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 21 #define DRV_VERSION "0.4.2" 22 23 /* Addresses to scan: none 24 * This chip cannot be reliably autodetected. An empty eeprom 25 * located at 0x51 will pass the validation routine due to 26 * the way the registers are implemented. 27 */ 28 static const unsigned short normal_i2c[] = { I2C_CLIENT_END }; 29 30 /* Module parameters */ 31 I2C_CLIENT_INSMOD; 32 33 #define PCF8563_REG_ST1 0x00 /* status */ 34 #define PCF8563_REG_ST2 0x01 35 36 #define PCF8563_REG_SC 0x02 /* datetime */ 37 #define PCF8563_REG_MN 0x03 38 #define PCF8563_REG_HR 0x04 39 #define PCF8563_REG_DM 0x05 40 #define PCF8563_REG_DW 0x06 41 #define PCF8563_REG_MO 0x07 42 #define PCF8563_REG_YR 0x08 43 44 #define PCF8563_REG_AMN 0x09 /* alarm */ 45 #define PCF8563_REG_AHR 0x0A 46 #define PCF8563_REG_ADM 0x0B 47 #define PCF8563_REG_ADW 0x0C 48 49 #define PCF8563_REG_CLKO 0x0D /* clock out */ 50 #define PCF8563_REG_TMRC 0x0E /* timer control */ 51 #define PCF8563_REG_TMR 0x0F /* timer */ 52 53 #define PCF8563_SC_LV 0x80 /* low voltage */ 54 #define PCF8563_MO_C 0x80 /* century */ 55 56 struct pcf8563 { 57 struct i2c_client client; 58 /* 59 * The meaning of MO_C bit varies by the chip type. 60 * From PCF8563 datasheet: this bit is toggled when the years 61 * register overflows from 99 to 00 62 * 0 indicates the century is 20xx 63 * 1 indicates the century is 19xx 64 * From RTC8564 datasheet: this bit indicates change of 65 * century. When the year digit data overflows from 99 to 00, 66 * this bit is set. By presetting it to 0 while still in the 67 * 20th century, it will be set in year 2000, ... 68 * There seems no reliable way to know how the system use this 69 * bit. So let's do it heuristically, assuming we are live in 70 * 1970...2069. 71 */ 72 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */ 73 }; 74 75 static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind); 76 static int pcf8563_detach(struct i2c_client *client); 77 78 /* 79 * In the routines that deal directly with the pcf8563 hardware, we use 80 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 81 */ 82 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm) 83 { 84 struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client); 85 unsigned char buf[13] = { PCF8563_REG_ST1 }; 86 87 struct i2c_msg msgs[] = { 88 { client->addr, 0, 1, buf }, /* setup read ptr */ 89 { client->addr, I2C_M_RD, 13, buf }, /* read status + date */ 90 }; 91 92 /* read registers */ 93 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) { 94 dev_err(&client->dev, "%s: read error\n", __FUNCTION__); 95 return -EIO; 96 } 97 98 if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) 99 dev_info(&client->dev, 100 "low voltage detected, date/time is not reliable.\n"); 101 102 dev_dbg(&client->dev, 103 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, " 104 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", 105 __FUNCTION__, 106 buf[0], buf[1], buf[2], buf[3], 107 buf[4], buf[5], buf[6], buf[7], 108 buf[8]); 109 110 111 tm->tm_sec = BCD2BIN(buf[PCF8563_REG_SC] & 0x7F); 112 tm->tm_min = BCD2BIN(buf[PCF8563_REG_MN] & 0x7F); 113 tm->tm_hour = BCD2BIN(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */ 114 tm->tm_mday = BCD2BIN(buf[PCF8563_REG_DM] & 0x3F); 115 tm->tm_wday = buf[PCF8563_REG_DW] & 0x07; 116 tm->tm_mon = BCD2BIN(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 117 tm->tm_year = BCD2BIN(buf[PCF8563_REG_YR]); 118 if (tm->tm_year < 70) 119 tm->tm_year += 100; /* assume we are in 1970...2069 */ 120 /* detect the polarity heuristically. see note above. */ 121 pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ? 122 (tm->tm_year >= 100) : (tm->tm_year < 100); 123 124 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 125 "mday=%d, mon=%d, year=%d, wday=%d\n", 126 __FUNCTION__, 127 tm->tm_sec, tm->tm_min, tm->tm_hour, 128 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 129 130 /* the clock can give out invalid datetime, but we cannot return 131 * -EINVAL otherwise hwclock will refuse to set the time on bootup. 132 */ 133 if (rtc_valid_tm(tm) < 0) 134 dev_err(&client->dev, "retrieved date/time is not valid.\n"); 135 136 return 0; 137 } 138 139 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm) 140 { 141 struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client); 142 int i, err; 143 unsigned char buf[9]; 144 145 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 146 "mday=%d, mon=%d, year=%d, wday=%d\n", 147 __FUNCTION__, 148 tm->tm_sec, tm->tm_min, tm->tm_hour, 149 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 150 151 /* hours, minutes and seconds */ 152 buf[PCF8563_REG_SC] = BIN2BCD(tm->tm_sec); 153 buf[PCF8563_REG_MN] = BIN2BCD(tm->tm_min); 154 buf[PCF8563_REG_HR] = BIN2BCD(tm->tm_hour); 155 156 buf[PCF8563_REG_DM] = BIN2BCD(tm->tm_mday); 157 158 /* month, 1 - 12 */ 159 buf[PCF8563_REG_MO] = BIN2BCD(tm->tm_mon + 1); 160 161 /* year and century */ 162 buf[PCF8563_REG_YR] = BIN2BCD(tm->tm_year % 100); 163 if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100)) 164 buf[PCF8563_REG_MO] |= PCF8563_MO_C; 165 166 buf[PCF8563_REG_DW] = tm->tm_wday & 0x07; 167 168 /* write register's data */ 169 for (i = 0; i < 7; i++) { 170 unsigned char data[2] = { PCF8563_REG_SC + i, 171 buf[PCF8563_REG_SC + i] }; 172 173 err = i2c_master_send(client, data, sizeof(data)); 174 if (err != sizeof(data)) { 175 dev_err(&client->dev, 176 "%s: err=%d addr=%02x, data=%02x\n", 177 __FUNCTION__, err, data[0], data[1]); 178 return -EIO; 179 } 180 }; 181 182 return 0; 183 } 184 185 struct pcf8563_limit 186 { 187 unsigned char reg; 188 unsigned char mask; 189 unsigned char min; 190 unsigned char max; 191 }; 192 193 static int pcf8563_validate_client(struct i2c_client *client) 194 { 195 int i; 196 197 static const struct pcf8563_limit pattern[] = { 198 /* register, mask, min, max */ 199 { PCF8563_REG_SC, 0x7F, 0, 59 }, 200 { PCF8563_REG_MN, 0x7F, 0, 59 }, 201 { PCF8563_REG_HR, 0x3F, 0, 23 }, 202 { PCF8563_REG_DM, 0x3F, 0, 31 }, 203 { PCF8563_REG_MO, 0x1F, 0, 12 }, 204 }; 205 206 /* check limits (only registers with bcd values) */ 207 for (i = 0; i < ARRAY_SIZE(pattern); i++) { 208 int xfer; 209 unsigned char value; 210 unsigned char buf = pattern[i].reg; 211 212 struct i2c_msg msgs[] = { 213 { client->addr, 0, 1, &buf }, 214 { client->addr, I2C_M_RD, 1, &buf }, 215 }; 216 217 xfer = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 218 219 if (xfer != ARRAY_SIZE(msgs)) { 220 dev_err(&client->dev, 221 "%s: could not read register 0x%02X\n", 222 __FUNCTION__, pattern[i].reg); 223 224 return -EIO; 225 } 226 227 value = BCD2BIN(buf & pattern[i].mask); 228 229 if (value > pattern[i].max || 230 value < pattern[i].min) { 231 dev_dbg(&client->dev, 232 "%s: pattern=%d, reg=%x, mask=0x%02x, min=%d, " 233 "max=%d, value=%d, raw=0x%02X\n", 234 __FUNCTION__, i, pattern[i].reg, pattern[i].mask, 235 pattern[i].min, pattern[i].max, 236 value, buf); 237 238 return -ENODEV; 239 } 240 } 241 242 return 0; 243 } 244 245 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm) 246 { 247 return pcf8563_get_datetime(to_i2c_client(dev), tm); 248 } 249 250 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm) 251 { 252 return pcf8563_set_datetime(to_i2c_client(dev), tm); 253 } 254 255 static const struct rtc_class_ops pcf8563_rtc_ops = { 256 .read_time = pcf8563_rtc_read_time, 257 .set_time = pcf8563_rtc_set_time, 258 }; 259 260 static int pcf8563_attach(struct i2c_adapter *adapter) 261 { 262 return i2c_probe(adapter, &addr_data, pcf8563_probe); 263 } 264 265 static struct i2c_driver pcf8563_driver = { 266 .driver = { 267 .name = "pcf8563", 268 }, 269 .id = I2C_DRIVERID_PCF8563, 270 .attach_adapter = &pcf8563_attach, 271 .detach_client = &pcf8563_detach, 272 }; 273 274 static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind) 275 { 276 struct pcf8563 *pcf8563; 277 struct i2c_client *client; 278 struct rtc_device *rtc; 279 280 int err = 0; 281 282 dev_dbg(&adapter->dev, "%s\n", __FUNCTION__); 283 284 if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) { 285 err = -ENODEV; 286 goto exit; 287 } 288 289 if (!(pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL))) { 290 err = -ENOMEM; 291 goto exit; 292 } 293 294 client = &pcf8563->client; 295 client->addr = address; 296 client->driver = &pcf8563_driver; 297 client->adapter = adapter; 298 299 strlcpy(client->name, pcf8563_driver.driver.name, I2C_NAME_SIZE); 300 301 /* Verify the chip is really an PCF8563 */ 302 if (kind < 0) { 303 if (pcf8563_validate_client(client) < 0) { 304 err = -ENODEV; 305 goto exit_kfree; 306 } 307 } 308 309 /* Inform the i2c layer */ 310 if ((err = i2c_attach_client(client))) 311 goto exit_kfree; 312 313 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 314 315 rtc = rtc_device_register(pcf8563_driver.driver.name, &client->dev, 316 &pcf8563_rtc_ops, THIS_MODULE); 317 318 if (IS_ERR(rtc)) { 319 err = PTR_ERR(rtc); 320 goto exit_detach; 321 } 322 323 i2c_set_clientdata(client, rtc); 324 325 return 0; 326 327 exit_detach: 328 i2c_detach_client(client); 329 330 exit_kfree: 331 kfree(pcf8563); 332 333 exit: 334 return err; 335 } 336 337 static int pcf8563_detach(struct i2c_client *client) 338 { 339 struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client); 340 int err; 341 struct rtc_device *rtc = i2c_get_clientdata(client); 342 343 if (rtc) 344 rtc_device_unregister(rtc); 345 346 if ((err = i2c_detach_client(client))) 347 return err; 348 349 kfree(pcf8563); 350 351 return 0; 352 } 353 354 static int __init pcf8563_init(void) 355 { 356 return i2c_add_driver(&pcf8563_driver); 357 } 358 359 static void __exit pcf8563_exit(void) 360 { 361 i2c_del_driver(&pcf8563_driver); 362 } 363 364 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 365 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver"); 366 MODULE_LICENSE("GPL"); 367 MODULE_VERSION(DRV_VERSION); 368 369 module_init(pcf8563_init); 370 module_exit(pcf8563_exit); 371