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 #include <linux/init.h> 12 #include <linux/module.h> 13 #include <linux/kernel.h> 14 #include <linux/platform_device.h> 15 #include <linux/time.h> 16 #include <linux/rtc.h> 17 #include <linux/spinlock.h> 18 #include <linux/io.h> 19 #include <linux/bcd.h> 20 #include <asm/rtc.h> 21 22 #define DRV_NAME "rtc-ds1302" 23 #define DRV_VERSION "0.1.0" 24 25 #define RTC_CMD_READ 0x81 /* Read command */ 26 #define RTC_CMD_WRITE 0x80 /* Write command */ 27 28 #define RTC_ADDR_RAM0 0x20 /* Address of RAM0 */ 29 #define RTC_ADDR_TCR 0x08 /* Address of trickle charge register */ 30 #define RTC_ADDR_YEAR 0x06 /* Address of year register */ 31 #define RTC_ADDR_DAY 0x05 /* Address of day of week register */ 32 #define RTC_ADDR_MON 0x04 /* Address of month register */ 33 #define RTC_ADDR_DATE 0x03 /* Address of day of month register */ 34 #define RTC_ADDR_HOUR 0x02 /* Address of hour register */ 35 #define RTC_ADDR_MIN 0x01 /* Address of minute register */ 36 #define RTC_ADDR_SEC 0x00 /* Address of second register */ 37 38 #define RTC_RESET 0x1000 39 #define RTC_IODATA 0x0800 40 #define RTC_SCLK 0x0400 41 42 #ifdef CONFIG_SH_SECUREEDGE5410 43 #include <asm/snapgear.h> 44 #define set_dp(x) SECUREEDGE_WRITE_IOPORT(x, 0x1c00) 45 #define get_dp() SECUREEDGE_READ_IOPORT() 46 #else 47 #error "Add support for your platform" 48 #endif 49 50 struct ds1302_rtc { 51 struct rtc_device *rtc_dev; 52 spinlock_t lock; 53 }; 54 55 static void ds1302_sendbits(unsigned int val) 56 { 57 int i; 58 59 for (i = 8; (i); i--, val >>= 1) { 60 set_dp((get_dp() & ~RTC_IODATA) | ((val & 0x1) ? 61 RTC_IODATA : 0)); 62 set_dp(get_dp() | RTC_SCLK); /* clock high */ 63 set_dp(get_dp() & ~RTC_SCLK); /* clock low */ 64 } 65 } 66 67 static unsigned int ds1302_recvbits(void) 68 { 69 unsigned int val; 70 int i; 71 72 for (i = 0, val = 0; (i < 8); i++) { 73 val |= (((get_dp() & RTC_IODATA) ? 1 : 0) << i); 74 set_dp(get_dp() | RTC_SCLK); /* clock high */ 75 set_dp(get_dp() & ~RTC_SCLK); /* clock low */ 76 } 77 78 return val; 79 } 80 81 static unsigned int ds1302_readbyte(unsigned int addr) 82 { 83 unsigned int val; 84 85 set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); 86 87 set_dp(get_dp() | RTC_RESET); 88 ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ); 89 val = ds1302_recvbits(); 90 set_dp(get_dp() & ~RTC_RESET); 91 92 return val; 93 } 94 95 static void ds1302_writebyte(unsigned int addr, unsigned int val) 96 { 97 set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); 98 set_dp(get_dp() | RTC_RESET); 99 ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE); 100 ds1302_sendbits(val); 101 set_dp(get_dp() & ~RTC_RESET); 102 } 103 104 static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm) 105 { 106 struct ds1302_rtc *rtc = dev_get_drvdata(dev); 107 108 spin_lock_irq(&rtc->lock); 109 110 tm->tm_sec = BCD2BIN(ds1302_readbyte(RTC_ADDR_SEC)); 111 tm->tm_min = BCD2BIN(ds1302_readbyte(RTC_ADDR_MIN)); 112 tm->tm_hour = BCD2BIN(ds1302_readbyte(RTC_ADDR_HOUR)); 113 tm->tm_wday = BCD2BIN(ds1302_readbyte(RTC_ADDR_DAY)); 114 tm->tm_mday = BCD2BIN(ds1302_readbyte(RTC_ADDR_DATE)); 115 tm->tm_mon = BCD2BIN(ds1302_readbyte(RTC_ADDR_MON)) - 1; 116 tm->tm_year = BCD2BIN(ds1302_readbyte(RTC_ADDR_YEAR)); 117 118 if (tm->tm_year < 70) 119 tm->tm_year += 100; 120 121 spin_unlock_irq(&rtc->lock); 122 123 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 124 "mday=%d, mon=%d, year=%d, wday=%d\n", 125 __func__, 126 tm->tm_sec, tm->tm_min, tm->tm_hour, 127 tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday); 128 129 if (rtc_valid_tm(tm) < 0) 130 dev_err(dev, "invalid date\n"); 131 132 return 0; 133 } 134 135 static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm) 136 { 137 struct ds1302_rtc *rtc = dev_get_drvdata(dev); 138 139 spin_lock_irq(&rtc->lock); 140 141 /* Stop RTC */ 142 ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80); 143 144 ds1302_writebyte(RTC_ADDR_SEC, BIN2BCD(tm->tm_sec)); 145 ds1302_writebyte(RTC_ADDR_MIN, BIN2BCD(tm->tm_min)); 146 ds1302_writebyte(RTC_ADDR_HOUR, BIN2BCD(tm->tm_hour)); 147 ds1302_writebyte(RTC_ADDR_DAY, BIN2BCD(tm->tm_wday)); 148 ds1302_writebyte(RTC_ADDR_DATE, BIN2BCD(tm->tm_mday)); 149 ds1302_writebyte(RTC_ADDR_MON, BIN2BCD(tm->tm_mon + 1)); 150 ds1302_writebyte(RTC_ADDR_YEAR, BIN2BCD(tm->tm_year % 100)); 151 152 /* Start RTC */ 153 ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80); 154 155 spin_unlock_irq(&rtc->lock); 156 157 return 0; 158 } 159 160 static int ds1302_rtc_ioctl(struct device *dev, unsigned int cmd, 161 unsigned long arg) 162 { 163 switch (cmd) { 164 #ifdef RTC_SET_CHARGE 165 case RTC_SET_CHARGE: 166 { 167 struct ds1302_rtc *rtc = dev_get_drvdata(dev); 168 int tcs_val; 169 170 if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int))) 171 return -EFAULT; 172 173 spin_lock_irq(&rtc->lock); 174 ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf)); 175 spin_unlock_irq(&rtc->lock); 176 return 0; 177 } 178 #endif 179 } 180 181 return -ENOIOCTLCMD; 182 } 183 184 static struct rtc_class_ops ds1302_rtc_ops = { 185 .read_time = ds1302_rtc_read_time, 186 .set_time = ds1302_rtc_set_time, 187 .ioctl = ds1302_rtc_ioctl, 188 }; 189 190 static int __devinit ds1302_rtc_probe(struct platform_device *pdev) 191 { 192 struct ds1302_rtc *rtc; 193 int ret; 194 195 /* Reset */ 196 set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); 197 198 /* Write a magic value to the DS1302 RAM, and see if it sticks. */ 199 ds1302_writebyte(RTC_ADDR_RAM0, 0x42); 200 if (ds1302_readbyte(RTC_ADDR_RAM0) != 0x42) 201 return -ENODEV; 202 203 rtc = kzalloc(sizeof(struct ds1302_rtc), GFP_KERNEL); 204 if (unlikely(!rtc)) 205 return -ENOMEM; 206 207 spin_lock_init(&rtc->lock); 208 rtc->rtc_dev = rtc_device_register("ds1302", &pdev->dev, 209 &ds1302_rtc_ops, THIS_MODULE); 210 if (IS_ERR(rtc->rtc_dev)) { 211 ret = PTR_ERR(rtc->rtc_dev); 212 goto out; 213 } 214 215 platform_set_drvdata(pdev, rtc); 216 217 return 0; 218 out: 219 kfree(rtc); 220 return ret; 221 } 222 223 static int __devexit ds1302_rtc_remove(struct platform_device *pdev) 224 { 225 struct ds1302_rtc *rtc = platform_get_drvdata(pdev); 226 227 if (likely(rtc->rtc_dev)) 228 rtc_device_unregister(rtc->rtc_dev); 229 230 platform_set_drvdata(pdev, NULL); 231 232 kfree(rtc); 233 234 return 0; 235 } 236 237 static struct platform_driver ds1302_platform_driver = { 238 .driver = { 239 .name = DRV_NAME, 240 .owner = THIS_MODULE, 241 }, 242 .probe = ds1302_rtc_probe, 243 .remove = __devexit_p(ds1302_rtc_remove), 244 }; 245 246 static int __init ds1302_rtc_init(void) 247 { 248 return platform_driver_register(&ds1302_platform_driver); 249 } 250 251 static void __exit ds1302_rtc_exit(void) 252 { 253 platform_driver_unregister(&ds1302_platform_driver); 254 } 255 256 module_init(ds1302_rtc_init); 257 module_exit(ds1302_rtc_exit); 258 259 MODULE_DESCRIPTION("Dallas DS1302 RTC driver"); 260 MODULE_VERSION(DRV_VERSION); 261 MODULE_AUTHOR("Paul Mundt, David McCullough"); 262 MODULE_LICENSE("GPL v2"); 263