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 "0.4.3" 22 23 #define PCF8563_REG_ST1 0x00 /* status */ 24 #define PCF8563_REG_ST2 0x01 25 26 #define PCF8563_REG_SC 0x02 /* datetime */ 27 #define PCF8563_REG_MN 0x03 28 #define PCF8563_REG_HR 0x04 29 #define PCF8563_REG_DM 0x05 30 #define PCF8563_REG_DW 0x06 31 #define PCF8563_REG_MO 0x07 32 #define PCF8563_REG_YR 0x08 33 34 #define PCF8563_REG_AMN 0x09 /* alarm */ 35 #define PCF8563_REG_AHR 0x0A 36 #define PCF8563_REG_ADM 0x0B 37 #define PCF8563_REG_ADW 0x0C 38 39 #define PCF8563_REG_CLKO 0x0D /* clock out */ 40 #define PCF8563_REG_TMRC 0x0E /* timer control */ 41 #define PCF8563_REG_TMR 0x0F /* timer */ 42 43 #define PCF8563_SC_LV 0x80 /* low voltage */ 44 #define PCF8563_MO_C 0x80 /* century */ 45 46 static struct i2c_driver pcf8563_driver; 47 48 struct pcf8563 { 49 struct rtc_device *rtc; 50 /* 51 * The meaning of MO_C bit varies by the chip type. 52 * From PCF8563 datasheet: this bit is toggled when the years 53 * register overflows from 99 to 00 54 * 0 indicates the century is 20xx 55 * 1 indicates the century is 19xx 56 * From RTC8564 datasheet: this bit indicates change of 57 * century. When the year digit data overflows from 99 to 00, 58 * this bit is set. By presetting it to 0 while still in the 59 * 20th century, it will be set in year 2000, ... 60 * There seems no reliable way to know how the system use this 61 * bit. So let's do it heuristically, assuming we are live in 62 * 1970...2069. 63 */ 64 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */ 65 }; 66 67 /* 68 * In the routines that deal directly with the pcf8563 hardware, we use 69 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 70 */ 71 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm) 72 { 73 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 74 unsigned char buf[13] = { PCF8563_REG_ST1 }; 75 76 struct i2c_msg msgs[] = { 77 { client->addr, 0, 1, buf }, /* setup read ptr */ 78 { client->addr, I2C_M_RD, 13, buf }, /* read status + date */ 79 }; 80 81 /* read registers */ 82 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) { 83 dev_err(&client->dev, "%s: read error\n", __func__); 84 return -EIO; 85 } 86 87 if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) 88 dev_info(&client->dev, 89 "low voltage detected, date/time is not reliable.\n"); 90 91 dev_dbg(&client->dev, 92 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, " 93 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", 94 __func__, 95 buf[0], buf[1], buf[2], buf[3], 96 buf[4], buf[5], buf[6], buf[7], 97 buf[8]); 98 99 100 tm->tm_sec = BCD2BIN(buf[PCF8563_REG_SC] & 0x7F); 101 tm->tm_min = BCD2BIN(buf[PCF8563_REG_MN] & 0x7F); 102 tm->tm_hour = BCD2BIN(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */ 103 tm->tm_mday = BCD2BIN(buf[PCF8563_REG_DM] & 0x3F); 104 tm->tm_wday = buf[PCF8563_REG_DW] & 0x07; 105 tm->tm_mon = BCD2BIN(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 106 tm->tm_year = BCD2BIN(buf[PCF8563_REG_YR]); 107 if (tm->tm_year < 70) 108 tm->tm_year += 100; /* assume we are in 1970...2069 */ 109 /* detect the polarity heuristically. see note above. */ 110 pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ? 111 (tm->tm_year >= 100) : (tm->tm_year < 100); 112 113 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 114 "mday=%d, mon=%d, year=%d, wday=%d\n", 115 __func__, 116 tm->tm_sec, tm->tm_min, tm->tm_hour, 117 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 118 119 /* the clock can give out invalid datetime, but we cannot return 120 * -EINVAL otherwise hwclock will refuse to set the time on bootup. 121 */ 122 if (rtc_valid_tm(tm) < 0) 123 dev_err(&client->dev, "retrieved date/time is not valid.\n"); 124 125 return 0; 126 } 127 128 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm) 129 { 130 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 131 int i, err; 132 unsigned char buf[9]; 133 134 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 135 "mday=%d, mon=%d, year=%d, wday=%d\n", 136 __func__, 137 tm->tm_sec, tm->tm_min, tm->tm_hour, 138 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 139 140 /* hours, minutes and seconds */ 141 buf[PCF8563_REG_SC] = BIN2BCD(tm->tm_sec); 142 buf[PCF8563_REG_MN] = BIN2BCD(tm->tm_min); 143 buf[PCF8563_REG_HR] = BIN2BCD(tm->tm_hour); 144 145 buf[PCF8563_REG_DM] = BIN2BCD(tm->tm_mday); 146 147 /* month, 1 - 12 */ 148 buf[PCF8563_REG_MO] = BIN2BCD(tm->tm_mon + 1); 149 150 /* year and century */ 151 buf[PCF8563_REG_YR] = BIN2BCD(tm->tm_year % 100); 152 if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100)) 153 buf[PCF8563_REG_MO] |= PCF8563_MO_C; 154 155 buf[PCF8563_REG_DW] = tm->tm_wday & 0x07; 156 157 /* write register's data */ 158 for (i = 0; i < 7; i++) { 159 unsigned char data[2] = { PCF8563_REG_SC + i, 160 buf[PCF8563_REG_SC + i] }; 161 162 err = i2c_master_send(client, data, sizeof(data)); 163 if (err != sizeof(data)) { 164 dev_err(&client->dev, 165 "%s: err=%d addr=%02x, data=%02x\n", 166 __func__, err, data[0], data[1]); 167 return -EIO; 168 } 169 }; 170 171 return 0; 172 } 173 174 struct pcf8563_limit 175 { 176 unsigned char reg; 177 unsigned char mask; 178 unsigned char min; 179 unsigned char max; 180 }; 181 182 static int pcf8563_validate_client(struct i2c_client *client) 183 { 184 int i; 185 186 static const struct pcf8563_limit pattern[] = { 187 /* register, mask, min, max */ 188 { PCF8563_REG_SC, 0x7F, 0, 59 }, 189 { PCF8563_REG_MN, 0x7F, 0, 59 }, 190 { PCF8563_REG_HR, 0x3F, 0, 23 }, 191 { PCF8563_REG_DM, 0x3F, 0, 31 }, 192 { PCF8563_REG_MO, 0x1F, 0, 12 }, 193 }; 194 195 /* check limits (only registers with bcd values) */ 196 for (i = 0; i < ARRAY_SIZE(pattern); i++) { 197 int xfer; 198 unsigned char value; 199 unsigned char buf = pattern[i].reg; 200 201 struct i2c_msg msgs[] = { 202 { client->addr, 0, 1, &buf }, 203 { client->addr, I2C_M_RD, 1, &buf }, 204 }; 205 206 xfer = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 207 208 if (xfer != ARRAY_SIZE(msgs)) { 209 dev_err(&client->dev, 210 "%s: could not read register 0x%02X\n", 211 __func__, pattern[i].reg); 212 213 return -EIO; 214 } 215 216 value = BCD2BIN(buf & pattern[i].mask); 217 218 if (value > pattern[i].max || 219 value < pattern[i].min) { 220 dev_dbg(&client->dev, 221 "%s: pattern=%d, reg=%x, mask=0x%02x, min=%d, " 222 "max=%d, value=%d, raw=0x%02X\n", 223 __func__, i, pattern[i].reg, pattern[i].mask, 224 pattern[i].min, pattern[i].max, 225 value, buf); 226 227 return -ENODEV; 228 } 229 } 230 231 return 0; 232 } 233 234 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm) 235 { 236 return pcf8563_get_datetime(to_i2c_client(dev), tm); 237 } 238 239 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm) 240 { 241 return pcf8563_set_datetime(to_i2c_client(dev), tm); 242 } 243 244 static const struct rtc_class_ops pcf8563_rtc_ops = { 245 .read_time = pcf8563_rtc_read_time, 246 .set_time = pcf8563_rtc_set_time, 247 }; 248 249 static int pcf8563_probe(struct i2c_client *client, 250 const struct i2c_device_id *id) 251 { 252 struct pcf8563 *pcf8563; 253 254 int err = 0; 255 256 dev_dbg(&client->dev, "%s\n", __func__); 257 258 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 259 return -ENODEV; 260 261 pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL); 262 if (!pcf8563) 263 return -ENOMEM; 264 265 /* Verify the chip is really an PCF8563 */ 266 if (pcf8563_validate_client(client) < 0) { 267 err = -ENODEV; 268 goto exit_kfree; 269 } 270 271 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 272 273 pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name, 274 &client->dev, &pcf8563_rtc_ops, THIS_MODULE); 275 276 if (IS_ERR(pcf8563->rtc)) { 277 err = PTR_ERR(pcf8563->rtc); 278 goto exit_kfree; 279 } 280 281 i2c_set_clientdata(client, pcf8563); 282 283 return 0; 284 285 exit_kfree: 286 kfree(pcf8563); 287 288 return err; 289 } 290 291 static int pcf8563_remove(struct i2c_client *client) 292 { 293 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 294 295 if (pcf8563->rtc) 296 rtc_device_unregister(pcf8563->rtc); 297 298 kfree(pcf8563); 299 300 return 0; 301 } 302 303 static const struct i2c_device_id pcf8563_id[] = { 304 { "pcf8563", 0 }, 305 { } 306 }; 307 MODULE_DEVICE_TABLE(i2c, pcf8563_id); 308 309 static struct i2c_driver pcf8563_driver = { 310 .driver = { 311 .name = "rtc-pcf8563", 312 }, 313 .probe = pcf8563_probe, 314 .remove = pcf8563_remove, 315 .id_table = pcf8563_id, 316 }; 317 318 static int __init pcf8563_init(void) 319 { 320 return i2c_add_driver(&pcf8563_driver); 321 } 322 323 static void __exit pcf8563_exit(void) 324 { 325 i2c_del_driver(&pcf8563_driver); 326 } 327 328 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 329 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver"); 330 MODULE_LICENSE("GPL"); 331 MODULE_VERSION(DRV_VERSION); 332 333 module_init(pcf8563_init); 334 module_exit(pcf8563_exit); 335