| 1 | /* |
| 2 | * An I2C driver for the Epson RX8581 RTC |
| 3 | * |
| 4 | * Author: Martyn Welch <martyn.welch@gefanuc.com> |
| 5 | * Copyright 2008 GE Fanuc 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 DRV_VERSION "0.1" |
| 22 | |
| 23 | #define RX8581_REG_SC 0x00 /* Second in BCD */ |
| 24 | #define RX8581_REG_MN 0x01 /* Minute in BCD */ |
| 25 | #define RX8581_REG_HR 0x02 /* Hour in BCD */ |
| 26 | #define RX8581_REG_DW 0x03 /* Day of Week */ |
| 27 | #define RX8581_REG_DM 0x04 /* Day of Month in BCD */ |
| 28 | #define RX8581_REG_MO 0x05 /* Month in BCD */ |
| 29 | #define RX8581_REG_YR 0x06 /* Year in BCD */ |
| 30 | #define RX8581_REG_RAM 0x07 /* RAM */ |
| 31 | #define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/ |
| 32 | #define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */ |
| 33 | #define RX8581_REG_ADM 0x0A |
| 34 | #define RX8581_REG_ADW 0x0A |
| 35 | #define RX8581_REG_TMR0 0x0B |
| 36 | #define RX8581_REG_TMR1 0x0C |
| 37 | #define RX8581_REG_EXT 0x0D /* Extension Register */ |
| 38 | #define RX8581_REG_FLAG 0x0E /* Flag Register */ |
| 39 | #define RX8581_REG_CTRL 0x0F /* Control Register */ |
| 40 | |
| 41 | |
| 42 | /* Flag Register bit definitions */ |
| 43 | #define RX8581_FLAG_UF 0x20 /* Update */ |
| 44 | #define RX8581_FLAG_TF 0x10 /* Timer */ |
| 45 | #define RX8581_FLAG_AF 0x08 /* Alarm */ |
| 46 | #define RX8581_FLAG_VLF 0x02 /* Voltage Low */ |
| 47 | |
| 48 | /* Control Register bit definitions */ |
| 49 | #define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */ |
| 50 | #define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */ |
| 51 | #define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */ |
| 52 | #define RX8581_CTRL_STOP 0x02 /* STOP bit */ |
| 53 | #define RX8581_CTRL_RESET 0x01 /* RESET bit */ |
| 54 | |
| 55 | static struct i2c_driver rx8581_driver; |
| 56 | |
| 57 | /* |
| 58 | * In the routines that deal directly with the rx8581 hardware, we use |
| 59 | * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. |
| 60 | */ |
| 61 | static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm) |
| 62 | { |
| 63 | unsigned char date[7]; |
| 64 | int data, err; |
| 65 | |
| 66 | /* First we ensure that the "update flag" is not set, we read the |
| 67 | * time and date then re-read the "update flag". If the update flag |
| 68 | * has been set, we know that the time has changed during the read so |
| 69 | * we repeat the whole process again. |
| 70 | */ |
| 71 | data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); |
| 72 | if (data < 0) { |
| 73 | dev_err(&client->dev, "Unable to read device flags\n"); |
| 74 | return -EIO; |
| 75 | } |
| 76 | |
| 77 | do { |
| 78 | /* If update flag set, clear it */ |
| 79 | if (data & RX8581_FLAG_UF) { |
| 80 | err = i2c_smbus_write_byte_data(client, |
| 81 | RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF)); |
| 82 | if (err != 0) { |
| 83 | dev_err(&client->dev, "Unable to write device " |
| 84 | "flags\n"); |
| 85 | return -EIO; |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | /* Now read time and date */ |
| 90 | err = i2c_smbus_read_i2c_block_data(client, RX8581_REG_SC, |
| 91 | 7, date); |
| 92 | if (err < 0) { |
| 93 | dev_err(&client->dev, "Unable to read date\n"); |
| 94 | return -EIO; |
| 95 | } |
| 96 | |
| 97 | /* Check flag register */ |
| 98 | data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG); |
| 99 | if (data < 0) { |
| 100 | dev_err(&client->dev, "Unable to read device flags\n"); |
| 101 | return -EIO; |
| 102 | } |
| 103 | } while (data & RX8581_FLAG_UF); |
| 104 | |
| 105 | if (data & RX8581_FLAG_VLF) |
| 106 | dev_info(&client->dev, |
| 107 | "low voltage detected, date/time is not reliable.\n"); |
| 108 | |
| 109 | dev_dbg(&client->dev, |
| 110 | "%s: raw data is sec=%02x, min=%02x, hr=%02x, " |
| 111 | "wday=%02x, mday=%02x, mon=%02x, year=%02x\n", |
| 112 | __func__, |
| 113 | date[0], date[1], date[2], date[3], date[4], date[5], date[6]); |
| 114 | |
| 115 | tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F); |
| 116 | tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F); |
| 117 | tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */ |
| 118 | tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F); |
| 119 | tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F); |
| 120 | tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ |
| 121 | tm->tm_year = bcd2bin(date[RX8581_REG_YR]); |
| 122 | if (tm->tm_year < 70) |
| 123 | tm->tm_year += 100; /* assume we are in 1970...2069 */ |
| 124 | |
| 125 | |
| 126 | dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " |
| 127 | "mday=%d, mon=%d, year=%d, wday=%d\n", |
| 128 | __func__, |
| 129 | tm->tm_sec, tm->tm_min, tm->tm_hour, |
| 130 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); |
| 131 | |
| 132 | err = rtc_valid_tm(tm); |
| 133 | if (err < 0) |
| 134 | dev_err(&client->dev, "retrieved date/time is not valid.\n"); |
| 135 | |
| 136 | return err; |
| 137 | } |
| 138 | |
| 139 | static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm) |
| 140 | { |
| 141 | int data, err; |
| 142 | unsigned char buf[7]; |
| 143 | |
| 144 | dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " |
| 145 | "mday=%d, mon=%d, year=%d, wday=%d\n", |
| 146 | __func__, |
| 147 | tm->tm_sec, tm->tm_min, tm->tm_hour, |
| 148 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); |
| 149 | |
| 150 | /* hours, minutes and seconds */ |
| 151 | buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec); |
| 152 | buf[RX8581_REG_MN] = bin2bcd(tm->tm_min); |
| 153 | buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour); |
| 154 | |
| 155 | buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday); |
| 156 | |
| 157 | /* month, 1 - 12 */ |
| 158 | buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1); |
| 159 | |
| 160 | /* year and century */ |
| 161 | buf[RX8581_REG_YR] = bin2bcd(tm->tm_year % 100); |
| 162 | buf[RX8581_REG_DW] = (0x1 << tm->tm_wday); |
| 163 | |
| 164 | /* Stop the clock */ |
| 165 | data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL); |
| 166 | if (data < 0) { |
| 167 | dev_err(&client->dev, "Unable to read control register\n"); |
| 168 | return -EIO; |
| 169 | } |
| 170 | |
| 171 | err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG, |
| 172 | (data | RX8581_CTRL_STOP)); |
| 173 | if (err < 0) { |
| 174 | dev_err(&client->dev, "Unable to write control register\n"); |
| 175 | return -EIO; |
| 176 | } |
| 177 | |
| 178 | /* write register's data */ |
| 179 | err = i2c_smbus_write_i2c_block_data(client, RX8581_REG_SC, 7, buf); |
| 180 | if (err < 0) { |
| 181 | dev_err(&client->dev, "Unable to write to date registers\n"); |
| 182 | return -EIO; |
| 183 | } |
| 184 | |
| 185 | /* Restart the clock */ |
| 186 | data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL); |
| 187 | if (data < 0) { |
| 188 | dev_err(&client->dev, "Unable to read control register\n"); |
| 189 | return -EIO; |
| 190 | } |
| 191 | |
| 192 | err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG, |
| 193 | (data | ~(RX8581_CTRL_STOP))); |
| 194 | if (err != 0) { |
| 195 | dev_err(&client->dev, "Unable to write control register\n"); |
| 196 | return -EIO; |
| 197 | } |
| 198 | |
| 199 | return 0; |
| 200 | } |
| 201 | |
| 202 | static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm) |
| 203 | { |
| 204 | return rx8581_get_datetime(to_i2c_client(dev), tm); |
| 205 | } |
| 206 | |
| 207 | static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm) |
| 208 | { |
| 209 | return rx8581_set_datetime(to_i2c_client(dev), tm); |
| 210 | } |
| 211 | |
| 212 | static const struct rtc_class_ops rx8581_rtc_ops = { |
| 213 | .read_time = rx8581_rtc_read_time, |
| 214 | .set_time = rx8581_rtc_set_time, |
| 215 | }; |
| 216 | |
| 217 | static int __devinit rx8581_probe(struct i2c_client *client, |
| 218 | const struct i2c_device_id *id) |
| 219 | { |
| 220 | struct rtc_device *rtc; |
| 221 | |
| 222 | dev_dbg(&client->dev, "%s\n", __func__); |
| 223 | |
| 224 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
| 225 | return -ENODEV; |
| 226 | |
| 227 | dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); |
| 228 | |
| 229 | rtc = rtc_device_register(rx8581_driver.driver.name, |
| 230 | &client->dev, &rx8581_rtc_ops, THIS_MODULE); |
| 231 | |
| 232 | if (IS_ERR(rtc)) |
| 233 | return PTR_ERR(rtc); |
| 234 | |
| 235 | i2c_set_clientdata(client, rtc); |
| 236 | |
| 237 | return 0; |
| 238 | } |
| 239 | |
| 240 | static int __devexit rx8581_remove(struct i2c_client *client) |
| 241 | { |
| 242 | struct rtc_device *rtc = i2c_get_clientdata(client); |
| 243 | |
| 244 | rtc_device_unregister(rtc); |
| 245 | |
| 246 | return 0; |
| 247 | } |
| 248 | |
| 249 | static const struct i2c_device_id rx8581_id[] = { |
| 250 | { "rx8581", 0 }, |
| 251 | { } |
| 252 | }; |
| 253 | MODULE_DEVICE_TABLE(i2c, rx8581_id); |
| 254 | |
| 255 | static struct i2c_driver rx8581_driver = { |
| 256 | .driver = { |
| 257 | .name = "rtc-rx8581", |
| 258 | .owner = THIS_MODULE, |
| 259 | }, |
| 260 | .probe = rx8581_probe, |
| 261 | .remove = __devexit_p(rx8581_remove), |
| 262 | .id_table = rx8581_id, |
| 263 | }; |
| 264 | |
| 265 | static int __init rx8581_init(void) |
| 266 | { |
| 267 | return i2c_add_driver(&rx8581_driver); |
| 268 | } |
| 269 | |
| 270 | static void __exit rx8581_exit(void) |
| 271 | { |
| 272 | i2c_del_driver(&rx8581_driver); |
| 273 | } |
| 274 | |
| 275 | MODULE_AUTHOR("Martyn Welch <martyn.welch@gefanuc.com>"); |
| 276 | MODULE_DESCRIPTION("Epson RX-8581 RTC driver"); |
| 277 | MODULE_LICENSE("GPL"); |
| 278 | MODULE_VERSION(DRV_VERSION); |
| 279 | |
| 280 | module_init(rx8581_init); |
| 281 | module_exit(rx8581_exit); |