1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * An I2C driver for the Epson RX8581 RTC 4 * 5 * Author: Martyn Welch <martyn.welch@ge.com> 6 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc. 7 * 8 * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC) 9 * Copyright 2005-06 Tower Technologies 10 */ 11 12 #include <linux/module.h> 13 #include <linux/i2c.h> 14 #include <linux/bcd.h> 15 #include <linux/of.h> 16 #include <linux/of_device.h> 17 #include <linux/regmap.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 #define RX8571_USER_RAM 0x10 54 #define RX8571_NVRAM_SIZE 0x10 55 56 struct rx8581 { 57 struct regmap *regmap; 58 struct rtc_device *rtc; 59 }; 60 61 struct rx85x1_config { 62 struct regmap_config regmap; 63 unsigned int num_nvram; 64 }; 65 66 /* 67 * In the routines that deal directly with the rx8581 hardware, we use 68 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 69 */ 70 static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm) 71 { 72 struct i2c_client *client = to_i2c_client(dev); 73 unsigned char date[7]; 74 unsigned int data; 75 int err; 76 struct rx8581 *rx8581 = i2c_get_clientdata(client); 77 78 /* First we ensure that the "update flag" is not set, we read the 79 * time and date then re-read the "update flag". If the update flag 80 * has been set, we know that the time has changed during the read so 81 * we repeat the whole process again. 82 */ 83 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data); 84 if (err < 0) 85 return err; 86 87 if (data & RX8581_FLAG_VLF) { 88 dev_warn(dev, 89 "low voltage detected, date/time is not reliable.\n"); 90 return -EINVAL; 91 } 92 93 do { 94 /* If update flag set, clear it */ 95 if (data & RX8581_FLAG_UF) { 96 err = regmap_write(rx8581->regmap, RX8581_REG_FLAG, 97 data & ~RX8581_FLAG_UF); 98 if (err < 0) 99 return err; 100 } 101 102 /* Now read time and date */ 103 err = regmap_bulk_read(rx8581->regmap, RX8581_REG_SC, date, 104 sizeof(date)); 105 if (err < 0) 106 return err; 107 108 /* Check flag register */ 109 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data); 110 if (err < 0) 111 return err; 112 } while (data & RX8581_FLAG_UF); 113 114 dev_dbg(dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, " 115 "wday=%02x, mday=%02x, mon=%02x, year=%02x\n", 116 __func__, 117 date[0], date[1], date[2], date[3], date[4], date[5], date[6]); 118 119 tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F); 120 tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F); 121 tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */ 122 tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F); 123 tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F); 124 tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 125 tm->tm_year = bcd2bin(date[RX8581_REG_YR]) + 100; 126 127 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 128 "mday=%d, mon=%d, year=%d, wday=%d\n", 129 __func__, 130 tm->tm_sec, tm->tm_min, tm->tm_hour, 131 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 132 133 return 0; 134 } 135 136 static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm) 137 { 138 struct i2c_client *client = to_i2c_client(dev); 139 int err; 140 unsigned char buf[7]; 141 struct rx8581 *rx8581 = i2c_get_clientdata(client); 142 143 dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, " 144 "mday=%d, mon=%d, year=%d, wday=%d\n", 145 __func__, 146 tm->tm_sec, tm->tm_min, tm->tm_hour, 147 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 148 149 /* hours, minutes and seconds */ 150 buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec); 151 buf[RX8581_REG_MN] = bin2bcd(tm->tm_min); 152 buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour); 153 154 buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday); 155 156 /* month, 1 - 12 */ 157 buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1); 158 159 /* year and century */ 160 buf[RX8581_REG_YR] = bin2bcd(tm->tm_year - 100); 161 buf[RX8581_REG_DW] = (0x1 << tm->tm_wday); 162 163 /* Stop the clock */ 164 err = regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL, 165 RX8581_CTRL_STOP, RX8581_CTRL_STOP); 166 if (err < 0) 167 return err; 168 169 /* write register's data */ 170 err = regmap_bulk_write(rx8581->regmap, RX8581_REG_SC, 171 buf, sizeof(buf)); 172 if (err < 0) 173 return err; 174 175 /* get VLF and clear it */ 176 err = regmap_update_bits(rx8581->regmap, RX8581_REG_FLAG, 177 RX8581_FLAG_VLF, 0); 178 if (err < 0) 179 return err; 180 181 /* Restart the clock */ 182 return regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL, 183 RX8581_CTRL_STOP, 0); 184 } 185 186 static const struct rtc_class_ops rx8581_rtc_ops = { 187 .read_time = rx8581_rtc_read_time, 188 .set_time = rx8581_rtc_set_time, 189 }; 190 191 static int rx8571_nvram_read(void *priv, unsigned int offset, void *val, 192 size_t bytes) 193 { 194 struct rx8581 *rx8581 = priv; 195 196 return regmap_bulk_read(rx8581->regmap, RX8571_USER_RAM + offset, 197 val, bytes); 198 } 199 200 static int rx8571_nvram_write(void *priv, unsigned int offset, void *val, 201 size_t bytes) 202 { 203 struct rx8581 *rx8581 = priv; 204 205 return regmap_bulk_write(rx8581->regmap, RX8571_USER_RAM + offset, 206 val, bytes); 207 } 208 209 static int rx85x1_nvram_read(void *priv, unsigned int offset, void *val, 210 size_t bytes) 211 { 212 struct rx8581 *rx8581 = priv; 213 unsigned int tmp_val; 214 int ret; 215 216 ret = regmap_read(rx8581->regmap, RX8581_REG_RAM, &tmp_val); 217 (*(unsigned char *)val) = (unsigned char) tmp_val; 218 219 return ret; 220 } 221 222 static int rx85x1_nvram_write(void *priv, unsigned int offset, void *val, 223 size_t bytes) 224 { 225 struct rx8581 *rx8581 = priv; 226 unsigned char tmp_val; 227 228 tmp_val = *((unsigned char *)val); 229 return regmap_write(rx8581->regmap, RX8581_REG_RAM, 230 (unsigned int)tmp_val); 231 } 232 233 static const struct rx85x1_config rx8581_config = { 234 .regmap = { 235 .reg_bits = 8, 236 .val_bits = 8, 237 .max_register = 0xf, 238 }, 239 .num_nvram = 1 240 }; 241 242 static const struct rx85x1_config rx8571_config = { 243 .regmap = { 244 .reg_bits = 8, 245 .val_bits = 8, 246 .max_register = 0x1f, 247 }, 248 .num_nvram = 2 249 }; 250 251 static int rx8581_probe(struct i2c_client *client, 252 const struct i2c_device_id *id) 253 { 254 struct rx8581 *rx8581; 255 const struct rx85x1_config *config = &rx8581_config; 256 const void *data = of_device_get_match_data(&client->dev); 257 static struct nvmem_config nvmem_cfg[] = { 258 { 259 .name = "rx85x1-", 260 .word_size = 1, 261 .stride = 1, 262 .size = 1, 263 .reg_read = rx85x1_nvram_read, 264 .reg_write = rx85x1_nvram_write, 265 }, { 266 .name = "rx8571-", 267 .word_size = 1, 268 .stride = 1, 269 .size = RX8571_NVRAM_SIZE, 270 .reg_read = rx8571_nvram_read, 271 .reg_write = rx8571_nvram_write, 272 }, 273 }; 274 int ret, i; 275 276 dev_dbg(&client->dev, "%s\n", __func__); 277 278 if (data) 279 config = data; 280 281 rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL); 282 if (!rx8581) 283 return -ENOMEM; 284 285 i2c_set_clientdata(client, rx8581); 286 287 rx8581->regmap = devm_regmap_init_i2c(client, &config->regmap); 288 if (IS_ERR(rx8581->regmap)) 289 return PTR_ERR(rx8581->regmap); 290 291 rx8581->rtc = devm_rtc_allocate_device(&client->dev); 292 if (IS_ERR(rx8581->rtc)) 293 return PTR_ERR(rx8581->rtc); 294 295 rx8581->rtc->ops = &rx8581_rtc_ops; 296 rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; 297 rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099; 298 rx8581->rtc->start_secs = 0; 299 rx8581->rtc->set_start_time = true; 300 301 ret = devm_rtc_register_device(rx8581->rtc); 302 303 for (i = 0; i < config->num_nvram; i++) { 304 nvmem_cfg[i].priv = rx8581; 305 devm_rtc_nvmem_register(rx8581->rtc, &nvmem_cfg[i]); 306 } 307 308 return ret; 309 } 310 311 static const struct i2c_device_id rx8581_id[] = { 312 { "rx8581", 0 }, 313 { } 314 }; 315 MODULE_DEVICE_TABLE(i2c, rx8581_id); 316 317 static const __maybe_unused struct of_device_id rx8581_of_match[] = { 318 { .compatible = "epson,rx8571", .data = &rx8571_config }, 319 { .compatible = "epson,rx8581", .data = &rx8581_config }, 320 { /* sentinel */ } 321 }; 322 MODULE_DEVICE_TABLE(of, rx8581_of_match); 323 324 static struct i2c_driver rx8581_driver = { 325 .driver = { 326 .name = "rtc-rx8581", 327 .of_match_table = of_match_ptr(rx8581_of_match), 328 }, 329 .probe = rx8581_probe, 330 .id_table = rx8581_id, 331 }; 332 333 module_i2c_driver(rx8581_driver); 334 335 MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>"); 336 MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver"); 337 MODULE_LICENSE("GPL"); 338