drivers/hwmon/ltc4245.c

   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 /*
 323  * These macros are used below in constructing device attribute objects
 324  * for use with sysfs_create_group() to make a sysfs device file
 325  * for each register.
 326  */
 327
 328 #define LTC4245_VOLTAGE(name, ltc4245_cmd_idx) \
 329         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 330         ltc4245_show_voltage, NULL, ltc4245_cmd_idx)
 331
 332 #define LTC4245_CURRENT(name, ltc4245_cmd_idx) \
 333         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 334         ltc4245_show_current, NULL, ltc4245_cmd_idx)
 335
 336 #define LTC4245_POWER(name, ltc4245_cmd_idx) \
 337         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 338         ltc4245_show_power, NULL, ltc4245_cmd_idx)
 339
 340 #define LTC4245_ALARM(name, mask, reg) \
 341         static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \
 342         ltc4245_show_alarm, NULL, (mask), reg)
 343
 344 #define LTC4245_GPIO_VOLTAGE(name, gpio_num) \
 345         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 346         ltc4245_show_gpio, NULL, gpio_num)
 347
 348 /* Construct a sensor_device_attribute structure for each register */
 349
 350 /* Input voltages */
 351 LTC4245_VOLTAGE(in1_input,                      LTC4245_12VIN);
 352 LTC4245_VOLTAGE(in2_input,                      LTC4245_5VIN);
 353 LTC4245_VOLTAGE(in3_input,                      LTC4245_3VIN);
 354 LTC4245_VOLTAGE(in4_input,                      LTC4245_VEEIN);
 355
 356 /* Input undervoltage alarms */
 357 LTC4245_ALARM(in1_min_alarm,    (1 << 0),       LTC4245_FAULT1);
 358 LTC4245_ALARM(in2_min_alarm,    (1 << 1),       LTC4245_FAULT1);
 359 LTC4245_ALARM(in3_min_alarm,    (1 << 2),       LTC4245_FAULT1);
 360 LTC4245_ALARM(in4_min_alarm,    (1 << 3),       LTC4245_FAULT1);
 361
 362 /* Currents (via sense resistor) */
 363 LTC4245_CURRENT(curr1_input,                    LTC4245_12VSENSE);
 364 LTC4245_CURRENT(curr2_input,                    LTC4245_5VSENSE);
 365 LTC4245_CURRENT(curr3_input,                    LTC4245_3VSENSE);
 366 LTC4245_CURRENT(curr4_input,                    LTC4245_VEESENSE);
 367
 368 /* Overcurrent alarms */
 369 LTC4245_ALARM(curr1_max_alarm,  (1 << 4),       LTC4245_FAULT1);
 370 LTC4245_ALARM(curr2_max_alarm,  (1 << 5),       LTC4245_FAULT1);
 371 LTC4245_ALARM(curr3_max_alarm,  (1 << 6),       LTC4245_FAULT1);
 372 LTC4245_ALARM(curr4_max_alarm,  (1 << 7),       LTC4245_FAULT1);
 373
 374 /* Output voltages */
 375 LTC4245_VOLTAGE(in5_input,                      LTC4245_12VOUT);
 376 LTC4245_VOLTAGE(in6_input,                      LTC4245_5VOUT);
 377 LTC4245_VOLTAGE(in7_input,                      LTC4245_3VOUT);
 378 LTC4245_VOLTAGE(in8_input,                      LTC4245_VEEOUT);
 379
 380 /* Power Bad alarms */
 381 LTC4245_ALARM(in5_min_alarm,    (1 << 0),       LTC4245_FAULT2);
 382 LTC4245_ALARM(in6_min_alarm,    (1 << 1),       LTC4245_FAULT2);
 383 LTC4245_ALARM(in7_min_alarm,    (1 << 2),       LTC4245_FAULT2);
 384 LTC4245_ALARM(in8_min_alarm,    (1 << 3),       LTC4245_FAULT2);
 385
 386 /* GPIO voltages */
 387 LTC4245_GPIO_VOLTAGE(in9_input,                 0);
 388 LTC4245_GPIO_VOLTAGE(in10_input,                1);
 389 LTC4245_GPIO_VOLTAGE(in11_input,                2);
 390
 391 /* Power Consumption (virtual) */
 392 LTC4245_POWER(power1_input,                     LTC4245_12VSENSE);
 393 LTC4245_POWER(power2_input,                     LTC4245_5VSENSE);
 394 LTC4245_POWER(power3_input,                     LTC4245_3VSENSE);
 395 LTC4245_POWER(power4_input,                     LTC4245_VEESENSE);
 396
 397 /*
 398  * Finally, construct an array of pointers to members of the above objects,
 399  * as required for sysfs_create_group()
 400  */
 401 static struct attribute *ltc4245_std_attributes[] = {
 402         &sensor_dev_attr_in1_input.dev_attr.attr,
 403         &sensor_dev_attr_in2_input.dev_attr.attr,
 404         &sensor_dev_attr_in3_input.dev_attr.attr,
 405         &sensor_dev_attr_in4_input.dev_attr.attr,
 406
 407         &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
 408         &sensor_dev_attr_in2_min_alarm.dev_attr.attr,
 409         &sensor_dev_attr_in3_min_alarm.dev_attr.attr,
 410         &sensor_dev_attr_in4_min_alarm.dev_attr.attr,
 411
 412         &sensor_dev_attr_curr1_input.dev_attr.attr,
 413         &sensor_dev_attr_curr2_input.dev_attr.attr,
 414         &sensor_dev_attr_curr3_input.dev_attr.attr,
 415         &sensor_dev_attr_curr4_input.dev_attr.attr,
 416
 417         &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
 418         &sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
 419         &sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
 420         &sensor_dev_attr_curr4_max_alarm.dev_attr.attr,
 421
 422         &sensor_dev_attr_in5_input.dev_attr.attr,
 423         &sensor_dev_attr_in6_input.dev_attr.attr,
 424         &sensor_dev_attr_in7_input.dev_attr.attr,
 425         &sensor_dev_attr_in8_input.dev_attr.attr,
 426
 427         &sensor_dev_attr_in5_min_alarm.dev_attr.attr,
 428         &sensor_dev_attr_in6_min_alarm.dev_attr.attr,
 429         &sensor_dev_attr_in7_min_alarm.dev_attr.attr,
 430         &sensor_dev_attr_in8_min_alarm.dev_attr.attr,
 431
 432         &sensor_dev_attr_in9_input.dev_attr.attr,
 433
 434         &sensor_dev_attr_power1_input.dev_attr.attr,
 435         &sensor_dev_attr_power2_input.dev_attr.attr,
 436         &sensor_dev_attr_power3_input.dev_attr.attr,
 437         &sensor_dev_attr_power4_input.dev_attr.attr,
 438
 439         NULL,
 440 };
 441
 442 static struct attribute *ltc4245_gpio_attributes[] = {
 443         &sensor_dev_attr_in10_input.dev_attr.attr,
 444         &sensor_dev_attr_in11_input.dev_attr.attr,
 445         NULL,
 446 };
 447
 448 static const struct attribute_group ltc4245_std_group = {
 449         .attrs = ltc4245_std_attributes,
 450 };
 451
 452 static const struct attribute_group ltc4245_gpio_group = {
 453         .attrs = ltc4245_gpio_attributes,
 454 };
 455
 456 static int ltc4245_sysfs_create_groups(struct i2c_client *client)
 457 {
 458         struct ltc4245_data *data = i2c_get_clientdata(client);
 459         struct device *dev = &client->dev;
 460         int ret;
 461
 462         /* register the standard sysfs attributes */
 463         ret = sysfs_create_group(&dev->kobj, &ltc4245_std_group);
 464         if (ret) {
 465                 dev_err(dev, "unable to register standard attributes\n");
 466                 return ret;
 467         }
 468
 469         /* if we're using the extra gpio support, register it's attributes */
 470         if (data->use_extra_gpios) {
 471                 ret = sysfs_create_group(&dev->kobj, &ltc4245_gpio_group);
 472                 if (ret) {
 473                         dev_err(dev, "unable to register gpio attributes\n");
 474                         sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
 475                         return ret;
 476                 }
 477         }
 478
 479         return 0;
 480 }
 481
 482 static void ltc4245_sysfs_remove_groups(struct i2c_client *client)
 483 {
 484         struct ltc4245_data *data = i2c_get_clientdata(client);
 485         struct device *dev = &client->dev;
 486
 487         if (data->use_extra_gpios)
 488                 sysfs_remove_group(&dev->kobj, &ltc4245_gpio_group);
 489
 490         sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
 491 }
 492
 493 static bool ltc4245_use_extra_gpios(struct i2c_client *client)
 494 {
 495         struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
 496 #ifdef CONFIG_OF
 497         struct device_node *np = client->dev.of_node;
 498 #endif
 499
 500         /* prefer platform data */
 501         if (pdata)
 502                 return pdata->use_extra_gpios;
 503
 504 #ifdef CONFIG_OF
 505         /* fallback on OF */
 506         if (of_find_property(np, "ltc4245,use-extra-gpios", NULL))
 507                 return true;
 508 #endif
 509
 510         return false;
 511 }
 512
 513 static int ltc4245_probe(struct i2c_client *client,
 514                          const struct i2c_device_id *id)
 515 {
 516         struct i2c_adapter *adapter = client->adapter;
 517         struct ltc4245_data *data;
 518         int ret;
 519
 520         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 521                 return -ENODEV;
 522
 523         data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 524         if (!data)
 525                 return -ENOMEM;
 526
 527         i2c_set_clientdata(client, data);
 528         mutex_init(&data->update_lock);
 529         data->use_extra_gpios = ltc4245_use_extra_gpios(client);
 530
 531         /* Initialize the LTC4245 chip */
 532         i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
 533         i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
 534
 535         /* Register sysfs hooks */
 536         ret = ltc4245_sysfs_create_groups(client);
 537         if (ret)
 538                 return ret;
 539
 540         data->hwmon_dev = hwmon_device_register(&client->dev);
 541         if (IS_ERR(data->hwmon_dev)) {
 542                 ret = PTR_ERR(data->hwmon_dev);
 543                 goto out_hwmon_device_register;
 544         }
 545
 546         return 0;
 547
 548 out_hwmon_device_register:
 549         ltc4245_sysfs_remove_groups(client);
 550         return ret;
 551 }
 552
 553 static int ltc4245_remove(struct i2c_client *client)
 554 {
 555         struct ltc4245_data *data = i2c_get_clientdata(client);
 556
 557         hwmon_device_unregister(data->hwmon_dev);
 558         ltc4245_sysfs_remove_groups(client);
 559
 560         return 0;
 561 }
 562
 563 static const struct i2c_device_id ltc4245_id[] = {
 564         { "ltc4245", 0 },
 565         { }
 566 };
 567 MODULE_DEVICE_TABLE(i2c, ltc4245_id);
 568
 569 /* This is the driver that will be inserted */
 570 static struct i2c_driver ltc4245_driver = {
 571         .driver = {
 572                 .name   = "ltc4245",
 573         },
 574         .probe          = ltc4245_probe,
 575         .remove         = ltc4245_remove,
 576         .id_table       = ltc4245_id,
 577 };
 578
 579 module_i2c_driver(ltc4245_driver);
 580
 581 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
 582 MODULE_DESCRIPTION("LTC4245 driver");
 583 MODULE_LICENSE("GPL");