1 /* 2 * An I2C driver for the Epson RX8581 RTC 3 * 4 * Author: Martyn Welch <martyn.welch@ge.com> 5 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc. 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC) 12 * Copyright 2005-06 Tower Technologies 13 */ 14 15 #include <linux/module.h> 16 #include <linux/i2c.h> 17 #include <linux/bcd.h> 18 #include <linux/rtc.h> 19 #include <linux/log2.h> 20 21 #define RX8581_REG_SC 0x00 /* Second in BCD */ 22 #define RX8581_REG_MN 0x01 /* Minute in BCD */ 23 #define RX8581_REG_HR 0x02 /* Hour in BCD */ 24 #define RX8581_REG_DW 0x03 /* Day of Week */ 25 #define RX8581_REG_DM 0x04 /* Day of Month in BCD */ 26 #define RX8581_REG_MO 0x05 /* Month in BCD */ 27 #define RX8581_REG_YR 0x06 /* Year in BCD */ 28 #define RX8581_REG_RAM 0x07 /* RAM */ 29 #define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/ 30 #define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */ 31 #define RX8581_REG_ADM 0x0A 32 #define RX8581_REG_ADW 0x0A 33 #define RX8581_REG_TMR0 0x0B 34 #define RX8581_REG_TMR1 0x0C 35 #define RX8581_REG_EXT 0x0D /* Extension Register */ 36 #define RX8581_REG_FLAG 0x0E /* Flag Register */ 37 #define RX8581_REG_CTRL 0x0F /* Control Register */ 38 39 40 /* Flag Register bit definitions */ 41 #define RX8581_FLAG_UF 0x20 /* Update */ 42 #define RX8581_FLAG_TF 0x10 /* Timer */ 43 #define RX8581_FLAG_AF 0x08 /* Alarm */ 44 #define RX8581_FLAG_VLF 0x02 /* Voltage Low */ 45 46 /* Control Register bit definitions */ 47 #define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */ 48 #define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */ 49 #define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */ 50 #define RX8581_CTRL_STOP 0x02 /* STOP bit */ 51 #define RX8581_CTRL_RESET 0x01 /* RESET bit */ 52 53 struct rx8581 { 54 struct i2c_client *client; 55 struct rtc_device *rtc; 56 s32 (*read_block_data)(const struct i2c_client *client, u8 command, 57 u8 length, u8 *values); 58 s32 (*write_block_data)(const struct i2c_client *client, u8 command, 59 u8 length, const u8 *values); 60 }; 61 62 static struct i2c_driver rx8581_driver; 63 64 static int rx8581_read_block_data(const struct i2c_client *client, u8 command, 65 u8 length, u8 *values) 66 { 67 s32 i, data; 68 69 for (i = 0; i < length; i++) { 70 data = i2c_smbus_read_byte_data(client, command + i); 71 if (data < 0) 72 return data; 73 values[i] = data; 74 } 75 return i; 76 } 77 78 static int rx8581_write_block_data(const struct i2c_client *client, u8 command, 79 u8 length, const u8 *values) 80 { 81 s32 i, ret; 82 83 for (i = 0; i < length; i++) { 84 ret = i2c_smbus_write_byte_data(client, command + i, 85 values[i]); 86 if (ret < 0) 87 return ret; 88 } 89 return length; 90 } 91 92 /* 93 * In the routines that deal directly with the rx8581 hardware, we use 94 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 95 */ 96 static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm) 97 { 98 unsigned char date[7]; 99 int data, err; 100 struct rx8581 *rx8581 = i2c_get_clientdata(client); 101 102 /* First we ensure that the "update flag" is not set, we read the 103 * time and date then re-read the "update flag". If the update flag 104 * has been set, we know that the time has changed during the read so 105 * we repeat the whole process again. 106 */ 107 data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); 108 if (data < 0) { 109 dev_err(&client->dev, "Unable to read device flags\n"); 110 return -EIO; 111 } 112 113 do { 114 /* If update flag set, clear it */ 115 if (data & RX8581_FLAG_UF) { 116 err = i2c_smbus_write_byte_data(client, 117 RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF)); 118 if (err != 0) { 119 dev_err(&client->dev, "Unable to write device flags\n"); 120 return -EIO; 121 } 122 } 123 124 /* Now read time and date */ 125 err = rx8581->read_block_data(client, RX8581_REG_SC, 126 7, date); 127 if (err < 0) { 128 dev_err(&client->dev, "Unable to read date\n"); 129 return -EIO; 130 } 131 132 /* Check flag register */ 133 data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); 134 if (data < 0) { 135 dev_err(&client->dev, "Unable to read device flags\n"); 136 return -EIO; 137 } 138 } while (data & RX8581_FLAG_UF); 139 140 if (data & RX8581_FLAG_VLF) 141 dev_info(&client->dev, 142 "low voltage detected, date/time is not reliable.\n"); 143 144 dev_dbg(&client->dev, 145 "%s: raw data is sec=%02x, min=%02x, hr=%02x, " 146 "wday=%02x, mday=%02x, mon=%02x, year=%02x\n", 147 __func__, 148 date[0], date[1], date[2], date[3], date[4], date[5], date[6]); 149 150 tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F); 151 tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F); 152 tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */ 153 tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F); 154 tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F); 155 tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 156 tm->tm_year = bcd2bin(date[RX8581_REG_YR]); 157 if (tm->tm_year < 70) 158 tm->tm_year += 100; /* assume we are in 1970...2069 */ 159 160 161 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 162 "mday=%d, mon=%d, year=%d, wday=%d\n", 163 __func__, 164 tm->tm_sec, tm->tm_min, tm->tm_hour, 165 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 166 167 err = rtc_valid_tm(tm); 168 if (err < 0) 169 dev_err(&client->dev, "retrieved date/time is not valid.\n"); 170 171 return err; 172 } 173 174 static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm) 175 { 176 int data, err; 177 unsigned char buf[7]; 178 struct rx8581 *rx8581 = i2c_get_clientdata(client); 179 180 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 181 "mday=%d, mon=%d, year=%d, wday=%d\n", 182 __func__, 183 tm->tm_sec, tm->tm_min, tm->tm_hour, 184 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 185 186 /* hours, minutes and seconds */ 187 buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec); 188 buf[RX8581_REG_MN] = bin2bcd(tm->tm_min); 189 buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour); 190 191 buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday); 192 193 /* month, 1 - 12 */ 194 buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1); 195 196 /* year and century */ 197 buf[RX8581_REG_YR] = bin2bcd(tm->tm_year % 100); 198 buf[RX8581_REG_DW] = (0x1 << tm->tm_wday); 199 200 /* Stop the clock */ 201 data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL); 202 if (data < 0) { 203 dev_err(&client->dev, "Unable to read control register\n"); 204 return -EIO; 205 } 206 207 err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL, 208 (data | RX8581_CTRL_STOP)); 209 if (err < 0) { 210 dev_err(&client->dev, "Unable to write control register\n"); 211 return -EIO; 212 } 213 214 /* write register's data */ 215 err = rx8581->write_block_data(client, RX8581_REG_SC, 7, buf); 216 if (err < 0) { 217 dev_err(&client->dev, "Unable to write to date registers\n"); 218 return -EIO; 219 } 220 221 /* get VLF and clear it */ 222 data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); 223 if (data < 0) { 224 dev_err(&client->dev, "Unable to read flag register\n"); 225 return -EIO; 226 } 227 228 err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG, 229 (data & ~(RX8581_FLAG_VLF))); 230 if (err != 0) { 231 dev_err(&client->dev, "Unable to write flag register\n"); 232 return -EIO; 233 } 234 235 /* Restart the clock */ 236 data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL); 237 if (data < 0) { 238 dev_err(&client->dev, "Unable to read control register\n"); 239 return -EIO; 240 } 241 242 err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL, 243 (data & ~(RX8581_CTRL_STOP))); 244 if (err != 0) { 245 dev_err(&client->dev, "Unable to write control register\n"); 246 return -EIO; 247 } 248 249 return 0; 250 } 251 252 static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm) 253 { 254 return rx8581_get_datetime(to_i2c_client(dev), tm); 255 } 256 257 static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm) 258 { 259 return rx8581_set_datetime(to_i2c_client(dev), tm); 260 } 261 262 static const struct rtc_class_ops rx8581_rtc_ops = { 263 .read_time = rx8581_rtc_read_time, 264 .set_time = rx8581_rtc_set_time, 265 }; 266 267 static int rx8581_probe(struct i2c_client *client, 268 const struct i2c_device_id *id) 269 { 270 struct rx8581 *rx8581; 271 272 dev_dbg(&client->dev, "%s\n", __func__); 273 274 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA) 275 && !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) 276 return -EIO; 277 278 rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL); 279 if (!rx8581) 280 return -ENOMEM; 281 282 i2c_set_clientdata(client, rx8581); 283 rx8581->client = client; 284 285 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) { 286 rx8581->read_block_data = i2c_smbus_read_i2c_block_data; 287 rx8581->write_block_data = i2c_smbus_write_i2c_block_data; 288 } else { 289 rx8581->read_block_data = rx8581_read_block_data; 290 rx8581->write_block_data = rx8581_write_block_data; 291 } 292 293 rx8581->rtc = devm_rtc_device_register(&client->dev, 294 rx8581_driver.driver.name, &rx8581_rtc_ops, THIS_MODULE); 295 296 if (IS_ERR(rx8581->rtc)) { 297 dev_err(&client->dev, 298 "unable to register the class device\n"); 299 return PTR_ERR(rx8581->rtc); 300 } 301 302 return 0; 303 } 304 305 static const struct i2c_device_id rx8581_id[] = { 306 { "rx8581", 0 }, 307 { } 308 }; 309 MODULE_DEVICE_TABLE(i2c, rx8581_id); 310 311 static struct i2c_driver rx8581_driver = { 312 .driver = { 313 .name = "rtc-rx8581", 314 }, 315 .probe = rx8581_probe, 316 .id_table = rx8581_id, 317 }; 318 319 module_i2c_driver(rx8581_driver); 320 321 MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>"); 322 MODULE_DESCRIPTION("Epson RX-8581 RTC driver"); 323 MODULE_LICENSE("GPL"); 324