1 /* 2 * Driver for the Epson RTC module RX-6110 SA 3 * 4 * Copyright(C) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de> 5 * Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved. 6 * 7 * This driver software is distributed as is, without any warranty of any kind, 8 * either express or implied as further specified in the GNU Public License. 9 * This software may be used and distributed according to the terms of the GNU 10 * Public License, version 2 as published by the Free Software Foundation. 11 * See the file COPYING in the main directory of this archive for more details. 12 * 13 * You should have received a copy of the GNU General Public License along with 14 * this program. If not, see <http://www.gnu.org/licenses/>. 15 */ 16 17 #include <linux/bcd.h> 18 #include <linux/init.h> 19 #include <linux/kernel.h> 20 #include <linux/module.h> 21 #include <linux/of_gpio.h> 22 #include <linux/regmap.h> 23 #include <linux/rtc.h> 24 #include <linux/spi/spi.h> 25 26 /* RX-6110 Register definitions */ 27 #define RX6110_REG_SEC 0x10 28 #define RX6110_REG_MIN 0x11 29 #define RX6110_REG_HOUR 0x12 30 #define RX6110_REG_WDAY 0x13 31 #define RX6110_REG_MDAY 0x14 32 #define RX6110_REG_MONTH 0x15 33 #define RX6110_REG_YEAR 0x16 34 #define RX6110_REG_RES1 0x17 35 #define RX6110_REG_ALMIN 0x18 36 #define RX6110_REG_ALHOUR 0x19 37 #define RX6110_REG_ALWDAY 0x1A 38 #define RX6110_REG_TCOUNT0 0x1B 39 #define RX6110_REG_TCOUNT1 0x1C 40 #define RX6110_REG_EXT 0x1D 41 #define RX6110_REG_FLAG 0x1E 42 #define RX6110_REG_CTRL 0x1F 43 #define RX6110_REG_USER0 0x20 44 #define RX6110_REG_USER1 0x21 45 #define RX6110_REG_USER2 0x22 46 #define RX6110_REG_USER3 0x23 47 #define RX6110_REG_USER4 0x24 48 #define RX6110_REG_USER5 0x25 49 #define RX6110_REG_USER6 0x26 50 #define RX6110_REG_USER7 0x27 51 #define RX6110_REG_USER8 0x28 52 #define RX6110_REG_USER9 0x29 53 #define RX6110_REG_USERA 0x2A 54 #define RX6110_REG_USERB 0x2B 55 #define RX6110_REG_USERC 0x2C 56 #define RX6110_REG_USERD 0x2D 57 #define RX6110_REG_USERE 0x2E 58 #define RX6110_REG_USERF 0x2F 59 #define RX6110_REG_RES2 0x30 60 #define RX6110_REG_RES3 0x31 61 #define RX6110_REG_IRQ 0x32 62 63 #define RX6110_BIT_ALARM_EN BIT(7) 64 65 /* Extension Register (1Dh) bit positions */ 66 #define RX6110_BIT_EXT_TSEL0 BIT(0) 67 #define RX6110_BIT_EXT_TSEL1 BIT(1) 68 #define RX6110_BIT_EXT_TSEL2 BIT(2) 69 #define RX6110_BIT_EXT_WADA BIT(3) 70 #define RX6110_BIT_EXT_TE BIT(4) 71 #define RX6110_BIT_EXT_USEL BIT(5) 72 #define RX6110_BIT_EXT_FSEL0 BIT(6) 73 #define RX6110_BIT_EXT_FSEL1 BIT(7) 74 75 /* Flag Register (1Eh) bit positions */ 76 #define RX6110_BIT_FLAG_VLF BIT(1) 77 #define RX6110_BIT_FLAG_AF BIT(3) 78 #define RX6110_BIT_FLAG_TF BIT(4) 79 #define RX6110_BIT_FLAG_UF BIT(5) 80 81 /* Control Register (1Fh) bit positions */ 82 #define RX6110_BIT_CTRL_TBKE BIT(0) 83 #define RX6110_BIT_CTRL_TBKON BIT(1) 84 #define RX6110_BIT_CTRL_TSTP BIT(2) 85 #define RX6110_BIT_CTRL_AIE BIT(3) 86 #define RX6110_BIT_CTRL_TIE BIT(4) 87 #define RX6110_BIT_CTRL_UIE BIT(5) 88 #define RX6110_BIT_CTRL_STOP BIT(6) 89 #define RX6110_BIT_CTRL_TEST BIT(7) 90 91 enum { 92 RTC_SEC = 0, 93 RTC_MIN, 94 RTC_HOUR, 95 RTC_WDAY, 96 RTC_MDAY, 97 RTC_MONTH, 98 RTC_YEAR, 99 RTC_NR_TIME 100 }; 101 102 #define RX6110_DRIVER_NAME "rx6110" 103 104 struct rx6110_data { 105 struct rtc_device *rtc; 106 struct regmap *regmap; 107 }; 108 109 /** 110 * rx6110_rtc_tm_to_data - convert rtc_time to native time encoding 111 * 112 * @tm: holds date and time 113 * @data: holds the encoding in rx6110 native form 114 */ 115 static int rx6110_rtc_tm_to_data(struct rtc_time *tm, u8 *data) 116 { 117 pr_debug("%s: date %ds %dm %dh %dmd %dm %dy\n", __func__, 118 tm->tm_sec, tm->tm_min, tm->tm_hour, 119 tm->tm_mday, tm->tm_mon, tm->tm_year); 120 121 /* 122 * The year in the RTC is a value between 0 and 99. 123 * Assume that this represents the current century 124 * and disregard all other values. 125 */ 126 if (tm->tm_year < 100 || tm->tm_year >= 200) 127 return -EINVAL; 128 129 data[RTC_SEC] = bin2bcd(tm->tm_sec); 130 data[RTC_MIN] = bin2bcd(tm->tm_min); 131 data[RTC_HOUR] = bin2bcd(tm->tm_hour); 132 data[RTC_WDAY] = BIT(bin2bcd(tm->tm_wday)); 133 data[RTC_MDAY] = bin2bcd(tm->tm_mday); 134 data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1); 135 data[RTC_YEAR] = bin2bcd(tm->tm_year % 100); 136 137 return 0; 138 } 139 140 /** 141 * rx6110_data_to_rtc_tm - convert native time encoding to rtc_time 142 * 143 * @data: holds the encoding in rx6110 native form 144 * @tm: holds date and time 145 */ 146 static int rx6110_data_to_rtc_tm(u8 *data, struct rtc_time *tm) 147 { 148 tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f); 149 tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f); 150 /* only 24-hour clock */ 151 tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f); 152 tm->tm_wday = ffs(data[RTC_WDAY] & 0x7f); 153 tm->tm_mday = bcd2bin(data[RTC_MDAY] & 0x3f); 154 tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1; 155 tm->tm_year = bcd2bin(data[RTC_YEAR]) + 100; 156 157 pr_debug("%s: date %ds %dm %dh %dmd %dm %dy\n", __func__, 158 tm->tm_sec, tm->tm_min, tm->tm_hour, 159 tm->tm_mday, tm->tm_mon, tm->tm_year); 160 161 /* 162 * The year in the RTC is a value between 0 and 99. 163 * Assume that this represents the current century 164 * and disregard all other values. 165 */ 166 if (tm->tm_year < 100 || tm->tm_year >= 200) 167 return -EINVAL; 168 169 return 0; 170 } 171 172 /** 173 * rx6110_set_time - set the current time in the rx6110 registers 174 * 175 * @dev: the rtc device in use 176 * @tm: holds date and time 177 * 178 * BUG: The HW assumes every year that is a multiple of 4 to be a leap 179 * year. Next time this is wrong is 2100, which will not be a leap year 180 * 181 * Note: If STOP is not set/cleared, the clock will start when the seconds 182 * register is written 183 * 184 */ 185 static int rx6110_set_time(struct device *dev, struct rtc_time *tm) 186 { 187 struct rx6110_data *rx6110 = dev_get_drvdata(dev); 188 u8 data[RTC_NR_TIME]; 189 int ret; 190 191 ret = rx6110_rtc_tm_to_data(tm, data); 192 if (ret < 0) 193 return ret; 194 195 /* set STOP bit before changing clock/calendar */ 196 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL, 197 RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP); 198 if (ret) 199 return ret; 200 201 ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data, 202 RTC_NR_TIME); 203 if (ret) 204 return ret; 205 206 /* The time in the RTC is valid. Be sure to have VLF cleared. */ 207 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG, 208 RX6110_BIT_FLAG_VLF, 0); 209 if (ret) 210 return ret; 211 212 /* clear STOP bit after changing clock/calendar */ 213 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL, 214 RX6110_BIT_CTRL_STOP, 0); 215 216 return ret; 217 } 218 219 /** 220 * rx6110_get_time - get the current time from the rx6110 registers 221 * @dev: the rtc device in use 222 * @tm: holds date and time 223 */ 224 static int rx6110_get_time(struct device *dev, struct rtc_time *tm) 225 { 226 struct rx6110_data *rx6110 = dev_get_drvdata(dev); 227 u8 data[RTC_NR_TIME]; 228 int flags; 229 int ret; 230 231 ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags); 232 if (ret) 233 return -EINVAL; 234 235 /* check for VLF Flag (set at power-on) */ 236 if ((flags & RX6110_BIT_FLAG_VLF)) { 237 dev_warn(dev, "Voltage low, data is invalid.\n"); 238 return -EINVAL; 239 } 240 241 /* read registers to date */ 242 ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data, 243 RTC_NR_TIME); 244 if (ret) 245 return ret; 246 247 ret = rx6110_data_to_rtc_tm(data, tm); 248 if (ret) 249 return ret; 250 251 dev_dbg(dev, "%s: date %ds %dm %dh %dmd %dm %dy\n", __func__, 252 tm->tm_sec, tm->tm_min, tm->tm_hour, 253 tm->tm_mday, tm->tm_mon, tm->tm_year); 254 255 return rtc_valid_tm(tm); 256 } 257 258 static const struct reg_sequence rx6110_default_regs[] = { 259 { RX6110_REG_RES1, 0xB8 }, 260 { RX6110_REG_RES2, 0x00 }, 261 { RX6110_REG_RES3, 0x10 }, 262 { RX6110_REG_IRQ, 0x00 }, 263 { RX6110_REG_ALMIN, 0x00 }, 264 { RX6110_REG_ALHOUR, 0x00 }, 265 { RX6110_REG_ALWDAY, 0x00 }, 266 }; 267 268 /** 269 * rx6110_init - initialize the rx6110 registers 270 * 271 * @rx6110: pointer to the rx6110 struct in use 272 * 273 */ 274 static int rx6110_init(struct rx6110_data *rx6110) 275 { 276 struct rtc_device *rtc = rx6110->rtc; 277 int flags; 278 int ret; 279 280 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT, 281 RX6110_BIT_EXT_TE, 0); 282 if (ret) 283 return ret; 284 285 ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs, 286 ARRAY_SIZE(rx6110_default_regs)); 287 if (ret) 288 return ret; 289 290 ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags); 291 if (ret) 292 return ret; 293 294 /* check for VLF Flag (set at power-on) */ 295 if ((flags & RX6110_BIT_FLAG_VLF)) 296 dev_warn(&rtc->dev, "Voltage low, data loss detected.\n"); 297 298 /* check for Alarm Flag */ 299 if (flags & RX6110_BIT_FLAG_AF) 300 dev_warn(&rtc->dev, "An alarm may have been missed.\n"); 301 302 /* check for Periodic Timer Flag */ 303 if (flags & RX6110_BIT_FLAG_TF) 304 dev_warn(&rtc->dev, "Periodic timer was detected\n"); 305 306 /* check for Update Timer Flag */ 307 if (flags & RX6110_BIT_FLAG_UF) 308 dev_warn(&rtc->dev, "Update timer was detected\n"); 309 310 /* clear all flags BUT VLF */ 311 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG, 312 RX6110_BIT_FLAG_AF | 313 RX6110_BIT_FLAG_UF | 314 RX6110_BIT_FLAG_TF, 315 0); 316 317 return ret; 318 } 319 320 static const struct rtc_class_ops rx6110_rtc_ops = { 321 .read_time = rx6110_get_time, 322 .set_time = rx6110_set_time, 323 }; 324 325 static struct regmap_config regmap_spi_config = { 326 .reg_bits = 8, 327 .val_bits = 8, 328 .max_register = RX6110_REG_IRQ, 329 .read_flag_mask = 0x80, 330 }; 331 332 /** 333 * rx6110_probe - initialize rtc driver 334 * @spi: pointer to spi device 335 */ 336 static int rx6110_probe(struct spi_device *spi) 337 { 338 struct rx6110_data *rx6110; 339 int err; 340 341 if ((spi->bits_per_word && spi->bits_per_word != 8) || 342 (spi->max_speed_hz > 2000000) || 343 (spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) { 344 dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n", 345 spi->bits_per_word, spi->max_speed_hz, spi->mode); 346 dev_warn(&spi->dev, "driving device in an unsupported mode"); 347 } 348 349 rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL); 350 if (!rx6110) 351 return -ENOMEM; 352 353 rx6110->regmap = devm_regmap_init_spi(spi, ®map_spi_config); 354 if (IS_ERR(rx6110->regmap)) { 355 dev_err(&spi->dev, "regmap init failed for rtc rx6110\n"); 356 return PTR_ERR(rx6110->regmap); 357 } 358 359 spi_set_drvdata(spi, rx6110); 360 361 rx6110->rtc = devm_rtc_device_register(&spi->dev, 362 RX6110_DRIVER_NAME, 363 &rx6110_rtc_ops, THIS_MODULE); 364 365 if (IS_ERR(rx6110->rtc)) 366 return PTR_ERR(rx6110->rtc); 367 368 err = rx6110_init(rx6110); 369 if (err) 370 return err; 371 372 rx6110->rtc->max_user_freq = 1; 373 374 return 0; 375 } 376 377 static int rx6110_remove(struct spi_device *spi) 378 { 379 return 0; 380 } 381 382 static const struct spi_device_id rx6110_id[] = { 383 { "rx6110", 0 }, 384 { } 385 }; 386 MODULE_DEVICE_TABLE(spi, rx6110_id); 387 388 static struct spi_driver rx6110_driver = { 389 .driver = { 390 .name = RX6110_DRIVER_NAME, 391 }, 392 .probe = rx6110_probe, 393 .remove = rx6110_remove, 394 .id_table = rx6110_id, 395 }; 396 397 module_spi_driver(rx6110_driver); 398 399 MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>"); 400 MODULE_DESCRIPTION("RX-6110 SA RTC driver"); 401 MODULE_LICENSE("GPL"); 402