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/regmap.h> 17 #include <linux/rtc.h> 18 #include <linux/log2.h> 19 20 #define RX8581_REG_SC 0x00 /* Second in BCD */ 21 #define RX8581_REG_MN 0x01 /* Minute in BCD */ 22 #define RX8581_REG_HR 0x02 /* Hour in BCD */ 23 #define RX8581_REG_DW 0x03 /* Day of Week */ 24 #define RX8581_REG_DM 0x04 /* Day of Month in BCD */ 25 #define RX8581_REG_MO 0x05 /* Month in BCD */ 26 #define RX8581_REG_YR 0x06 /* Year in BCD */ 27 #define RX8581_REG_RAM 0x07 /* RAM */ 28 #define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/ 29 #define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */ 30 #define RX8581_REG_ADM 0x0A 31 #define RX8581_REG_ADW 0x0A 32 #define RX8581_REG_TMR0 0x0B 33 #define RX8581_REG_TMR1 0x0C 34 #define RX8581_REG_EXT 0x0D /* Extension Register */ 35 #define RX8581_REG_FLAG 0x0E /* Flag Register */ 36 #define RX8581_REG_CTRL 0x0F /* Control Register */ 37 38 39 /* Flag Register bit definitions */ 40 #define RX8581_FLAG_UF 0x20 /* Update */ 41 #define RX8581_FLAG_TF 0x10 /* Timer */ 42 #define RX8581_FLAG_AF 0x08 /* Alarm */ 43 #define RX8581_FLAG_VLF 0x02 /* Voltage Low */ 44 45 /* Control Register bit definitions */ 46 #define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */ 47 #define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */ 48 #define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */ 49 #define RX8581_CTRL_STOP 0x02 /* STOP bit */ 50 #define RX8581_CTRL_RESET 0x01 /* RESET bit */ 51 52 #define RX8571_USER_RAM 0x10 53 #define RX8571_NVRAM_SIZE 0x10 54 55 struct rx8581 { 56 struct regmap *regmap; 57 struct rtc_device *rtc; 58 }; 59 60 struct rx85x1_config { 61 struct regmap_config regmap; 62 unsigned int num_nvram; 63 }; 64 65 /* 66 * In the routines that deal directly with the rx8581 hardware, we use 67 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. 68 */ 69 static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm) 70 { 71 struct i2c_client *client = to_i2c_client(dev); 72 unsigned char date[7]; 73 unsigned int data; 74 int err; 75 struct rx8581 *rx8581 = i2c_get_clientdata(client); 76 77 /* First we ensure that the "update flag" is not set, we read the 78 * time and date then re-read the "update flag". If the update flag 79 * has been set, we know that the time has changed during the read so 80 * we repeat the whole process again. 81 */ 82 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data); 83 if (err < 0) 84 return err; 85 86 if (data & RX8581_FLAG_VLF) { 87 dev_warn(dev, 88 "low voltage detected, date/time is not reliable.\n"); 89 return -EINVAL; 90 } 91 92 do { 93 /* If update flag set, clear it */ 94 if (data & RX8581_FLAG_UF) { 95 err = regmap_write(rx8581->regmap, RX8581_REG_FLAG, 96 data & ~RX8581_FLAG_UF); 97 if (err < 0) 98 return err; 99 } 100 101 /* Now read time and date */ 102 err = regmap_bulk_read(rx8581->regmap, RX8581_REG_SC, date, 103 sizeof(date)); 104 if (err < 0) 105 return err; 106 107 /* Check flag register */ 108 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data); 109 if (err < 0) 110 return err; 111 } while (data & RX8581_FLAG_UF); 112 113 dev_dbg(dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, " 114 "wday=%02x, mday=%02x, mon=%02x, year=%02x\n", 115 __func__, 116 date[0], date[1], date[2], date[3], date[4], date[5], date[6]); 117 118 tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F); 119 tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F); 120 tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */ 121 tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F); 122 tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F); 123 tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ 124 tm->tm_year = bcd2bin(date[RX8581_REG_YR]) + 100; 125 126 dev_dbg(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 return 0; 133 } 134 135 static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm) 136 { 137 struct i2c_client *client = to_i2c_client(dev); 138 int err; 139 unsigned char buf[7]; 140 struct rx8581 *rx8581 = i2c_get_clientdata(client); 141 142 dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, " 143 "mday=%d, mon=%d, year=%d, wday=%d\n", 144 __func__, 145 tm->tm_sec, tm->tm_min, tm->tm_hour, 146 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 147 148 /* hours, minutes and seconds */ 149 buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec); 150 buf[RX8581_REG_MN] = bin2bcd(tm->tm_min); 151 buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour); 152 153 buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday); 154 155 /* month, 1 - 12 */ 156 buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1); 157 158 /* year and century */ 159 buf[RX8581_REG_YR] = bin2bcd(tm->tm_year - 100); 160 buf[RX8581_REG_DW] = (0x1 << tm->tm_wday); 161 162 /* Stop the clock */ 163 err = regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL, 164 RX8581_CTRL_STOP, RX8581_CTRL_STOP); 165 if (err < 0) 166 return err; 167 168 /* write register's data */ 169 err = regmap_bulk_write(rx8581->regmap, RX8581_REG_SC, 170 buf, sizeof(buf)); 171 if (err < 0) 172 return err; 173 174 /* get VLF and clear it */ 175 err = regmap_update_bits(rx8581->regmap, RX8581_REG_FLAG, 176 RX8581_FLAG_VLF, 0); 177 if (err < 0) 178 return err; 179 180 /* Restart the clock */ 181 return regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL, 182 RX8581_CTRL_STOP, 0); 183 } 184 185 static const struct rtc_class_ops rx8581_rtc_ops = { 186 .read_time = rx8581_rtc_read_time, 187 .set_time = rx8581_rtc_set_time, 188 }; 189 190 static int rx8571_nvram_read(void *priv, unsigned int offset, void *val, 191 size_t bytes) 192 { 193 struct rx8581 *rx8581 = priv; 194 195 return regmap_bulk_read(rx8581->regmap, RX8571_USER_RAM + offset, 196 val, bytes); 197 } 198 199 static int rx8571_nvram_write(void *priv, unsigned int offset, void *val, 200 size_t bytes) 201 { 202 struct rx8581 *rx8581 = priv; 203 204 return regmap_bulk_write(rx8581->regmap, RX8571_USER_RAM + offset, 205 val, bytes); 206 } 207 208 static int rx85x1_nvram_read(void *priv, unsigned int offset, void *val, 209 size_t bytes) 210 { 211 struct rx8581 *rx8581 = priv; 212 unsigned int tmp_val; 213 int ret; 214 215 ret = regmap_read(rx8581->regmap, RX8581_REG_RAM, &tmp_val); 216 (*(unsigned char *)val) = (unsigned char) tmp_val; 217 218 return ret; 219 } 220 221 static int rx85x1_nvram_write(void *priv, unsigned int offset, void *val, 222 size_t bytes) 223 { 224 struct rx8581 *rx8581 = priv; 225 unsigned char tmp_val; 226 227 tmp_val = *((unsigned char *)val); 228 return regmap_write(rx8581->regmap, RX8581_REG_RAM, 229 (unsigned int)tmp_val); 230 } 231 232 static const struct rx85x1_config rx8581_config = { 233 .regmap = { 234 .reg_bits = 8, 235 .val_bits = 8, 236 .max_register = 0xf, 237 }, 238 .num_nvram = 1 239 }; 240 241 static const struct rx85x1_config rx8571_config = { 242 .regmap = { 243 .reg_bits = 8, 244 .val_bits = 8, 245 .max_register = 0x1f, 246 }, 247 .num_nvram = 2 248 }; 249 250 static int rx8581_probe(struct i2c_client *client) 251 { 252 struct rx8581 *rx8581; 253 const struct rx85x1_config *config = &rx8581_config; 254 const void *data = of_device_get_match_data(&client->dev); 255 static struct nvmem_config nvmem_cfg[] = { 256 { 257 .name = "rx85x1-", 258 .word_size = 1, 259 .stride = 1, 260 .size = 1, 261 .reg_read = rx85x1_nvram_read, 262 .reg_write = rx85x1_nvram_write, 263 }, { 264 .name = "rx8571-", 265 .word_size = 1, 266 .stride = 1, 267 .size = RX8571_NVRAM_SIZE, 268 .reg_read = rx8571_nvram_read, 269 .reg_write = rx8571_nvram_write, 270 }, 271 }; 272 int ret, i; 273 274 dev_dbg(&client->dev, "%s\n", __func__); 275 276 if (data) 277 config = data; 278 279 rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL); 280 if (!rx8581) 281 return -ENOMEM; 282 283 i2c_set_clientdata(client, rx8581); 284 285 rx8581->regmap = devm_regmap_init_i2c(client, &config->regmap); 286 if (IS_ERR(rx8581->regmap)) 287 return PTR_ERR(rx8581->regmap); 288 289 rx8581->rtc = devm_rtc_allocate_device(&client->dev); 290 if (IS_ERR(rx8581->rtc)) 291 return PTR_ERR(rx8581->rtc); 292 293 rx8581->rtc->ops = &rx8581_rtc_ops; 294 rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; 295 rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099; 296 rx8581->rtc->start_secs = 0; 297 rx8581->rtc->set_start_time = true; 298 299 ret = devm_rtc_register_device(rx8581->rtc); 300 301 for (i = 0; i < config->num_nvram; i++) { 302 nvmem_cfg[i].priv = rx8581; 303 devm_rtc_nvmem_register(rx8581->rtc, &nvmem_cfg[i]); 304 } 305 306 return ret; 307 } 308 309 static const struct i2c_device_id rx8581_id[] = { 310 { "rx8581", 0 }, 311 { } 312 }; 313 MODULE_DEVICE_TABLE(i2c, rx8581_id); 314 315 static const __maybe_unused struct of_device_id rx8581_of_match[] = { 316 { .compatible = "epson,rx8571", .data = &rx8571_config }, 317 { .compatible = "epson,rx8581", .data = &rx8581_config }, 318 { /* sentinel */ } 319 }; 320 MODULE_DEVICE_TABLE(of, rx8581_of_match); 321 322 static struct i2c_driver rx8581_driver = { 323 .driver = { 324 .name = "rtc-rx8581", 325 .of_match_table = of_match_ptr(rx8581_of_match), 326 }, 327 .probe = rx8581_probe, 328 .id_table = rx8581_id, 329 }; 330 331 module_i2c_driver(rx8581_driver); 332 333 MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>"); 334 MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver"); 335 MODULE_LICENSE("GPL"); 336