1 /* 2 * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller 3 * 4 * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; version 2 of the License. 9 * 10 * This driver is based on the ds1621 and ina209 drivers. 11 * 12 * Datasheet: 13 * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517 14 */ 15 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/init.h> 19 #include <linux/err.h> 20 #include <linux/slab.h> 21 #include <linux/i2c.h> 22 #include <linux/hwmon.h> 23 #include <linux/hwmon-sysfs.h> 24 #include <linux/jiffies.h> 25 #include <linux/i2c/ltc4245.h> 26 27 /* Here are names of the chip's registers (a.k.a. commands) */ 28 enum ltc4245_cmd { 29 LTC4245_STATUS = 0x00, /* readonly */ 30 LTC4245_ALERT = 0x01, 31 LTC4245_CONTROL = 0x02, 32 LTC4245_ON = 0x03, 33 LTC4245_FAULT1 = 0x04, 34 LTC4245_FAULT2 = 0x05, 35 LTC4245_GPIO = 0x06, 36 LTC4245_ADCADR = 0x07, 37 38 LTC4245_12VIN = 0x10, 39 LTC4245_12VSENSE = 0x11, 40 LTC4245_12VOUT = 0x12, 41 LTC4245_5VIN = 0x13, 42 LTC4245_5VSENSE = 0x14, 43 LTC4245_5VOUT = 0x15, 44 LTC4245_3VIN = 0x16, 45 LTC4245_3VSENSE = 0x17, 46 LTC4245_3VOUT = 0x18, 47 LTC4245_VEEIN = 0x19, 48 LTC4245_VEESENSE = 0x1a, 49 LTC4245_VEEOUT = 0x1b, 50 LTC4245_GPIOADC = 0x1c, 51 }; 52 53 struct ltc4245_data { 54 struct device *hwmon_dev; 55 56 struct mutex update_lock; 57 bool valid; 58 unsigned long last_updated; /* in jiffies */ 59 60 /* Control registers */ 61 u8 cregs[0x08]; 62 63 /* Voltage registers */ 64 u8 vregs[0x0d]; 65 66 /* GPIO ADC registers */ 67 bool use_extra_gpios; 68 int gpios[3]; 69 }; 70 71 /* 72 * Update the readings from the GPIO pins. If the driver has been configured to 73 * sample all GPIO's as analog voltages, a round-robin sampling method is used. 74 * Otherwise, only the configured GPIO pin is sampled. 75 * 76 * LOCKING: must hold data->update_lock 77 */ 78 static void ltc4245_update_gpios(struct device *dev) 79 { 80 struct i2c_client *client = to_i2c_client(dev); 81 struct ltc4245_data *data = i2c_get_clientdata(client); 82 u8 gpio_curr, gpio_next, gpio_reg; 83 int i; 84 85 /* no extra gpio support, we're basically done */ 86 if (!data->use_extra_gpios) { 87 data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10]; 88 return; 89 } 90 91 /* 92 * If the last reading was too long ago, then we mark all old GPIO 93 * readings as stale by setting them to -EAGAIN 94 */ 95 if (time_after(jiffies, data->last_updated + 5 * HZ)) { 96 dev_dbg(&client->dev, "Marking GPIOs invalid\n"); 97 for (i = 0; i < ARRAY_SIZE(data->gpios); i++) 98 data->gpios[i] = -EAGAIN; 99 } 100 101 /* 102 * Get the current GPIO pin 103 * 104 * The datasheet calls these GPIO[1-3], but we'll calculate the zero 105 * based array index instead, and call them GPIO[0-2]. This is much 106 * easier to think about. 107 */ 108 gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6; 109 if (gpio_curr > 0) 110 gpio_curr -= 1; 111 112 /* Read the GPIO voltage from the GPIOADC register */ 113 data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10]; 114 115 /* Find the next GPIO pin to read */ 116 gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios); 117 118 /* 119 * Calculate the correct setting for the GPIO register so it will 120 * sample the next GPIO pin 121 */ 122 gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6); 123 124 /* Update the GPIO register */ 125 i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg); 126 127 /* Update saved data */ 128 data->cregs[LTC4245_GPIO] = gpio_reg; 129 } 130 131 static struct ltc4245_data *ltc4245_update_device(struct device *dev) 132 { 133 struct i2c_client *client = to_i2c_client(dev); 134 struct ltc4245_data *data = i2c_get_clientdata(client); 135 s32 val; 136 int i; 137 138 mutex_lock(&data->update_lock); 139 140 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { 141 142 dev_dbg(&client->dev, "Starting ltc4245 update\n"); 143 144 /* Read control registers -- 0x00 to 0x07 */ 145 for (i = 0; i < ARRAY_SIZE(data->cregs); i++) { 146 val = i2c_smbus_read_byte_data(client, i); 147 if (unlikely(val < 0)) 148 data->cregs[i] = 0; 149 else 150 data->cregs[i] = val; 151 } 152 153 /* Read voltage registers -- 0x10 to 0x1c */ 154 for (i = 0; i < ARRAY_SIZE(data->vregs); i++) { 155 val = i2c_smbus_read_byte_data(client, i+0x10); 156 if (unlikely(val < 0)) 157 data->vregs[i] = 0; 158 else 159 data->vregs[i] = val; 160 } 161 162 /* Update GPIO readings */ 163 ltc4245_update_gpios(dev); 164 165 data->last_updated = jiffies; 166 data->valid = 1; 167 } 168 169 mutex_unlock(&data->update_lock); 170 171 return data; 172 } 173 174 /* Return the voltage from the given register in millivolts */ 175 static int ltc4245_get_voltage(struct device *dev, u8 reg) 176 { 177 struct ltc4245_data *data = ltc4245_update_device(dev); 178 const u8 regval = data->vregs[reg - 0x10]; 179 u32 voltage = 0; 180 181 switch (reg) { 182 case LTC4245_12VIN: 183 case LTC4245_12VOUT: 184 voltage = regval * 55; 185 break; 186 case LTC4245_5VIN: 187 case LTC4245_5VOUT: 188 voltage = regval * 22; 189 break; 190 case LTC4245_3VIN: 191 case LTC4245_3VOUT: 192 voltage = regval * 15; 193 break; 194 case LTC4245_VEEIN: 195 case LTC4245_VEEOUT: 196 voltage = regval * -55; 197 break; 198 case LTC4245_GPIOADC: 199 voltage = regval * 10; 200 break; 201 default: 202 /* If we get here, the developer messed up */ 203 WARN_ON_ONCE(1); 204 break; 205 } 206 207 return voltage; 208 } 209 210 /* Return the current in the given sense register in milliAmperes */ 211 static unsigned int ltc4245_get_current(struct device *dev, u8 reg) 212 { 213 struct ltc4245_data *data = ltc4245_update_device(dev); 214 const u8 regval = data->vregs[reg - 0x10]; 215 unsigned int voltage; 216 unsigned int curr; 217 218 /* 219 * The strange looking conversions that follow are fixed-point 220 * math, since we cannot do floating point in the kernel. 221 * 222 * Step 1: convert sense register to microVolts 223 * Step 2: convert voltage to milliAmperes 224 * 225 * If you play around with the V=IR equation, you come up with 226 * the following: X uV / Y mOhm == Z mA 227 * 228 * With the resistors that are fractions of a milliOhm, we multiply 229 * the voltage and resistance by 10, to shift the decimal point. 230 * Now we can use the normal division operator again. 231 */ 232 233 switch (reg) { 234 case LTC4245_12VSENSE: 235 voltage = regval * 250; /* voltage in uV */ 236 curr = voltage / 50; /* sense resistor 50 mOhm */ 237 break; 238 case LTC4245_5VSENSE: 239 voltage = regval * 125; /* voltage in uV */ 240 curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */ 241 break; 242 case LTC4245_3VSENSE: 243 voltage = regval * 125; /* voltage in uV */ 244 curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */ 245 break; 246 case LTC4245_VEESENSE: 247 voltage = regval * 250; /* voltage in uV */ 248 curr = voltage / 100; /* sense resistor 100 mOhm */ 249 break; 250 default: 251 /* If we get here, the developer messed up */ 252 WARN_ON_ONCE(1); 253 curr = 0; 254 break; 255 } 256 257 return curr; 258 } 259 260 static ssize_t ltc4245_show_voltage(struct device *dev, 261 struct device_attribute *da, 262 char *buf) 263 { 264 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 265 const int voltage = ltc4245_get_voltage(dev, attr->index); 266 267 return snprintf(buf, PAGE_SIZE, "%d\n", voltage); 268 } 269 270 static ssize_t ltc4245_show_current(struct device *dev, 271 struct device_attribute *da, 272 char *buf) 273 { 274 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 275 const unsigned int curr = ltc4245_get_current(dev, attr->index); 276 277 return snprintf(buf, PAGE_SIZE, "%u\n", curr); 278 } 279 280 static ssize_t ltc4245_show_power(struct device *dev, 281 struct device_attribute *da, 282 char *buf) 283 { 284 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 285 const unsigned int curr = ltc4245_get_current(dev, attr->index); 286 const int output_voltage = ltc4245_get_voltage(dev, attr->index+1); 287 288 /* current in mA * voltage in mV == power in uW */ 289 const unsigned int power = abs(output_voltage * curr); 290 291 return snprintf(buf, PAGE_SIZE, "%u\n", power); 292 } 293 294 static ssize_t ltc4245_show_alarm(struct device *dev, 295 struct device_attribute *da, 296 char *buf) 297 { 298 struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da); 299 struct ltc4245_data *data = ltc4245_update_device(dev); 300 const u8 reg = data->cregs[attr->index]; 301 const u32 mask = attr->nr; 302 303 return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0); 304 } 305 306 static ssize_t ltc4245_show_gpio(struct device *dev, 307 struct device_attribute *da, 308 char *buf) 309 { 310 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 311 struct ltc4245_data *data = ltc4245_update_device(dev); 312 int val = data->gpios[attr->index]; 313 314 /* handle stale GPIO's */ 315 if (val < 0) 316 return val; 317 318 /* Convert to millivolts and print */ 319 return snprintf(buf, PAGE_SIZE, "%u\n", val * 10); 320 } 321 322 /* Construct a sensor_device_attribute structure for each register */ 323 324 /* Input voltages */ 325 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4245_show_voltage, NULL, 326 LTC4245_12VIN); 327 static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4245_show_voltage, NULL, 328 LTC4245_5VIN); 329 static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4245_show_voltage, NULL, 330 LTC4245_3VIN); 331 static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4245_show_voltage, NULL, 332 LTC4245_VEEIN); 333 334 /* Input undervoltage alarms */ 335 static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 336 1 << 0, LTC4245_FAULT1); 337 static SENSOR_DEVICE_ATTR_2(in2_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 338 1 << 1, LTC4245_FAULT1); 339 static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 340 1 << 2, LTC4245_FAULT1); 341 static SENSOR_DEVICE_ATTR_2(in4_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 342 1 << 3, LTC4245_FAULT1); 343 344 /* Currents (via sense resistor) */ 345 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4245_show_current, NULL, 346 LTC4245_12VSENSE); 347 static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4245_show_current, NULL, 348 LTC4245_5VSENSE); 349 static SENSOR_DEVICE_ATTR(curr3_input, S_IRUGO, ltc4245_show_current, NULL, 350 LTC4245_3VSENSE); 351 static SENSOR_DEVICE_ATTR(curr4_input, S_IRUGO, ltc4245_show_current, NULL, 352 LTC4245_VEESENSE); 353 354 /* Overcurrent alarms */ 355 static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 356 1 << 4, LTC4245_FAULT1); 357 static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 358 1 << 5, LTC4245_FAULT1); 359 static SENSOR_DEVICE_ATTR_2(curr3_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 360 1 << 6, LTC4245_FAULT1); 361 static SENSOR_DEVICE_ATTR_2(curr4_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 362 1 << 7, LTC4245_FAULT1); 363 364 /* Output voltages */ 365 static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ltc4245_show_voltage, NULL, 366 LTC4245_12VOUT); 367 static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ltc4245_show_voltage, NULL, 368 LTC4245_5VOUT); 369 static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ltc4245_show_voltage, NULL, 370 LTC4245_3VOUT); 371 static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, ltc4245_show_voltage, NULL, 372 LTC4245_VEEOUT); 373 374 /* Power Bad alarms */ 375 static SENSOR_DEVICE_ATTR_2(in5_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 376 1 << 0, LTC4245_FAULT2); 377 static SENSOR_DEVICE_ATTR_2(in6_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 378 1 << 1, LTC4245_FAULT2); 379 static SENSOR_DEVICE_ATTR_2(in7_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 380 1 << 2, LTC4245_FAULT2); 381 static SENSOR_DEVICE_ATTR_2(in8_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 382 1 << 3, LTC4245_FAULT2); 383 384 /* GPIO voltages */ 385 static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, ltc4245_show_gpio, NULL, 0); 386 static SENSOR_DEVICE_ATTR(in10_input, S_IRUGO, ltc4245_show_gpio, NULL, 1); 387 static SENSOR_DEVICE_ATTR(in11_input, S_IRUGO, ltc4245_show_gpio, NULL, 2); 388 389 /* Power Consumption (virtual) */ 390 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ltc4245_show_power, NULL, 391 LTC4245_12VSENSE); 392 static SENSOR_DEVICE_ATTR(power2_input, S_IRUGO, ltc4245_show_power, NULL, 393 LTC4245_5VSENSE); 394 static SENSOR_DEVICE_ATTR(power3_input, S_IRUGO, ltc4245_show_power, NULL, 395 LTC4245_3VSENSE); 396 static SENSOR_DEVICE_ATTR(power4_input, S_IRUGO, ltc4245_show_power, NULL, 397 LTC4245_VEESENSE); 398 399 /* 400 * Finally, construct an array of pointers to members of the above objects, 401 * as required for sysfs_create_group() 402 */ 403 static struct attribute *ltc4245_std_attributes[] = { 404 &sensor_dev_attr_in1_input.dev_attr.attr, 405 &sensor_dev_attr_in2_input.dev_attr.attr, 406 &sensor_dev_attr_in3_input.dev_attr.attr, 407 &sensor_dev_attr_in4_input.dev_attr.attr, 408 409 &sensor_dev_attr_in1_min_alarm.dev_attr.attr, 410 &sensor_dev_attr_in2_min_alarm.dev_attr.attr, 411 &sensor_dev_attr_in3_min_alarm.dev_attr.attr, 412 &sensor_dev_attr_in4_min_alarm.dev_attr.attr, 413 414 &sensor_dev_attr_curr1_input.dev_attr.attr, 415 &sensor_dev_attr_curr2_input.dev_attr.attr, 416 &sensor_dev_attr_curr3_input.dev_attr.attr, 417 &sensor_dev_attr_curr4_input.dev_attr.attr, 418 419 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, 420 &sensor_dev_attr_curr2_max_alarm.dev_attr.attr, 421 &sensor_dev_attr_curr3_max_alarm.dev_attr.attr, 422 &sensor_dev_attr_curr4_max_alarm.dev_attr.attr, 423 424 &sensor_dev_attr_in5_input.dev_attr.attr, 425 &sensor_dev_attr_in6_input.dev_attr.attr, 426 &sensor_dev_attr_in7_input.dev_attr.attr, 427 &sensor_dev_attr_in8_input.dev_attr.attr, 428 429 &sensor_dev_attr_in5_min_alarm.dev_attr.attr, 430 &sensor_dev_attr_in6_min_alarm.dev_attr.attr, 431 &sensor_dev_attr_in7_min_alarm.dev_attr.attr, 432 &sensor_dev_attr_in8_min_alarm.dev_attr.attr, 433 434 &sensor_dev_attr_in9_input.dev_attr.attr, 435 436 &sensor_dev_attr_power1_input.dev_attr.attr, 437 &sensor_dev_attr_power2_input.dev_attr.attr, 438 &sensor_dev_attr_power3_input.dev_attr.attr, 439 &sensor_dev_attr_power4_input.dev_attr.attr, 440 441 NULL, 442 }; 443 444 static struct attribute *ltc4245_gpio_attributes[] = { 445 &sensor_dev_attr_in10_input.dev_attr.attr, 446 &sensor_dev_attr_in11_input.dev_attr.attr, 447 NULL, 448 }; 449 450 static const struct attribute_group ltc4245_std_group = { 451 .attrs = ltc4245_std_attributes, 452 }; 453 454 static const struct attribute_group ltc4245_gpio_group = { 455 .attrs = ltc4245_gpio_attributes, 456 }; 457 458 static int ltc4245_sysfs_create_groups(struct i2c_client *client) 459 { 460 struct ltc4245_data *data = i2c_get_clientdata(client); 461 struct device *dev = &client->dev; 462 int ret; 463 464 /* register the standard sysfs attributes */ 465 ret = sysfs_create_group(&dev->kobj, <c4245_std_group); 466 if (ret) { 467 dev_err(dev, "unable to register standard attributes\n"); 468 return ret; 469 } 470 471 /* if we're using the extra gpio support, register it's attributes */ 472 if (data->use_extra_gpios) { 473 ret = sysfs_create_group(&dev->kobj, <c4245_gpio_group); 474 if (ret) { 475 dev_err(dev, "unable to register gpio attributes\n"); 476 sysfs_remove_group(&dev->kobj, <c4245_std_group); 477 return ret; 478 } 479 } 480 481 return 0; 482 } 483 484 static void ltc4245_sysfs_remove_groups(struct i2c_client *client) 485 { 486 struct ltc4245_data *data = i2c_get_clientdata(client); 487 struct device *dev = &client->dev; 488 489 if (data->use_extra_gpios) 490 sysfs_remove_group(&dev->kobj, <c4245_gpio_group); 491 492 sysfs_remove_group(&dev->kobj, <c4245_std_group); 493 } 494 495 static bool ltc4245_use_extra_gpios(struct i2c_client *client) 496 { 497 struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev); 498 #ifdef CONFIG_OF 499 struct device_node *np = client->dev.of_node; 500 #endif 501 502 /* prefer platform data */ 503 if (pdata) 504 return pdata->use_extra_gpios; 505 506 #ifdef CONFIG_OF 507 /* fallback on OF */ 508 if (of_find_property(np, "ltc4245,use-extra-gpios", NULL)) 509 return true; 510 #endif 511 512 return false; 513 } 514 515 static int ltc4245_probe(struct i2c_client *client, 516 const struct i2c_device_id *id) 517 { 518 struct i2c_adapter *adapter = client->adapter; 519 struct ltc4245_data *data; 520 int ret; 521 522 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 523 return -ENODEV; 524 525 data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); 526 if (!data) 527 return -ENOMEM; 528 529 i2c_set_clientdata(client, data); 530 mutex_init(&data->update_lock); 531 data->use_extra_gpios = ltc4245_use_extra_gpios(client); 532 533 /* Initialize the LTC4245 chip */ 534 i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00); 535 i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00); 536 537 /* Register sysfs hooks */ 538 ret = ltc4245_sysfs_create_groups(client); 539 if (ret) 540 return ret; 541 542 data->hwmon_dev = hwmon_device_register(&client->dev); 543 if (IS_ERR(data->hwmon_dev)) { 544 ret = PTR_ERR(data->hwmon_dev); 545 goto out_hwmon_device_register; 546 } 547 548 return 0; 549 550 out_hwmon_device_register: 551 ltc4245_sysfs_remove_groups(client); 552 return ret; 553 } 554 555 static int ltc4245_remove(struct i2c_client *client) 556 { 557 struct ltc4245_data *data = i2c_get_clientdata(client); 558 559 hwmon_device_unregister(data->hwmon_dev); 560 ltc4245_sysfs_remove_groups(client); 561 562 return 0; 563 } 564 565 static const struct i2c_device_id ltc4245_id[] = { 566 { "ltc4245", 0 }, 567 { } 568 }; 569 MODULE_DEVICE_TABLE(i2c, ltc4245_id); 570 571 /* This is the driver that will be inserted */ 572 static struct i2c_driver ltc4245_driver = { 573 .driver = { 574 .name = "ltc4245", 575 }, 576 .probe = ltc4245_probe, 577 .remove = ltc4245_remove, 578 .id_table = ltc4245_id, 579 }; 580 581 module_i2c_driver(ltc4245_driver); 582 583 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>"); 584 MODULE_DESCRIPTION("LTC4245 driver"); 585 MODULE_LICENSE("GPL"); 586