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