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