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 20 #define DRV_NAME "rtc-ds1302" 21 #define DRV_VERSION "0.1.1" 22 23 #define RTC_CMD_READ 0x81 /* Read command */ 24 #define RTC_CMD_WRITE 0x80 /* Write command */ 25 26 #define RTC_ADDR_RAM0 0x20 /* Address of RAM0 */ 27 #define RTC_ADDR_TCR 0x08 /* Address of trickle charge register */ 28 #define RTC_ADDR_YEAR 0x06 /* Address of year register */ 29 #define RTC_ADDR_DAY 0x05 /* Address of day of week register */ 30 #define RTC_ADDR_MON 0x04 /* Address of month register */ 31 #define RTC_ADDR_DATE 0x03 /* Address of day of month register */ 32 #define RTC_ADDR_HOUR 0x02 /* Address of hour register */ 33 #define RTC_ADDR_MIN 0x01 /* Address of minute register */ 34 #define RTC_ADDR_SEC 0x00 /* Address of second register */ 35 36 #ifdef CONFIG_SH_SECUREEDGE5410 37 #include <asm/rtc.h> 38 #include <mach/snapgear.h> 39 40 #define RTC_RESET 0x1000 41 #define RTC_IODATA 0x0800 42 #define RTC_SCLK 0x0400 43 44 #define set_dp(x) SECUREEDGE_WRITE_IOPORT(x, 0x1c00) 45 #define get_dp() SECUREEDGE_READ_IOPORT() 46 #define ds1302_set_tx() 47 #define ds1302_set_rx() 48 49 static inline int ds1302_hw_init(void) 50 { 51 return 0; 52 } 53 54 static inline void ds1302_reset(void) 55 { 56 set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); 57 } 58 59 static inline void ds1302_clock(void) 60 { 61 set_dp(get_dp() | RTC_SCLK); /* clock high */ 62 set_dp(get_dp() & ~RTC_SCLK); /* clock low */ 63 } 64 65 static inline void ds1302_start(void) 66 { 67 set_dp(get_dp() | RTC_RESET); 68 } 69 70 static inline void ds1302_stop(void) 71 { 72 set_dp(get_dp() & ~RTC_RESET); 73 } 74 75 static inline void ds1302_txbit(int bit) 76 { 77 set_dp((get_dp() & ~RTC_IODATA) | (bit ? RTC_IODATA : 0)); 78 } 79 80 static inline int ds1302_rxbit(void) 81 { 82 return !!(get_dp() & RTC_IODATA); 83 } 84 85 #else 86 #error "Add support for your platform" 87 #endif 88 89 static void ds1302_sendbits(unsigned int val) 90 { 91 int i; 92 93 ds1302_set_tx(); 94 95 for (i = 8; (i); i--, val >>= 1) { 96 ds1302_txbit(val & 0x1); 97 ds1302_clock(); 98 } 99 } 100 101 static unsigned int ds1302_recvbits(void) 102 { 103 unsigned int val; 104 int i; 105 106 ds1302_set_rx(); 107 108 for (i = 0, val = 0; (i < 8); i++) { 109 val |= (ds1302_rxbit() << i); 110 ds1302_clock(); 111 } 112 113 return val; 114 } 115 116 static unsigned int ds1302_readbyte(unsigned int addr) 117 { 118 unsigned int val; 119 120 ds1302_reset(); 121 122 ds1302_start(); 123 ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ); 124 val = ds1302_recvbits(); 125 ds1302_stop(); 126 127 return val; 128 } 129 130 static void ds1302_writebyte(unsigned int addr, unsigned int val) 131 { 132 ds1302_reset(); 133 134 ds1302_start(); 135 ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE); 136 ds1302_sendbits(val); 137 ds1302_stop(); 138 } 139 140 static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm) 141 { 142 tm->tm_sec = bcd2bin(ds1302_readbyte(RTC_ADDR_SEC)); 143 tm->tm_min = bcd2bin(ds1302_readbyte(RTC_ADDR_MIN)); 144 tm->tm_hour = bcd2bin(ds1302_readbyte(RTC_ADDR_HOUR)); 145 tm->tm_wday = bcd2bin(ds1302_readbyte(RTC_ADDR_DAY)); 146 tm->tm_mday = bcd2bin(ds1302_readbyte(RTC_ADDR_DATE)); 147 tm->tm_mon = bcd2bin(ds1302_readbyte(RTC_ADDR_MON)) - 1; 148 tm->tm_year = bcd2bin(ds1302_readbyte(RTC_ADDR_YEAR)); 149 150 if (tm->tm_year < 70) 151 tm->tm_year += 100; 152 153 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 154 "mday=%d, mon=%d, year=%d, wday=%d\n", 155 __func__, 156 tm->tm_sec, tm->tm_min, tm->tm_hour, 157 tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday); 158 159 return rtc_valid_tm(tm); 160 } 161 162 static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm) 163 { 164 /* Stop RTC */ 165 ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80); 166 167 ds1302_writebyte(RTC_ADDR_SEC, bin2bcd(tm->tm_sec)); 168 ds1302_writebyte(RTC_ADDR_MIN, bin2bcd(tm->tm_min)); 169 ds1302_writebyte(RTC_ADDR_HOUR, bin2bcd(tm->tm_hour)); 170 ds1302_writebyte(RTC_ADDR_DAY, bin2bcd(tm->tm_wday)); 171 ds1302_writebyte(RTC_ADDR_DATE, bin2bcd(tm->tm_mday)); 172 ds1302_writebyte(RTC_ADDR_MON, bin2bcd(tm->tm_mon + 1)); 173 ds1302_writebyte(RTC_ADDR_YEAR, bin2bcd(tm->tm_year % 100)); 174 175 /* Start RTC */ 176 ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80); 177 178 return 0; 179 } 180 181 static int ds1302_rtc_ioctl(struct device *dev, unsigned int cmd, 182 unsigned long arg) 183 { 184 switch (cmd) { 185 #ifdef RTC_SET_CHARGE 186 case RTC_SET_CHARGE: 187 { 188 int tcs_val; 189 190 if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int))) 191 return -EFAULT; 192 193 ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf)); 194 return 0; 195 } 196 #endif 197 } 198 199 return -ENOIOCTLCMD; 200 } 201 202 static struct rtc_class_ops ds1302_rtc_ops = { 203 .read_time = ds1302_rtc_read_time, 204 .set_time = ds1302_rtc_set_time, 205 .ioctl = ds1302_rtc_ioctl, 206 }; 207 208 static int __init ds1302_rtc_probe(struct platform_device *pdev) 209 { 210 struct rtc_device *rtc; 211 212 if (ds1302_hw_init()) { 213 dev_err(&pdev->dev, "Failed to init communication channel"); 214 return -EINVAL; 215 } 216 217 /* Reset */ 218 ds1302_reset(); 219 220 /* Write a magic value to the DS1302 RAM, and see if it sticks. */ 221 ds1302_writebyte(RTC_ADDR_RAM0, 0x42); 222 if (ds1302_readbyte(RTC_ADDR_RAM0) != 0x42) { 223 dev_err(&pdev->dev, "Failed to probe"); 224 return -ENODEV; 225 } 226 227 rtc = rtc_device_register("ds1302", &pdev->dev, 228 &ds1302_rtc_ops, THIS_MODULE); 229 if (IS_ERR(rtc)) 230 return PTR_ERR(rtc); 231 232 platform_set_drvdata(pdev, rtc); 233 234 return 0; 235 } 236 237 static int __devexit ds1302_rtc_remove(struct platform_device *pdev) 238 { 239 struct rtc_device *rtc = platform_get_drvdata(pdev); 240 241 rtc_device_unregister(rtc); 242 platform_set_drvdata(pdev, NULL); 243 244 return 0; 245 } 246 247 static struct platform_driver ds1302_platform_driver = { 248 .driver = { 249 .name = DRV_NAME, 250 .owner = THIS_MODULE, 251 }, 252 .remove = __devexit_p(ds1302_rtc_remove), 253 }; 254 255 static int __init ds1302_rtc_init(void) 256 { 257 return platform_driver_probe(&ds1302_platform_driver, ds1302_rtc_probe); 258 } 259 260 static void __exit ds1302_rtc_exit(void) 261 { 262 platform_driver_unregister(&ds1302_platform_driver); 263 } 264 265 module_init(ds1302_rtc_init); 266 module_exit(ds1302_rtc_exit); 267 268 MODULE_DESCRIPTION("Dallas DS1302 RTC driver"); 269 MODULE_VERSION(DRV_VERSION); 270 MODULE_AUTHOR("Paul Mundt, David McCullough"); 271 MODULE_LICENSE("GPL v2"); 272