1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Hardware monitoring driver for Maxim MAX6620 4 * 5 * Originally from L. Grunenberg. 6 * (C) 2012 by L. Grunenberg <contact@lgrunenberg.de> 7 * 8 * Copyright (c) 2021 Dell Inc. or its subsidiaries. All Rights Reserved. 9 * 10 * based on code written by : 11 * 2007 by Hans J. Koch <hjk@hansjkoch.de> 12 * John Morris <john.morris@spirentcom.com> 13 * Copyright (c) 2003 Spirent Communications 14 * and Claus Gindhart <claus.gindhart@kontron.com> 15 * 16 * This module has only been tested with the MAX6620 chip. 17 * 18 * The datasheet was last seen at: 19 * 20 * http://pdfserv.maxim-ic.com/en/ds/MAX6620.pdf 21 * 22 */ 23 24 #include <linux/bits.h> 25 #include <linux/err.h> 26 #include <linux/hwmon.h> 27 #include <linux/i2c.h> 28 #include <linux/init.h> 29 #include <linux/jiffies.h> 30 #include <linux/module.h> 31 #include <linux/slab.h> 32 33 /* 34 * MAX 6620 registers 35 */ 36 37 #define MAX6620_REG_CONFIG 0x00 38 #define MAX6620_REG_FAULT 0x01 39 #define MAX6620_REG_CONF_FAN0 0x02 40 #define MAX6620_REG_CONF_FAN1 0x03 41 #define MAX6620_REG_CONF_FAN2 0x04 42 #define MAX6620_REG_CONF_FAN3 0x05 43 #define MAX6620_REG_DYN_FAN0 0x06 44 #define MAX6620_REG_DYN_FAN1 0x07 45 #define MAX6620_REG_DYN_FAN2 0x08 46 #define MAX6620_REG_DYN_FAN3 0x09 47 #define MAX6620_REG_TACH0 0x10 48 #define MAX6620_REG_TACH1 0x12 49 #define MAX6620_REG_TACH2 0x14 50 #define MAX6620_REG_TACH3 0x16 51 #define MAX6620_REG_VOLT0 0x18 52 #define MAX6620_REG_VOLT1 0x1A 53 #define MAX6620_REG_VOLT2 0x1C 54 #define MAX6620_REG_VOLT3 0x1E 55 #define MAX6620_REG_TAR0 0x20 56 #define MAX6620_REG_TAR1 0x22 57 #define MAX6620_REG_TAR2 0x24 58 #define MAX6620_REG_TAR3 0x26 59 #define MAX6620_REG_DAC0 0x28 60 #define MAX6620_REG_DAC1 0x2A 61 #define MAX6620_REG_DAC2 0x2C 62 #define MAX6620_REG_DAC3 0x2E 63 64 /* 65 * Config register bits 66 */ 67 68 #define MAX6620_CFG_RUN BIT(7) 69 #define MAX6620_CFG_POR BIT(6) 70 #define MAX6620_CFG_TIMEOUT BIT(5) 71 #define MAX6620_CFG_FULLFAN BIT(4) 72 #define MAX6620_CFG_OSC BIT(3) 73 #define MAX6620_CFG_WD_MASK (BIT(2) | BIT(1)) 74 #define MAX6620_CFG_WD_2 BIT(1) 75 #define MAX6620_CFG_WD_6 BIT(2) 76 #define MAX6620_CFG_WD10 (BIT(2) | BIT(1)) 77 #define MAX6620_CFG_WD BIT(0) 78 79 /* 80 * Failure status register bits 81 */ 82 83 #define MAX6620_FAIL_TACH0 BIT(4) 84 #define MAX6620_FAIL_TACH1 BIT(5) 85 #define MAX6620_FAIL_TACH2 BIT(6) 86 #define MAX6620_FAIL_TACH3 BIT(7) 87 #define MAX6620_FAIL_MASK0 BIT(0) 88 #define MAX6620_FAIL_MASK1 BIT(1) 89 #define MAX6620_FAIL_MASK2 BIT(2) 90 #define MAX6620_FAIL_MASK3 BIT(3) 91 92 #define MAX6620_CLOCK_FREQ 8192 /* Clock frequency in Hz */ 93 #define MAX6620_PULSE_PER_REV 2 /* Tachometer pulses per revolution */ 94 95 /* Minimum and maximum values of the FAN-RPM */ 96 #define FAN_RPM_MIN 240 97 #define FAN_RPM_MAX 30000 98 99 static const u8 config_reg[] = { 100 MAX6620_REG_CONF_FAN0, 101 MAX6620_REG_CONF_FAN1, 102 MAX6620_REG_CONF_FAN2, 103 MAX6620_REG_CONF_FAN3, 104 }; 105 106 static const u8 dyn_reg[] = { 107 MAX6620_REG_DYN_FAN0, 108 MAX6620_REG_DYN_FAN1, 109 MAX6620_REG_DYN_FAN2, 110 MAX6620_REG_DYN_FAN3, 111 }; 112 113 static const u8 tach_reg[] = { 114 MAX6620_REG_TACH0, 115 MAX6620_REG_TACH1, 116 MAX6620_REG_TACH2, 117 MAX6620_REG_TACH3, 118 }; 119 120 static const u8 target_reg[] = { 121 MAX6620_REG_TAR0, 122 MAX6620_REG_TAR1, 123 MAX6620_REG_TAR2, 124 MAX6620_REG_TAR3, 125 }; 126 127 /* 128 * Client data (each client gets its own) 129 */ 130 131 struct max6620_data { 132 struct i2c_client *client; 133 struct mutex update_lock; 134 bool valid; /* false until following fields are valid */ 135 unsigned long last_updated; /* in jiffies */ 136 137 /* register values */ 138 u8 fancfg[4]; 139 u8 fandyn[4]; 140 u8 fault; 141 u16 tach[4]; 142 u16 target[4]; 143 }; 144 145 static u8 max6620_fan_div_from_reg(u8 val) 146 { 147 return BIT((val & 0xE0) >> 5); 148 } 149 150 static u16 max6620_fan_rpm_to_tach(u8 div, int rpm) 151 { 152 return (60 * div * MAX6620_CLOCK_FREQ) / (rpm * MAX6620_PULSE_PER_REV); 153 } 154 155 static int max6620_fan_tach_to_rpm(u8 div, u16 tach) 156 { 157 return (60 * div * MAX6620_CLOCK_FREQ) / (tach * MAX6620_PULSE_PER_REV); 158 } 159 160 static int max6620_update_device(struct device *dev) 161 { 162 struct max6620_data *data = dev_get_drvdata(dev); 163 struct i2c_client *client = data->client; 164 int i; 165 int ret = 0; 166 167 mutex_lock(&data->update_lock); 168 169 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { 170 for (i = 0; i < 4; i++) { 171 ret = i2c_smbus_read_byte_data(client, config_reg[i]); 172 if (ret < 0) 173 goto error; 174 data->fancfg[i] = ret; 175 176 ret = i2c_smbus_read_byte_data(client, dyn_reg[i]); 177 if (ret < 0) 178 goto error; 179 data->fandyn[i] = ret; 180 181 ret = i2c_smbus_read_byte_data(client, tach_reg[i]); 182 if (ret < 0) 183 goto error; 184 data->tach[i] = (ret << 3) & 0x7f8; 185 ret = i2c_smbus_read_byte_data(client, tach_reg[i] + 1); 186 if (ret < 0) 187 goto error; 188 data->tach[i] |= (ret >> 5) & 0x7; 189 190 ret = i2c_smbus_read_byte_data(client, target_reg[i]); 191 if (ret < 0) 192 goto error; 193 data->target[i] = (ret << 3) & 0x7f8; 194 ret = i2c_smbus_read_byte_data(client, target_reg[i] + 1); 195 if (ret < 0) 196 goto error; 197 data->target[i] |= (ret >> 5) & 0x7; 198 } 199 200 /* 201 * Alarms are cleared on read in case the condition that 202 * caused the alarm is removed. Keep the value latched here 203 * for providing the register through different alarm files. 204 */ 205 ret = i2c_smbus_read_byte_data(client, MAX6620_REG_FAULT); 206 if (ret < 0) 207 goto error; 208 data->fault |= (ret >> 4) & (ret & 0x0F); 209 210 data->last_updated = jiffies; 211 data->valid = true; 212 } 213 214 error: 215 mutex_unlock(&data->update_lock); 216 return ret; 217 } 218 219 static umode_t 220 max6620_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, 221 int channel) 222 { 223 switch (type) { 224 case hwmon_fan: 225 switch (attr) { 226 case hwmon_fan_alarm: 227 case hwmon_fan_input: 228 return 0444; 229 case hwmon_fan_div: 230 case hwmon_fan_target: 231 return 0644; 232 default: 233 break; 234 } 235 break; 236 default: 237 break; 238 } 239 240 return 0; 241 } 242 243 static int 244 max6620_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, 245 int channel, long *val) 246 { 247 struct max6620_data *data; 248 struct i2c_client *client; 249 int ret; 250 u8 div; 251 u8 val1; 252 u8 val2; 253 254 ret = max6620_update_device(dev); 255 if (ret < 0) 256 return ret; 257 data = dev_get_drvdata(dev); 258 client = data->client; 259 260 switch (type) { 261 case hwmon_fan: 262 switch (attr) { 263 case hwmon_fan_alarm: 264 mutex_lock(&data->update_lock); 265 *val = !!(data->fault & BIT(channel)); 266 267 /* Setting TACH count to re-enable fan fault detection */ 268 if (*val == 1) { 269 val1 = (data->target[channel] >> 3) & 0xff; 270 val2 = (data->target[channel] << 5) & 0xe0; 271 ret = i2c_smbus_write_byte_data(client, 272 target_reg[channel], val1); 273 if (ret < 0) { 274 mutex_unlock(&data->update_lock); 275 return ret; 276 } 277 ret = i2c_smbus_write_byte_data(client, 278 target_reg[channel] + 1, val2); 279 if (ret < 0) { 280 mutex_unlock(&data->update_lock); 281 return ret; 282 } 283 284 data->fault &= ~BIT(channel); 285 } 286 mutex_unlock(&data->update_lock); 287 288 break; 289 case hwmon_fan_div: 290 *val = max6620_fan_div_from_reg(data->fandyn[channel]); 291 break; 292 case hwmon_fan_input: 293 if (data->tach[channel] == 0) { 294 *val = 0; 295 } else { 296 div = max6620_fan_div_from_reg(data->fandyn[channel]); 297 *val = max6620_fan_tach_to_rpm(div, data->tach[channel]); 298 } 299 break; 300 case hwmon_fan_target: 301 if (data->target[channel] == 0) { 302 *val = 0; 303 } else { 304 div = max6620_fan_div_from_reg(data->fandyn[channel]); 305 *val = max6620_fan_tach_to_rpm(div, data->target[channel]); 306 } 307 break; 308 default: 309 return -EOPNOTSUPP; 310 } 311 break; 312 313 default: 314 return -EOPNOTSUPP; 315 } 316 317 return 0; 318 } 319 320 static int 321 max6620_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, 322 int channel, long val) 323 { 324 struct max6620_data *data; 325 struct i2c_client *client; 326 int ret; 327 u8 div; 328 u16 tach; 329 u8 val1; 330 u8 val2; 331 332 ret = max6620_update_device(dev); 333 if (ret < 0) 334 return ret; 335 data = dev_get_drvdata(dev); 336 client = data->client; 337 mutex_lock(&data->update_lock); 338 339 switch (type) { 340 case hwmon_fan: 341 switch (attr) { 342 case hwmon_fan_div: 343 switch (val) { 344 case 1: 345 div = 0; 346 break; 347 case 2: 348 div = 1; 349 break; 350 case 4: 351 div = 2; 352 break; 353 case 8: 354 div = 3; 355 break; 356 case 16: 357 div = 4; 358 break; 359 case 32: 360 div = 5; 361 break; 362 default: 363 ret = -EINVAL; 364 goto error; 365 } 366 data->fandyn[channel] &= 0x1F; 367 data->fandyn[channel] |= div << 5; 368 ret = i2c_smbus_write_byte_data(client, dyn_reg[channel], 369 data->fandyn[channel]); 370 break; 371 case hwmon_fan_target: 372 val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX); 373 div = max6620_fan_div_from_reg(data->fandyn[channel]); 374 tach = max6620_fan_rpm_to_tach(div, val); 375 val1 = (tach >> 3) & 0xff; 376 val2 = (tach << 5) & 0xe0; 377 ret = i2c_smbus_write_byte_data(client, target_reg[channel], val1); 378 if (ret < 0) 379 break; 380 ret = i2c_smbus_write_byte_data(client, target_reg[channel] + 1, val2); 381 if (ret < 0) 382 break; 383 384 /* Setting TACH count re-enables fan fault detection */ 385 data->fault &= ~BIT(channel); 386 387 break; 388 default: 389 ret = -EOPNOTSUPP; 390 break; 391 } 392 break; 393 394 default: 395 ret = -EOPNOTSUPP; 396 break; 397 } 398 399 error: 400 mutex_unlock(&data->update_lock); 401 return ret; 402 } 403 404 static const struct hwmon_channel_info * const max6620_info[] = { 405 HWMON_CHANNEL_INFO(fan, 406 HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM, 407 HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM, 408 HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM, 409 HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM), 410 NULL 411 }; 412 413 static const struct hwmon_ops max6620_hwmon_ops = { 414 .read = max6620_read, 415 .write = max6620_write, 416 .is_visible = max6620_is_visible, 417 }; 418 419 static const struct hwmon_chip_info max6620_chip_info = { 420 .ops = &max6620_hwmon_ops, 421 .info = max6620_info, 422 }; 423 424 static int max6620_init_client(struct max6620_data *data) 425 { 426 struct i2c_client *client = data->client; 427 int config; 428 int err; 429 int i; 430 int reg; 431 432 config = i2c_smbus_read_byte_data(client, MAX6620_REG_CONFIG); 433 if (config < 0) { 434 dev_err(&client->dev, "Error reading config, aborting.\n"); 435 return config; 436 } 437 438 /* 439 * Set bit 4, disable other fans from going full speed on a fail 440 * failure. 441 */ 442 err = i2c_smbus_write_byte_data(client, MAX6620_REG_CONFIG, config | 0x10); 443 if (err < 0) { 444 dev_err(&client->dev, "Config write error, aborting.\n"); 445 return err; 446 } 447 448 for (i = 0; i < 4; i++) { 449 reg = i2c_smbus_read_byte_data(client, config_reg[i]); 450 if (reg < 0) 451 return reg; 452 data->fancfg[i] = reg; 453 454 /* Enable RPM mode */ 455 data->fancfg[i] |= 0xa8; 456 err = i2c_smbus_write_byte_data(client, config_reg[i], data->fancfg[i]); 457 if (err < 0) 458 return err; 459 460 /* 2 counts (001) and Rate change 100 (0.125 secs) */ 461 data->fandyn[i] = 0x30; 462 err = i2c_smbus_write_byte_data(client, dyn_reg[i], data->fandyn[i]); 463 if (err < 0) 464 return err; 465 } 466 return 0; 467 } 468 469 static int max6620_probe(struct i2c_client *client) 470 { 471 struct device *dev = &client->dev; 472 struct max6620_data *data; 473 struct device *hwmon_dev; 474 int err; 475 476 data = devm_kzalloc(dev, sizeof(struct max6620_data), GFP_KERNEL); 477 if (!data) 478 return -ENOMEM; 479 480 data->client = client; 481 mutex_init(&data->update_lock); 482 483 err = max6620_init_client(data); 484 if (err) 485 return err; 486 487 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, 488 data, 489 &max6620_chip_info, 490 NULL); 491 492 return PTR_ERR_OR_ZERO(hwmon_dev); 493 } 494 495 static const struct i2c_device_id max6620_id[] = { 496 { "max6620", 0 }, 497 { } 498 }; 499 MODULE_DEVICE_TABLE(i2c, max6620_id); 500 501 static struct i2c_driver max6620_driver = { 502 .class = I2C_CLASS_HWMON, 503 .driver = { 504 .name = "max6620", 505 }, 506 .probe = max6620_probe, 507 .id_table = max6620_id, 508 }; 509 510 module_i2c_driver(max6620_driver); 511 512 MODULE_AUTHOR("Lucas Grunenberg"); 513 MODULE_DESCRIPTION("MAX6620 sensor driver"); 514 MODULE_LICENSE("GPL"); 515