1 /* 2 * An I2C driver for the Intersil ISL 12022 3 * 4 * Author: Roman Fietze <roman.fietze@telemotive.de> 5 * 6 * Based on the Philips PCF8563 RTC 7 * by Alessandro Zummo <a.zummo@towertech.it>. 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License version 11 * 2 as published by the Free Software Foundation. 12 */ 13 14 #include <linux/i2c.h> 15 #include <linux/bcd.h> 16 #include <linux/rtc.h> 17 #include <linux/slab.h> 18 19 #define DRV_VERSION "0.1" 20 21 /* ISL register offsets */ 22 #define ISL12022_REG_SC 0x00 23 #define ISL12022_REG_MN 0x01 24 #define ISL12022_REG_HR 0x02 25 #define ISL12022_REG_DT 0x03 26 #define ISL12022_REG_MO 0x04 27 #define ISL12022_REG_YR 0x05 28 #define ISL12022_REG_DW 0x06 29 30 #define ISL12022_REG_SR 0x07 31 #define ISL12022_REG_INT 0x08 32 33 /* ISL register bits */ 34 #define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */ 35 36 #define ISL12022_SR_LBAT85 (1 << 2) 37 #define ISL12022_SR_LBAT75 (1 << 1) 38 39 #define ISL12022_INT_WRTC (1 << 6) 40 41 42 static struct i2c_driver isl12022_driver; 43 44 struct isl12022 { 45 struct rtc_device *rtc; 46 47 bool write_enabled; /* true if write enable is set */ 48 }; 49 50 51 static int isl12022_read_regs(struct i2c_client *client, uint8_t reg, 52 uint8_t *data, size_t n) 53 { 54 struct i2c_msg msgs[] = { 55 { 56 .addr = client->addr, 57 .flags = 0, 58 .len = 1, 59 .buf = data 60 }, /* setup read ptr */ 61 { 62 .addr = client->addr, 63 .flags = I2C_M_RD, 64 .len = n, 65 .buf = data 66 } 67 }; 68 69 int ret; 70 71 data[0] = reg; 72 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 73 if (ret != ARRAY_SIZE(msgs)) { 74 dev_err(&client->dev, "%s: read error, ret=%d\n", 75 __func__, ret); 76 return -EIO; 77 } 78 79 return 0; 80 } 81 82 83 static int isl12022_write_reg(struct i2c_client *client, 84 uint8_t reg, uint8_t val) 85 { 86 uint8_t data[2] = { reg, val }; 87 int err; 88 89 err = i2c_master_send(client, data, sizeof(data)); 90 if (err != sizeof(data)) { 91 dev_err(&client->dev, 92 "%s: err=%d addr=%02x, data=%02x\n", 93 __func__, err, data[0], data[1]); 94 return -EIO; 95 } 96 97 return 0; 98 } 99 100 101 /* 102 * In the routines that deal directly with the isl12022 hardware, we use 103 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 104 */ 105 static int isl12022_get_datetime(struct i2c_client *client, struct rtc_time *tm) 106 { 107 uint8_t buf[ISL12022_REG_INT + 1]; 108 int ret; 109 110 ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf)); 111 if (ret) 112 return ret; 113 114 if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) { 115 dev_warn(&client->dev, 116 "voltage dropped below %u%%, " 117 "date and time is not reliable.\n", 118 buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75); 119 } 120 121 dev_dbg(&client->dev, 122 "%s: raw data is sec=%02x, min=%02x, hr=%02x, " 123 "mday=%02x, mon=%02x, year=%02x, wday=%02x, " 124 "sr=%02x, int=%02x", 125 __func__, 126 buf[ISL12022_REG_SC], 127 buf[ISL12022_REG_MN], 128 buf[ISL12022_REG_HR], 129 buf[ISL12022_REG_DT], 130 buf[ISL12022_REG_MO], 131 buf[ISL12022_REG_YR], 132 buf[ISL12022_REG_DW], 133 buf[ISL12022_REG_SR], 134 buf[ISL12022_REG_INT]); 135 136 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F); 137 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F); 138 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F); 139 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F); 140 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07; 141 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1; 142 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100; 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 /* The clock can give out invalid datetime, but we cannot return 151 * -EINVAL otherwise hwclock will refuse to set the time on bootup. */ 152 if (rtc_valid_tm(tm) < 0) 153 dev_err(&client->dev, "retrieved date and time is invalid.\n"); 154 155 return 0; 156 } 157 158 static int isl12022_set_datetime(struct i2c_client *client, struct rtc_time *tm) 159 { 160 struct isl12022 *isl12022 = i2c_get_clientdata(client); 161 size_t i; 162 int ret; 163 uint8_t buf[ISL12022_REG_DW + 1]; 164 165 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 166 "mday=%d, mon=%d, year=%d, wday=%d\n", 167 __func__, 168 tm->tm_sec, tm->tm_min, tm->tm_hour, 169 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 170 171 if (!isl12022->write_enabled) { 172 173 ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1); 174 if (ret) 175 return ret; 176 177 /* Check if WRTC (write rtc enable) is set factory default is 178 * 0 (not set) */ 179 if (!(buf[0] & ISL12022_INT_WRTC)) { 180 dev_info(&client->dev, 181 "init write enable and 24 hour format\n"); 182 183 /* Set the write enable bit. */ 184 ret = isl12022_write_reg(client, 185 ISL12022_REG_INT, 186 buf[0] | ISL12022_INT_WRTC); 187 if (ret) 188 return ret; 189 190 /* Write to any RTC register to start RTC, we use the 191 * HR register, setting the MIL bit to use the 24 hour 192 * format. */ 193 ret = isl12022_read_regs(client, ISL12022_REG_HR, 194 buf, 1); 195 if (ret) 196 return ret; 197 198 ret = isl12022_write_reg(client, 199 ISL12022_REG_HR, 200 buf[0] | ISL12022_HR_MIL); 201 if (ret) 202 return ret; 203 } 204 205 isl12022->write_enabled = 1; 206 } 207 208 /* hours, minutes and seconds */ 209 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec); 210 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min); 211 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL; 212 213 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday); 214 215 /* month, 1 - 12 */ 216 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1); 217 218 /* year and century */ 219 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100); 220 221 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07; 222 223 /* write register's data */ 224 for (i = 0; i < ARRAY_SIZE(buf); i++) { 225 ret = isl12022_write_reg(client, ISL12022_REG_SC + i, 226 buf[ISL12022_REG_SC + i]); 227 if (ret) 228 return -EIO; 229 }; 230 231 return 0; 232 } 233 234 static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm) 235 { 236 return isl12022_get_datetime(to_i2c_client(dev), tm); 237 } 238 239 static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm) 240 { 241 return isl12022_set_datetime(to_i2c_client(dev), tm); 242 } 243 244 static const struct rtc_class_ops isl12022_rtc_ops = { 245 .read_time = isl12022_rtc_read_time, 246 .set_time = isl12022_rtc_set_time, 247 }; 248 249 static int isl12022_probe(struct i2c_client *client, 250 const struct i2c_device_id *id) 251 { 252 struct isl12022 *isl12022; 253 254 int ret = 0; 255 256 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 257 return -ENODEV; 258 259 isl12022 = kzalloc(sizeof(struct isl12022), GFP_KERNEL); 260 if (!isl12022) 261 return -ENOMEM; 262 263 dev_dbg(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 264 265 i2c_set_clientdata(client, isl12022); 266 267 isl12022->rtc = rtc_device_register(isl12022_driver.driver.name, 268 &client->dev, 269 &isl12022_rtc_ops, 270 THIS_MODULE); 271 272 if (IS_ERR(isl12022->rtc)) { 273 ret = PTR_ERR(isl12022->rtc); 274 goto exit_kfree; 275 } 276 277 return 0; 278 279 exit_kfree: 280 kfree(isl12022); 281 282 return ret; 283 } 284 285 static int isl12022_remove(struct i2c_client *client) 286 { 287 struct isl12022 *isl12022 = i2c_get_clientdata(client); 288 289 rtc_device_unregister(isl12022->rtc); 290 kfree(isl12022); 291 292 return 0; 293 } 294 295 static const struct i2c_device_id isl12022_id[] = { 296 { "isl12022", 0 }, 297 { "rtc8564", 0 }, 298 { } 299 }; 300 MODULE_DEVICE_TABLE(i2c, isl12022_id); 301 302 static struct i2c_driver isl12022_driver = { 303 .driver = { 304 .name = "rtc-isl12022", 305 }, 306 .probe = isl12022_probe, 307 .remove = isl12022_remove, 308 .id_table = isl12022_id, 309 }; 310 311 static int __init isl12022_init(void) 312 { 313 return i2c_add_driver(&isl12022_driver); 314 } 315 316 static void __exit isl12022_exit(void) 317 { 318 i2c_del_driver(&isl12022_driver); 319 } 320 321 module_init(isl12022_init); 322 module_exit(isl12022_exit); 323 324 MODULE_AUTHOR("roman.fietze@telemotive.de"); 325 MODULE_DESCRIPTION("ISL 12022 RTC driver"); 326 MODULE_LICENSE("GPL"); 327 MODULE_VERSION(DRV_VERSION); 328