1 /* 2 * An I2C driver for the Philips PCF8563 RTC 3 * Copyright 2005-06 Tower Technologies 4 * 5 * Author: Alessandro Zummo <a.zummo@towertech.it> 6 * Maintainers: http://www.nslu2-linux.org/ 7 * 8 * based on the other drivers in this same directory. 9 * 10 * http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License version 2 as 14 * published by the Free Software Foundation. 15 */ 16 17 #include <linux/i2c.h> 18 #include <linux/bcd.h> 19 #include <linux/rtc.h> 20 #include <linux/slab.h> 21 #include <linux/module.h> 22 23 #define DRV_VERSION "0.4.3" 24 25 #define PCF8563_REG_ST1 0x00 /* status */ 26 #define PCF8563_REG_ST2 0x01 27 28 #define PCF8563_REG_SC 0x02 /* datetime */ 29 #define PCF8563_REG_MN 0x03 30 #define PCF8563_REG_HR 0x04 31 #define PCF8563_REG_DM 0x05 32 #define PCF8563_REG_DW 0x06 33 #define PCF8563_REG_MO 0x07 34 #define PCF8563_REG_YR 0x08 35 36 #define PCF8563_REG_AMN 0x09 /* alarm */ 37 #define PCF8563_REG_AHR 0x0A 38 #define PCF8563_REG_ADM 0x0B 39 #define PCF8563_REG_ADW 0x0C 40 41 #define PCF8563_REG_CLKO 0x0D /* clock out */ 42 #define PCF8563_REG_TMRC 0x0E /* timer control */ 43 #define PCF8563_REG_TMR 0x0F /* timer */ 44 45 #define PCF8563_SC_LV 0x80 /* low voltage */ 46 #define PCF8563_MO_C 0x80 /* century */ 47 48 static struct i2c_driver pcf8563_driver; 49 50 struct pcf8563 { 51 struct rtc_device *rtc; 52 /* 53 * The meaning of MO_C bit varies by the chip type. 54 * From PCF8563 datasheet: this bit is toggled when the years 55 * register overflows from 99 to 00 56 * 0 indicates the century is 20xx 57 * 1 indicates the century is 19xx 58 * From RTC8564 datasheet: this bit indicates change of 59 * century. When the year digit data overflows from 99 to 00, 60 * this bit is set. By presetting it to 0 while still in the 61 * 20th century, it will be set in year 2000, ... 62 * There seems no reliable way to know how the system use this 63 * bit. So let's do it heuristically, assuming we are live in 64 * 1970...2069. 65 */ 66 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */ 67 int voltage_low; /* incicates if a low_voltage was detected */ 68 }; 69 70 /* 71 * In the routines that deal directly with the pcf8563 hardware, we use 72 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 73 */ 74 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm) 75 { 76 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 77 unsigned char buf[13] = { PCF8563_REG_ST1 }; 78 79 struct i2c_msg msgs[] = { 80 { client->addr, 0, 1, buf }, /* setup read ptr */ 81 { client->addr, I2C_M_RD, 13, buf }, /* read status + date */ 82 }; 83 84 /* read registers */ 85 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) { 86 dev_err(&client->dev, "%s: read error\n", __func__); 87 return -EIO; 88 } 89 90 if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) { 91 pcf8563->voltage_low = 1; 92 dev_info(&client->dev, 93 "low voltage detected, date/time is not reliable.\n"); 94 } 95 96 dev_dbg(&client->dev, 97 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, " 98 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", 99 __func__, 100 buf[0], buf[1], buf[2], buf[3], 101 buf[4], buf[5], buf[6], buf[7], 102 buf[8]); 103 104 105 tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F); 106 tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F); 107 tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */ 108 tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F); 109 tm->tm_wday = buf[PCF8563_REG_DW] & 0x07; 110 tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 111 tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]); 112 if (tm->tm_year < 70) 113 tm->tm_year += 100; /* assume we are in 1970...2069 */ 114 /* detect the polarity heuristically. see note above. */ 115 pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ? 116 (tm->tm_year >= 100) : (tm->tm_year < 100); 117 118 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 119 "mday=%d, mon=%d, year=%d, wday=%d\n", 120 __func__, 121 tm->tm_sec, tm->tm_min, tm->tm_hour, 122 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 123 124 /* the clock can give out invalid datetime, but we cannot return 125 * -EINVAL otherwise hwclock will refuse to set the time on bootup. 126 */ 127 if (rtc_valid_tm(tm) < 0) 128 dev_err(&client->dev, "retrieved date/time is not valid.\n"); 129 130 return 0; 131 } 132 133 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm) 134 { 135 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 136 int i, err; 137 unsigned char buf[9]; 138 139 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 140 "mday=%d, mon=%d, year=%d, wday=%d\n", 141 __func__, 142 tm->tm_sec, tm->tm_min, tm->tm_hour, 143 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 144 145 /* hours, minutes and seconds */ 146 buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec); 147 buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min); 148 buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour); 149 150 buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday); 151 152 /* month, 1 - 12 */ 153 buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1); 154 155 /* year and century */ 156 buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100); 157 if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100)) 158 buf[PCF8563_REG_MO] |= PCF8563_MO_C; 159 160 buf[PCF8563_REG_DW] = tm->tm_wday & 0x07; 161 162 /* write register's data */ 163 for (i = 0; i < 7; i++) { 164 unsigned char data[2] = { PCF8563_REG_SC + i, 165 buf[PCF8563_REG_SC + i] }; 166 167 err = i2c_master_send(client, data, sizeof(data)); 168 if (err != sizeof(data)) { 169 dev_err(&client->dev, 170 "%s: err=%d addr=%02x, data=%02x\n", 171 __func__, err, data[0], data[1]); 172 return -EIO; 173 } 174 }; 175 176 return 0; 177 } 178 179 #ifdef CONFIG_RTC_INTF_DEV 180 static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 181 { 182 struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev)); 183 struct rtc_time tm; 184 185 switch (cmd) { 186 case RTC_VL_READ: 187 if (pcf8563->voltage_low) 188 dev_info(dev, "low voltage detected, date/time is not reliable.\n"); 189 190 if (copy_to_user((void __user *)arg, &pcf8563->voltage_low, 191 sizeof(int))) 192 return -EFAULT; 193 return 0; 194 case RTC_VL_CLR: 195 /* 196 * Clear the VL bit in the seconds register in case 197 * the time has not been set already (which would 198 * have cleared it). This does not really matter 199 * because of the cached voltage_low value but do it 200 * anyway for consistency. 201 */ 202 if (pcf8563_get_datetime(to_i2c_client(dev), &tm)) 203 pcf8563_set_datetime(to_i2c_client(dev), &tm); 204 205 /* Clear the cached value. */ 206 pcf8563->voltage_low = 0; 207 208 return 0; 209 default: 210 return -ENOIOCTLCMD; 211 } 212 } 213 #else 214 #define pcf8563_rtc_ioctl NULL 215 #endif 216 217 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm) 218 { 219 return pcf8563_get_datetime(to_i2c_client(dev), tm); 220 } 221 222 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm) 223 { 224 return pcf8563_set_datetime(to_i2c_client(dev), tm); 225 } 226 227 static const struct rtc_class_ops pcf8563_rtc_ops = { 228 .ioctl = pcf8563_rtc_ioctl, 229 .read_time = pcf8563_rtc_read_time, 230 .set_time = pcf8563_rtc_set_time, 231 }; 232 233 static int pcf8563_probe(struct i2c_client *client, 234 const struct i2c_device_id *id) 235 { 236 struct pcf8563 *pcf8563; 237 238 int err = 0; 239 240 dev_dbg(&client->dev, "%s\n", __func__); 241 242 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 243 return -ENODEV; 244 245 pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL); 246 if (!pcf8563) 247 return -ENOMEM; 248 249 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 250 251 i2c_set_clientdata(client, pcf8563); 252 253 pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name, 254 &client->dev, &pcf8563_rtc_ops, THIS_MODULE); 255 256 if (IS_ERR(pcf8563->rtc)) { 257 err = PTR_ERR(pcf8563->rtc); 258 goto exit_kfree; 259 } 260 261 return 0; 262 263 exit_kfree: 264 kfree(pcf8563); 265 266 return err; 267 } 268 269 static int pcf8563_remove(struct i2c_client *client) 270 { 271 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 272 273 if (pcf8563->rtc) 274 rtc_device_unregister(pcf8563->rtc); 275 276 kfree(pcf8563); 277 278 return 0; 279 } 280 281 static const struct i2c_device_id pcf8563_id[] = { 282 { "pcf8563", 0 }, 283 { "rtc8564", 0 }, 284 { } 285 }; 286 MODULE_DEVICE_TABLE(i2c, pcf8563_id); 287 288 static struct i2c_driver pcf8563_driver = { 289 .driver = { 290 .name = "rtc-pcf8563", 291 }, 292 .probe = pcf8563_probe, 293 .remove = pcf8563_remove, 294 .id_table = pcf8563_id, 295 }; 296 297 module_i2c_driver(pcf8563_driver); 298 299 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 300 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver"); 301 MODULE_LICENSE("GPL"); 302 MODULE_VERSION(DRV_VERSION); 303