1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * An SPI driver for the Philips PCF2123 RTC 4 * Copyright 2009 Cyber Switching, Inc. 5 * 6 * Author: Chris Verges <chrisv@cyberswitching.com> 7 * Maintainers: http://www.cyberswitching.com 8 * 9 * based on the RS5C348 driver in this same directory. 10 * 11 * Thanks to Christian Pellegrin <chripell@fsfe.org> for 12 * the sysfs contributions to this driver. 13 * 14 * Please note that the CS is active high, so platform data 15 * should look something like: 16 * 17 * static struct spi_board_info ek_spi_devices[] = { 18 * ... 19 * { 20 * .modalias = "rtc-pcf2123", 21 * .chip_select = 1, 22 * .controller_data = (void *)AT91_PIN_PA10, 23 * .max_speed_hz = 1000 * 1000, 24 * .mode = SPI_CS_HIGH, 25 * .bus_num = 0, 26 * }, 27 * ... 28 *}; 29 */ 30 31 #include <linux/bcd.h> 32 #include <linux/delay.h> 33 #include <linux/device.h> 34 #include <linux/errno.h> 35 #include <linux/init.h> 36 #include <linux/kernel.h> 37 #include <linux/of.h> 38 #include <linux/string.h> 39 #include <linux/slab.h> 40 #include <linux/rtc.h> 41 #include <linux/spi/spi.h> 42 #include <linux/module.h> 43 #include <linux/regmap.h> 44 45 /* REGISTERS */ 46 #define PCF2123_REG_CTRL1 (0x00) /* Control Register 1 */ 47 #define PCF2123_REG_CTRL2 (0x01) /* Control Register 2 */ 48 #define PCF2123_REG_SC (0x02) /* datetime */ 49 #define PCF2123_REG_MN (0x03) 50 #define PCF2123_REG_HR (0x04) 51 #define PCF2123_REG_DM (0x05) 52 #define PCF2123_REG_DW (0x06) 53 #define PCF2123_REG_MO (0x07) 54 #define PCF2123_REG_YR (0x08) 55 #define PCF2123_REG_ALRM_MN (0x09) /* Alarm Registers */ 56 #define PCF2123_REG_ALRM_HR (0x0a) 57 #define PCF2123_REG_ALRM_DM (0x0b) 58 #define PCF2123_REG_ALRM_DW (0x0c) 59 #define PCF2123_REG_OFFSET (0x0d) /* Clock Rate Offset Register */ 60 #define PCF2123_REG_TMR_CLKOUT (0x0e) /* Timer Registers */ 61 #define PCF2123_REG_CTDWN_TMR (0x0f) 62 63 /* PCF2123_REG_CTRL1 BITS */ 64 #define CTRL1_CLEAR (0) /* Clear */ 65 #define CTRL1_CORR_INT BIT(1) /* Correction irq enable */ 66 #define CTRL1_12_HOUR BIT(2) /* 12 hour time */ 67 #define CTRL1_SW_RESET (BIT(3) | BIT(4) | BIT(6)) /* Software reset */ 68 #define CTRL1_STOP BIT(5) /* Stop the clock */ 69 #define CTRL1_EXT_TEST BIT(7) /* External clock test mode */ 70 71 /* PCF2123_REG_CTRL2 BITS */ 72 #define CTRL2_TIE BIT(0) /* Countdown timer irq enable */ 73 #define CTRL2_AIE BIT(1) /* Alarm irq enable */ 74 #define CTRL2_TF BIT(2) /* Countdown timer flag */ 75 #define CTRL2_AF BIT(3) /* Alarm flag */ 76 #define CTRL2_TI_TP BIT(4) /* Irq pin generates pulse */ 77 #define CTRL2_MSF BIT(5) /* Minute or second irq flag */ 78 #define CTRL2_SI BIT(6) /* Second irq enable */ 79 #define CTRL2_MI BIT(7) /* Minute irq enable */ 80 81 /* PCF2123_REG_SC BITS */ 82 #define OSC_HAS_STOPPED BIT(7) /* Clock has been stopped */ 83 84 /* PCF2123_REG_ALRM_XX BITS */ 85 #define ALRM_DISABLE BIT(7) /* MN, HR, DM, or DW alarm matching */ 86 87 /* PCF2123_REG_TMR_CLKOUT BITS */ 88 #define CD_TMR_4096KHZ (0) /* 4096 KHz countdown timer */ 89 #define CD_TMR_64HZ (1) /* 64 Hz countdown timer */ 90 #define CD_TMR_1HZ (2) /* 1 Hz countdown timer */ 91 #define CD_TMR_60th_HZ (3) /* 60th Hz countdown timer */ 92 #define CD_TMR_TE BIT(3) /* Countdown timer enable */ 93 94 /* PCF2123_REG_OFFSET BITS */ 95 #define OFFSET_SIGN_BIT 6 /* 2's complement sign bit */ 96 #define OFFSET_COARSE BIT(7) /* Coarse mode offset */ 97 #define OFFSET_STEP (2170) /* Offset step in parts per billion */ 98 #define OFFSET_MASK GENMASK(6, 0) /* Offset value */ 99 100 /* READ/WRITE ADDRESS BITS */ 101 #define PCF2123_WRITE BIT(4) 102 #define PCF2123_READ (BIT(4) | BIT(7)) 103 104 105 static struct spi_driver pcf2123_driver; 106 107 struct pcf2123_data { 108 struct rtc_device *rtc; 109 struct regmap *map; 110 }; 111 112 static const struct regmap_config pcf2123_regmap_config = { 113 .reg_bits = 8, 114 .val_bits = 8, 115 .read_flag_mask = PCF2123_READ, 116 .write_flag_mask = PCF2123_WRITE, 117 .max_register = PCF2123_REG_CTDWN_TMR, 118 }; 119 120 static int pcf2123_read_offset(struct device *dev, long *offset) 121 { 122 struct pcf2123_data *pcf2123 = dev_get_drvdata(dev); 123 int ret, val; 124 unsigned int reg; 125 126 ret = regmap_read(pcf2123->map, PCF2123_REG_OFFSET, ®); 127 if (ret) 128 return ret; 129 130 val = sign_extend32((reg & OFFSET_MASK), OFFSET_SIGN_BIT); 131 132 if (reg & OFFSET_COARSE) 133 val *= 2; 134 135 *offset = ((long)val) * OFFSET_STEP; 136 137 return 0; 138 } 139 140 /* 141 * The offset register is a 7 bit signed value with a coarse bit in bit 7. 142 * The main difference between the two is normal offset adjusts the first 143 * second of n minutes every other hour, with 61, 62 and 63 being shoved 144 * into the 60th minute. 145 * The coarse adjustment does the same, but every hour. 146 * the two overlap, with every even normal offset value corresponding 147 * to a coarse offset. Based on this algorithm, it seems that despite the 148 * name, coarse offset is a better fit for overlapping values. 149 */ 150 static int pcf2123_set_offset(struct device *dev, long offset) 151 { 152 struct pcf2123_data *pcf2123 = dev_get_drvdata(dev); 153 s8 reg; 154 155 if (offset > OFFSET_STEP * 127) 156 reg = 127; 157 else if (offset < OFFSET_STEP * -128) 158 reg = -128; 159 else 160 reg = DIV_ROUND_CLOSEST(offset, OFFSET_STEP); 161 162 /* choose fine offset only for odd values in the normal range */ 163 if (reg & 1 && reg <= 63 && reg >= -64) { 164 /* Normal offset. Clear the coarse bit */ 165 reg &= ~OFFSET_COARSE; 166 } else { 167 /* Coarse offset. Divide by 2 and set the coarse bit */ 168 reg >>= 1; 169 reg |= OFFSET_COARSE; 170 } 171 172 return regmap_write(pcf2123->map, PCF2123_REG_OFFSET, (unsigned int)reg); 173 } 174 175 static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm) 176 { 177 struct pcf2123_data *pcf2123 = dev_get_drvdata(dev); 178 u8 rxbuf[7]; 179 int ret; 180 181 ret = regmap_bulk_read(pcf2123->map, PCF2123_REG_SC, rxbuf, 182 sizeof(rxbuf)); 183 if (ret) 184 return ret; 185 186 if (rxbuf[0] & OSC_HAS_STOPPED) { 187 dev_info(dev, "clock was stopped. Time is not valid\n"); 188 return -EINVAL; 189 } 190 191 tm->tm_sec = bcd2bin(rxbuf[0] & 0x7F); 192 tm->tm_min = bcd2bin(rxbuf[1] & 0x7F); 193 tm->tm_hour = bcd2bin(rxbuf[2] & 0x3F); /* rtc hr 0-23 */ 194 tm->tm_mday = bcd2bin(rxbuf[3] & 0x3F); 195 tm->tm_wday = rxbuf[4] & 0x07; 196 tm->tm_mon = bcd2bin(rxbuf[5] & 0x1F) - 1; /* rtc mn 1-12 */ 197 tm->tm_year = bcd2bin(rxbuf[6]) + 100; 198 199 dev_dbg(dev, "%s: tm is %ptR\n", __func__, tm); 200 201 return 0; 202 } 203 204 static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm) 205 { 206 struct pcf2123_data *pcf2123 = dev_get_drvdata(dev); 207 u8 txbuf[7]; 208 int ret; 209 210 dev_dbg(dev, "%s: tm is %ptR\n", __func__, tm); 211 212 /* Stop the counter first */ 213 ret = regmap_write(pcf2123->map, PCF2123_REG_CTRL1, CTRL1_STOP); 214 if (ret) 215 return ret; 216 217 /* Set the new time */ 218 txbuf[0] = bin2bcd(tm->tm_sec & 0x7F); 219 txbuf[1] = bin2bcd(tm->tm_min & 0x7F); 220 txbuf[2] = bin2bcd(tm->tm_hour & 0x3F); 221 txbuf[3] = bin2bcd(tm->tm_mday & 0x3F); 222 txbuf[4] = tm->tm_wday & 0x07; 223 txbuf[5] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */ 224 txbuf[6] = bin2bcd(tm->tm_year - 100); 225 226 ret = regmap_bulk_write(pcf2123->map, PCF2123_REG_SC, txbuf, 227 sizeof(txbuf)); 228 if (ret) 229 return ret; 230 231 /* Start the counter */ 232 ret = regmap_write(pcf2123->map, PCF2123_REG_CTRL1, CTRL1_CLEAR); 233 if (ret) 234 return ret; 235 236 return 0; 237 } 238 239 static int pcf2123_rtc_alarm_irq_enable(struct device *dev, unsigned int en) 240 { 241 struct pcf2123_data *pcf2123 = dev_get_drvdata(dev); 242 243 return regmap_update_bits(pcf2123->map, PCF2123_REG_CTRL2, CTRL2_AIE, 244 en ? CTRL2_AIE : 0); 245 } 246 247 static int pcf2123_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) 248 { 249 struct pcf2123_data *pcf2123 = dev_get_drvdata(dev); 250 u8 rxbuf[4]; 251 int ret; 252 unsigned int val = 0; 253 254 ret = regmap_bulk_read(pcf2123->map, PCF2123_REG_ALRM_MN, rxbuf, 255 sizeof(rxbuf)); 256 if (ret) 257 return ret; 258 259 alm->time.tm_min = bcd2bin(rxbuf[0] & 0x7F); 260 alm->time.tm_hour = bcd2bin(rxbuf[1] & 0x3F); 261 alm->time.tm_mday = bcd2bin(rxbuf[2] & 0x3F); 262 alm->time.tm_wday = bcd2bin(rxbuf[3] & 0x07); 263 264 dev_dbg(dev, "%s: alm is %ptR\n", __func__, &alm->time); 265 266 ret = regmap_read(pcf2123->map, PCF2123_REG_CTRL2, &val); 267 if (ret) 268 return ret; 269 270 alm->enabled = !!(val & CTRL2_AIE); 271 272 return 0; 273 } 274 275 static int pcf2123_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) 276 { 277 struct pcf2123_data *pcf2123 = dev_get_drvdata(dev); 278 u8 txbuf[4]; 279 int ret; 280 281 dev_dbg(dev, "%s: alm is %ptR\n", __func__, &alm->time); 282 283 /* Disable alarm interrupt */ 284 ret = regmap_update_bits(pcf2123->map, PCF2123_REG_CTRL2, CTRL2_AIE, 0); 285 if (ret) 286 return ret; 287 288 /* Ensure alarm flag is clear */ 289 ret = regmap_update_bits(pcf2123->map, PCF2123_REG_CTRL2, CTRL2_AF, 0); 290 if (ret) 291 return ret; 292 293 /* Set new alarm */ 294 txbuf[0] = bin2bcd(alm->time.tm_min & 0x7F); 295 txbuf[1] = bin2bcd(alm->time.tm_hour & 0x3F); 296 txbuf[2] = bin2bcd(alm->time.tm_mday & 0x3F); 297 txbuf[3] = ALRM_DISABLE; 298 299 ret = regmap_bulk_write(pcf2123->map, PCF2123_REG_ALRM_MN, txbuf, 300 sizeof(txbuf)); 301 if (ret) 302 return ret; 303 304 return pcf2123_rtc_alarm_irq_enable(dev, alm->enabled); 305 } 306 307 static irqreturn_t pcf2123_rtc_irq(int irq, void *dev) 308 { 309 struct pcf2123_data *pcf2123 = dev_get_drvdata(dev); 310 unsigned int val = 0; 311 int ret = IRQ_NONE; 312 313 rtc_lock(pcf2123->rtc); 314 regmap_read(pcf2123->map, PCF2123_REG_CTRL2, &val); 315 316 /* Alarm? */ 317 if (val & CTRL2_AF) { 318 ret = IRQ_HANDLED; 319 320 /* Clear alarm flag */ 321 regmap_update_bits(pcf2123->map, PCF2123_REG_CTRL2, CTRL2_AF, 0); 322 323 rtc_update_irq(pcf2123->rtc, 1, RTC_IRQF | RTC_AF); 324 } 325 326 rtc_unlock(pcf2123->rtc); 327 328 return ret; 329 } 330 331 static int pcf2123_reset(struct device *dev) 332 { 333 struct pcf2123_data *pcf2123 = dev_get_drvdata(dev); 334 int ret; 335 unsigned int val = 0; 336 337 ret = regmap_write(pcf2123->map, PCF2123_REG_CTRL1, CTRL1_SW_RESET); 338 if (ret) 339 return ret; 340 341 /* Stop the counter */ 342 dev_dbg(dev, "stopping RTC\n"); 343 ret = regmap_write(pcf2123->map, PCF2123_REG_CTRL1, CTRL1_STOP); 344 if (ret) 345 return ret; 346 347 /* See if the counter was actually stopped */ 348 dev_dbg(dev, "checking for presence of RTC\n"); 349 ret = regmap_read(pcf2123->map, PCF2123_REG_CTRL1, &val); 350 if (ret) 351 return ret; 352 353 dev_dbg(dev, "received data from RTC (0x%08X)\n", val); 354 if (!(val & CTRL1_STOP)) 355 return -ENODEV; 356 357 /* Start the counter */ 358 ret = regmap_write(pcf2123->map, PCF2123_REG_CTRL1, CTRL1_CLEAR); 359 if (ret) 360 return ret; 361 362 return 0; 363 } 364 365 static const struct rtc_class_ops pcf2123_rtc_ops = { 366 .read_time = pcf2123_rtc_read_time, 367 .set_time = pcf2123_rtc_set_time, 368 .read_offset = pcf2123_read_offset, 369 .set_offset = pcf2123_set_offset, 370 .read_alarm = pcf2123_rtc_read_alarm, 371 .set_alarm = pcf2123_rtc_set_alarm, 372 .alarm_irq_enable = pcf2123_rtc_alarm_irq_enable, 373 }; 374 375 static int pcf2123_probe(struct spi_device *spi) 376 { 377 struct rtc_device *rtc; 378 struct rtc_time tm; 379 struct pcf2123_data *pcf2123; 380 int ret = 0; 381 382 pcf2123 = devm_kzalloc(&spi->dev, sizeof(struct pcf2123_data), 383 GFP_KERNEL); 384 if (!pcf2123) 385 return -ENOMEM; 386 387 dev_set_drvdata(&spi->dev, pcf2123); 388 389 pcf2123->map = devm_regmap_init_spi(spi, &pcf2123_regmap_config); 390 if (IS_ERR(pcf2123->map)) { 391 dev_err(&spi->dev, "regmap init failed.\n"); 392 return PTR_ERR(pcf2123->map); 393 } 394 395 ret = pcf2123_rtc_read_time(&spi->dev, &tm); 396 if (ret < 0) { 397 ret = pcf2123_reset(&spi->dev); 398 if (ret < 0) { 399 dev_err(&spi->dev, "chip not found\n"); 400 return ret; 401 } 402 } 403 404 dev_info(&spi->dev, "spiclk %u KHz.\n", 405 (spi->max_speed_hz + 500) / 1000); 406 407 /* Finalize the initialization */ 408 rtc = devm_rtc_allocate_device(&spi->dev); 409 if (IS_ERR(rtc)) 410 return PTR_ERR(rtc); 411 412 pcf2123->rtc = rtc; 413 414 /* Register alarm irq */ 415 if (spi->irq > 0) { 416 ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL, 417 pcf2123_rtc_irq, 418 IRQF_TRIGGER_LOW | IRQF_ONESHOT, 419 pcf2123_driver.driver.name, &spi->dev); 420 if (!ret) 421 device_init_wakeup(&spi->dev, true); 422 else 423 dev_err(&spi->dev, "could not request irq.\n"); 424 } 425 426 /* The PCF2123's alarm only has minute accuracy. Must add timer 427 * support to this driver to generate interrupts more than once 428 * per minute. 429 */ 430 rtc->uie_unsupported = 1; 431 rtc->ops = &pcf2123_rtc_ops; 432 rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; 433 rtc->range_max = RTC_TIMESTAMP_END_2099; 434 rtc->set_start_time = true; 435 436 ret = devm_rtc_register_device(rtc); 437 if (ret) 438 return ret; 439 440 return 0; 441 } 442 443 #ifdef CONFIG_OF 444 static const struct of_device_id pcf2123_dt_ids[] = { 445 { .compatible = "nxp,pcf2123", }, 446 { .compatible = "microcrystal,rv2123", }, 447 /* Deprecated, do not use */ 448 { .compatible = "nxp,rtc-pcf2123", }, 449 { /* sentinel */ } 450 }; 451 MODULE_DEVICE_TABLE(of, pcf2123_dt_ids); 452 #endif 453 454 static struct spi_driver pcf2123_driver = { 455 .driver = { 456 .name = "rtc-pcf2123", 457 .of_match_table = of_match_ptr(pcf2123_dt_ids), 458 }, 459 .probe = pcf2123_probe, 460 }; 461 462 module_spi_driver(pcf2123_driver); 463 464 MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>"); 465 MODULE_DESCRIPTION("NXP PCF2123 RTC driver"); 466 MODULE_LICENSE("GPL"); 467