); 193 platform_set_drvdata(pdev, NULL); 194 195 return 0; 196 } 197 198 static struct platform_driver ds1302_platform_driver = { 199 .driver = { 200 .name = DRV_NAME, 201 .owner = THIS_MODULE, 202 }, 203 .remove = __devexit_p(ds1302_rtc_remove), 204 }; 205 206 static int __init ds1302_rtc_init(void) 207 { 208 return platform_driver_probe(&ds1302_platform_driver, ds1302_rtc_probe); 209 } 210 211 static void __exit ds1302_rtc_exit(void) 212 { 213 platform_driver_unregister(&ds1302_platform_driver); 214 } 215 216 module_init(ds1302_rtc_init); 217 module_exit(ds1302_rtc_exit); 218 219 MODULE_DESCRIPTION("Dallas DS1302 RTC driver"); 220 MODULE_VERSION(DRV_VERSION); 221 MODULE_AUTHOR("Paul Mundt, David McCullough"); 222 MODULE_LICENSE("GPL v2"); 223