| 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 | { |
| 253 | struct rx8581 *rx8581; |
| 254 | const struct rx85x1_config *config = &rx8581_config; |
| 255 | const void *data = of_device_get_match_data(&client->dev); |
| 256 | static struct nvmem_config nvmem_cfg[] = { |
| 257 | { |
| 258 | .name = "rx85x1-", |
| 259 | .word_size = 1, |
| 260 | .stride = 1, |
| 261 | .size = 1, |
| 262 | .reg_read = rx85x1_nvram_read, |
| 263 | .reg_write = rx85x1_nvram_write, |
| 264 | }, { |
| 265 | .name = "rx8571-", |
| 266 | .word_size = 1, |
| 267 | .stride = 1, |
| 268 | .size = RX8571_NVRAM_SIZE, |
| 269 | .reg_read = rx8571_nvram_read, |
| 270 | .reg_write = rx8571_nvram_write, |
| 271 | }, |
| 272 | }; |
| 273 | int ret, i; |
| 274 | |
| 275 | dev_dbg(&client->dev, "%s\n", __func__); |
| 276 | |
| 277 | if (data) |
| 278 | config = data; |
| 279 | |
| 280 | rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL); |
| 281 | if (!rx8581) |
| 282 | return -ENOMEM; |
| 283 | |
| 284 | i2c_set_clientdata(client, rx8581); |
| 285 | |
| 286 | rx8581->regmap = devm_regmap_init_i2c(client, &config->regmap); |
| 287 | if (IS_ERR(rx8581->regmap)) |
| 288 | return PTR_ERR(rx8581->regmap); |
| 289 | |
| 290 | rx8581->rtc = devm_rtc_allocate_device(&client->dev); |
| 291 | if (IS_ERR(rx8581->rtc)) |
| 292 | return PTR_ERR(rx8581->rtc); |
| 293 | |
| 294 | rx8581->rtc->ops = &rx8581_rtc_ops; |
| 295 | rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; |
| 296 | rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099; |
| 297 | rx8581->rtc->start_secs = 0; |
| 298 | rx8581->rtc->set_start_time = true; |
| 299 | |
| 300 | ret = devm_rtc_register_device(rx8581->rtc); |
| 301 | |
| 302 | for (i = 0; i < config->num_nvram; i++) { |
| 303 | nvmem_cfg[i].priv = rx8581; |
| 304 | devm_rtc_nvmem_register(rx8581->rtc, &nvmem_cfg[i]); |
| 305 | } |
| 306 | |
| 307 | return ret; |
| 308 | } |
| 309 | |
| 310 | static const struct i2c_device_id rx8581_id[] = { |
| 311 | { "rx8581", 0 }, |
| 312 | { } |
| 313 | }; |
| 314 | MODULE_DEVICE_TABLE(i2c, rx8581_id); |
| 315 | |
| 316 | static const __maybe_unused struct of_device_id rx8581_of_match[] = { |
| 317 | { .compatible = "epson,rx8571", .data = &rx8571_config }, |
| 318 | { .compatible = "epson,rx8581", .data = &rx8581_config }, |
| 319 | { /* sentinel */ } |
| 320 | }; |
| 321 | MODULE_DEVICE_TABLE(of, rx8581_of_match); |
| 322 | |
| 323 | static struct i2c_driver rx8581_driver = { |
| 324 | .driver = { |
| 325 | .name = "rtc-rx8581", |
| 326 | .of_match_table = of_match_ptr(rx8581_of_match), |
| 327 | }, |
| 328 | .probe_new = rx8581_probe, |
| 329 | .id_table = rx8581_id, |
| 330 | }; |
| 331 | |
| 332 | module_i2c_driver(rx8581_driver); |
| 333 | |
| 334 | MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>"); |
| 335 | MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver"); |
| 336 | MODULE_LICENSE("GPL"); |