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_ENABLE BIT(7) /* MN, HR, DM, or DW alarm enable */ 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_plat_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_plat_data *pdata = dev_get_platdata(dev); 123 int ret, val; 124 unsigned int reg; 125 126 ret = regmap_read(pdata->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_plat_data *pdata = dev_get_platdata(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(pdata->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_plat_data *pdata = dev_get_platdata(dev); 178 u8 rxbuf[7]; 179 int ret; 180 181 ret = regmap_bulk_read(pdata->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]); 198 if (tm->tm_year < 70) 199 tm->tm_year += 100; /* assume we are in 1970...2069 */ 200 201 dev_dbg(dev, "%s: tm is %ptR\n", __func__, tm); 202 203 return 0; 204 } 205 206 static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm) 207 { 208 struct pcf2123_plat_data *pdata = dev_get_platdata(dev); 209 u8 txbuf[7]; 210 int ret; 211 212 dev_dbg(dev, "%s: tm is %ptR\n", __func__, tm); 213 214 /* Stop the counter first */ 215 ret = regmap_write(pdata->map, PCF2123_REG_CTRL1, CTRL1_STOP); 216 if (ret) 217 return ret; 218 219 /* Set the new time */ 220 txbuf[0] = bin2bcd(tm->tm_sec & 0x7F); 221 txbuf[1] = bin2bcd(tm->tm_min & 0x7F); 222 txbuf[2] = bin2bcd(tm->tm_hour & 0x3F); 223 txbuf[3] = bin2bcd(tm->tm_mday & 0x3F); 224 txbuf[4] = tm->tm_wday & 0x07; 225 txbuf[5] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */ 226 txbuf[6] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100); 227 228 ret = regmap_bulk_write(pdata->map, PCF2123_REG_SC, txbuf, 229 sizeof(txbuf)); 230 if (ret) 231 return ret; 232 233 /* Start the counter */ 234 ret = regmap_write(pdata->map, PCF2123_REG_CTRL1, CTRL1_CLEAR); 235 if (ret) 236 return ret; 237 238 return 0; 239 } 240 241 static int pcf2123_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) 242 { 243 struct pcf2123_plat_data *pdata = dev_get_platdata(dev); 244 u8 rxbuf[4]; 245 int ret; 246 unsigned int val = 0; 247 248 ret = regmap_bulk_read(pdata->map, PCF2123_REG_ALRM_MN, rxbuf, 249 sizeof(rxbuf)); 250 if (ret) 251 return ret; 252 253 alm->time.tm_min = bcd2bin(rxbuf[0] & 0x7F); 254 alm->time.tm_hour = bcd2bin(rxbuf[1] & 0x3F); 255 alm->time.tm_mday = bcd2bin(rxbuf[2] & 0x3F); 256 alm->time.tm_wday = bcd2bin(rxbuf[3] & 0x07); 257 258 dev_dbg(dev, "%s: alm is %ptR\n", __func__, &alm->time); 259 260 ret = regmap_read(pdata->map, PCF2123_REG_CTRL2, &val); 261 if (ret) 262 return ret; 263 264 alm->enabled = !!(val & CTRL2_AIE); 265 266 return 0; 267 } 268 269 static int pcf2123_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) 270 { 271 struct pcf2123_plat_data *pdata = dev_get_platdata(dev); 272 u8 txbuf[4]; 273 int ret; 274 275 dev_dbg(dev, "%s: alm is %ptR\n", __func__, &alm->time); 276 277 /* Ensure alarm flag is clear */ 278 ret = regmap_update_bits(pdata->map, PCF2123_REG_CTRL2, CTRL2_AF, 0); 279 if (ret) 280 return ret; 281 282 /* Disable alarm interrupt */ 283 ret = regmap_update_bits(pdata->map, PCF2123_REG_CTRL2, CTRL2_AIE, 0); 284 if (ret) 285 return ret; 286 287 /* Set new alarm */ 288 txbuf[0] = bin2bcd(alm->time.tm_min & 0x7F); 289 txbuf[1] = bin2bcd(alm->time.tm_hour & 0x3F); 290 txbuf[2] = bin2bcd(alm->time.tm_mday & 0x3F); 291 txbuf[3] = bin2bcd(alm->time.tm_wday & 0x07); 292 293 ret = regmap_bulk_write(pdata->map, PCF2123_REG_ALRM_MN, txbuf, 294 sizeof(txbuf)); 295 if (ret) 296 return ret; 297 298 /* Enable alarm interrupt */ 299 if (alm->enabled) { 300 ret = regmap_update_bits(pdata->map, PCF2123_REG_CTRL2, 301 CTRL2_AIE, CTRL2_AIE); 302 if (ret) 303 return ret; 304 } 305 306 return 0; 307 } 308 309 static irqreturn_t pcf2123_rtc_irq(int irq, void *dev) 310 { 311 struct pcf2123_plat_data *pdata = dev_get_platdata(dev); 312 struct mutex *lock = &pdata->rtc->ops_lock; 313 unsigned int val = 0; 314 int ret = IRQ_NONE; 315 316 mutex_lock(lock); 317 regmap_read(pdata->map, PCF2123_REG_CTRL2, &val); 318 319 /* Alarm? */ 320 if (val & CTRL2_AF) { 321 ret = IRQ_HANDLED; 322 323 /* Clear alarm flag */ 324 regmap_update_bits(pdata->map, PCF2123_REG_CTRL2, CTRL2_AF, 0); 325 326 rtc_update_irq(pdata->rtc, 1, RTC_IRQF | RTC_AF); 327 } 328 329 mutex_unlock(lock); 330 331 return ret; 332 } 333 334 static int pcf2123_reset(struct device *dev) 335 { 336 struct pcf2123_plat_data *pdata = dev_get_platdata(dev); 337 int ret; 338 unsigned int val = 0; 339 340 ret = regmap_write(pdata->map, PCF2123_REG_CTRL1, CTRL1_SW_RESET); 341 if (ret) 342 return ret; 343 344 /* Stop the counter */ 345 dev_dbg(dev, "stopping RTC\n"); 346 ret = regmap_write(pdata->map, PCF2123_REG_CTRL1, CTRL1_STOP); 347 if (ret) 348 return ret; 349 350 /* See if the counter was actually stopped */ 351 dev_dbg(dev, "checking for presence of RTC\n"); 352 ret = regmap_read(pdata->map, PCF2123_REG_CTRL1, &val); 353 if (ret) 354 return ret; 355 356 dev_dbg(dev, "received data from RTC (0x%08X)\n", val); 357 if (!(val & CTRL1_STOP)) 358 return -ENODEV; 359 360 /* Start the counter */ 361 ret = regmap_write(pdata->map, PCF2123_REG_CTRL1, CTRL1_CLEAR); 362 if (ret) 363 return ret; 364 365 return 0; 366 } 367 368 static const struct rtc_class_ops pcf2123_rtc_ops = { 369 .read_time = pcf2123_rtc_read_time, 370 .set_time = pcf2123_rtc_set_time, 371 .read_offset = pcf2123_read_offset, 372 .set_offset = pcf2123_set_offset, 373 .read_alarm = pcf2123_rtc_read_alarm, 374 .set_alarm = pcf2123_rtc_set_alarm, 375 }; 376 377 static int pcf2123_probe(struct spi_device *spi) 378 { 379 struct rtc_device *rtc; 380 struct rtc_time tm; 381 struct pcf2123_plat_data *pdata; 382 int ret = 0; 383 384 pdata = devm_kzalloc(&spi->dev, sizeof(struct pcf2123_plat_data), 385 GFP_KERNEL); 386 if (!pdata) 387 return -ENOMEM; 388 spi->dev.platform_data = pdata; 389 390 pdata->map = devm_regmap_init_spi(spi, &pcf2123_regmap_config); 391 392 if (IS_ERR(pdata->map)) { 393 dev_err(&spi->dev, "regmap init failed.\n"); 394 goto kfree_exit; 395 } 396 397 ret = pcf2123_rtc_read_time(&spi->dev, &tm); 398 if (ret < 0) { 399 ret = pcf2123_reset(&spi->dev); 400 if (ret < 0) { 401 dev_err(&spi->dev, "chip not found\n"); 402 goto kfree_exit; 403 } 404 } 405 406 dev_info(&spi->dev, "spiclk %u KHz.\n", 407 (spi->max_speed_hz + 500) / 1000); 408 409 /* Finalize the initialization */ 410 rtc = devm_rtc_device_register(&spi->dev, pcf2123_driver.driver.name, 411 &pcf2123_rtc_ops, THIS_MODULE); 412 413 if (IS_ERR(rtc)) { 414 dev_err(&spi->dev, "failed to register.\n"); 415 ret = PTR_ERR(rtc); 416 goto kfree_exit; 417 } 418 419 pdata->rtc = rtc; 420 421 /* Register alarm irq */ 422 if (spi->irq > 0) { 423 ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL, 424 pcf2123_rtc_irq, 425 IRQF_TRIGGER_LOW | IRQF_ONESHOT, 426 pcf2123_driver.driver.name, &spi->dev); 427 if (!ret) 428 device_init_wakeup(&spi->dev, true); 429 else 430 dev_err(&spi->dev, "could not request irq.\n"); 431 } 432 433 /* The PCF2123's alarm only has minute accuracy. Must add timer 434 * support to this driver to generate interrupts more than once 435 * per minute. 436 */ 437 pdata->rtc->uie_unsupported = 1; 438 439 return 0; 440 441 kfree_exit: 442 spi->dev.platform_data = NULL; 443 return ret; 444 } 445 446 #ifdef CONFIG_OF 447 static const struct of_device_id pcf2123_dt_ids[] = { 448 { .compatible = "nxp,rtc-pcf2123", }, 449 { .compatible = "microcrystal,rv2123", }, 450 { /* sentinel */ } 451 }; 452 MODULE_DEVICE_TABLE(of, pcf2123_dt_ids); 453 #endif 454 455 static struct spi_driver pcf2123_driver = { 456 .driver = { 457 .name = "rtc-pcf2123", 458 .of_match_table = of_match_ptr(pcf2123_dt_ids), 459 }, 460 .probe = pcf2123_probe, 461 }; 462 463 module_spi_driver(pcf2123_driver); 464 465 MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>"); 466 MODULE_DESCRIPTION("NXP PCF2123 RTC driver"); 467 MODULE_LICENSE("GPL"); 468