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/of.h> 19 #include <linux/of_device.h> 20 #include <linux/regmap.h> 21 #include <linux/rtc.h> 22 #include <linux/log2.h> 23 24 #define RX8581_REG_SC 0x00 /* Second in BCD */ 25 #define RX8581_REG_MN 0x01 /* Minute in BCD */ 26 #define RX8581_REG_HR 0x02 /* Hour in BCD */ 27 #define RX8581_REG_DW 0x03 /* Day of Week */ 28 #define RX8581_REG_DM 0x04 /* Day of Month in BCD */ 29 #define RX8581_REG_MO 0x05 /* Month in BCD */ 30 #define RX8581_REG_YR 0x06 /* Year in BCD */ 31 #define RX8581_REG_RAM 0x07 /* RAM */ 32 #define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/ 33 #define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */ 34 #define RX8581_REG_ADM 0x0A 35 #define RX8581_REG_ADW 0x0A 36 #define RX8581_REG_TMR0 0x0B 37 #define RX8581_REG_TMR1 0x0C 38 #define RX8581_REG_EXT 0x0D /* Extension Register */ 39 #define RX8581_REG_FLAG 0x0E /* Flag Register */ 40 #define RX8581_REG_CTRL 0x0F /* Control Register */ 41 42 43 /* Flag Register bit definitions */ 44 #define RX8581_FLAG_UF 0x20 /* Update */ 45 #define RX8581_FLAG_TF 0x10 /* Timer */ 46 #define RX8581_FLAG_AF 0x08 /* Alarm */ 47 #define RX8581_FLAG_VLF 0x02 /* Voltage Low */ 48 49 /* Control Register bit definitions */ 50 #define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */ 51 #define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */ 52 #define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */ 53 #define RX8581_CTRL_STOP 0x02 /* STOP bit */ 54 #define RX8581_CTRL_RESET 0x01 /* RESET bit */ 55 56 #define RX8571_USER_RAM 0x10 57 #define RX8571_NVRAM_SIZE 0x10 58 59 struct rx8581 { 60 struct regmap *regmap; 61 struct rtc_device *rtc; 62 }; 63 64 struct rx85x1_config { 65 struct regmap_config regmap; 66 unsigned int num_nvram; 67 }; 68 69 /* 70 * In the routines that deal directly with the rx8581 hardware, we use 71 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 72 */ 73 static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm) 74 { 75 struct i2c_client *client = to_i2c_client(dev); 76 unsigned char date[7]; 77 unsigned int data; 78 int err; 79 struct rx8581 *rx8581 = i2c_get_clientdata(client); 80 81 /* First we ensure that the "update flag" is not set, we read the 82 * time and date then re-read the "update flag". If the update flag 83 * has been set, we know that the time has changed during the read so 84 * we repeat the whole process again. 85 */ 86 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data); 87 if (err < 0) 88 return err; 89 90 if (data & RX8581_FLAG_VLF) { 91 dev_warn(dev, 92 "low voltage detected, date/time is not reliable.\n"); 93 return -EINVAL; 94 } 95 96 do { 97 /* If update flag set, clear it */ 98 if (data & RX8581_FLAG_UF) { 99 err = regmap_write(rx8581->regmap, RX8581_REG_FLAG, 100 data & ~RX8581_FLAG_UF); 101 if (err < 0) 102 return err; 103 } 104 105 /* Now read time and date */ 106 err = regmap_bulk_read(rx8581->regmap, RX8581_REG_SC, date, 107 sizeof(date)); 108 if (err < 0) 109 return err; 110 111 /* Check flag register */ 112 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data); 113 if (err < 0) 114 return err; 115 } while (data & RX8581_FLAG_UF); 116 117 dev_dbg(dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, " 118 "wday=%02x, mday=%02x, mon=%02x, year=%02x\n", 119 __func__, 120 date[0], date[1], date[2], date[3], date[4], date[5], date[6]); 121 122 tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F); 123 tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F); 124 tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */ 125 tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F); 126 tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F); 127 tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 128 tm->tm_year = bcd2bin(date[RX8581_REG_YR]) + 100; 129 130 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 131 "mday=%d, mon=%d, year=%d, wday=%d\n", 132 __func__, 133 tm->tm_sec, tm->tm_min, tm->tm_hour, 134 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 135 136 return 0; 137 } 138 139 static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm) 140 { 141 struct i2c_client *client = to_i2c_client(dev); 142 int err; 143 unsigned char buf[7]; 144 struct rx8581 *rx8581 = i2c_get_clientdata(client); 145 146 dev_dbg(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 /* hours, minutes and seconds */ 153 buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec); 154 buf[RX8581_REG_MN] = bin2bcd(tm->tm_min); 155 buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour); 156 157 buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday); 158 159 /* month, 1 - 12 */ 160 buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1); 161 162 /* year and century */ 163 buf[RX8581_REG_YR] = bin2bcd(tm->tm_year - 100); 164 buf[RX8581_REG_DW] = (0x1 << tm->tm_wday); 165 166 /* Stop the clock */ 167 err = regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL, 168 RX8581_CTRL_STOP, RX8581_CTRL_STOP); 169 if (err < 0) 170 return err; 171 172 /* write register's data */ 173 err = regmap_bulk_write(rx8581->regmap, RX8581_REG_SC, 174 buf, sizeof(buf)); 175 if (err < 0) 176 return err; 177 178 /* get VLF and clear it */ 179 err = regmap_update_bits(rx8581->regmap, RX8581_REG_FLAG, 180 RX8581_FLAG_VLF, 0); 181 if (err < 0) 182 return err; 183 184 /* Restart the clock */ 185 return regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL, 186 RX8581_CTRL_STOP, 0); 187 } 188 189 static const struct rtc_class_ops rx8581_rtc_ops = { 190 .read_time = rx8581_rtc_read_time, 191 .set_time = rx8581_rtc_set_time, 192 }; 193 194 static int rx8571_nvram_read(void *priv, unsigned int offset, void *val, 195 size_t bytes) 196 { 197 struct rx8581 *rx8581 = priv; 198 199 return regmap_bulk_read(rx8581->regmap, RX8571_USER_RAM + offset, 200 val, bytes); 201 } 202 203 static int rx8571_nvram_write(void *priv, unsigned int offset, void *val, 204 size_t bytes) 205 { 206 struct rx8581 *rx8581 = priv; 207 208 return regmap_bulk_write(rx8581->regmap, RX8571_USER_RAM + offset, 209 val, bytes); 210 } 211 212 static int rx85x1_nvram_read(void *priv, unsigned int offset, void *val, 213 size_t bytes) 214 { 215 struct rx8581 *rx8581 = priv; 216 unsigned int tmp_val; 217 int ret; 218 219 ret = regmap_read(rx8581->regmap, RX8581_REG_RAM, &tmp_val); 220 (*(unsigned char *)val) = (unsigned char) tmp_val; 221 222 return ret; 223 } 224 225 static int rx85x1_nvram_write(void *priv, unsigned int offset, void *val, 226 size_t bytes) 227 { 228 struct rx8581 *rx8581 = priv; 229 unsigned char tmp_val; 230 231 tmp_val = *((unsigned char *)val); 232 return regmap_write(rx8581->regmap, RX8581_REG_RAM, 233 (unsigned int)tmp_val); 234 } 235 236 static const struct rx85x1_config rx8581_config = { 237 .regmap = { 238 .reg_bits = 8, 239 .val_bits = 8, 240 .max_register = 0xf, 241 }, 242 .num_nvram = 1 243 }; 244 245 static const struct rx85x1_config rx8571_config = { 246 .regmap = { 247 .reg_bits = 8, 248 .val_bits = 8, 249 .max_register = 0x1f, 250 }, 251 .num_nvram = 2 252 }; 253 254 static int rx8581_probe(struct i2c_client *client, 255 const struct i2c_device_id *id) 256 { 257 struct rx8581 *rx8581; 258 const struct rx85x1_config *config = &rx8581_config; 259 const void *data = of_device_get_match_data(&client->dev); 260 static struct nvmem_config nvmem_cfg[] = { 261 { 262 .name = "rx85x1-", 263 .word_size = 1, 264 .stride = 1, 265 .size = 1, 266 .reg_read = rx85x1_nvram_read, 267 .reg_write = rx85x1_nvram_write, 268 }, { 269 .name = "rx8571-", 270 .word_size = 1, 271 .stride = 1, 272 .size = RX8571_NVRAM_SIZE, 273 .reg_read = rx8571_nvram_read, 274 .reg_write = rx8571_nvram_write, 275 }, 276 }; 277 int ret, i; 278 279 dev_dbg(&client->dev, "%s\n", __func__); 280 281 if (data) 282 config = data; 283 284 rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL); 285 if (!rx8581) 286 return -ENOMEM; 287 288 i2c_set_clientdata(client, rx8581); 289 290 rx8581->regmap = devm_regmap_init_i2c(client, &config->regmap); 291 if (IS_ERR(rx8581->regmap)) 292 return PTR_ERR(rx8581->regmap); 293 294 rx8581->rtc = devm_rtc_allocate_device(&client->dev); 295 if (IS_ERR(rx8581->rtc)) 296 return PTR_ERR(rx8581->rtc); 297 298 rx8581->rtc->ops = &rx8581_rtc_ops; 299 rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; 300 rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099; 301 rx8581->rtc->start_secs = 0; 302 rx8581->rtc->set_start_time = true; 303 304 ret = rtc_register_device(rx8581->rtc); 305 306 for (i = 0; i < config->num_nvram; i++) { 307 nvmem_cfg[i].priv = rx8581; 308 rtc_nvmem_register(rx8581->rtc, &nvmem_cfg[i]); 309 } 310 311 return ret; 312 } 313 314 static const struct i2c_device_id rx8581_id[] = { 315 { "rx8581", 0 }, 316 { } 317 }; 318 MODULE_DEVICE_TABLE(i2c, rx8581_id); 319 320 static const struct of_device_id rx8581_of_match[] = { 321 { .compatible = "epson,rx8571", .data = &rx8571_config }, 322 { .compatible = "epson,rx8581", .data = &rx8581_config }, 323 { /* sentinel */ } 324 }; 325 MODULE_DEVICE_TABLE(of, rx8581_of_match); 326 327 static struct i2c_driver rx8581_driver = { 328 .driver = { 329 .name = "rtc-rx8581", 330 .of_match_table = of_match_ptr(rx8581_of_match), 331 }, 332 .probe = rx8581_probe, 333 .id_table = rx8581_id, 334 }; 335 336 module_i2c_driver(rx8581_driver); 337 338 MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>"); 339 MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver"); 340 MODULE_LICENSE("GPL"); 341