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_CMD_WRITE_ENABLE 0x00 /* Write enable */ 27 #define RTC_CMD_WRITE_DISABLE 0x80 /* Write disable */ 28 29 #define RTC_ADDR_RAM0 0x20 /* Address of RAM0 */ 30 #define RTC_ADDR_TCR 0x08 /* Address of trickle charge register */ 31 #define RTC_ADDR_CTRL 0x07 /* Address of control register */ 32 #define RTC_ADDR_YEAR 0x06 /* Address of year register */ 33 #define RTC_ADDR_DAY 0x05 /* Address of day of week register */ 34 #define RTC_ADDR_MON 0x04 /* Address of month register */ 35 #define RTC_ADDR_DATE 0x03 /* Address of day of month register */ 36 #define RTC_ADDR_HOUR 0x02 /* Address of hour register */ 37 #define RTC_ADDR_MIN 0x01 /* Address of minute register */ 38 #define RTC_ADDR_SEC 0x00 /* Address of second register */ 39 40 #ifdef CONFIG_SH_SECUREEDGE5410 41 #include <asm/rtc.h> 42 #include <mach/secureedge5410.h> 43 44 #define RTC_RESET 0x1000 45 #define RTC_IODATA 0x0800 46 #define RTC_SCLK 0x0400 47 48 #define set_dp(x) SECUREEDGE_WRITE_IOPORT(x, 0x1c00) 49 #define get_dp() SECUREEDGE_READ_IOPORT() 50 #define ds1302_set_tx() 51 #define ds1302_set_rx() 52 53 static inline int ds1302_hw_init(void) 54 { 55 return 0; 56 } 57 58 static inline void ds1302_reset(void) 59 { 60 set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); 61 } 62 63 static inline void ds1302_clock(void) 64 { 65 set_dp(get_dp() | RTC_SCLK); /* clock high */ 66 set_dp(get_dp() & ~RTC_SCLK); /* clock low */ 67 } 68 69 static inline void ds1302_start(void) 70 { 71 set_dp(get_dp() | RTC_RESET); 72 } 73 74 static inline void ds1302_stop(void) 75 { 76 set_dp(get_dp() & ~RTC_RESET); 77 } 78 79 static inline void ds1302_txbit(int bit) 80 { 81 set_dp((get_dp() & ~RTC_IODATA) | (bit ? RTC_IODATA : 0)); 82 } 83 84 static inline int ds1302_rxbit(void) 85 { 86 return !!(get_dp() & RTC_IODATA); 87 } 88 89 #else 90 #error "Add support for your platform" 91 #endif 92 93 static void ds1302_sendbits(unsigned int val) 94 { 95 int i; 96 97 ds1302_set_tx(); 98 99 for (i = 8; (i); i--, val >>= 1) { 100 ds1302_txbit(val & 0x1); 101 ds1302_clock(); 102 } 103 } 104 105 static unsigned int ds1302_recvbits(void) 106 { 107 unsigned int val; 108 int i; 109 110 ds1302_set_rx(); 111 112 for (i = 0, val = 0; (i < 8); i++) { 113 val |= (ds1302_rxbit() << i); 114 ds1302_clock(); 115 } 116 117 return val; 118 } 119 120 static unsigned int ds1302_readbyte(unsigned int addr) 121 { 122 unsigned int val; 123 124 ds1302_reset(); 125 126 ds1302_start(); 127 ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ); 128 val = ds1302_recvbits(); 129 ds1302_stop(); 130 131 return val; 132 } 133 134 static void ds1302_writebyte(unsigned int addr, unsigned int val) 135 { 136 ds1302_reset(); 137 138 ds1302_start(); 139 ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE); 140 ds1302_sendbits(val); 141 ds1302_stop(); 142 } 143 144 static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm) 145 { 146 tm->tm_sec = bcd2bin(ds1302_readbyte(RTC_ADDR_SEC)); 147 tm->tm_min = bcd2bin(ds1302_readbyte(RTC_ADDR_MIN)); 148 tm->tm_hour = bcd2bin(ds1302_readbyte(RTC_ADDR_HOUR)); 149 tm->tm_wday = bcd2bin(ds1302_readbyte(RTC_ADDR_DAY)); 150 tm->tm_mday = bcd2bin(ds1302_readbyte(RTC_ADDR_DATE)); 151 tm->tm_mon = bcd2bin(ds1302_readbyte(RTC_ADDR_MON)) - 1; 152 tm->tm_year = bcd2bin(ds1302_readbyte(RTC_ADDR_YEAR)); 153 154 if (tm->tm_year < 70) 155 tm->tm_year += 100; 156 157 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 158 "mday=%d, mon=%d, year=%d, wday=%d\n", 159 __func__, 160 tm->tm_sec, tm->tm_min, tm->tm_hour, 161 tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday); 162 163 return rtc_valid_tm(tm); 164 } 165 166 static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm) 167 { 168 ds1302_writebyte(RTC_ADDR_CTRL, RTC_CMD_WRITE_ENABLE); 169 /* Stop RTC */ 170 ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80); 171 172 ds1302_writebyte(RTC_ADDR_SEC, bin2bcd(tm->tm_sec)); 173 ds1302_writebyte(RTC_ADDR_MIN, bin2bcd(tm->tm_min)); 174 ds1302_writebyte(RTC_ADDR_HOUR, bin2bcd(tm->tm_hour)); 175 ds1302_writebyte(RTC_ADDR_DAY, bin2bcd(tm->tm_wday)); 176 ds1302_writebyte(RTC_ADDR_DATE, bin2bcd(tm->tm_mday)); 177 ds1302_writebyte(RTC_ADDR_MON, bin2bcd(tm->tm_mon + 1)); 178 ds1302_writebyte(RTC_ADDR_YEAR, bin2bcd(tm->tm_year % 100)); 179 180 /* Start RTC */ 181 ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80); 182 183 ds1302_writebyte(RTC_ADDR_CTRL, RTC_CMD_WRITE_DISABLE); 184 185 return 0; 186 } 187 188 static int ds1302_rtc_ioctl(struct device *dev, unsigned int cmd, 189 unsigned long arg) 190 { 191 switch (cmd) { 192 #ifdef RTC_SET_CHARGE 193 case RTC_SET_CHARGE: 194 { 195 int tcs_val; 196 197 if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int))) 198 return -EFAULT; 199 200 ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf)); 201 return 0; 202 } 203 #endif 204 } 205 206 return -ENOIOCTLCMD; 207 } 208 209 static struct rtc_class_ops ds1302_rtc_ops = { 210 .read_time = ds1302_rtc_read_time, 211 .set_time = ds1302_rtc_set_time, 212 .ioctl = ds1302_rtc_ioctl, 213 }; 214 215 static int __init ds1302_rtc_probe(struct platform_device *pdev) 216 { 217 struct rtc_device *rtc; 218 219 if (ds1302_hw_init()) { 220 dev_err(&pdev->dev, "Failed to init communication channel"); 221 return -EINVAL; 222 } 223 224 /* Reset */ 225 ds1302_reset(); 226 227 /* Write a magic value to the DS1302 RAM, and see if it sticks. */ 228 ds1302_writebyte(RTC_ADDR_RAM0, 0x42); 229 if (ds1302_readbyte(RTC_ADDR_RAM0) != 0x42) { 230 dev_err(&pdev->dev, "Failed to probe"); 231 return -ENODEV; 232 } 233 234 rtc = devm_rtc_device_register(&pdev->dev, "ds1302", 235 &ds1302_rtc_ops, THIS_MODULE); 236 if (IS_ERR(rtc)) 237 return PTR_ERR(rtc); 238 239 platform_set_drvdata(pdev, rtc); 240 241 return 0; 242 } 243 244 static struct platform_driver ds1302_platform_driver = { 245 .driver = { 246 .name = DRV_NAME, 247 }, 248 }; 249 250 module_platform_driver_probe(ds1302_platform_driver, ds1302_rtc_probe); 251 252 MODULE_DESCRIPTION("Dallas DS1302 RTC driver"); 253 MODULE_VERSION(DRV_VERSION); 254 MODULE_AUTHOR("Paul Mundt, David McCullough"); 255 MODULE_LICENSE("GPL v2"); 256