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 22#define DRV_VERSION "0.4.3" 23 24#define PCF8563_REG_ST1 0x00 /* status */ 25#define PCF8563_REG_ST2 0x01 26 27#define PCF8563_REG_SC 0x02 /* datetime */ 28#define PCF8563_REG_MN 0x03 29#define PCF8563_REG_HR 0x04 30#define PCF8563_REG_DM 0x05 31#define PCF8563_REG_DW 0x06 32#define PCF8563_REG_MO 0x07 33#define PCF8563_REG_YR 0x08 34 35#define PCF8563_REG_AMN 0x09 /* alarm */ 36#define PCF8563_REG_AHR 0x0A 37#define PCF8563_REG_ADM 0x0B 38#define PCF8563_REG_ADW 0x0C 39 40#define PCF8563_REG_CLKO 0x0D /* clock out */ 41#define PCF8563_REG_TMRC 0x0E /* timer control */ 42#define PCF8563_REG_TMR 0x0F /* timer */ 43 44#define PCF8563_SC_LV 0x80 /* low voltage */ 45#define PCF8563_MO_C 0x80 /* century */ 46 47static struct i2c_driver pcf8563_driver; 48 49struct pcf8563 { 50 struct rtc_device *rtc; 51 /* 52 * The meaning of MO_C bit varies by the chip type. 53 * From PCF8563 datasheet: this bit is toggled when the years 54 * register overflows from 99 to 00 55 * 0 indicates the century is 20xx 56 * 1 indicates the century is 19xx 57 * From RTC8564 datasheet: this bit indicates change of 58 * century. When the year digit data overflows from 99 to 00, 59 * this bit is set. By presetting it to 0 while still in the 60 * 20th century, it will be set in year 2000, ... 61 * There seems no reliable way to know how the system use this 62 * bit. So let's do it heuristically, assuming we are live in 63 * 1970...2069. 64 */ 65 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */ 66}; 67 68/* 69 * In the routines that deal directly with the pcf8563 hardware, we use 70 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 71 */ 72static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm) 73{ 74 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 75 unsigned char buf[13] = { PCF8563_REG_ST1 }; 76 77 struct i2c_msg msgs[] = { 78 { client->addr, 0, 1, buf }, /* setup read ptr */ 79 { client->addr, I2C_M_RD, 13, buf }, /* read status + date */ 80 }; 81 82 /* read registers */ 83 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) { 84 dev_err(&client->dev, "%s: read error\n", __func__); 85 return -EIO; 86 } 87 88 if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) 89 dev_info(&client->dev, 90 "low voltage detected, date/time is not reliable.\n"); 91 92 dev_dbg(&client->dev, 93 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, " 94 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", 95 __func__, 96 buf[0], buf[1], buf[2], buf[3], 97 buf[4], buf[5], buf[6], buf[7], 98 buf[8]); 99 100 101 tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F); 102 tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F); 103 tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */ 104 tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F); 105 tm->tm_wday = buf[PCF8563_REG_DW] & 0x07; 106 tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 107 tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]); 108 if (tm->tm_year < 70) 109 tm->tm_year += 100; /* assume we are in 1970...2069 */ 110 /* detect the polarity heuristically. see note above. */ 111 pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ? 112 (tm->tm_year >= 100) : (tm->tm_year < 100); 113 114 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 115 "mday=%d, mon=%d, year=%d, wday=%d\n", 116 __func__, 117 tm->tm_sec, tm->tm_min, tm->tm_hour, 118 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 119 120 /* the clock can give out invalid datetime, but we cannot return 121 * -EINVAL otherwise hwclock will refuse to set the time on bootup. 122 */ 123 if (rtc_valid_tm(tm) < 0) 124 dev_err(&client->dev, "retrieved date/time is not valid.\n"); 125 126 return 0; 127} 128 129static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm) 130{ 131 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 132 int i, err; 133 unsigned char buf[9]; 134 135 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 136 "mday=%d, mon=%d, year=%d, wday=%d\n", 137 __func__, 138 tm->tm_sec, tm->tm_min, tm->tm_hour, 139 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 140 141 /* hours, minutes and seconds */ 142 buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec); 143 buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min); 144 buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour); 145 146 buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday); 147 148 /* month, 1 - 12 */ 149 buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1); 150 151 /* year and century */ 152 buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100); 153 if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100)) 154 buf[PCF8563_REG_MO] |= PCF8563_MO_C; 155 156 buf[PCF8563_REG_DW] = tm->tm_wday & 0x07; 157 158 /* write register's data */ 159 for (i = 0; i < 7; i++) { 160 unsigned char data[2] = { PCF8563_REG_SC + i, 161 buf[PCF8563_REG_SC + i] }; 162 163 err = i2c_master_send(client, data, sizeof(data)); 164 if (err != sizeof(data)) { 165 dev_err(&client->dev, 166 "%s: err=%d addr=%02x, data=%02x\n", 167 __func__, err, data[0], data[1]); 168 return -EIO; 169 } 170 }; 171 172 return 0; 173} 174 175static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm) 176{ 177 return pcf8563_get_datetime(to_i2c_client(dev), tm); 178} 179 180static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm) 181{ 182 return pcf8563_set_datetime(to_i2c_client(dev), tm); 183} 184 185static const struct rtc_class_ops pcf8563_rtc_ops = { 186 .read_time = pcf8563_rtc_read_time, 187 .set_time = pcf8563_rtc_set_time, 188}; 189 190static int pcf8563_probe(struct i2c_client *client, 191 const struct i2c_device_id *id) 192{ 193 struct pcf8563 *pcf8563; 194 195 int err = 0; 196 197 dev_dbg(&client->dev, "%s\n", __func__); 198 199 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 200 return -ENODEV; 201 202 pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL); 203 if (!pcf8563) 204 return -ENOMEM; 205 206 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 207 208 i2c_set_clientdata(client, pcf8563); 209 210 pcf8563->rtc = rtc_device_register(pcf8563_driver.driver.name, 211 &client->dev, &pcf8563_rtc_ops, THIS_MODULE); 212 213 if (IS_ERR(pcf8563->rtc)) { 214 err = PTR_ERR(pcf8563->rtc); 215 goto exit_kfree; 216 } 217 218 return 0; 219 220exit_kfree: 221 kfree(pcf8563); 222 223 return err; 224} 225 226static int pcf8563_remove(struct i2c_client *client) 227{ 228 struct pcf8563 *pcf8563 = i2c_get_clientdata(client); 229 230 if (pcf8563->rtc) 231 rtc_device_unregister(pcf8563->rtc); 232 233 kfree(pcf8563); 234 235 return 0; 236} 237 238static const struct i2c_device_id pcf8563_id[] = { 239 { "pcf8563", 0 }, 240 { "rtc8564", 0 }, 241 { } 242}; 243MODULE_DEVICE_TABLE(i2c, pcf8563_id); 244 245static struct i2c_driver pcf8563_driver = { 246 .driver = { 247 .name = "rtc-pcf8563", 248 }, 249 .probe = pcf8563_probe, 250 .remove = pcf8563_remove, 251 .id_table = pcf8563_id, 252}; 253 254static int __init pcf8563_init(void) 255{ 256 return i2c_add_driver(&pcf8563_driver); 257} 258 259static void __exit pcf8563_exit(void) 260{ 261 i2c_del_driver(&pcf8563_driver); 262} 263 264MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 265MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver"); 266MODULE_LICENSE("GPL"); 267MODULE_VERSION(DRV_VERSION); 268 269module_init(pcf8563_init); 270module_exit(pcf8563_exit); 271