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, <c4245_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, <c4245_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, <c4245_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(<c4245_driver); 427 } 428 429 static void __exit ltc4245_exit(void) 430 { 431 i2c_del_driver(<c4245_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); 440