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 25 /* Valid addresses are 0x20 - 0x3f 26 * 27 * For now, we do not probe, since some of these addresses 28 * are known to be unfriendly to probing */ 29 static const unsigned short normal_i2c[] = { I2C_CLIENT_END }; 30 31 /* Insmod parameters */ 32 I2C_CLIENT_INSMOD_1(ltc4245); 33 34 /* Here are names of the chip's registers (a.k.a. commands) */ 35 enum ltc4245_cmd { 36 LTC4245_STATUS = 0x00, /* readonly */ 37 LTC4245_ALERT = 0x01, 38 LTC4245_CONTROL = 0x02, 39 LTC4245_ON = 0x03, 40 LTC4245_FAULT1 = 0x04, 41 LTC4245_FAULT2 = 0x05, 42 LTC4245_GPIO = 0x06, 43 LTC4245_ADCADR = 0x07, 44 45 LTC4245_12VIN = 0x10, 46 LTC4245_12VSENSE = 0x11, 47 LTC4245_12VOUT = 0x12, 48 LTC4245_5VIN = 0x13, 49 LTC4245_5VSENSE = 0x14, 50 LTC4245_5VOUT = 0x15, 51 LTC4245_3VIN = 0x16, 52 LTC4245_3VSENSE = 0x17, 53 LTC4245_3VOUT = 0x18, 54 LTC4245_VEEIN = 0x19, 55 LTC4245_VEESENSE = 0x1a, 56 LTC4245_VEEOUT = 0x1b, 57 LTC4245_GPIOADC1 = 0x1c, 58 LTC4245_GPIOADC2 = 0x1d, 59 LTC4245_GPIOADC3 = 0x1e, 60 }; 61 62 struct ltc4245_data { 63 struct device *hwmon_dev; 64 65 struct mutex update_lock; 66 bool valid; 67 unsigned long last_updated; /* in jiffies */ 68 69 /* Control registers */ 70 u8 cregs[0x08]; 71 72 /* Voltage registers */ 73 u8 vregs[0x0f]; 74 }; 75 76 static struct ltc4245_data *ltc4245_update_device(struct device *dev) 77 { 78 struct i2c_client *client = to_i2c_client(dev); 79 struct ltc4245_data *data = i2c_get_clientdata(client); 80 s32 val; 81 int i; 82 83 mutex_lock(&data->update_lock); 84 85 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { 86 87 dev_dbg(&client->dev, "Starting ltc4245 update\n"); 88 89 /* Read control registers -- 0x00 to 0x07 */ 90 for (i = 0; i < ARRAY_SIZE(data->cregs); i++) { 91 val = i2c_smbus_read_byte_data(client, i); 92 if (unlikely(val < 0)) 93 data->cregs[i] = 0; 94 else 95 data->cregs[i] = val; 96 } 97 98 /* Read voltage registers -- 0x10 to 0x1f */ 99 for (i = 0; i < ARRAY_SIZE(data->vregs); i++) { 100 val = i2c_smbus_read_byte_data(client, i+0x10); 101 if (unlikely(val < 0)) 102 data->vregs[i] = 0; 103 else 104 data->vregs[i] = val; 105 } 106 107 data->last_updated = jiffies; 108 data->valid = 1; 109 } 110 111 mutex_unlock(&data->update_lock); 112 113 return data; 114 } 115 116 /* Return the voltage from the given register in millivolts */ 117 static int ltc4245_get_voltage(struct device *dev, u8 reg) 118 { 119 struct ltc4245_data *data = ltc4245_update_device(dev); 120 const u8 regval = data->vregs[reg - 0x10]; 121 u32 voltage = 0; 122 123 switch (reg) { 124 case LTC4245_12VIN: 125 case LTC4245_12VOUT: 126 voltage = regval * 55; 127 break; 128 case LTC4245_5VIN: 129 case LTC4245_5VOUT: 130 voltage = regval * 22; 131 break; 132 case LTC4245_3VIN: 133 case LTC4245_3VOUT: 134 voltage = regval * 15; 135 break; 136 case LTC4245_VEEIN: 137 case LTC4245_VEEOUT: 138 voltage = regval * -55; 139 break; 140 case LTC4245_GPIOADC1: 141 case LTC4245_GPIOADC2: 142 case LTC4245_GPIOADC3: 143 voltage = regval * 10; 144 break; 145 default: 146 /* If we get here, the developer messed up */ 147 WARN_ON_ONCE(1); 148 break; 149 } 150 151 return voltage; 152 } 153 154 /* Return the current in the given sense register in milliAmperes */ 155 static unsigned int ltc4245_get_current(struct device *dev, u8 reg) 156 { 157 struct ltc4245_data *data = ltc4245_update_device(dev); 158 const u8 regval = data->vregs[reg - 0x10]; 159 unsigned int voltage; 160 unsigned int curr; 161 162 /* The strange looking conversions that follow are fixed-point 163 * math, since we cannot do floating point in the kernel. 164 * 165 * Step 1: convert sense register to microVolts 166 * Step 2: convert voltage to milliAmperes 167 * 168 * If you play around with the V=IR equation, you come up with 169 * the following: X uV / Y mOhm == Z mA 170 * 171 * With the resistors that are fractions of a milliOhm, we multiply 172 * the voltage and resistance by 10, to shift the decimal point. 173 * Now we can use the normal division operator again. 174 */ 175 176 switch (reg) { 177 case LTC4245_12VSENSE: 178 voltage = regval * 250; /* voltage in uV */ 179 curr = voltage / 50; /* sense resistor 50 mOhm */ 180 break; 181 case LTC4245_5VSENSE: 182 voltage = regval * 125; /* voltage in uV */ 183 curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */ 184 break; 185 case LTC4245_3VSENSE: 186 voltage = regval * 125; /* voltage in uV */ 187 curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */ 188 break; 189 case LTC4245_VEESENSE: 190 voltage = regval * 250; /* voltage in uV */ 191 curr = voltage / 100; /* sense resistor 100 mOhm */ 192 break; 193 default: 194 /* If we get here, the developer messed up */ 195 WARN_ON_ONCE(1); 196 curr = 0; 197 break; 198 } 199 200 return curr; 201 } 202 203 static ssize_t ltc4245_show_voltage(struct device *dev, 204 struct device_attribute *da, 205 char *buf) 206 { 207 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 208 const int voltage = ltc4245_get_voltage(dev, attr->index); 209 210 return snprintf(buf, PAGE_SIZE, "%d\n", voltage); 211 } 212 213 static ssize_t ltc4245_show_current(struct device *dev, 214 struct device_attribute *da, 215 char *buf) 216 { 217 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 218 const unsigned int curr = ltc4245_get_current(dev, attr->index); 219 220 return snprintf(buf, PAGE_SIZE, "%u\n", curr); 221 } 222 223 static ssize_t ltc4245_show_power(struct device *dev, 224 struct device_attribute *da, 225 char *buf) 226 { 227 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 228 const unsigned int curr = ltc4245_get_current(dev, attr->index); 229 const int output_voltage = ltc4245_get_voltage(dev, attr->index+1); 230 231 /* current in mA * voltage in mV == power in uW */ 232 const unsigned int power = abs(output_voltage * curr); 233 234 return snprintf(buf, PAGE_SIZE, "%u\n", power); 235 } 236 237 static ssize_t ltc4245_show_alarm(struct device *dev, 238 struct device_attribute *da, 239 char *buf) 240 { 241 struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da); 242 struct ltc4245_data *data = ltc4245_update_device(dev); 243 const u8 reg = data->cregs[attr->index]; 244 const u32 mask = attr->nr; 245 246 return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0); 247 } 248 249 /* These macros are used below in constructing device attribute objects 250 * for use with sysfs_create_group() to make a sysfs device file 251 * for each register. 252 */ 253 254 #define LTC4245_VOLTAGE(name, ltc4245_cmd_idx) \ 255 static SENSOR_DEVICE_ATTR(name, S_IRUGO, \ 256 ltc4245_show_voltage, NULL, ltc4245_cmd_idx) 257 258 #define LTC4245_CURRENT(name, ltc4245_cmd_idx) \ 259 static SENSOR_DEVICE_ATTR(name, S_IRUGO, \ 260 ltc4245_show_current, NULL, ltc4245_cmd_idx) 261 262 #define LTC4245_POWER(name, ltc4245_cmd_idx) \ 263 static SENSOR_DEVICE_ATTR(name, S_IRUGO, \ 264 ltc4245_show_power, NULL, ltc4245_cmd_idx) 265 266 #define LTC4245_ALARM(name, mask, reg) \ 267 static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \ 268 ltc4245_show_alarm, NULL, (mask), reg) 269 270 /* Construct a sensor_device_attribute structure for each register */ 271 272 /* Input voltages */ 273 LTC4245_VOLTAGE(in1_input, LTC4245_12VIN); 274 LTC4245_VOLTAGE(in2_input, LTC4245_5VIN); 275 LTC4245_VOLTAGE(in3_input, LTC4245_3VIN); 276 LTC4245_VOLTAGE(in4_input, LTC4245_VEEIN); 277 278 /* Input undervoltage alarms */ 279 LTC4245_ALARM(in1_min_alarm, (1 << 0), LTC4245_FAULT1); 280 LTC4245_ALARM(in2_min_alarm, (1 << 1), LTC4245_FAULT1); 281 LTC4245_ALARM(in3_min_alarm, (1 << 2), LTC4245_FAULT1); 282 LTC4245_ALARM(in4_min_alarm, (1 << 3), LTC4245_FAULT1); 283 284 /* Currents (via sense resistor) */ 285 LTC4245_CURRENT(curr1_input, LTC4245_12VSENSE); 286 LTC4245_CURRENT(curr2_input, LTC4245_5VSENSE); 287 LTC4245_CURRENT(curr3_input, LTC4245_3VSENSE); 288 LTC4245_CURRENT(curr4_input, LTC4245_VEESENSE); 289 290 /* Overcurrent alarms */ 291 LTC4245_ALARM(curr1_max_alarm, (1 << 4), LTC4245_FAULT1); 292 LTC4245_ALARM(curr2_max_alarm, (1 << 5), LTC4245_FAULT1); 293 LTC4245_ALARM(curr3_max_alarm, (1 << 6), LTC4245_FAULT1); 294 LTC4245_ALARM(curr4_max_alarm, (1 << 7), LTC4245_FAULT1); 295 296 /* Output voltages */ 297 LTC4245_VOLTAGE(in5_input, LTC4245_12VOUT); 298 LTC4245_VOLTAGE(in6_input, LTC4245_5VOUT); 299 LTC4245_VOLTAGE(in7_input, LTC4245_3VOUT); 300 LTC4245_VOLTAGE(in8_input, LTC4245_VEEOUT); 301 302 /* Power Bad alarms */ 303 LTC4245_ALARM(in5_min_alarm, (1 << 0), LTC4245_FAULT2); 304 LTC4245_ALARM(in6_min_alarm, (1 << 1), LTC4245_FAULT2); 305 LTC4245_ALARM(in7_min_alarm, (1 << 2), LTC4245_FAULT2); 306 LTC4245_ALARM(in8_min_alarm, (1 << 3), LTC4245_FAULT2); 307 308 /* GPIO voltages */ 309 LTC4245_VOLTAGE(in9_input, LTC4245_GPIOADC1); 310 LTC4245_VOLTAGE(in10_input, LTC4245_GPIOADC2); 311 LTC4245_VOLTAGE(in11_input, LTC4245_GPIOADC3); 312 313 /* Power Consumption (virtual) */ 314 LTC4245_POWER(power1_input, LTC4245_12VSENSE); 315 LTC4245_POWER(power2_input, LTC4245_5VSENSE); 316 LTC4245_POWER(power3_input, LTC4245_3VSENSE); 317 LTC4245_POWER(power4_input, LTC4245_VEESENSE); 318 319 /* Finally, construct an array of pointers to members of the above objects, 320 * as required for sysfs_create_group() 321 */ 322 static struct attribute *ltc4245_attributes[] = { 323 &sensor_dev_attr_in1_input.dev_attr.attr, 324 &sensor_dev_attr_in2_input.dev_attr.attr, 325 &sensor_dev_attr_in3_input.dev_attr.attr, 326 &sensor_dev_attr_in4_input.dev_attr.attr, 327 328 &sensor_dev_attr_in1_min_alarm.dev_attr.attr, 329 &sensor_dev_attr_in2_min_alarm.dev_attr.attr, 330 &sensor_dev_attr_in3_min_alarm.dev_attr.attr, 331 &sensor_dev_attr_in4_min_alarm.dev_attr.attr, 332 333 &sensor_dev_attr_curr1_input.dev_attr.attr, 334 &sensor_dev_attr_curr2_input.dev_attr.attr, 335 &sensor_dev_attr_curr3_input.dev_attr.attr, 336 &sensor_dev_attr_curr4_input.dev_attr.attr, 337 338 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, 339 &sensor_dev_attr_curr2_max_alarm.dev_attr.attr, 340 &sensor_dev_attr_curr3_max_alarm.dev_attr.attr, 341 &sensor_dev_attr_curr4_max_alarm.dev_attr.attr, 342 343 &sensor_dev_attr_in5_input.dev_attr.attr, 344 &sensor_dev_attr_in6_input.dev_attr.attr, 345 &sensor_dev_attr_in7_input.dev_attr.attr, 346 &sensor_dev_attr_in8_input.dev_attr.attr, 347 348 &sensor_dev_attr_in5_min_alarm.dev_attr.attr, 349 &sensor_dev_attr_in6_min_alarm.dev_attr.attr, 350 &sensor_dev_attr_in7_min_alarm.dev_attr.attr, 351 &sensor_dev_attr_in8_min_alarm.dev_attr.attr, 352 353 &sensor_dev_attr_in9_input.dev_attr.attr, 354 &sensor_dev_attr_in10_input.dev_attr.attr, 355 &sensor_dev_attr_in11_input.dev_attr.attr, 356 357 &sensor_dev_attr_power1_input.dev_attr.attr, 358 &sensor_dev_attr_power2_input.dev_attr.attr, 359 &sensor_dev_attr_power3_input.dev_attr.attr, 360 &sensor_dev_attr_power4_input.dev_attr.attr, 361 362 NULL, 363 }; 364 365 static const struct attribute_group ltc4245_group = { 366 .attrs = ltc4245_attributes, 367 }; 368 369 static int ltc4245_probe(struct i2c_client *client, 370 const struct i2c_device_id *id) 371 { 372 struct ltc4245_data *data; 373 int ret; 374 375 data = kzalloc(sizeof(*data), GFP_KERNEL); 376 if (!data) { 377 ret = -ENOMEM; 378 goto out_kzalloc; 379 } 380 381 i2c_set_clientdata(client, data); 382 mutex_init(&data->update_lock); 383 384 /* Initialize the LTC4245 chip */ 385 /* TODO */ 386 387 /* Register sysfs hooks */ 388 ret = sysfs_create_group(&client->dev.kobj, <c4245_group); 389 if (ret) 390 goto out_sysfs_create_group; 391 392 data->hwmon_dev = hwmon_device_register(&client->dev); 393 if (IS_ERR(data->hwmon_dev)) { 394 ret = PTR_ERR(data->hwmon_dev); 395 goto out_hwmon_device_register; 396 } 397 398 return 0; 399 400 out_hwmon_device_register: 401 sysfs_remove_group(&client->dev.kobj, <c4245_group); 402 out_sysfs_create_group: 403 kfree(data); 404 out_kzalloc: 405 return ret; 406 } 407 408 static int ltc4245_remove(struct i2c_client *client) 409 { 410 struct ltc4245_data *data = i2c_get_clientdata(client); 411 412 hwmon_device_unregister(data->hwmon_dev); 413 sysfs_remove_group(&client->dev.kobj, <c4245_group); 414 415 kfree(data); 416 417 return 0; 418 } 419 420 /* Check that some bits in a control register appear at all possible 421 * locations without changing value 422 * 423 * @client: the i2c client to use 424 * @reg: the register to read 425 * @bits: the bits to check (0xff checks all bits, 426 * 0x03 checks only the last two bits) 427 * 428 * return -ERRNO if the register read failed 429 * return -ENODEV if the register value doesn't stay constant at all 430 * possible addresses 431 * 432 * return 0 for success 433 */ 434 static int ltc4245_check_control_reg(struct i2c_client *client, u8 reg, u8 bits) 435 { 436 int i; 437 s32 v, voff1, voff2; 438 439 /* Read register and check for error */ 440 v = i2c_smbus_read_byte_data(client, reg); 441 if (v < 0) 442 return v; 443 444 v &= bits; 445 446 for (i = 0x00; i < 0xff; i += 0x20) { 447 448 voff1 = i2c_smbus_read_byte_data(client, reg + i); 449 if (voff1 < 0) 450 return voff1; 451 452 voff2 = i2c_smbus_read_byte_data(client, reg + i + 0x08); 453 if (voff2 < 0) 454 return voff2; 455 456 voff1 &= bits; 457 voff2 &= bits; 458 459 if (v != voff1 || v != voff2) 460 return -ENODEV; 461 } 462 463 return 0; 464 } 465 466 static int ltc4245_detect(struct i2c_client *client, 467 int kind, 468 struct i2c_board_info *info) 469 { 470 struct i2c_adapter *adapter = client->adapter; 471 472 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 473 return -ENODEV; 474 475 if (kind < 0) { /* probed detection - check the chip type */ 476 s32 v; /* 8 bits from the chip, or -ERRNO */ 477 478 /* Chip registers 0x00-0x07 are control registers 479 * Chip registers 0x10-0x1f are data registers 480 * 481 * Address bits b7-b5 are ignored. This makes the chip "repeat" 482 * in steps of 0x20. Any control registers should appear with 483 * the same values across all duplicated addresses. 484 * 485 * Register 0x02 bit b2 is reserved, expect 0 486 * Register 0x07 bits b7 to b4 are reserved, expect 0 487 * 488 * Registers 0x01, 0x02 are control registers and should not 489 * change on their own. 490 * 491 * Register 0x06 bits b6 and b7 are control bits, and should 492 * not change on their own. 493 * 494 * Register 0x07 bits b3 to b0 are control bits, and should 495 * not change on their own. 496 */ 497 498 /* read register 0x02 reserved bit, expect 0 */ 499 v = i2c_smbus_read_byte_data(client, LTC4245_CONTROL); 500 if (v < 0 || (v & 0x04) != 0) 501 return -ENODEV; 502 503 /* read register 0x07 reserved bits, expect 0 */ 504 v = i2c_smbus_read_byte_data(client, LTC4245_ADCADR); 505 if (v < 0 || (v & 0xf0) != 0) 506 return -ENODEV; 507 508 /* check that the alert register appears at all locations */ 509 if (ltc4245_check_control_reg(client, LTC4245_ALERT, 0xff)) 510 return -ENODEV; 511 512 /* check that the control register appears at all locations */ 513 if (ltc4245_check_control_reg(client, LTC4245_CONTROL, 0xff)) 514 return -ENODEV; 515 516 /* check that register 0x06 bits b6 and b7 stay constant */ 517 if (ltc4245_check_control_reg(client, LTC4245_GPIO, 0xc0)) 518 return -ENODEV; 519 520 /* check that register 0x07 bits b3-b0 stay constant */ 521 if (ltc4245_check_control_reg(client, LTC4245_ADCADR, 0x0f)) 522 return -ENODEV; 523 } 524 525 strlcpy(info->type, "ltc4245", I2C_NAME_SIZE); 526 dev_info(&adapter->dev, "ltc4245 %s at address 0x%02x\n", 527 kind < 0 ? "probed" : "forced", 528 client->addr); 529 530 return 0; 531 } 532 533 static const struct i2c_device_id ltc4245_id[] = { 534 { "ltc4245", ltc4245 }, 535 { } 536 }; 537 MODULE_DEVICE_TABLE(i2c, ltc4245_id); 538 539 /* This is the driver that will be inserted */ 540 static struct i2c_driver ltc4245_driver = { 541 .class = I2C_CLASS_HWMON, 542 .driver = { 543 .name = "ltc4245", 544 }, 545 .probe = ltc4245_probe, 546 .remove = ltc4245_remove, 547 .id_table = ltc4245_id, 548 .detect = ltc4245_detect, 549 .address_data = &addr_data, 550 }; 551 552 static int __init ltc4245_init(void) 553 { 554 return i2c_add_driver(<c4245_driver); 555 } 556 557 static void __exit ltc4245_exit(void) 558 { 559 i2c_del_driver(<c4245_driver); 560 } 561 562 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>"); 563 MODULE_DESCRIPTION("LTC4245 driver"); 564 MODULE_LICENSE("GPL"); 565 566 module_init(ltc4245_init); 567 module_exit(ltc4245_exit); 568