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 #include <linux/module.h> 19 #include <linux/err.h> 20 #include <linux/of.h> 21 #include <linux/of_device.h> 22 23 /* ISL register offsets */ 24 #define ISL12022_REG_SC 0x00 25 #define ISL12022_REG_MN 0x01 26 #define ISL12022_REG_HR 0x02 27 #define ISL12022_REG_DT 0x03 28 #define ISL12022_REG_MO 0x04 29 #define ISL12022_REG_YR 0x05 30 #define ISL12022_REG_DW 0x06 31 32 #define ISL12022_REG_SR 0x07 33 #define ISL12022_REG_INT 0x08 34 35 /* ISL register bits */ 36 #define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */ 37 38 #define ISL12022_SR_LBAT85 (1 << 2) 39 #define ISL12022_SR_LBAT75 (1 << 1) 40 41 #define ISL12022_INT_WRTC (1 << 6) 42 43 44 static struct i2c_driver isl12022_driver; 45 46 struct isl12022 { 47 struct rtc_device *rtc; 48 49 bool write_enabled; /* true if write enable is set */ 50 }; 51 52 53 static int isl12022_read_regs(struct i2c_client *client, uint8_t reg, 54 uint8_t *data, size_t n) 55 { 56 struct i2c_msg msgs[] = { 57 { 58 .addr = client->addr, 59 .flags = 0, 60 .len = 1, 61 .buf = data 62 }, /* setup read ptr */ 63 { 64 .addr = client->addr, 65 .flags = I2C_M_RD, 66 .len = n, 67 .buf = data 68 } 69 }; 70 71 int ret; 72 73 data[0] = reg; 74 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 75 if (ret != ARRAY_SIZE(msgs)) { 76 dev_err(&client->dev, "%s: read error, ret=%d\n", 77 __func__, ret); 78 return -EIO; 79 } 80 81 return 0; 82 } 83 84 85 static int isl12022_write_reg(struct i2c_client *client, 86 uint8_t reg, uint8_t val) 87 { 88 uint8_t data[2] = { reg, val }; 89 int err; 90 91 err = i2c_master_send(client, data, sizeof(data)); 92 if (err != sizeof(data)) { 93 dev_err(&client->dev, 94 "%s: err=%d addr=%02x, data=%02x\n", 95 __func__, err, data[0], data[1]); 96 return -EIO; 97 } 98 99 return 0; 100 } 101 102 103 /* 104 * In the routines that deal directly with the isl12022 hardware, we use 105 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 106 */ 107 static int isl12022_get_datetime(struct i2c_client *client, struct rtc_time *tm) 108 { 109 uint8_t buf[ISL12022_REG_INT + 1]; 110 int ret; 111 112 ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf)); 113 if (ret) 114 return ret; 115 116 if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) { 117 dev_warn(&client->dev, 118 "voltage dropped below %u%%, " 119 "date and time is not reliable.\n", 120 buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75); 121 } 122 123 dev_dbg(&client->dev, 124 "%s: raw data is sec=%02x, min=%02x, hr=%02x, " 125 "mday=%02x, mon=%02x, year=%02x, wday=%02x, " 126 "sr=%02x, int=%02x", 127 __func__, 128 buf[ISL12022_REG_SC], 129 buf[ISL12022_REG_MN], 130 buf[ISL12022_REG_HR], 131 buf[ISL12022_REG_DT], 132 buf[ISL12022_REG_MO], 133 buf[ISL12022_REG_YR], 134 buf[ISL12022_REG_DW], 135 buf[ISL12022_REG_SR], 136 buf[ISL12022_REG_INT]); 137 138 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F); 139 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F); 140 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F); 141 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F); 142 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07; 143 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1; 144 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100; 145 146 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 147 "mday=%d, mon=%d, year=%d, wday=%d\n", 148 __func__, 149 tm->tm_sec, tm->tm_min, tm->tm_hour, 150 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 151 152 return rtc_valid_tm(tm); 153 } 154 155 static int isl12022_set_datetime(struct i2c_client *client, struct rtc_time *tm) 156 { 157 struct isl12022 *isl12022 = i2c_get_clientdata(client); 158 size_t i; 159 int ret; 160 uint8_t buf[ISL12022_REG_DW + 1]; 161 162 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " 163 "mday=%d, mon=%d, year=%d, wday=%d\n", 164 __func__, 165 tm->tm_sec, tm->tm_min, tm->tm_hour, 166 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 167 168 if (!isl12022->write_enabled) { 169 170 ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1); 171 if (ret) 172 return ret; 173 174 /* Check if WRTC (write rtc enable) is set factory default is 175 * 0 (not set) */ 176 if (!(buf[0] & ISL12022_INT_WRTC)) { 177 dev_info(&client->dev, 178 "init write enable and 24 hour format\n"); 179 180 /* Set the write enable bit. */ 181 ret = isl12022_write_reg(client, 182 ISL12022_REG_INT, 183 buf[0] | ISL12022_INT_WRTC); 184 if (ret) 185 return ret; 186 187 /* Write to any RTC register to start RTC, we use the 188 * HR register, setting the MIL bit to use the 24 hour 189 * format. */ 190 ret = isl12022_read_regs(client, ISL12022_REG_HR, 191 buf, 1); 192 if (ret) 193 return ret; 194 195 ret = isl12022_write_reg(client, 196 ISL12022_REG_HR, 197 buf[0] | ISL12022_HR_MIL); 198 if (ret) 199 return ret; 200 } 201 202 isl12022->write_enabled = 1; 203 } 204 205 /* hours, minutes and seconds */ 206 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec); 207 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min); 208 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL; 209 210 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday); 211 212 /* month, 1 - 12 */ 213 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1); 214 215 /* year and century */ 216 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100); 217 218 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07; 219 220 /* write register's data */ 221 for (i = 0; i < ARRAY_SIZE(buf); i++) { 222 ret = isl12022_write_reg(client, ISL12022_REG_SC + i, 223 buf[ISL12022_REG_SC + i]); 224 if (ret) 225 return -EIO; 226 } 227 228 return 0; 229 } 230 231 static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm) 232 { 233 return isl12022_get_datetime(to_i2c_client(dev), tm); 234 } 235 236 static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm) 237 { 238 return isl12022_set_datetime(to_i2c_client(dev), tm); 239 } 240 241 static const struct rtc_class_ops isl12022_rtc_ops = { 242 .read_time = isl12022_rtc_read_time, 243 .set_time = isl12022_rtc_set_time, 244 }; 245 246 static int isl12022_probe(struct i2c_client *client, 247 const struct i2c_device_id *id) 248 { 249 struct isl12022 *isl12022; 250 251 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 252 return -ENODEV; 253 254 isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022), 255 GFP_KERNEL); 256 if (!isl12022) 257 return -ENOMEM; 258 259 i2c_set_clientdata(client, isl12022); 260 261 isl12022->rtc = devm_rtc_device_register(&client->dev, 262 isl12022_driver.driver.name, 263 &isl12022_rtc_ops, THIS_MODULE); 264 return PTR_ERR_OR_ZERO(isl12022->rtc); 265 } 266 267 #ifdef CONFIG_OF 268 static const struct of_device_id isl12022_dt_match[] = { 269 { .compatible = "isl,isl12022" }, /* for backward compat., don't use */ 270 { .compatible = "isil,isl12022" }, 271 { }, 272 }; 273 MODULE_DEVICE_TABLE(of, isl12022_dt_match); 274 #endif 275 276 static const struct i2c_device_id isl12022_id[] = { 277 { "isl12022", 0 }, 278 { } 279 }; 280 MODULE_DEVICE_TABLE(i2c, isl12022_id); 281 282 static struct i2c_driver isl12022_driver = { 283 .driver = { 284 .name = "rtc-isl12022", 285 #ifdef CONFIG_OF 286 .of_match_table = of_match_ptr(isl12022_dt_match), 287 #endif 288 }, 289 .probe = isl12022_probe, 290 .id_table = isl12022_id, 291 }; 292 293 module_i2c_driver(isl12022_driver); 294 295 MODULE_AUTHOR("roman.fietze@telemotive.de"); 296 MODULE_DESCRIPTION("ISL 12022 RTC driver"); 297 MODULE_LICENSE("GPL"); 298