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 #include <linux/of.h> 23 24 #define DRV_VERSION "0.4.3" 25 26 #define PCF8563_REG_ST1 0x00 /* status */ 27 #define PCF8563_REG_ST2 0x01 28 29 #define PCF8563_REG_SC 0x02 /* datetime */ 30 #define PCF8563_REG_MN 0x03 31 #define PCF8563_REG_HR 0x04 32 #define PCF8563_REG_DM 0x05 33 #define PCF8563_REG_DW 0x06 34 #define PCF8563_REG_MO 0x07 35 #define PCF8563_REG_YR 0x08 36 37 #define PCF8563_REG_AMN 0x09 /* alarm */ 38 #define PCF8563_REG_AHR 0x0A 39 #define PCF8563_REG_ADM 0x0B 40 #define PCF8563_REG_ADW 0x0C 41 42 #define PCF8563_REG_CLKO 0x0D /* clock out */ 43 #define PCF8563_REG_TMRC 0x0E /* timer control */ 44 #define PCF8563_REG_TMR 0x0F /* timer */ 45 46 #define PCF8563_SC_LV 0x80 /* low voltage */ 47 #define PCF8563_MO_C 0x80 /* century */ 48 49 static struct i2c_driver pcf8563_driver; 50 51 struct pcf8563 { 52 struct rtc_device *rtc; 53 /* 54 * The meaning of MO_C bit varies by the chip type. 55 * From PCF8563 datasheet: this bit is toggled when the years 56 * register overflows from 99 to 00 57 * 0 indicates the century is 20xx 58 * 1 indicates the century is 19xx 59 * From RTC8564 datasheet: this bit indicates change of 60 * century. When the year digit data overflows from 99 to 00, 61 * this bit is set. By presetting it to 0 while still in the 62 * 20th century, it will be set in year 2000, ... 63 * There seems no reliable way to know how the system use this 64 * bit. So let's do it heuristically, assuming we are live in 65 * 1970...2069. 66 */ 67 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */ 68 int voltage_low; /* incicates if a low_voltage was detected */ 69 }; 70 71 /* 72 * In the routines that deal directly with the pcf8563 hardware, we use 73 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 74 */ 75 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm) 76 { 77 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 78 unsigned char buf[13] = { PCF8563_REG_ST1 }; 79 80 struct i2c_msg msgs[] = { 81 { client->addr, 0, 1, buf }, /* setup read ptr */ 82 { client->addr, I2C_M_RD, 13, buf }, /* read status + date */ 83 }; 84 85 /* read registers */ 86 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) { 87 dev_err(&client->dev, "%s: read error\n", __func__); 88 return -EIO; 89 } 90 91 if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) { 92 pcf8563->voltage_low = 1; 93 dev_info(&client->dev, 94 "low voltage detected, date/time is not reliable.\n"); 95 } 96 97 dev_dbg(&client->dev, 98 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, " 99 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", 100 __func__, 101 buf[0], buf[1], buf[2], buf[3], 102 buf[4], buf[5], buf[6], buf[7], 103 buf[8]); 104 105 106 tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F); 107 tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F); 108 tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */ 109 tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F); 110 tm->tm_wday = buf[PCF8563_REG_DW] & 0x07; 111 tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 112 tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]); 113 if (tm->tm_year < 70) 114 tm->tm_year += 100; /* assume we are in 1970...2069 */ 115 /* detect the polarity heuristically. see note above. */ 116 pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ? 117 (tm->tm_year >= 100) : (tm->tm_year < 100); 118 119 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 120 "mday=%d, mon=%d, year=%d, wday=%d\n", 121 __func__, 122 tm->tm_sec, tm->tm_min, tm->tm_hour, 123 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 124 125 /* the clock can give out invalid datetime, but we cannot return 126 * -EINVAL otherwise hwclock will refuse to set the time on bootup. 127 */ 128 if (rtc_valid_tm(tm) < 0) 129 dev_err(&client->dev, "retrieved date/time is not valid.\n"); 130 131 return 0; 132 } 133 134 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm) 135 { 136 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 137 int i, err; 138 unsigned char buf[9]; 139 140 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 141 "mday=%d, mon=%d, year=%d, wday=%d\n", 142 __func__, 143 tm->tm_sec, tm->tm_min, tm->tm_hour, 144 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 145 146 /* hours, minutes and seconds */ 147 buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec); 148 buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min); 149 buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour); 150 151 buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday); 152 153 /* month, 1 - 12 */ 154 buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1); 155 156 /* year and century */ 157 buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100); 158 if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100)) 159 buf[PCF8563_REG_MO] |= PCF8563_MO_C; 160 161 buf[PCF8563_REG_DW] = tm->tm_wday & 0x07; 162 163 /* write register's data */ 164 for (i = 0; i < 7; i++) { 165 unsigned char data[2] = { PCF8563_REG_SC + i, 166 buf[PCF8563_REG_SC + i] }; 167 168 err = i2c_master_send(client, data, sizeof(data)); 169 if (err != sizeof(data)) { 170 dev_err(&client->dev, 171 "%s: err=%d addr=%02x, data=%02x\n", 172 __func__, err, data[0], data[1]); 173 return -EIO; 174 } 175 }; 176 177 return 0; 178 } 179 180 #ifdef CONFIG_RTC_INTF_DEV 181 static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 182 { 183 struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev)); 184 struct rtc_time tm; 185 186 switch (cmd) { 187 case RTC_VL_READ: 188 if (pcf8563->voltage_low) 189 dev_info(dev, "low voltage detected, date/time is not reliable.\n"); 190 191 if (copy_to_user((void __user *)arg, &pcf8563->voltage_low, 192 sizeof(int))) 193 return -EFAULT; 194 return 0; 195 case RTC_VL_CLR: 196 /* 197 * Clear the VL bit in the seconds register in case 198 * the time has not been set already (which would 199 * have cleared it). This does not really matter 200 * because of the cached voltage_low value but do it 201 * anyway for consistency. 202 */ 203 if (pcf8563_get_datetime(to_i2c_client(dev), &tm)) 204 pcf8563_set_datetime(to_i2c_client(dev), &tm); 205 206 /* Clear the cached value. */ 207 pcf8563->voltage_low = 0; 208 209 return 0; 210 default: 211 return -ENOIOCTLCMD; 212 } 213 } 214 #else 215 #define pcf8563_rtc_ioctl NULL 216 #endif 217 218 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm) 219 { 220 return pcf8563_get_datetime(to_i2c_client(dev), tm); 221 } 222 223 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm) 224 { 225 return pcf8563_set_datetime(to_i2c_client(dev), tm); 226 } 227 228 static const struct rtc_class_ops pcf8563_rtc_ops = { 229 .ioctl = pcf8563_rtc_ioctl, 230 .read_time = pcf8563_rtc_read_time, 231 .set_time = pcf8563_rtc_set_time, 232 }; 233 234 static int pcf8563_probe(struct i2c_client *client, 235 const struct i2c_device_id *id) 236 { 237 struct pcf8563 *pcf8563; 238 239 int err = 0; 240 241 dev_dbg(&client->dev, "%s\n", __func__); 242 243 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 244 return -ENODEV; 245 246 pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL); 247 if (!pcf8563) 248 return -ENOMEM; 249 250 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 251 252 i2c_set_clientdata(client, pcf8563); 253 254 pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name, 255 &client->dev, &pcf8563_rtc_ops, THIS_MODULE); 256 257 if (IS_ERR(pcf8563->rtc)) { 258 err = PTR_ERR(pcf8563->rtc); 259 goto exit_kfree; 260 } 261 262 return 0; 263 264 exit_kfree: 265 kfree(pcf8563); 266 267 return err; 268 } 269 270 static int pcf8563_remove(struct i2c_client *client) 271 { 272 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 273 274 if (pcf8563->rtc) 275 rtc_device_unregister(pcf8563->rtc); 276 277 kfree(pcf8563); 278 279 return 0; 280 } 281 282 static const struct i2c_device_id pcf8563_id[] = { 283 { "pcf8563", 0 }, 284 { "rtc8564", 0 }, 285 { } 286 }; 287 MODULE_DEVICE_TABLE(i2c, pcf8563_id); 288 289 #ifdef CONFIG_OF 290 static const struct of_device_id pcf8563_of_match[] __devinitconst = { 291 { .compatible = "nxp,pcf8563" }, 292 {} 293 }; 294 MODULE_DEVICE_TABLE(of, pcf8563_of_match); 295 #endif 296 297 static struct i2c_driver pcf8563_driver = { 298 .driver = { 299 .name = "rtc-pcf8563", 300 .owner = THIS_MODULE, 301 .of_match_table = of_match_ptr(pcf8563_of_match), 302 }, 303 .probe = pcf8563_probe, 304 .remove = pcf8563_remove, 305 .id_table = pcf8563_id, 306 }; 307 308 module_i2c_driver(pcf8563_driver); 309 310 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 311 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver"); 312 MODULE_LICENSE("GPL"); 313 MODULE_VERSION(DRV_VERSION); 314