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 /* Here are names of the chip's registers (a.k.a. commands) */
  26 enum ltc4245_cmd {
  27         LTC4245_STATUS                  = 0x00, /* readonly */
  28         LTC4245_ALERT                   = 0x01,
  29         LTC4245_CONTROL                 = 0x02,
  30         LTC4245_ON                      = 0x03,
  31         LTC4245_FAULT1                  = 0x04,
  32         LTC4245_FAULT2                  = 0x05,
  33         LTC4245_GPIO                    = 0x06,
  34         LTC4245_ADCADR                  = 0x07,
  35
  36         LTC4245_12VIN                   = 0x10,
  37         LTC4245_12VSENSE                = 0x11,
  38         LTC4245_12VOUT                  = 0x12,
  39         LTC4245_5VIN                    = 0x13,
  40         LTC4245_5VSENSE                 = 0x14,
  41         LTC4245_5VOUT                   = 0x15,
  42         LTC4245_3VIN                    = 0x16,
  43         LTC4245_3VSENSE                 = 0x17,
  44         LTC4245_3VOUT                   = 0x18,
  45         LTC4245_VEEIN                   = 0x19,
  46         LTC4245_VEESENSE                = 0x1a,
  47         LTC4245_VEEOUT                  = 0x1b,
  48         LTC4245_GPIOADC                 = 0x1c,
  49 };
  50
  51 struct ltc4245_data {
  52         struct device *hwmon_dev;
  53
  54         struct mutex update_lock;
  55         bool valid;
  56         unsigned long last_updated; /* in jiffies */
  57
  58         /* Control registers */
  59         u8 cregs[0x08];
  60
  61         /* Voltage registers */
  62         u8 vregs[0x0d];
  63 };
  64
  65 static struct ltc4245_data *ltc4245_update_device(struct device *dev)
  66 {
  67         struct i2c_client *client = to_i2c_client(dev);
  68         struct ltc4245_data *data = i2c_get_clientdata(client);
  69         s32 val;
  70         int i;
  71
  72         mutex_lock(&data->update_lock);
  73
  74         if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
  75
  76                 dev_dbg(&client->dev, "Starting ltc4245 update\n");
  77
  78                 /* Read control registers -- 0x00 to 0x07 */
  79                 for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
  80                         val = i2c_smbus_read_byte_data(client, i);
  81                         if (unlikely(val < 0))
  82                                 data->cregs[i] = 0;
  83                         else
  84                                 data->cregs[i] = val;
  85                 }
  86
  87                 /* Read voltage registers -- 0x10 to 0x1c */
  88                 for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
  89                         val = i2c_smbus_read_byte_data(client, i+0x10);
  90                         if (unlikely(val < 0))
  91                                 data->vregs[i] = 0;
  92                         else
  93                                 data->vregs[i] = val;
  94                 }
  95
  96                 data->last_updated = jiffies;
  97                 data->valid = 1;
  98         }
  99
 100         mutex_unlock(&data->update_lock);
 101
 102         return data;
 103 }
 104
 105 /* Return the voltage from the given register in millivolts */
 106 static int ltc4245_get_voltage(struct device *dev, u8 reg)
 107 {
 108         struct ltc4245_data *data = ltc4245_update_device(dev);
 109         const u8 regval = data->vregs[reg - 0x10];
 110         u32 voltage = 0;
 111
 112         switch (reg) {
 113         case LTC4245_12VIN:
 114         case LTC4245_12VOUT:
 115                 voltage = regval * 55;
 116                 break;
 117         case LTC4245_5VIN:
 118         case LTC4245_5VOUT:
 119                 voltage = regval * 22;
 120                 break;
 121         case LTC4245_3VIN:
 122         case LTC4245_3VOUT:
 123                 voltage = regval * 15;
 124                 break;
 125         case LTC4245_VEEIN:
 126         case LTC4245_VEEOUT:
 127                 voltage = regval * -55;
 128                 break;
 129         case LTC4245_GPIOADC:
 130                 voltage = regval * 10;
 131                 break;
 132         default:
 133                 /* If we get here, the developer messed up */
 134                 WARN_ON_ONCE(1);
 135                 break;
 136         }
 137
 138         return voltage;
 139 }
 140
 141 /* Return the current in the given sense register in milliAmperes */
 142 static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
 143 {
 144         struct ltc4245_data *data = ltc4245_update_device(dev);
 145         const u8 regval = data->vregs[reg - 0x10];
 146         unsigned int voltage;
 147         unsigned int curr;
 148
 149         /* The strange looking conversions that follow are fixed-point
 150          * math, since we cannot do floating point in the kernel.
 151          *
 152          * Step 1: convert sense register to microVolts
 153          * Step 2: convert voltage to milliAmperes
 154          *
 155          * If you play around with the V=IR equation, you come up with
 156          * the following: X uV / Y mOhm == Z mA
 157          *
 158          * With the resistors that are fractions of a milliOhm, we multiply
 159          * the voltage and resistance by 10, to shift the decimal point.
 160          * Now we can use the normal division operator again.
 161          */
 162
 163         switch (reg) {
 164         case LTC4245_12VSENSE:
 165                 voltage = regval * 250; /* voltage in uV */
 166                 curr = voltage / 50; /* sense resistor 50 mOhm */
 167                 break;
 168         case LTC4245_5VSENSE:
 169                 voltage = regval * 125; /* voltage in uV */
 170                 curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
 171                 break;
 172         case LTC4245_3VSENSE:
 173                 voltage = regval * 125; /* voltage in uV */
 174                 curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
 175                 break;
 176         case LTC4245_VEESENSE:
 177                 voltage = regval * 250; /* voltage in uV */
 178                 curr = voltage / 100; /* sense resistor 100 mOhm */
 179                 break;
 180         default:
 181                 /* If we get here, the developer messed up */
 182                 WARN_ON_ONCE(1);
 183                 curr = 0;
 184                 break;
 185         }
 186
 187         return curr;
 188 }
 189
 190 static ssize_t ltc4245_show_voltage(struct device *dev,
 191                                     struct device_attribute *da,
 192                                     char *buf)
 193 {
 194         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 195         const int voltage = ltc4245_get_voltage(dev, attr->index);
 196
 197         return snprintf(buf, PAGE_SIZE, "%d\n", voltage);
 198 }
 199
 200 static ssize_t ltc4245_show_current(struct device *dev,
 201                                     struct device_attribute *da,
 202                                     char *buf)
 203 {
 204         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 205         const unsigned int curr = ltc4245_get_current(dev, attr->index);
 206
 207         return snprintf(buf, PAGE_SIZE, "%u\n", curr);
 208 }
 209
 210 static ssize_t ltc4245_show_power(struct device *dev,
 211                                   struct device_attribute *da,
 212                                   char *buf)
 213 {
 214         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 215         const unsigned int curr = ltc4245_get_current(dev, attr->index);
 216         const int output_voltage = ltc4245_get_voltage(dev, attr->index+1);
 217
 218         /* current in mA * voltage in mV == power in uW */
 219         const unsigned int power = abs(output_voltage * curr);
 220
 221         return snprintf(buf, PAGE_SIZE, "%u\n", power);
 222 }
 223
 224 static ssize_t ltc4245_show_alarm(struct device *dev,
 225                                           struct device_attribute *da,
 226                                           char *buf)
 227 {
 228         struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
 229         struct ltc4245_data *data = ltc4245_update_device(dev);
 230         const u8 reg = data->cregs[attr->index];
 231         const u32 mask = attr->nr;
 232
 233         return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0);
 234 }
 235
 236 /* These macros are used below in constructing device attribute objects
 237  * for use with sysfs_create_group() to make a sysfs device file
 238  * for each register.
 239  */
 240
 241 #define LTC4245_VOLTAGE(name, ltc4245_cmd_idx) \
 242         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 243         ltc4245_show_voltage, NULL, ltc4245_cmd_idx)
 244
 245 #define LTC4245_CURRENT(name, ltc4245_cmd_idx) \
 246         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 247         ltc4245_show_current, NULL, ltc4245_cmd_idx)
 248
 249 #define LTC4245_POWER(name, ltc4245_cmd_idx) \
 250         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 251         ltc4245_show_power, NULL, ltc4245_cmd_idx)
 252
 253 #define LTC4245_ALARM(name, mask, reg) \
 254         static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \
 255         ltc4245_show_alarm, NULL, (mask), reg)
 256
 257 /* Construct a sensor_device_attribute structure for each register */
 258
 259 /* Input voltages */
 260 LTC4245_VOLTAGE(in1_input,                      LTC4245_12VIN);
 261 LTC4245_VOLTAGE(in2_input,                      LTC4245_5VIN);
 262 LTC4245_VOLTAGE(in3_input,                      LTC4245_3VIN);
 263 LTC4245_VOLTAGE(in4_input,                      LTC4245_VEEIN);
 264
 265 /* Input undervoltage alarms */
 266 LTC4245_ALARM(in1_min_alarm,    (1 << 0),       LTC4245_FAULT1);
 267 LTC4245_ALARM(in2_min_alarm,    (1 << 1),       LTC4245_FAULT1);
 268 LTC4245_ALARM(in3_min_alarm,    (1 << 2),       LTC4245_FAULT1);
 269 LTC4245_ALARM(in4_min_alarm,    (1 << 3),       LTC4245_FAULT1);
 270
 271 /* Currents (via sense resistor) */
 272 LTC4245_CURRENT(curr1_input,                    LTC4245_12VSENSE);
 273 LTC4245_CURRENT(curr2_input,                    LTC4245_5VSENSE);
 274 LTC4245_CURRENT(curr3_input,                    LTC4245_3VSENSE);
 275 LTC4245_CURRENT(curr4_input,                    LTC4245_VEESENSE);
 276
 277 /* Overcurrent alarms */
 278 LTC4245_ALARM(curr1_max_alarm,  (1 << 4),       LTC4245_FAULT1);
 279 LTC4245_ALARM(curr2_max_alarm,  (1 << 5),       LTC4245_FAULT1);
 280 LTC4245_ALARM(curr3_max_alarm,  (1 << 6),       LTC4245_FAULT1);
 281 LTC4245_ALARM(curr4_max_alarm,  (1 << 7),       LTC4245_FAULT1);
 282
 283 /* Output voltages */
 284 LTC4245_VOLTAGE(in5_input,                      LTC4245_12VOUT);
 285 LTC4245_VOLTAGE(in6_input,                      LTC4245_5VOUT);
 286 LTC4245_VOLTAGE(in7_input,                      LTC4245_3VOUT);
 287 LTC4245_VOLTAGE(in8_input,                      LTC4245_VEEOUT);
 288
 289 /* Power Bad alarms */
 290 LTC4245_ALARM(in5_min_alarm,    (1 << 0),       LTC4245_FAULT2);
 291 LTC4245_ALARM(in6_min_alarm,    (1 << 1),       LTC4245_FAULT2);
 292 LTC4245_ALARM(in7_min_alarm,    (1 << 2),       LTC4245_FAULT2);
 293 LTC4245_ALARM(in8_min_alarm,    (1 << 3),       LTC4245_FAULT2);
 294
 295 /* GPIO voltages */
 296 LTC4245_VOLTAGE(in9_input,                      LTC4245_GPIOADC);
 297
 298 /* Power Consumption (virtual) */
 299 LTC4245_POWER(power1_input,                     LTC4245_12VSENSE);
 300 LTC4245_POWER(power2_input,                     LTC4245_5VSENSE);
 301 LTC4245_POWER(power3_input,                     LTC4245_3VSENSE);
 302 LTC4245_POWER(power4_input,                     LTC4245_VEESENSE);
 303
 304 /* Finally, construct an array of pointers to members of the above objects,
 305  * as required for sysfs_create_group()
 306  */
 307 static struct attribute *ltc4245_attributes[] = {
 308         &sensor_dev_attr_in1_input.dev_attr.attr,
 309         &sensor_dev_attr_in2_input.dev_attr.attr,
 310         &sensor_dev_attr_in3_input.dev_attr.attr,
 311         &sensor_dev_attr_in4_input.dev_attr.attr,
 312
 313         &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
 314         &sensor_dev_attr_in2_min_alarm.dev_attr.attr,
 315         &sensor_dev_attr_in3_min_alarm.dev_attr.attr,
 316         &sensor_dev_attr_in4_min_alarm.dev_attr.attr,
 317
 318         &sensor_dev_attr_curr1_input.dev_attr.attr,
 319         &sensor_dev_attr_curr2_input.dev_attr.attr,
 320         &sensor_dev_attr_curr3_input.dev_attr.attr,
 321         &sensor_dev_attr_curr4_input.dev_attr.attr,
 322
 323         &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
 324         &sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
 325         &sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
 326         &sensor_dev_attr_curr4_max_alarm.dev_attr.attr,
 327
 328         &sensor_dev_attr_in5_input.dev_attr.attr,
 329         &sensor_dev_attr_in6_input.dev_attr.attr,
 330         &sensor_dev_attr_in7_input.dev_attr.attr,
 331         &sensor_dev_attr_in8_input.dev_attr.attr,
 332
 333         &sensor_dev_attr_in5_min_alarm.dev_attr.attr,
 334         &sensor_dev_attr_in6_min_alarm.dev_attr.attr,
 335         &sensor_dev_attr_in7_min_alarm.dev_attr.attr,
 336         &sensor_dev_attr_in8_min_alarm.dev_attr.attr,
 337
 338         &sensor_dev_attr_in9_input.dev_attr.attr,
 339
 340         &sensor_dev_attr_power1_input.dev_attr.attr,
 341         &sensor_dev_attr_power2_input.dev_attr.attr,
 342         &sensor_dev_attr_power3_input.dev_attr.attr,
 343         &sensor_dev_attr_power4_input.dev_attr.attr,
 344
 345         NULL,
 346 };
 347
 348 static const struct attribute_group ltc4245_group = {
 349         .attrs = ltc4245_attributes,
 350 };
 351
 352 static int ltc4245_probe(struct i2c_client *client,
 353                          const struct i2c_device_id *id)
 354 {
 355         struct i2c_adapter *adapter = client->adapter;
 356         struct ltc4245_data *data;
 357         int ret;
 358
 359         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 360                 return -ENODEV;
 361
 362         data = kzalloc(sizeof(*data), GFP_KERNEL);
 363         if (!data) {
 364                 ret = -ENOMEM;
 365                 goto out_kzalloc;
 366         }
 367
 368         i2c_set_clientdata(client, data);
 369         mutex_init(&data->update_lock);
 370
 371         /* Initialize the LTC4245 chip */
 372         i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
 373         i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
 374
 375         /* Register sysfs hooks */
 376         ret = sysfs_create_group(&client->dev.kobj, &ltc4245_group);
 377         if (ret)
 378                 goto out_sysfs_create_group;
 379
 380         data->hwmon_dev = hwmon_device_register(&client->dev);
 381         if (IS_ERR(data->hwmon_dev)) {
 382                 ret = PTR_ERR(data->hwmon_dev);
 383                 goto out_hwmon_device_register;
 384         }
 385
 386         return 0;
 387
 388 out_hwmon_device_register:
 389         sysfs_remove_group(&client->dev.kobj, &ltc4245_group);
 390 out_sysfs_create_group:
 391         kfree(data);
 392 out_kzalloc:
 393         return ret;
 394 }
 395
 396 static int ltc4245_remove(struct i2c_client *client)
 397 {
 398         struct ltc4245_data *data = i2c_get_clientdata(client);
 399
 400         hwmon_device_unregister(data->hwmon_dev);
 401         sysfs_remove_group(&client->dev.kobj, &ltc4245_group);
 402
 403         kfree(data);
 404
 405         return 0;
 406 }
 407
 408 static const struct i2c_device_id ltc4245_id[] = {
 409         { "ltc4245", 0 },
 410         { }
 411 };
 412 MODULE_DEVICE_TABLE(i2c, ltc4245_id);
 413
 414 /* This is the driver that will be inserted */
 415 static struct i2c_driver ltc4245_driver = {
 416         .driver = {
 417                 .name   = "ltc4245",
 418         },
 419         .probe          = ltc4245_probe,
 420         .remove         = ltc4245_remove,
 421         .id_table       = ltc4245_id,
 422 };
 423
 424 static int __init ltc4245_init(void)
 425 {
 426         return i2c_add_driver(&ltc4245_driver);
 427 }
 428
 429 static void __exit ltc4245_exit(void)
 430 {
 431         i2c_del_driver(&ltc4245_driver);
 432 }
 433
 434 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
 435 MODULE_DESCRIPTION("LTC4245 driver");
 436 MODULE_LICENSE("GPL");
 437
 438 module_init(ltc4245_init);
 439 module_exit(ltc4245_exit);