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 %ptRr\n", __func__, tm); 118 119 /* 120 * The year in the RTC is a value between 0 and 99. 121 * Assume that this represents the current century 122 * and disregard all other values. 123 */ 124 if (tm->tm_year < 100 || tm->tm_year >= 200) 125 return -EINVAL; 126 127 data[RTC_SEC] = bin2bcd(tm->tm_sec); 128 data[RTC_MIN] = bin2bcd(tm->tm_min); 129 data[RTC_HOUR] = bin2bcd(tm->tm_hour); 130 data[RTC_WDAY] = BIT(bin2bcd(tm->tm_wday)); 131 data[RTC_MDAY] = bin2bcd(tm->tm_mday); 132 data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1); 133 data[RTC_YEAR] = bin2bcd(tm->tm_year % 100); 134 135 return 0; 136 } 137 138 /** 139 * rx6110_data_to_rtc_tm - convert native time encoding to rtc_time 140 * 141 * @data: holds the encoding in rx6110 native form 142 * @tm: holds date and time 143 */ 144 static int rx6110_data_to_rtc_tm(u8 *data, struct rtc_time *tm) 145 { 146 tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f); 147 tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f); 148 /* only 24-hour clock */ 149 tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f); 150 tm->tm_wday = ffs(data[RTC_WDAY] & 0x7f); 151 tm->tm_mday = bcd2bin(data[RTC_MDAY] & 0x3f); 152 tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1; 153 tm->tm_year = bcd2bin(data[RTC_YEAR]) + 100; 154 155 pr_debug("%s: date %ptRr\n", __func__, tm); 156 157 /* 158 * The year in the RTC is a value between 0 and 99. 159 * Assume that this represents the current century 160 * and disregard all other values. 161 */ 162 if (tm->tm_year < 100 || tm->tm_year >= 200) 163 return -EINVAL; 164 165 return 0; 166 } 167 168 /** 169 * rx6110_set_time - set the current time in the rx6110 registers 170 * 171 * @dev: the rtc device in use 172 * @tm: holds date and time 173 * 174 * BUG: The HW assumes every year that is a multiple of 4 to be a leap 175 * year. Next time this is wrong is 2100, which will not be a leap year 176 * 177 * Note: If STOP is not set/cleared, the clock will start when the seconds 178 * register is written 179 * 180 */ 181 static int rx6110_set_time(struct device *dev, struct rtc_time *tm) 182 { 183 struct rx6110_data *rx6110 = dev_get_drvdata(dev); 184 u8 data[RTC_NR_TIME]; 185 int ret; 186 187 ret = rx6110_rtc_tm_to_data(tm, data); 188 if (ret < 0) 189 return ret; 190 191 /* set STOP bit before changing clock/calendar */ 192 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL, 193 RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP); 194 if (ret) 195 return ret; 196 197 ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data, 198 RTC_NR_TIME); 199 if (ret) 200 return ret; 201 202 /* The time in the RTC is valid. Be sure to have VLF cleared. */ 203 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG, 204 RX6110_BIT_FLAG_VLF, 0); 205 if (ret) 206 return ret; 207 208 /* clear STOP bit after changing clock/calendar */ 209 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL, 210 RX6110_BIT_CTRL_STOP, 0); 211 212 return ret; 213 } 214 215 /** 216 * rx6110_get_time - get the current time from the rx6110 registers 217 * @dev: the rtc device in use 218 * @tm: holds date and time 219 */ 220 static int rx6110_get_time(struct device *dev, struct rtc_time *tm) 221 { 222 struct rx6110_data *rx6110 = dev_get_drvdata(dev); 223 u8 data[RTC_NR_TIME]; 224 int flags; 225 int ret; 226 227 ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags); 228 if (ret) 229 return -EINVAL; 230 231 /* check for VLF Flag (set at power-on) */ 232 if ((flags & RX6110_BIT_FLAG_VLF)) { 233 dev_warn(dev, "Voltage low, data is invalid.\n"); 234 return -EINVAL; 235 } 236 237 /* read registers to date */ 238 ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data, 239 RTC_NR_TIME); 240 if (ret) 241 return ret; 242 243 ret = rx6110_data_to_rtc_tm(data, tm); 244 if (ret) 245 return ret; 246 247 dev_dbg(dev, "%s: date %ptRr\n", __func__, tm); 248 249 return 0; 250 } 251 252 static const struct reg_sequence rx6110_default_regs[] = { 253 { RX6110_REG_RES1, 0xB8 }, 254 { RX6110_REG_RES2, 0x00 }, 255 { RX6110_REG_RES3, 0x10 }, 256 { RX6110_REG_IRQ, 0x00 }, 257 { RX6110_REG_ALMIN, 0x00 }, 258 { RX6110_REG_ALHOUR, 0x00 }, 259 { RX6110_REG_ALWDAY, 0x00 }, 260 }; 261 262 /** 263 * rx6110_init - initialize the rx6110 registers 264 * 265 * @rx6110: pointer to the rx6110 struct in use 266 * 267 */ 268 static int rx6110_init(struct rx6110_data *rx6110) 269 { 270 struct rtc_device *rtc = rx6110->rtc; 271 int flags; 272 int ret; 273 274 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT, 275 RX6110_BIT_EXT_TE, 0); 276 if (ret) 277 return ret; 278 279 ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs, 280 ARRAY_SIZE(rx6110_default_regs)); 281 if (ret) 282 return ret; 283 284 ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags); 285 if (ret) 286 return ret; 287 288 /* check for VLF Flag (set at power-on) */ 289 if ((flags & RX6110_BIT_FLAG_VLF)) 290 dev_warn(&rtc->dev, "Voltage low, data loss detected.\n"); 291 292 /* check for Alarm Flag */ 293 if (flags & RX6110_BIT_FLAG_AF) 294 dev_warn(&rtc->dev, "An alarm may have been missed.\n"); 295 296 /* check for Periodic Timer Flag */ 297 if (flags & RX6110_BIT_FLAG_TF) 298 dev_warn(&rtc->dev, "Periodic timer was detected\n"); 299 300 /* check for Update Timer Flag */ 301 if (flags & RX6110_BIT_FLAG_UF) 302 dev_warn(&rtc->dev, "Update timer was detected\n"); 303 304 /* clear all flags BUT VLF */ 305 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG, 306 RX6110_BIT_FLAG_AF | 307 RX6110_BIT_FLAG_UF | 308 RX6110_BIT_FLAG_TF, 309 0); 310 311 return ret; 312 } 313 314 static const struct rtc_class_ops rx6110_rtc_ops = { 315 .read_time = rx6110_get_time, 316 .set_time = rx6110_set_time, 317 }; 318 319 static struct regmap_config regmap_spi_config = { 320 .reg_bits = 8, 321 .val_bits = 8, 322 .max_register = RX6110_REG_IRQ, 323 .read_flag_mask = 0x80, 324 }; 325 326 /** 327 * rx6110_probe - initialize rtc driver 328 * @spi: pointer to spi device 329 */ 330 static int rx6110_probe(struct spi_device *spi) 331 { 332 struct rx6110_data *rx6110; 333 int err; 334 335 if ((spi->bits_per_word && spi->bits_per_word != 8) || 336 (spi->max_speed_hz > 2000000) || 337 (spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) { 338 dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n", 339 spi->bits_per_word, spi->max_speed_hz, spi->mode); 340 dev_warn(&spi->dev, "driving device in an unsupported mode"); 341 } 342 343 rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL); 344 if (!rx6110) 345 return -ENOMEM; 346 347 rx6110->regmap = devm_regmap_init_spi(spi, ®map_spi_config); 348 if (IS_ERR(rx6110->regmap)) { 349 dev_err(&spi->dev, "regmap init failed for rtc rx6110\n"); 350 return PTR_ERR(rx6110->regmap); 351 } 352 353 spi_set_drvdata(spi, rx6110); 354 355 rx6110->rtc = devm_rtc_device_register(&spi->dev, 356 RX6110_DRIVER_NAME, 357 &rx6110_rtc_ops, THIS_MODULE); 358 359 if (IS_ERR(rx6110->rtc)) 360 return PTR_ERR(rx6110->rtc); 361 362 err = rx6110_init(rx6110); 363 if (err) 364 return err; 365 366 rx6110->rtc->max_user_freq = 1; 367 368 return 0; 369 } 370 371 static int rx6110_remove(struct spi_device *spi) 372 { 373 return 0; 374 } 375 376 static const struct spi_device_id rx6110_id[] = { 377 { "rx6110", 0 }, 378 { } 379 }; 380 MODULE_DEVICE_TABLE(spi, rx6110_id); 381 382 static struct spi_driver rx6110_driver = { 383 .driver = { 384 .name = RX6110_DRIVER_NAME, 385 }, 386 .probe = rx6110_probe, 387 .remove = rx6110_remove, 388 .id_table = rx6110_id, 389 }; 390 391 module_spi_driver(rx6110_driver); 392 393 MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>"); 394 MODULE_DESCRIPTION("RX-6110 SA RTC driver"); 395 MODULE_LICENSE("GPL"); 396