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
  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, &ltc4245_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, &ltc4245_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, &ltc4245_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(&ltc4245_driver);
 555 }
 556
 557 static void __exit ltc4245_exit(void)
 558 {
 559         i2c_del_driver(&ltc4245_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);