1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * An I2C driver for the Intersil ISL 12026 4 * 5 * Copyright (c) 2018 Cavium, Inc. 6 */ 7 #include <linux/bcd.h> 8 #include <linux/delay.h> 9 #include <linux/i2c.h> 10 #include <linux/module.h> 11 #include <linux/mutex.h> 12 #include <linux/nvmem-provider.h> 13 #include <linux/of.h> 14 #include <linux/of_device.h> 15 #include <linux/rtc.h> 16 #include <linux/slab.h> 17 18 /* register offsets */ 19 #define ISL12026_REG_PWR 0x14 20 # define ISL12026_REG_PWR_BSW BIT(6) 21 # define ISL12026_REG_PWR_SBIB BIT(7) 22 #define ISL12026_REG_SC 0x30 23 #define ISL12026_REG_HR 0x32 24 # define ISL12026_REG_HR_MIL BIT(7) /* military or 24 hour time */ 25 #define ISL12026_REG_SR 0x3f 26 # define ISL12026_REG_SR_RTCF BIT(0) 27 # define ISL12026_REG_SR_WEL BIT(1) 28 # define ISL12026_REG_SR_RWEL BIT(2) 29 # define ISL12026_REG_SR_MBZ BIT(3) 30 # define ISL12026_REG_SR_OSCF BIT(4) 31 32 /* The EEPROM array responds at i2c address 0x57 */ 33 #define ISL12026_EEPROM_ADDR 0x57 34 35 #define ISL12026_PAGESIZE 16 36 #define ISL12026_NVMEM_WRITE_TIME 20 37 38 struct isl12026 { 39 struct rtc_device *rtc; 40 struct i2c_client *nvm_client; 41 }; 42 43 static int isl12026_read_reg(struct i2c_client *client, int reg) 44 { 45 u8 addr[] = {0, reg}; 46 u8 val; 47 int ret; 48 49 struct i2c_msg msgs[] = { 50 { 51 .addr = client->addr, 52 .flags = 0, 53 .len = sizeof(addr), 54 .buf = addr 55 }, { 56 .addr = client->addr, 57 .flags = I2C_M_RD, 58 .len = 1, 59 .buf = &val 60 } 61 }; 62 63 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 64 if (ret != ARRAY_SIZE(msgs)) { 65 dev_err(&client->dev, "read reg error, ret=%d\n", ret); 66 ret = ret < 0 ? ret : -EIO; 67 } else { 68 ret = val; 69 } 70 71 return ret; 72 } 73 74 static int isl12026_arm_write(struct i2c_client *client) 75 { 76 int ret; 77 u8 op[3]; 78 struct i2c_msg msg = { 79 .addr = client->addr, 80 .flags = 0, 81 .len = 1, 82 .buf = op 83 }; 84 85 /* Set SR.WEL */ 86 op[0] = 0; 87 op[1] = ISL12026_REG_SR; 88 op[2] = ISL12026_REG_SR_WEL; 89 msg.len = 3; 90 ret = i2c_transfer(client->adapter, &msg, 1); 91 if (ret != 1) { 92 dev_err(&client->dev, "write error SR.WEL, ret=%d\n", ret); 93 ret = ret < 0 ? ret : -EIO; 94 goto out; 95 } 96 97 /* Set SR.WEL and SR.RWEL */ 98 op[2] = ISL12026_REG_SR_WEL | ISL12026_REG_SR_RWEL; 99 msg.len = 3; 100 ret = i2c_transfer(client->adapter, &msg, 1); 101 if (ret != 1) { 102 dev_err(&client->dev, 103 "write error SR.WEL|SR.RWEL, ret=%d\n", ret); 104 ret = ret < 0 ? ret : -EIO; 105 goto out; 106 } else { 107 ret = 0; 108 } 109 out: 110 return ret; 111 } 112 113 static int isl12026_disarm_write(struct i2c_client *client) 114 { 115 int ret; 116 u8 op[3] = {0, ISL12026_REG_SR, 0}; 117 struct i2c_msg msg = { 118 .addr = client->addr, 119 .flags = 0, 120 .len = sizeof(op), 121 .buf = op 122 }; 123 124 ret = i2c_transfer(client->adapter, &msg, 1); 125 if (ret != 1) { 126 dev_err(&client->dev, 127 "write error SR, ret=%d\n", ret); 128 ret = ret < 0 ? ret : -EIO; 129 } else { 130 ret = 0; 131 } 132 133 return ret; 134 } 135 136 static int isl12026_write_reg(struct i2c_client *client, int reg, u8 val) 137 { 138 int ret; 139 u8 op[3] = {0, reg, val}; 140 struct i2c_msg msg = { 141 .addr = client->addr, 142 .flags = 0, 143 .len = sizeof(op), 144 .buf = op 145 }; 146 147 ret = isl12026_arm_write(client); 148 if (ret) 149 return ret; 150 151 ret = i2c_transfer(client->adapter, &msg, 1); 152 if (ret != 1) { 153 dev_err(&client->dev, "write error CCR, ret=%d\n", ret); 154 ret = ret < 0 ? ret : -EIO; 155 goto out; 156 } 157 158 msleep(ISL12026_NVMEM_WRITE_TIME); 159 160 ret = isl12026_disarm_write(client); 161 out: 162 return ret; 163 } 164 165 static int isl12026_rtc_set_time(struct device *dev, struct rtc_time *tm) 166 { 167 struct i2c_client *client = to_i2c_client(dev); 168 int ret; 169 u8 op[10]; 170 struct i2c_msg msg = { 171 .addr = client->addr, 172 .flags = 0, 173 .len = sizeof(op), 174 .buf = op 175 }; 176 177 ret = isl12026_arm_write(client); 178 if (ret) 179 return ret; 180 181 /* Set the CCR registers */ 182 op[0] = 0; 183 op[1] = ISL12026_REG_SC; 184 op[2] = bin2bcd(tm->tm_sec); /* SC */ 185 op[3] = bin2bcd(tm->tm_min); /* MN */ 186 op[4] = bin2bcd(tm->tm_hour) | ISL12026_REG_HR_MIL; /* HR */ 187 op[5] = bin2bcd(tm->tm_mday); /* DT */ 188 op[6] = bin2bcd(tm->tm_mon + 1); /* MO */ 189 op[7] = bin2bcd(tm->tm_year % 100); /* YR */ 190 op[8] = bin2bcd(tm->tm_wday & 7); /* DW */ 191 op[9] = bin2bcd(tm->tm_year >= 100 ? 20 : 19); /* Y2K */ 192 ret = i2c_transfer(client->adapter, &msg, 1); 193 if (ret != 1) { 194 dev_err(&client->dev, "write error CCR, ret=%d\n", ret); 195 ret = ret < 0 ? ret : -EIO; 196 goto out; 197 } 198 199 ret = isl12026_disarm_write(client); 200 out: 201 return ret; 202 } 203 204 static int isl12026_rtc_read_time(struct device *dev, struct rtc_time *tm) 205 { 206 struct i2c_client *client = to_i2c_client(dev); 207 u8 ccr[8]; 208 u8 addr[2]; 209 u8 sr; 210 int ret; 211 struct i2c_msg msgs[] = { 212 { 213 .addr = client->addr, 214 .flags = 0, 215 .len = sizeof(addr), 216 .buf = addr 217 }, { 218 .addr = client->addr, 219 .flags = I2C_M_RD, 220 } 221 }; 222 223 /* First, read SR */ 224 addr[0] = 0; 225 addr[1] = ISL12026_REG_SR; 226 msgs[1].len = 1; 227 msgs[1].buf = &sr; 228 229 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 230 if (ret != ARRAY_SIZE(msgs)) { 231 dev_err(&client->dev, "read error, ret=%d\n", ret); 232 ret = ret < 0 ? ret : -EIO; 233 goto out; 234 } 235 236 if (sr & ISL12026_REG_SR_RTCF) 237 dev_warn(&client->dev, "Real-Time Clock Failure on read\n"); 238 if (sr & ISL12026_REG_SR_OSCF) 239 dev_warn(&client->dev, "Oscillator Failure on read\n"); 240 241 /* Second, CCR regs */ 242 addr[0] = 0; 243 addr[1] = ISL12026_REG_SC; 244 msgs[1].len = sizeof(ccr); 245 msgs[1].buf = ccr; 246 247 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 248 if (ret != ARRAY_SIZE(msgs)) { 249 dev_err(&client->dev, "read error, ret=%d\n", ret); 250 ret = ret < 0 ? ret : -EIO; 251 goto out; 252 } 253 254 tm->tm_sec = bcd2bin(ccr[0] & 0x7F); 255 tm->tm_min = bcd2bin(ccr[1] & 0x7F); 256 if (ccr[2] & ISL12026_REG_HR_MIL) 257 tm->tm_hour = bcd2bin(ccr[2] & 0x3F); 258 else 259 tm->tm_hour = bcd2bin(ccr[2] & 0x1F) + 260 ((ccr[2] & 0x20) ? 12 : 0); 261 tm->tm_mday = bcd2bin(ccr[3] & 0x3F); 262 tm->tm_mon = bcd2bin(ccr[4] & 0x1F) - 1; 263 tm->tm_year = bcd2bin(ccr[5]); 264 if (bcd2bin(ccr[7]) == 20) 265 tm->tm_year += 100; 266 tm->tm_wday = ccr[6] & 0x07; 267 268 ret = 0; 269 out: 270 return ret; 271 } 272 273 static const struct rtc_class_ops isl12026_rtc_ops = { 274 .read_time = isl12026_rtc_read_time, 275 .set_time = isl12026_rtc_set_time, 276 }; 277 278 static int isl12026_nvm_read(void *p, unsigned int offset, 279 void *val, size_t bytes) 280 { 281 struct isl12026 *priv = p; 282 int ret; 283 u8 addr[2]; 284 struct i2c_msg msgs[] = { 285 { 286 .addr = priv->nvm_client->addr, 287 .flags = 0, 288 .len = sizeof(addr), 289 .buf = addr 290 }, { 291 .addr = priv->nvm_client->addr, 292 .flags = I2C_M_RD, 293 .buf = val 294 } 295 }; 296 297 /* 298 * offset and bytes checked and limited by nvmem core, so 299 * proceed without further checks. 300 */ 301 ret = mutex_lock_interruptible(&priv->rtc->ops_lock); 302 if (ret) 303 return ret; 304 305 /* 2 bytes of address, most significant first */ 306 addr[0] = offset >> 8; 307 addr[1] = offset; 308 msgs[1].len = bytes; 309 ret = i2c_transfer(priv->nvm_client->adapter, msgs, ARRAY_SIZE(msgs)); 310 311 mutex_unlock(&priv->rtc->ops_lock); 312 313 if (ret != ARRAY_SIZE(msgs)) { 314 dev_err(&priv->nvm_client->dev, 315 "nvmem read error, ret=%d\n", ret); 316 return ret < 0 ? ret : -EIO; 317 } 318 319 return 0; 320 } 321 322 static int isl12026_nvm_write(void *p, unsigned int offset, 323 void *val, size_t bytes) 324 { 325 struct isl12026 *priv = p; 326 int ret; 327 u8 *v = val; 328 size_t chunk_size, num_written; 329 u8 payload[ISL12026_PAGESIZE + 2]; /* page + 2 address bytes */ 330 struct i2c_msg msgs[] = { 331 { 332 .addr = priv->nvm_client->addr, 333 .flags = 0, 334 .buf = payload 335 } 336 }; 337 338 /* 339 * offset and bytes checked and limited by nvmem core, so 340 * proceed without further checks. 341 */ 342 ret = mutex_lock_interruptible(&priv->rtc->ops_lock); 343 if (ret) 344 return ret; 345 346 num_written = 0; 347 while (bytes) { 348 chunk_size = round_down(offset, ISL12026_PAGESIZE) + 349 ISL12026_PAGESIZE - offset; 350 chunk_size = min(bytes, chunk_size); 351 /* 352 * 2 bytes of address, most significant first, followed 353 * by page data bytes 354 */ 355 memcpy(payload + 2, v + num_written, chunk_size); 356 payload[0] = offset >> 8; 357 payload[1] = offset; 358 msgs[0].len = chunk_size + 2; 359 ret = i2c_transfer(priv->nvm_client->adapter, 360 msgs, ARRAY_SIZE(msgs)); 361 if (ret != ARRAY_SIZE(msgs)) { 362 dev_err(&priv->nvm_client->dev, 363 "nvmem write error, ret=%d\n", ret); 364 ret = ret < 0 ? ret : -EIO; 365 break; 366 } 367 ret = 0; 368 bytes -= chunk_size; 369 offset += chunk_size; 370 num_written += chunk_size; 371 msleep(ISL12026_NVMEM_WRITE_TIME); 372 } 373 374 mutex_unlock(&priv->rtc->ops_lock); 375 376 return ret; 377 } 378 379 static void isl12026_force_power_modes(struct i2c_client *client) 380 { 381 int ret; 382 int pwr, requested_pwr; 383 u32 bsw_val, sbib_val; 384 bool set_bsw, set_sbib; 385 386 /* 387 * If we can read the of_property, set the specified value. 388 * If there is an error reading the of_property (likely 389 * because it does not exist), keep the current value. 390 */ 391 ret = of_property_read_u32(client->dev.of_node, 392 "isil,pwr-bsw", &bsw_val); 393 set_bsw = (ret == 0); 394 395 ret = of_property_read_u32(client->dev.of_node, 396 "isil,pwr-sbib", &sbib_val); 397 set_sbib = (ret == 0); 398 399 /* Check if PWR.BSW and/or PWR.SBIB need specified values */ 400 if (!set_bsw && !set_sbib) 401 return; 402 403 pwr = isl12026_read_reg(client, ISL12026_REG_PWR); 404 if (pwr < 0) { 405 dev_warn(&client->dev, "Error: Failed to read PWR %d\n", pwr); 406 return; 407 } 408 409 requested_pwr = pwr; 410 411 if (set_bsw) { 412 if (bsw_val) 413 requested_pwr |= ISL12026_REG_PWR_BSW; 414 else 415 requested_pwr &= ~ISL12026_REG_PWR_BSW; 416 } /* else keep current BSW */ 417 418 if (set_sbib) { 419 if (sbib_val) 420 requested_pwr |= ISL12026_REG_PWR_SBIB; 421 else 422 requested_pwr &= ~ISL12026_REG_PWR_SBIB; 423 } /* else keep current SBIB */ 424 425 if (pwr >= 0 && pwr != requested_pwr) { 426 dev_dbg(&client->dev, "PWR: %02x\n", pwr); 427 dev_dbg(&client->dev, "Updating PWR to: %02x\n", requested_pwr); 428 isl12026_write_reg(client, ISL12026_REG_PWR, requested_pwr); 429 } 430 } 431 432 static int isl12026_probe_new(struct i2c_client *client) 433 { 434 struct isl12026 *priv; 435 int ret; 436 struct nvmem_config nvm_cfg = { 437 .name = "isl12026-", 438 .base_dev = &client->dev, 439 .stride = 1, 440 .word_size = 1, 441 .size = 512, 442 .reg_read = isl12026_nvm_read, 443 .reg_write = isl12026_nvm_write, 444 }; 445 446 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 447 return -ENODEV; 448 449 priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); 450 if (!priv) 451 return -ENOMEM; 452 453 i2c_set_clientdata(client, priv); 454 455 isl12026_force_power_modes(client); 456 457 priv->nvm_client = i2c_new_dummy_device(client->adapter, ISL12026_EEPROM_ADDR); 458 if (IS_ERR(priv->nvm_client)) 459 return PTR_ERR(priv->nvm_client); 460 461 priv->rtc = devm_rtc_allocate_device(&client->dev); 462 ret = PTR_ERR_OR_ZERO(priv->rtc); 463 if (ret) 464 return ret; 465 466 priv->rtc->ops = &isl12026_rtc_ops; 467 nvm_cfg.priv = priv; 468 ret = rtc_nvmem_register(priv->rtc, &nvm_cfg); 469 if (ret) 470 return ret; 471 472 return rtc_register_device(priv->rtc); 473 } 474 475 static int isl12026_remove(struct i2c_client *client) 476 { 477 struct isl12026 *priv = i2c_get_clientdata(client); 478 479 i2c_unregister_device(priv->nvm_client); 480 return 0; 481 } 482 483 static const struct of_device_id isl12026_dt_match[] = { 484 { .compatible = "isil,isl12026" }, 485 { } 486 }; 487 MODULE_DEVICE_TABLE(of, isl12026_dt_match); 488 489 static struct i2c_driver isl12026_driver = { 490 .driver = { 491 .name = "rtc-isl12026", 492 .of_match_table = isl12026_dt_match, 493 }, 494 .probe_new = isl12026_probe_new, 495 .remove = isl12026_remove, 496 }; 497 498 module_i2c_driver(isl12026_driver); 499 500 MODULE_DESCRIPTION("ISL 12026 RTC driver"); 501 MODULE_LICENSE("GPL"); 502