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_GPIOADC1                = 0x1c,
  49         LTC4245_GPIOADC2                = 0x1d,
  50         LTC4245_GPIOADC3                = 0x1e,
  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[0x0f];
  65 };
  66
  67 static struct ltc4245_data *ltc4245_update_device(struct device *dev)
  68 {
  69         struct i2c_client *client = to_i2c_client(dev);
  70         struct ltc4245_data *data = i2c_get_clientdata(client);
  71         s32 val;
  72         int i;
  73
  74         mutex_lock(&data->update_lock);
  75
  76         if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
  77
  78                 dev_dbg(&client->dev, "Starting ltc4245 update\n");
  79
  80                 /* Read control registers -- 0x00 to 0x07 */
  81                 for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
  82                         val = i2c_smbus_read_byte_data(client, i);
  83                         if (unlikely(val < 0))
  84                                 data->cregs[i] = 0;
  85                         else
  86                                 data->cregs[i] = val;
  87                 }
  88
  89                 /* Read voltage registers -- 0x10 to 0x1f */
  90                 for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
  91                         val = i2c_smbus_read_byte_data(client, i+0x10);
  92                         if (unlikely(val < 0))
  93                                 data->vregs[i] = 0;
  94                         else
  95                                 data->vregs[i] = val;
  96                 }
  97
  98                 data->last_updated = jiffies;
  99                 data->valid = 1;
 100         }
 101
 102         mutex_unlock(&data->update_lock);
 103
 104         return data;
 105 }
 106
 107 /* Return the voltage from the given register in millivolts */
 108 static int ltc4245_get_voltage(struct device *dev, u8 reg)
 109 {
 110         struct ltc4245_data *data = ltc4245_update_device(dev);
 111         const u8 regval = data->vregs[reg - 0x10];
 112         u32 voltage = 0;
 113
 114         switch (reg) {
 115         case LTC4245_12VIN:
 116         case LTC4245_12VOUT:
 117                 voltage = regval * 55;
 118                 break;
 119         case LTC4245_5VIN:
 120         case LTC4245_5VOUT:
 121                 voltage = regval * 22;
 122                 break;
 123         case LTC4245_3VIN:
 124         case LTC4245_3VOUT:
 125                 voltage = regval * 15;
 126                 break;
 127         case LTC4245_VEEIN:
 128         case LTC4245_VEEOUT:
 129                 voltage = regval * -55;
 130                 break;
 131         case LTC4245_GPIOADC1:
 132         case LTC4245_GPIOADC2:
 133         case LTC4245_GPIOADC3:
 134                 voltage = regval * 10;
 135                 break;
 136         default:
 137                 /* If we get here, the developer messed up */
 138                 WARN_ON_ONCE(1);
 139                 break;
 140         }
 141
 142         return voltage;
 143 }
 144
 145 /* Return the current in the given sense register in milliAmperes */
 146 static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
 147 {
 148         struct ltc4245_data *data = ltc4245_update_device(dev);
 149         const u8 regval = data->vregs[reg - 0x10];
 150         unsigned int voltage;
 151         unsigned int curr;
 152
 153         /* The strange looking conversions that follow are fixed-point
 154          * math, since we cannot do floating point in the kernel.
 155          *
 156          * Step 1: convert sense register to microVolts
 157          * Step 2: convert voltage to milliAmperes
 158          *
 159          * If you play around with the V=IR equation, you come up with
 160          * the following: X uV / Y mOhm == Z mA
 161          *
 162          * With the resistors that are fractions of a milliOhm, we multiply
 163          * the voltage and resistance by 10, to shift the decimal point.
 164          * Now we can use the normal division operator again.
 165          */
 166
 167         switch (reg) {
 168         case LTC4245_12VSENSE:
 169                 voltage = regval * 250; /* voltage in uV */
 170                 curr = voltage / 50; /* sense resistor 50 mOhm */
 171                 break;
 172         case LTC4245_5VSENSE:
 173                 voltage = regval * 125; /* voltage in uV */
 174                 curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
 175                 break;
 176         case LTC4245_3VSENSE:
 177                 voltage = regval * 125; /* voltage in uV */
 178                 curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
 179                 break;
 180         case LTC4245_VEESENSE:
 181                 voltage = regval * 250; /* voltage in uV */
 182                 curr = voltage / 100; /* sense resistor 100 mOhm */
 183                 break;
 184         default:
 185                 /* If we get here, the developer messed up */
 186                 WARN_ON_ONCE(1);
 187                 curr = 0;
 188                 break;
 189         }
 190
 191         return curr;
 192 }
 193
 194 static ssize_t ltc4245_show_voltage(struct device *dev,
 195                                     struct device_attribute *da,
 196                                     char *buf)
 197 {
 198         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 199         const int voltage = ltc4245_get_voltage(dev, attr->index);
 200
 201         return snprintf(buf, PAGE_SIZE, "%d\n", voltage);
 202 }
 203
 204 static ssize_t ltc4245_show_current(struct device *dev,
 205                                     struct device_attribute *da,
 206                                     char *buf)
 207 {
 208         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 209         const unsigned int curr = ltc4245_get_current(dev, attr->index);
 210
 211         return snprintf(buf, PAGE_SIZE, "%u\n", curr);
 212 }
 213
 214 static ssize_t ltc4245_show_power(struct device *dev,
 215                                   struct device_attribute *da,
 216                                   char *buf)
 217 {
 218         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 219         const unsigned int curr = ltc4245_get_current(dev, attr->index);
 220         const int output_voltage = ltc4245_get_voltage(dev, attr->index+1);
 221
 222         /* current in mA * voltage in mV == power in uW */
 223         const unsigned int power = abs(output_voltage * curr);
 224
 225         return snprintf(buf, PAGE_SIZE, "%u\n", power);
 226 }
 227
 228 static ssize_t ltc4245_show_alarm(struct device *dev,
 229                                           struct device_attribute *da,
 230                                           char *buf)
 231 {
 232         struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
 233         struct ltc4245_data *data = ltc4245_update_device(dev);
 234         const u8 reg = data->cregs[attr->index];
 235         const u32 mask = attr->nr;
 236
 237         return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0);
 238 }
 239
 240 /* These macros are used below in constructing device attribute objects
 241  * for use with sysfs_create_group() to make a sysfs device file
 242  * for each register.
 243  */
 244
 245 #define LTC4245_VOLTAGE(name, ltc4245_cmd_idx) \
 246         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 247         ltc4245_show_voltage, NULL, ltc4245_cmd_idx)
 248
 249 #define LTC4245_CURRENT(name, ltc4245_cmd_idx) \
 250         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 251         ltc4245_show_current, NULL, ltc4245_cmd_idx)
 252
 253 #define LTC4245_POWER(name, ltc4245_cmd_idx) \
 254         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 255         ltc4245_show_power, NULL, ltc4245_cmd_idx)
 256
 257 #define LTC4245_ALARM(name, mask, reg) \
 258         static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \
 259         ltc4245_show_alarm, NULL, (mask), reg)
 260
 261 /* Construct a sensor_device_attribute structure for each register */
 262
 263 /* Input voltages */
 264 LTC4245_VOLTAGE(in1_input,                      LTC4245_12VIN);
 265 LTC4245_VOLTAGE(in2_input,                      LTC4245_5VIN);
 266 LTC4245_VOLTAGE(in3_input,                      LTC4245_3VIN);
 267 LTC4245_VOLTAGE(in4_input,                      LTC4245_VEEIN);
 268
 269 /* Input undervoltage alarms */
 270 LTC4245_ALARM(in1_min_alarm,    (1 << 0),       LTC4245_FAULT1);
 271 LTC4245_ALARM(in2_min_alarm,    (1 << 1),       LTC4245_FAULT1);
 272 LTC4245_ALARM(in3_min_alarm,    (1 << 2),       LTC4245_FAULT1);
 273 LTC4245_ALARM(in4_min_alarm,    (1 << 3),       LTC4245_FAULT1);
 274
 275 /* Currents (via sense resistor) */
 276 LTC4245_CURRENT(curr1_input,                    LTC4245_12VSENSE);
 277 LTC4245_CURRENT(curr2_input,                    LTC4245_5VSENSE);
 278 LTC4245_CURRENT(curr3_input,                    LTC4245_3VSENSE);
 279 LTC4245_CURRENT(curr4_input,                    LTC4245_VEESENSE);
 280
 281 /* Overcurrent alarms */
 282 LTC4245_ALARM(curr1_max_alarm,  (1 << 4),       LTC4245_FAULT1);
 283 LTC4245_ALARM(curr2_max_alarm,  (1 << 5),       LTC4245_FAULT1);
 284 LTC4245_ALARM(curr3_max_alarm,  (1 << 6),       LTC4245_FAULT1);
 285 LTC4245_ALARM(curr4_max_alarm,  (1 << 7),       LTC4245_FAULT1);
 286
 287 /* Output voltages */
 288 LTC4245_VOLTAGE(in5_input,                      LTC4245_12VOUT);
 289 LTC4245_VOLTAGE(in6_input,                      LTC4245_5VOUT);
 290 LTC4245_VOLTAGE(in7_input,                      LTC4245_3VOUT);
 291 LTC4245_VOLTAGE(in8_input,                      LTC4245_VEEOUT);
 292
 293 /* Power Bad alarms */
 294 LTC4245_ALARM(in5_min_alarm,    (1 << 0),       LTC4245_FAULT2);
 295 LTC4245_ALARM(in6_min_alarm,    (1 << 1),       LTC4245_FAULT2);
 296 LTC4245_ALARM(in7_min_alarm,    (1 << 2),       LTC4245_FAULT2);
 297 LTC4245_ALARM(in8_min_alarm,    (1 << 3),       LTC4245_FAULT2);
 298
 299 /* GPIO voltages */
 300 LTC4245_VOLTAGE(in9_input,                      LTC4245_GPIOADC1);
 301 LTC4245_VOLTAGE(in10_input,                     LTC4245_GPIOADC2);
 302 LTC4245_VOLTAGE(in11_input,                     LTC4245_GPIOADC3);
 303
 304 /* Power Consumption (virtual) */
 305 LTC4245_POWER(power1_input,                     LTC4245_12VSENSE);
 306 LTC4245_POWER(power2_input,                     LTC4245_5VSENSE);
 307 LTC4245_POWER(power3_input,                     LTC4245_3VSENSE);
 308 LTC4245_POWER(power4_input,                     LTC4245_VEESENSE);
 309
 310 /* Finally, construct an array of pointers to members of the above objects,
 311  * as required for sysfs_create_group()
 312  */
 313 static struct attribute *ltc4245_attributes[] = {
 314         &sensor_dev_attr_in1_input.dev_attr.attr,
 315         &sensor_dev_attr_in2_input.dev_attr.attr,
 316         &sensor_dev_attr_in3_input.dev_attr.attr,
 317         &sensor_dev_attr_in4_input.dev_attr.attr,
 318
 319         &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
 320         &sensor_dev_attr_in2_min_alarm.dev_attr.attr,
 321         &sensor_dev_attr_in3_min_alarm.dev_attr.attr,
 322         &sensor_dev_attr_in4_min_alarm.dev_attr.attr,
 323
 324         &sensor_dev_attr_curr1_input.dev_attr.attr,
 325         &sensor_dev_attr_curr2_input.dev_attr.attr,
 326         &sensor_dev_attr_curr3_input.dev_attr.attr,
 327         &sensor_dev_attr_curr4_input.dev_attr.attr,
 328
 329         &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
 330         &sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
 331         &sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
 332         &sensor_dev_attr_curr4_max_alarm.dev_attr.attr,
 333
 334         &sensor_dev_attr_in5_input.dev_attr.attr,
 335         &sensor_dev_attr_in6_input.dev_attr.attr,
 336         &sensor_dev_attr_in7_input.dev_attr.attr,
 337         &sensor_dev_attr_in8_input.dev_attr.attr,
 338
 339         &sensor_dev_attr_in5_min_alarm.dev_attr.attr,
 340         &sensor_dev_attr_in6_min_alarm.dev_attr.attr,
 341         &sensor_dev_attr_in7_min_alarm.dev_attr.attr,
 342         &sensor_dev_attr_in8_min_alarm.dev_attr.attr,
 343
 344         &sensor_dev_attr_in9_input.dev_attr.attr,
 345         &sensor_dev_attr_in10_input.dev_attr.attr,
 346         &sensor_dev_attr_in11_input.dev_attr.attr,
 347
 348         &sensor_dev_attr_power1_input.dev_attr.attr,
 349         &sensor_dev_attr_power2_input.dev_attr.attr,
 350         &sensor_dev_attr_power3_input.dev_attr.attr,
 351         &sensor_dev_attr_power4_input.dev_attr.attr,
 352
 353         NULL,
 354 };
 355
 356 static const struct attribute_group ltc4245_group = {
 357         .attrs = ltc4245_attributes,
 358 };
 359
 360 static int ltc4245_probe(struct i2c_client *client,
 361                          const struct i2c_device_id *id)
 362 {
 363         struct i2c_adapter *adapter = client->adapter;
 364         struct ltc4245_data *data;
 365         int ret;
 366
 367         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 368                 return -ENODEV;
 369
 370         data = kzalloc(sizeof(*data), GFP_KERNEL);
 371         if (!data) {
 372                 ret = -ENOMEM;
 373                 goto out_kzalloc;
 374         }
 375
 376         i2c_set_clientdata(client, data);
 377         mutex_init(&data->update_lock);
 378
 379         /* Initialize the LTC4245 chip */
 380         i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
 381         i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
 382
 383         /* Register sysfs hooks */
 384         ret = sysfs_create_group(&client->dev.kobj, &ltc4245_group);
 385         if (ret)
 386                 goto out_sysfs_create_group;
 387
 388         data->hwmon_dev = hwmon_device_register(&client->dev);
 389         if (IS_ERR(data->hwmon_dev)) {
 390                 ret = PTR_ERR(data->hwmon_dev);
 391                 goto out_hwmon_device_register;
 392         }
 393
 394         return 0;
 395
 396 out_hwmon_device_register:
 397         sysfs_remove_group(&client->dev.kobj, &ltc4245_group);
 398 out_sysfs_create_group:
 399         kfree(data);
 400 out_kzalloc:
 401         return ret;
 402 }
 403
 404 static int ltc4245_remove(struct i2c_client *client)
 405 {
 406         struct ltc4245_data *data = i2c_get_clientdata(client);
 407
 408         hwmon_device_unregister(data->hwmon_dev);
 409         sysfs_remove_group(&client->dev.kobj, &ltc4245_group);
 410
 411         kfree(data);
 412
 413         return 0;
 414 }
 415
 416 static const struct i2c_device_id ltc4245_id[] = {
 417         { "ltc4245", 0 },
 418         { }
 419 };
 420 MODULE_DEVICE_TABLE(i2c, ltc4245_id);
 421
 422 /* This is the driver that will be inserted */
 423 static struct i2c_driver ltc4245_driver = {
 424         .driver = {
 425                 .name   = "ltc4245",
 426         },
 427         .probe          = ltc4245_probe,
 428         .remove         = ltc4245_remove,
 429         .id_table       = ltc4245_id,
 430 };
 431
 432 static int __init ltc4245_init(void)
 433 {
 434         return i2c_add_driver(&ltc4245_driver);
 435 }
 436
 437 static void __exit ltc4245_exit(void)
 438 {
 439         i2c_del_driver(&ltc4245_driver);
 440 }
 441
 442 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
 443 MODULE_DESCRIPTION("LTC4245 driver");
 444 MODULE_LICENSE("GPL");
 445
 446 module_init(ltc4245_init);
 447 module_exit(ltc4245_exit);