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 i2c_client *client; 55 56 const struct attribute_group *groups[3]; 57 58 struct mutex update_lock; 59 bool valid; 60 unsigned long last_updated; /* in jiffies */ 61 62 /* Control registers */ 63 u8 cregs[0x08]; 64 65 /* Voltage registers */ 66 u8 vregs[0x0d]; 67 68 /* GPIO ADC registers */ 69 bool use_extra_gpios; 70 int gpios[3]; 71 }; 72 73 /* 74 * Update the readings from the GPIO pins. If the driver has been configured to 75 * sample all GPIO's as analog voltages, a round-robin sampling method is used. 76 * Otherwise, only the configured GPIO pin is sampled. 77 * 78 * LOCKING: must hold data->update_lock 79 */ 80 static void ltc4245_update_gpios(struct device *dev) 81 { 82 struct ltc4245_data *data = dev_get_drvdata(dev); 83 struct i2c_client *client = data->client; 84 u8 gpio_curr, gpio_next, gpio_reg; 85 int i; 86 87 /* no extra gpio support, we're basically done */ 88 if (!data->use_extra_gpios) { 89 data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10]; 90 return; 91 } 92 93 /* 94 * If the last reading was too long ago, then we mark all old GPIO 95 * readings as stale by setting them to -EAGAIN 96 */ 97 if (time_after(jiffies, data->last_updated + 5 * HZ)) { 98 for (i = 0; i < ARRAY_SIZE(data->gpios); i++) 99 data->gpios[i] = -EAGAIN; 100 } 101 102 /* 103 * Get the current GPIO pin 104 * 105 * The datasheet calls these GPIO[1-3], but we'll calculate the zero 106 * based array index instead, and call them GPIO[0-2]. This is much 107 * easier to think about. 108 */ 109 gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6; 110 if (gpio_curr > 0) 111 gpio_curr -= 1; 112 113 /* Read the GPIO voltage from the GPIOADC register */ 114 data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10]; 115 116 /* Find the next GPIO pin to read */ 117 gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios); 118 119 /* 120 * Calculate the correct setting for the GPIO register so it will 121 * sample the next GPIO pin 122 */ 123 gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6); 124 125 /* Update the GPIO register */ 126 i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg); 127 128 /* Update saved data */ 129 data->cregs[LTC4245_GPIO] = gpio_reg; 130 } 131 132 static struct ltc4245_data *ltc4245_update_device(struct device *dev) 133 { 134 struct ltc4245_data *data = dev_get_drvdata(dev); 135 struct i2c_client *client = data->client; 136 s32 val; 137 int i; 138 139 mutex_lock(&data->update_lock); 140 141 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) { 142 143 /* Read control registers -- 0x00 to 0x07 */ 144 for (i = 0; i < ARRAY_SIZE(data->cregs); i++) { 145 val = i2c_smbus_read_byte_data(client, i); 146 if (unlikely(val < 0)) 147 data->cregs[i] = 0; 148 else 149 data->cregs[i] = val; 150 } 151 152 /* Read voltage registers -- 0x10 to 0x1c */ 153 for (i = 0; i < ARRAY_SIZE(data->vregs); i++) { 154 val = i2c_smbus_read_byte_data(client, i+0x10); 155 if (unlikely(val < 0)) 156 data->vregs[i] = 0; 157 else 158 data->vregs[i] = val; 159 } 160 161 /* Update GPIO readings */ 162 ltc4245_update_gpios(dev); 163 164 data->last_updated = jiffies; 165 data->valid = 1; 166 } 167 168 mutex_unlock(&data->update_lock); 169 170 return data; 171 } 172 173 /* Return the voltage from the given register in millivolts */ 174 static int ltc4245_get_voltage(struct device *dev, u8 reg) 175 { 176 struct ltc4245_data *data = ltc4245_update_device(dev); 177 const u8 regval = data->vregs[reg - 0x10]; 178 u32 voltage = 0; 179 180 switch (reg) { 181 case LTC4245_12VIN: 182 case LTC4245_12VOUT: 183 voltage = regval * 55; 184 break; 185 case LTC4245_5VIN: 186 case LTC4245_5VOUT: 187 voltage = regval * 22; 188 break; 189 case LTC4245_3VIN: 190 case LTC4245_3VOUT: 191 voltage = regval * 15; 192 break; 193 case LTC4245_VEEIN: 194 case LTC4245_VEEOUT: 195 voltage = regval * -55; 196 break; 197 case LTC4245_GPIOADC: 198 voltage = regval * 10; 199 break; 200 default: 201 /* If we get here, the developer messed up */ 202 WARN_ON_ONCE(1); 203 break; 204 } 205 206 return voltage; 207 } 208 209 /* Return the current in the given sense register in milliAmperes */ 210 static unsigned int ltc4245_get_current(struct device *dev, u8 reg) 211 { 212 struct ltc4245_data *data = ltc4245_update_device(dev); 213 const u8 regval = data->vregs[reg - 0x10]; 214 unsigned int voltage; 215 unsigned int curr; 216 217 /* 218 * The strange looking conversions that follow are fixed-point 219 * math, since we cannot do floating point in the kernel. 220 * 221 * Step 1: convert sense register to microVolts 222 * Step 2: convert voltage to milliAmperes 223 * 224 * If you play around with the V=IR equation, you come up with 225 * the following: X uV / Y mOhm == Z mA 226 * 227 * With the resistors that are fractions of a milliOhm, we multiply 228 * the voltage and resistance by 10, to shift the decimal point. 229 * Now we can use the normal division operator again. 230 */ 231 232 switch (reg) { 233 case LTC4245_12VSENSE: 234 voltage = regval * 250; /* voltage in uV */ 235 curr = voltage / 50; /* sense resistor 50 mOhm */ 236 break; 237 case LTC4245_5VSENSE: 238 voltage = regval * 125; /* voltage in uV */ 239 curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */ 240 break; 241 case LTC4245_3VSENSE: 242 voltage = regval * 125; /* voltage in uV */ 243 curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */ 244 break; 245 case LTC4245_VEESENSE: 246 voltage = regval * 250; /* voltage in uV */ 247 curr = voltage / 100; /* sense resistor 100 mOhm */ 248 break; 249 default: 250 /* If we get here, the developer messed up */ 251 WARN_ON_ONCE(1); 252 curr = 0; 253 break; 254 } 255 256 return curr; 257 } 258 259 static ssize_t ltc4245_show_voltage(struct device *dev, 260 struct device_attribute *da, 261 char *buf) 262 { 263 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 264 const int voltage = ltc4245_get_voltage(dev, attr->index); 265 266 return snprintf(buf, PAGE_SIZE, "%d\n", voltage); 267 } 268 269 static ssize_t ltc4245_show_current(struct device *dev, 270 struct device_attribute *da, 271 char *buf) 272 { 273 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 274 const unsigned int curr = ltc4245_get_current(dev, attr->index); 275 276 return snprintf(buf, PAGE_SIZE, "%u\n", curr); 277 } 278 279 static ssize_t ltc4245_show_power(struct device *dev, 280 struct device_attribute *da, 281 char *buf) 282 { 283 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 284 const unsigned int curr = ltc4245_get_current(dev, attr->index); 285 const int output_voltage = ltc4245_get_voltage(dev, attr->index+1); 286 287 /* current in mA * voltage in mV == power in uW */ 288 const unsigned int power = abs(output_voltage * curr); 289 290 return snprintf(buf, PAGE_SIZE, "%u\n", power); 291 } 292 293 static ssize_t ltc4245_show_alarm(struct device *dev, 294 struct device_attribute *da, 295 char *buf) 296 { 297 struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da); 298 struct ltc4245_data *data = ltc4245_update_device(dev); 299 const u8 reg = data->cregs[attr->index]; 300 const u32 mask = attr->nr; 301 302 return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0); 303 } 304 305 static ssize_t ltc4245_show_gpio(struct device *dev, 306 struct device_attribute *da, 307 char *buf) 308 { 309 struct sensor_device_attribute *attr = to_sensor_dev_attr(da); 310 struct ltc4245_data *data = ltc4245_update_device(dev); 311 int val = data->gpios[attr->index]; 312 313 /* handle stale GPIO's */ 314 if (val < 0) 315 return val; 316 317 /* Convert to millivolts and print */ 318 return snprintf(buf, PAGE_SIZE, "%u\n", val * 10); 319 } 320 321 /* Construct a sensor_device_attribute structure for each register */ 322 323 /* Input voltages */ 324 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4245_show_voltage, NULL, 325 LTC4245_12VIN); 326 static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4245_show_voltage, NULL, 327 LTC4245_5VIN); 328 static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4245_show_voltage, NULL, 329 LTC4245_3VIN); 330 static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4245_show_voltage, NULL, 331 LTC4245_VEEIN); 332 333 /* Input undervoltage alarms */ 334 static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 335 1 << 0, LTC4245_FAULT1); 336 static SENSOR_DEVICE_ATTR_2(in2_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 337 1 << 1, LTC4245_FAULT1); 338 static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 339 1 << 2, LTC4245_FAULT1); 340 static SENSOR_DEVICE_ATTR_2(in4_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 341 1 << 3, LTC4245_FAULT1); 342 343 /* Currents (via sense resistor) */ 344 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4245_show_current, NULL, 345 LTC4245_12VSENSE); 346 static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4245_show_current, NULL, 347 LTC4245_5VSENSE); 348 static SENSOR_DEVICE_ATTR(curr3_input, S_IRUGO, ltc4245_show_current, NULL, 349 LTC4245_3VSENSE); 350 static SENSOR_DEVICE_ATTR(curr4_input, S_IRUGO, ltc4245_show_current, NULL, 351 LTC4245_VEESENSE); 352 353 /* Overcurrent alarms */ 354 static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 355 1 << 4, LTC4245_FAULT1); 356 static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 357 1 << 5, LTC4245_FAULT1); 358 static SENSOR_DEVICE_ATTR_2(curr3_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 359 1 << 6, LTC4245_FAULT1); 360 static SENSOR_DEVICE_ATTR_2(curr4_max_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 361 1 << 7, LTC4245_FAULT1); 362 363 /* Output voltages */ 364 static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ltc4245_show_voltage, NULL, 365 LTC4245_12VOUT); 366 static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ltc4245_show_voltage, NULL, 367 LTC4245_5VOUT); 368 static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ltc4245_show_voltage, NULL, 369 LTC4245_3VOUT); 370 static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, ltc4245_show_voltage, NULL, 371 LTC4245_VEEOUT); 372 373 /* Power Bad alarms */ 374 static SENSOR_DEVICE_ATTR_2(in5_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 375 1 << 0, LTC4245_FAULT2); 376 static SENSOR_DEVICE_ATTR_2(in6_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 377 1 << 1, LTC4245_FAULT2); 378 static SENSOR_DEVICE_ATTR_2(in7_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 379 1 << 2, LTC4245_FAULT2); 380 static SENSOR_DEVICE_ATTR_2(in8_min_alarm, S_IRUGO, ltc4245_show_alarm, NULL, 381 1 << 3, LTC4245_FAULT2); 382 383 /* GPIO voltages */ 384 static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, ltc4245_show_gpio, NULL, 0); 385 static SENSOR_DEVICE_ATTR(in10_input, S_IRUGO, ltc4245_show_gpio, NULL, 1); 386 static SENSOR_DEVICE_ATTR(in11_input, S_IRUGO, ltc4245_show_gpio, NULL, 2); 387 388 /* Power Consumption (virtual) */ 389 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ltc4245_show_power, NULL, 390 LTC4245_12VSENSE); 391 static SENSOR_DEVICE_ATTR(power2_input, S_IRUGO, ltc4245_show_power, NULL, 392 LTC4245_5VSENSE); 393 static SENSOR_DEVICE_ATTR(power3_input, S_IRUGO, ltc4245_show_power, NULL, 394 LTC4245_3VSENSE); 395 static SENSOR_DEVICE_ATTR(power4_input, S_IRUGO, ltc4245_show_power, NULL, 396 LTC4245_VEESENSE); 397 398 /* 399 * Finally, construct an array of pointers to members of the above objects, 400 * as required for sysfs_create_group() 401 */ 402 static struct attribute *ltc4245_std_attributes[] = { 403 &sensor_dev_attr_in1_input.dev_attr.attr, 404 &sensor_dev_attr_in2_input.dev_attr.attr, 405 &sensor_dev_attr_in3_input.dev_attr.attr, 406 &sensor_dev_attr_in4_input.dev_attr.attr, 407 408 &sensor_dev_attr_in1_min_alarm.dev_attr.attr, 409 &sensor_dev_attr_in2_min_alarm.dev_attr.attr, 410 &sensor_dev_attr_in3_min_alarm.dev_attr.attr, 411 &sensor_dev_attr_in4_min_alarm.dev_attr.attr, 412 413 &sensor_dev_attr_curr1_input.dev_attr.attr, 414 &sensor_dev_attr_curr2_input.dev_attr.attr, 415 &sensor_dev_attr_curr3_input.dev_attr.attr, 416 &sensor_dev_attr_curr4_input.dev_attr.attr, 417 418 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, 419 &sensor_dev_attr_curr2_max_alarm.dev_attr.attr, 420 &sensor_dev_attr_curr3_max_alarm.dev_attr.attr, 421 &sensor_dev_attr_curr4_max_alarm.dev_attr.attr, 422 423 &sensor_dev_attr_in5_input.dev_attr.attr, 424 &sensor_dev_attr_in6_input.dev_attr.attr, 425 &sensor_dev_attr_in7_input.dev_attr.attr, 426 &sensor_dev_attr_in8_input.dev_attr.attr, 427 428 &sensor_dev_attr_in5_min_alarm.dev_attr.attr, 429 &sensor_dev_attr_in6_min_alarm.dev_attr.attr, 430 &sensor_dev_attr_in7_min_alarm.dev_attr.attr, 431 &sensor_dev_attr_in8_min_alarm.dev_attr.attr, 432 433 &sensor_dev_attr_in9_input.dev_attr.attr, 434 435 &sensor_dev_attr_power1_input.dev_attr.attr, 436 &sensor_dev_attr_power2_input.dev_attr.attr, 437 &sensor_dev_attr_power3_input.dev_attr.attr, 438 &sensor_dev_attr_power4_input.dev_attr.attr, 439 440 NULL, 441 }; 442 443 static struct attribute *ltc4245_gpio_attributes[] = { 444 &sensor_dev_attr_in10_input.dev_attr.attr, 445 &sensor_dev_attr_in11_input.dev_attr.attr, 446 NULL, 447 }; 448 449 static const struct attribute_group ltc4245_std_group = { 450 .attrs = ltc4245_std_attributes, 451 }; 452 453 static const struct attribute_group ltc4245_gpio_group = { 454 .attrs = ltc4245_gpio_attributes, 455 }; 456 457 static void ltc4245_sysfs_add_groups(struct ltc4245_data *data) 458 { 459 /* standard sysfs attributes */ 460 data->groups[0] = <c4245_std_group; 461 462 /* if we're using the extra gpio support, register it's attributes */ 463 if (data->use_extra_gpios) 464 data->groups[1] = <c4245_gpio_group; 465 } 466 467 static bool ltc4245_use_extra_gpios(struct i2c_client *client) 468 { 469 struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev); 470 struct device_node *np = client->dev.of_node; 471 472 /* prefer platform data */ 473 if (pdata) 474 return pdata->use_extra_gpios; 475 476 /* fallback on OF */ 477 if (of_find_property(np, "ltc4245,use-extra-gpios", NULL)) 478 return true; 479 480 return false; 481 } 482 483 static int ltc4245_probe(struct i2c_client *client, 484 const struct i2c_device_id *id) 485 { 486 struct i2c_adapter *adapter = client->adapter; 487 struct ltc4245_data *data; 488 struct device *hwmon_dev; 489 490 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 491 return -ENODEV; 492 493 data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); 494 if (!data) 495 return -ENOMEM; 496 497 data->client = client; 498 mutex_init(&data->update_lock); 499 data->use_extra_gpios = ltc4245_use_extra_gpios(client); 500 501 /* Initialize the LTC4245 chip */ 502 i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00); 503 i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00); 504 505 /* Add sysfs hooks */ 506 ltc4245_sysfs_add_groups(data); 507 508 hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev, 509 client->name, data, 510 data->groups); 511 return PTR_ERR_OR_ZERO(hwmon_dev); 512 } 513 514 static const struct i2c_device_id ltc4245_id[] = { 515 { "ltc4245", 0 }, 516 { } 517 }; 518 MODULE_DEVICE_TABLE(i2c, ltc4245_id); 519 520 /* This is the driver that will be inserted */ 521 static struct i2c_driver ltc4245_driver = { 522 .driver = { 523 .name = "ltc4245", 524 }, 525 .probe = ltc4245_probe, 526 .id_table = ltc4245_id, 527 }; 528 529 module_i2c_driver(ltc4245_driver); 530 531 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>"); 532 MODULE_DESCRIPTION("LTC4245 driver"); 533 MODULE_LICENSE("GPL"); 534