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/of.h> 25 #include <linux/of_device.h> 26 #include <linux/spi/spi.h> 27 28 /* RX-6110 Register definitions */ 29 #define RX6110_REG_SEC 0x10 30 #define RX6110_REG_MIN 0x11 31 #define RX6110_REG_HOUR 0x12 32 #define RX6110_REG_WDAY 0x13 33 #define RX6110_REG_MDAY 0x14 34 #define RX6110_REG_MONTH 0x15 35 #define RX6110_REG_YEAR 0x16 36 #define RX6110_REG_RES1 0x17 37 #define RX6110_REG_ALMIN 0x18 38 #define RX6110_REG_ALHOUR 0x19 39 #define RX6110_REG_ALWDAY 0x1A 40 #define RX6110_REG_TCOUNT0 0x1B 41 #define RX6110_REG_TCOUNT1 0x1C 42 #define RX6110_REG_EXT 0x1D 43 #define RX6110_REG_FLAG 0x1E 44 #define RX6110_REG_CTRL 0x1F 45 #define RX6110_REG_USER0 0x20 46 #define RX6110_REG_USER1 0x21 47 #define RX6110_REG_USER2 0x22 48 #define RX6110_REG_USER3 0x23 49 #define RX6110_REG_USER4 0x24 50 #define RX6110_REG_USER5 0x25 51 #define RX6110_REG_USER6 0x26 52 #define RX6110_REG_USER7 0x27 53 #define RX6110_REG_USER8 0x28 54 #define RX6110_REG_USER9 0x29 55 #define RX6110_REG_USERA 0x2A 56 #define RX6110_REG_USERB 0x2B 57 #define RX6110_REG_USERC 0x2C 58 #define RX6110_REG_USERD 0x2D 59 #define RX6110_REG_USERE 0x2E 60 #define RX6110_REG_USERF 0x2F 61 #define RX6110_REG_RES2 0x30 62 #define RX6110_REG_RES3 0x31 63 #define RX6110_REG_IRQ 0x32 64 65 #define RX6110_BIT_ALARM_EN BIT(7) 66 67 /* Extension Register (1Dh) bit positions */ 68 #define RX6110_BIT_EXT_TSEL0 BIT(0) 69 #define RX6110_BIT_EXT_TSEL1 BIT(1) 70 #define RX6110_BIT_EXT_TSEL2 BIT(2) 71 #define RX6110_BIT_EXT_WADA BIT(3) 72 #define RX6110_BIT_EXT_TE BIT(4) 73 #define RX6110_BIT_EXT_USEL BIT(5) 74 #define RX6110_BIT_EXT_FSEL0 BIT(6) 75 #define RX6110_BIT_EXT_FSEL1 BIT(7) 76 77 /* Flag Register (1Eh) bit positions */ 78 #define RX6110_BIT_FLAG_VLF BIT(1) 79 #define RX6110_BIT_FLAG_AF BIT(3) 80 #define RX6110_BIT_FLAG_TF BIT(4) 81 #define RX6110_BIT_FLAG_UF BIT(5) 82 83 /* Control Register (1Fh) bit positions */ 84 #define RX6110_BIT_CTRL_TBKE BIT(0) 85 #define RX6110_BIT_CTRL_TBKON BIT(1) 86 #define RX6110_BIT_CTRL_TSTP BIT(2) 87 #define RX6110_BIT_CTRL_AIE BIT(3) 88 #define RX6110_BIT_CTRL_TIE BIT(4) 89 #define RX6110_BIT_CTRL_UIE BIT(5) 90 #define RX6110_BIT_CTRL_STOP BIT(6) 91 #define RX6110_BIT_CTRL_TEST BIT(7) 92 93 enum { 94 RTC_SEC = 0, 95 RTC_MIN, 96 RTC_HOUR, 97 RTC_WDAY, 98 RTC_MDAY, 99 RTC_MONTH, 100 RTC_YEAR, 101 RTC_NR_TIME 102 }; 103 104 #define RX6110_DRIVER_NAME "rx6110" 105 106 struct rx6110_data { 107 struct rtc_device *rtc; 108 struct regmap *regmap; 109 }; 110 111 /** 112 * rx6110_rtc_tm_to_data - convert rtc_time to native time encoding 113 * 114 * @tm: holds date and time 115 * @data: holds the encoding in rx6110 native form 116 */ 117 static int rx6110_rtc_tm_to_data(struct rtc_time *tm, u8 *data) 118 { 119 pr_debug("%s: date %ptRr\n", __func__, tm); 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 %ptRr\n", __func__, tm); 158 159 /* 160 * The year in the RTC is a value between 0 and 99. 161 * Assume that this represents the current century 162 * and disregard all other values. 163 */ 164 if (tm->tm_year < 100 || tm->tm_year >= 200) 165 return -EINVAL; 166 167 return 0; 168 } 169 170 /** 171 * rx6110_set_time - set the current time in the rx6110 registers 172 * 173 * @dev: the rtc device in use 174 * @tm: holds date and time 175 * 176 * BUG: The HW assumes every year that is a multiple of 4 to be a leap 177 * year. Next time this is wrong is 2100, which will not be a leap year 178 * 179 * Note: If STOP is not set/cleared, the clock will start when the seconds 180 * register is written 181 * 182 */ 183 static int rx6110_set_time(struct device *dev, struct rtc_time *tm) 184 { 185 struct rx6110_data *rx6110 = dev_get_drvdata(dev); 186 u8 data[RTC_NR_TIME]; 187 int ret; 188 189 ret = rx6110_rtc_tm_to_data(tm, data); 190 if (ret < 0) 191 return ret; 192 193 /* set STOP bit before changing clock/calendar */ 194 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL, 195 RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP); 196 if (ret) 197 return ret; 198 199 ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data, 200 RTC_NR_TIME); 201 if (ret) 202 return ret; 203 204 /* The time in the RTC is valid. Be sure to have VLF cleared. */ 205 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG, 206 RX6110_BIT_FLAG_VLF, 0); 207 if (ret) 208 return ret; 209 210 /* clear STOP bit after changing clock/calendar */ 211 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL, 212 RX6110_BIT_CTRL_STOP, 0); 213 214 return ret; 215 } 216 217 /** 218 * rx6110_get_time - get the current time from the rx6110 registers 219 * @dev: the rtc device in use 220 * @tm: holds date and time 221 */ 222 static int rx6110_get_time(struct device *dev, struct rtc_time *tm) 223 { 224 struct rx6110_data *rx6110 = dev_get_drvdata(dev); 225 u8 data[RTC_NR_TIME]; 226 int flags; 227 int ret; 228 229 ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags); 230 if (ret) 231 return -EINVAL; 232 233 /* check for VLF Flag (set at power-on) */ 234 if ((flags & RX6110_BIT_FLAG_VLF)) { 235 dev_warn(dev, "Voltage low, data is invalid.\n"); 236 return -EINVAL; 237 } 238 239 /* read registers to date */ 240 ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data, 241 RTC_NR_TIME); 242 if (ret) 243 return ret; 244 245 ret = rx6110_data_to_rtc_tm(data, tm); 246 if (ret) 247 return ret; 248 249 dev_dbg(dev, "%s: date %ptRr\n", __func__, tm); 250 251 return 0; 252 } 253 254 static const struct reg_sequence rx6110_default_regs[] = { 255 { RX6110_REG_RES1, 0xB8 }, 256 { RX6110_REG_RES2, 0x00 }, 257 { RX6110_REG_RES3, 0x10 }, 258 { RX6110_REG_IRQ, 0x00 }, 259 { RX6110_REG_ALMIN, 0x00 }, 260 { RX6110_REG_ALHOUR, 0x00 }, 261 { RX6110_REG_ALWDAY, 0x00 }, 262 }; 263 264 /** 265 * rx6110_init - initialize the rx6110 registers 266 * 267 * @rx6110: pointer to the rx6110 struct in use 268 * 269 */ 270 static int rx6110_init(struct rx6110_data *rx6110) 271 { 272 struct rtc_device *rtc = rx6110->rtc; 273 int flags; 274 int ret; 275 276 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT, 277 RX6110_BIT_EXT_TE, 0); 278 if (ret) 279 return ret; 280 281 ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs, 282 ARRAY_SIZE(rx6110_default_regs)); 283 if (ret) 284 return ret; 285 286 ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags); 287 if (ret) 288 return ret; 289 290 /* check for VLF Flag (set at power-on) */ 291 if ((flags & RX6110_BIT_FLAG_VLF)) 292 dev_warn(&rtc->dev, "Voltage low, data loss detected.\n"); 293 294 /* check for Alarm Flag */ 295 if (flags & RX6110_BIT_FLAG_AF) 296 dev_warn(&rtc->dev, "An alarm may have been missed.\n"); 297 298 /* check for Periodic Timer Flag */ 299 if (flags & RX6110_BIT_FLAG_TF) 300 dev_warn(&rtc->dev, "Periodic timer was detected\n"); 301 302 /* check for Update Timer Flag */ 303 if (flags & RX6110_BIT_FLAG_UF) 304 dev_warn(&rtc->dev, "Update timer was detected\n"); 305 306 /* clear all flags BUT VLF */ 307 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG, 308 RX6110_BIT_FLAG_AF | 309 RX6110_BIT_FLAG_UF | 310 RX6110_BIT_FLAG_TF, 311 0); 312 313 return ret; 314 } 315 316 static const struct rtc_class_ops rx6110_rtc_ops = { 317 .read_time = rx6110_get_time, 318 .set_time = rx6110_set_time, 319 }; 320 321 static struct regmap_config regmap_spi_config = { 322 .reg_bits = 8, 323 .val_bits = 8, 324 .max_register = RX6110_REG_IRQ, 325 .read_flag_mask = 0x80, 326 }; 327 328 /** 329 * rx6110_probe - initialize rtc driver 330 * @spi: pointer to spi device 331 */ 332 static int rx6110_probe(struct spi_device *spi) 333 { 334 struct rx6110_data *rx6110; 335 int err; 336 337 if ((spi->bits_per_word && spi->bits_per_word != 8) || 338 (spi->max_speed_hz > 2000000) || 339 (spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) { 340 dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n", 341 spi->bits_per_word, spi->max_speed_hz, spi->mode); 342 dev_warn(&spi->dev, "driving device in an unsupported mode"); 343 } 344 345 rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL); 346 if (!rx6110) 347 return -ENOMEM; 348 349 rx6110->regmap = devm_regmap_init_spi(spi, ®map_spi_config); 350 if (IS_ERR(rx6110->regmap)) { 351 dev_err(&spi->dev, "regmap init failed for rtc rx6110\n"); 352 return PTR_ERR(rx6110->regmap); 353 } 354 355 spi_set_drvdata(spi, rx6110); 356 357 rx6110->rtc = devm_rtc_device_register(&spi->dev, 358 RX6110_DRIVER_NAME, 359 &rx6110_rtc_ops, THIS_MODULE); 360 361 if (IS_ERR(rx6110->rtc)) 362 return PTR_ERR(rx6110->rtc); 363 364 err = rx6110_init(rx6110); 365 if (err) 366 return err; 367 368 rx6110->rtc->max_user_freq = 1; 369 370 return 0; 371 } 372 373 static int rx6110_remove(struct spi_device *spi) 374 { 375 return 0; 376 } 377 378 static const struct spi_device_id rx6110_id[] = { 379 { "rx6110", 0 }, 380 { } 381 }; 382 MODULE_DEVICE_TABLE(spi, rx6110_id); 383 384 static const struct of_device_id rx6110_spi_of_match[] = { 385 { .compatible = "epson,rx6110" }, 386 { }, 387 }; 388 MODULE_DEVICE_TABLE(of, rx6110_spi_of_match); 389 390 static struct spi_driver rx6110_driver = { 391 .driver = { 392 .name = RX6110_DRIVER_NAME, 393 .of_match_table = of_match_ptr(rx6110_spi_of_match), 394 }, 395 .probe = rx6110_probe, 396 .remove = rx6110_remove, 397 .id_table = rx6110_id, 398 }; 399 400 module_spi_driver(rx6110_driver); 401 402 MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>"); 403 MODULE_DESCRIPTION("RX-6110 SA RTC driver"); 404 MODULE_LICENSE("GPL"); 405