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, <c4245_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, <c4245_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, <c4245_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(<c4245_driver); 435 } 436 437 static void __exit ltc4245_exit(void) 438 { 439 i2c_del_driver(<c4245_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); 448