ltc4245.c 15.4 KB
Newer Older
I
Ira Snyder 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567
/*
 * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
 *
 * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This driver is based on the ds1621 and ina209 drivers.
 *
 * Datasheet:
 * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>

/* Valid addresses are 0x20 - 0x3f
 *
 * For now, we do not probe, since some of these addresses
 * are known to be unfriendly to probing */
static const unsigned short normal_i2c[] = { I2C_CLIENT_END };

/* Insmod parameters */
I2C_CLIENT_INSMOD_1(ltc4245);

/* Here are names of the chip's registers (a.k.a. commands) */
enum ltc4245_cmd {
	LTC4245_STATUS			= 0x00, /* readonly */
	LTC4245_ALERT			= 0x01,
	LTC4245_CONTROL			= 0x02,
	LTC4245_ON			= 0x03,
	LTC4245_FAULT1			= 0x04,
	LTC4245_FAULT2			= 0x05,
	LTC4245_GPIO			= 0x06,
	LTC4245_ADCADR			= 0x07,

	LTC4245_12VIN			= 0x10,
	LTC4245_12VSENSE		= 0x11,
	LTC4245_12VOUT			= 0x12,
	LTC4245_5VIN			= 0x13,
	LTC4245_5VSENSE			= 0x14,
	LTC4245_5VOUT			= 0x15,
	LTC4245_3VIN			= 0x16,
	LTC4245_3VSENSE			= 0x17,
	LTC4245_3VOUT			= 0x18,
	LTC4245_VEEIN			= 0x19,
	LTC4245_VEESENSE		= 0x1a,
	LTC4245_VEEOUT			= 0x1b,
	LTC4245_GPIOADC1		= 0x1c,
	LTC4245_GPIOADC2		= 0x1d,
	LTC4245_GPIOADC3		= 0x1e,
};

struct ltc4245_data {
	struct device *hwmon_dev;

	struct mutex update_lock;
	bool valid;
	unsigned long last_updated; /* in jiffies */

	/* Control registers */
	u8 cregs[0x08];

	/* Voltage registers */
	u8 vregs[0x0f];
};

static struct ltc4245_data *ltc4245_update_device(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ltc4245_data *data = i2c_get_clientdata(client);
	s32 val;
	int i;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {

		dev_dbg(&client->dev, "Starting ltc4245 update\n");

		/* Read control registers -- 0x00 to 0x07 */
		for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
			val = i2c_smbus_read_byte_data(client, i);
			if (unlikely(val < 0))
				data->cregs[i] = 0;
			else
				data->cregs[i] = val;
		}

		/* Read voltage registers -- 0x10 to 0x1f */
		for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
			val = i2c_smbus_read_byte_data(client, i+0x10);
			if (unlikely(val < 0))
				data->vregs[i] = 0;
			else
				data->vregs[i] = val;
		}

		data->last_updated = jiffies;
		data->valid = 1;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

/* Return the voltage from the given register in millivolts */
static int ltc4245_get_voltage(struct device *dev, u8 reg)
{
	struct ltc4245_data *data = ltc4245_update_device(dev);
	const u8 regval = data->vregs[reg - 0x10];
	u32 voltage = 0;

	switch (reg) {
	case LTC4245_12VIN:
	case LTC4245_12VOUT:
		voltage = regval * 55;
		break;
	case LTC4245_5VIN:
	case LTC4245_5VOUT:
		voltage = regval * 22;
		break;
	case LTC4245_3VIN:
	case LTC4245_3VOUT:
		voltage = regval * 15;
		break;
	case LTC4245_VEEIN:
	case LTC4245_VEEOUT:
		voltage = regval * -55;
		break;
	case LTC4245_GPIOADC1:
	case LTC4245_GPIOADC2:
	case LTC4245_GPIOADC3:
		voltage = regval * 10;
		break;
	default:
		/* If we get here, the developer messed up */
		WARN_ON_ONCE(1);
		break;
	}

	return voltage;
}

/* Return the current in the given sense register in milliAmperes */
static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
{
	struct ltc4245_data *data = ltc4245_update_device(dev);
	const u8 regval = data->vregs[reg - 0x10];
	unsigned int voltage;
	unsigned int curr;

	/* The strange looking conversions that follow are fixed-point
	 * math, since we cannot do floating point in the kernel.
	 *
	 * Step 1: convert sense register to microVolts
	 * Step 2: convert voltage to milliAmperes
	 *
	 * If you play around with the V=IR equation, you come up with
	 * the following: X uV / Y mOhm == Z mA
	 *
	 * With the resistors that are fractions of a milliOhm, we multiply
	 * the voltage and resistance by 10, to shift the decimal point.
	 * Now we can use the normal division operator again.
	 */

	switch (reg) {
	case LTC4245_12VSENSE:
		voltage = regval * 250; /* voltage in uV */
		curr = voltage / 50; /* sense resistor 50 mOhm */
		break;
	case LTC4245_5VSENSE:
		voltage = regval * 125; /* voltage in uV */
		curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
		break;
	case LTC4245_3VSENSE:
		voltage = regval * 125; /* voltage in uV */
		curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
		break;
	case LTC4245_VEESENSE:
		voltage = regval * 250; /* voltage in uV */
		curr = voltage / 100; /* sense resistor 100 mOhm */
		break;
	default:
		/* If we get here, the developer messed up */
		WARN_ON_ONCE(1);
		curr = 0;
		break;
	}

	return curr;
}

static ssize_t ltc4245_show_voltage(struct device *dev,
				    struct device_attribute *da,
				    char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	const int voltage = ltc4245_get_voltage(dev, attr->index);

	return snprintf(buf, PAGE_SIZE, "%d\n", voltage);
}

static ssize_t ltc4245_show_current(struct device *dev,
				    struct device_attribute *da,
				    char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	const unsigned int curr = ltc4245_get_current(dev, attr->index);

	return snprintf(buf, PAGE_SIZE, "%u\n", curr);
}

static ssize_t ltc4245_show_power(struct device *dev,
				  struct device_attribute *da,
				  char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	const unsigned int curr = ltc4245_get_current(dev, attr->index);
	const int output_voltage = ltc4245_get_voltage(dev, attr->index+1);

	/* current in mA * voltage in mV == power in uW */
	const unsigned int power = abs(output_voltage * curr);

	return snprintf(buf, PAGE_SIZE, "%u\n", power);
}

static ssize_t ltc4245_show_alarm(struct device *dev,
					  struct device_attribute *da,
					  char *buf)
{
	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
	struct ltc4245_data *data = ltc4245_update_device(dev);
	const u8 reg = data->cregs[attr->index];
	const u32 mask = attr->nr;

	return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0);
}

/* These macros are used below in constructing device attribute objects
 * for use with sysfs_create_group() to make a sysfs device file
 * for each register.
 */

#define LTC4245_VOLTAGE(name, ltc4245_cmd_idx) \
	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
	ltc4245_show_voltage, NULL, ltc4245_cmd_idx)

#define LTC4245_CURRENT(name, ltc4245_cmd_idx) \
	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
	ltc4245_show_current, NULL, ltc4245_cmd_idx)

#define LTC4245_POWER(name, ltc4245_cmd_idx) \
	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
	ltc4245_show_power, NULL, ltc4245_cmd_idx)

#define LTC4245_ALARM(name, mask, reg) \
	static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \
	ltc4245_show_alarm, NULL, (mask), reg)

/* Construct a sensor_device_attribute structure for each register */

/* Input voltages */
LTC4245_VOLTAGE(in1_input,			LTC4245_12VIN);
LTC4245_VOLTAGE(in2_input,			LTC4245_5VIN);
LTC4245_VOLTAGE(in3_input,			LTC4245_3VIN);
LTC4245_VOLTAGE(in4_input,			LTC4245_VEEIN);

/* Input undervoltage alarms */
LTC4245_ALARM(in1_min_alarm,	(1 << 0),	LTC4245_FAULT1);
LTC4245_ALARM(in2_min_alarm,	(1 << 1),	LTC4245_FAULT1);
LTC4245_ALARM(in3_min_alarm,	(1 << 2),	LTC4245_FAULT1);
LTC4245_ALARM(in4_min_alarm,	(1 << 3),	LTC4245_FAULT1);

/* Currents (via sense resistor) */
LTC4245_CURRENT(curr1_input,			LTC4245_12VSENSE);
LTC4245_CURRENT(curr2_input,			LTC4245_5VSENSE);
LTC4245_CURRENT(curr3_input,			LTC4245_3VSENSE);
LTC4245_CURRENT(curr4_input,			LTC4245_VEESENSE);

/* Overcurrent alarms */
LTC4245_ALARM(curr1_max_alarm,	(1 << 4),	LTC4245_FAULT1);
LTC4245_ALARM(curr2_max_alarm,	(1 << 5),	LTC4245_FAULT1);
LTC4245_ALARM(curr3_max_alarm,	(1 << 6),	LTC4245_FAULT1);
LTC4245_ALARM(curr4_max_alarm,	(1 << 7),	LTC4245_FAULT1);

/* Output voltages */
LTC4245_VOLTAGE(in5_input,			LTC4245_12VOUT);
LTC4245_VOLTAGE(in6_input,			LTC4245_5VOUT);
LTC4245_VOLTAGE(in7_input,			LTC4245_3VOUT);
LTC4245_VOLTAGE(in8_input,			LTC4245_VEEOUT);

/* Power Bad alarms */
LTC4245_ALARM(in5_min_alarm,	(1 << 0),	LTC4245_FAULT2);
LTC4245_ALARM(in6_min_alarm,	(1 << 1),	LTC4245_FAULT2);
LTC4245_ALARM(in7_min_alarm,	(1 << 2),	LTC4245_FAULT2);
LTC4245_ALARM(in8_min_alarm,	(1 << 3),	LTC4245_FAULT2);

/* GPIO voltages */
LTC4245_VOLTAGE(in9_input,			LTC4245_GPIOADC1);
LTC4245_VOLTAGE(in10_input,			LTC4245_GPIOADC2);
LTC4245_VOLTAGE(in11_input,			LTC4245_GPIOADC3);

/* Power Consumption (virtual) */
LTC4245_POWER(power1_input,			LTC4245_12VSENSE);
LTC4245_POWER(power2_input,			LTC4245_5VSENSE);
LTC4245_POWER(power3_input,			LTC4245_3VSENSE);
LTC4245_POWER(power4_input,			LTC4245_VEESENSE);

/* Finally, construct an array of pointers to members of the above objects,
 * as required for sysfs_create_group()
 */
static struct attribute *ltc4245_attributes[] = {
	&sensor_dev_attr_in1_input.dev_attr.attr,
	&sensor_dev_attr_in2_input.dev_attr.attr,
	&sensor_dev_attr_in3_input.dev_attr.attr,
	&sensor_dev_attr_in4_input.dev_attr.attr,

	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in3_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in4_min_alarm.dev_attr.attr,

	&sensor_dev_attr_curr1_input.dev_attr.attr,
	&sensor_dev_attr_curr2_input.dev_attr.attr,
	&sensor_dev_attr_curr3_input.dev_attr.attr,
	&sensor_dev_attr_curr4_input.dev_attr.attr,

	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
	&sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
	&sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
	&sensor_dev_attr_curr4_max_alarm.dev_attr.attr,

	&sensor_dev_attr_in5_input.dev_attr.attr,
	&sensor_dev_attr_in6_input.dev_attr.attr,
	&sensor_dev_attr_in7_input.dev_attr.attr,
	&sensor_dev_attr_in8_input.dev_attr.attr,

	&sensor_dev_attr_in5_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in6_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in7_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in8_min_alarm.dev_attr.attr,

	&sensor_dev_attr_in9_input.dev_attr.attr,
	&sensor_dev_attr_in10_input.dev_attr.attr,
	&sensor_dev_attr_in11_input.dev_attr.attr,

	&sensor_dev_attr_power1_input.dev_attr.attr,
	&sensor_dev_attr_power2_input.dev_attr.attr,
	&sensor_dev_attr_power3_input.dev_attr.attr,
	&sensor_dev_attr_power4_input.dev_attr.attr,

	NULL,
};

static const struct attribute_group ltc4245_group = {
	.attrs = ltc4245_attributes,
};

static int ltc4245_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct ltc4245_data *data;
	int ret;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data) {
		ret = -ENOMEM;
		goto out_kzalloc;
	}

	i2c_set_clientdata(client, data);
	mutex_init(&data->update_lock);

	/* Initialize the LTC4245 chip */
	/* TODO */

	/* Register sysfs hooks */
	ret = sysfs_create_group(&client->dev.kobj, &ltc4245_group);
	if (ret)
		goto out_sysfs_create_group;

	data->hwmon_dev = hwmon_device_register(&client->dev);
	if (IS_ERR(data->hwmon_dev)) {
		ret = PTR_ERR(data->hwmon_dev);
		goto out_hwmon_device_register;
	}

	return 0;

out_hwmon_device_register:
	sysfs_remove_group(&client->dev.kobj, &ltc4245_group);
out_sysfs_create_group:
	kfree(data);
out_kzalloc:
	return ret;
}

static int ltc4245_remove(struct i2c_client *client)
{
	struct ltc4245_data *data = i2c_get_clientdata(client);

	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&client->dev.kobj, &ltc4245_group);

	kfree(data);

	return 0;
}

/* Check that some bits in a control register appear at all possible
 * locations without changing value
 *
 * @client: the i2c client to use
 * @reg: the register to read
 * @bits: the bits to check (0xff checks all bits,
 *                           0x03 checks only the last two bits)
 *
 * return -ERRNO if the register read failed
 * return -ENODEV if the register value doesn't stay constant at all
 * possible addresses
 *
 * return 0 for success
 */
static int ltc4245_check_control_reg(struct i2c_client *client, u8 reg, u8 bits)
{
	int i;
	s32 v, voff1, voff2;

	/* Read register and check for error */
	v = i2c_smbus_read_byte_data(client, reg);
	if (v < 0)
		return v;

	v &= bits;

	for (i = 0x00; i < 0xff; i += 0x20) {

		voff1 = i2c_smbus_read_byte_data(client, reg + i);
		if (voff1 < 0)
			return voff1;

		voff2 = i2c_smbus_read_byte_data(client, reg + i + 0x08);
		if (voff2 < 0)
			return voff2;

		voff1 &= bits;
		voff2 &= bits;

		if (v != voff1 || v != voff2)
			return -ENODEV;
	}

	return 0;
}

static int ltc4245_detect(struct i2c_client *client,
			  int kind,
			  struct i2c_board_info *info)
{
	struct i2c_adapter *adapter = client->adapter;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
		return -ENODEV;

	if (kind < 0) {		/* probed detection - check the chip type */
		s32 v;		/* 8 bits from the chip, or -ERRNO */

		/* Chip registers 0x00-0x07 are control registers
		 * Chip registers 0x10-0x1f are data registers
		 *
		 * Address bits b7-b5 are ignored. This makes the chip "repeat"
		 * in steps of 0x20. Any control registers should appear with
		 * the same values across all duplicated addresses.
		 *
		 * Register 0x02 bit b2 is reserved, expect 0
		 * Register 0x07 bits b7 to b4 are reserved, expect 0
		 *
		 * Registers 0x01, 0x02 are control registers and should not
		 * change on their own.
		 *
		 * Register 0x06 bits b6 and b7 are control bits, and should
		 * not change on their own.
		 *
		 * Register 0x07 bits b3 to b0 are control bits, and should
		 * not change on their own.
		 */

		/* read register 0x02 reserved bit, expect 0 */
		v = i2c_smbus_read_byte_data(client, LTC4245_CONTROL);
		if (v < 0 || (v & 0x04) != 0)
			return -ENODEV;

		/* read register 0x07 reserved bits, expect 0 */
		v = i2c_smbus_read_byte_data(client, LTC4245_ADCADR);
		if (v < 0 || (v & 0xf0) != 0)
			return -ENODEV;

		/* check that the alert register appears at all locations */
		if (ltc4245_check_control_reg(client, LTC4245_ALERT, 0xff))
			return -ENODEV;

		/* check that the control register appears at all locations */
		if (ltc4245_check_control_reg(client, LTC4245_CONTROL, 0xff))
			return -ENODEV;

		/* check that register 0x06 bits b6 and b7 stay constant */
		if (ltc4245_check_control_reg(client, LTC4245_GPIO, 0xc0))
			return -ENODEV;

		/* check that register 0x07 bits b3-b0 stay constant */
		if (ltc4245_check_control_reg(client, LTC4245_ADCADR, 0x0f))
			return -ENODEV;
	}

	strlcpy(info->type, "ltc4245", I2C_NAME_SIZE);
	dev_info(&adapter->dev, "ltc4245 %s at address 0x%02x\n",
			kind < 0 ? "probed" : "forced",
			client->addr);

	return 0;
}

static const struct i2c_device_id ltc4245_id[] = {
	{ "ltc4245", ltc4245 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ltc4245_id);

/* This is the driver that will be inserted */
static struct i2c_driver ltc4245_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver = {
		.name	= "ltc4245",
	},
	.probe		= ltc4245_probe,
	.remove		= ltc4245_remove,
	.id_table	= ltc4245_id,
	.detect		= ltc4245_detect,
	.address_data	= &addr_data,
};

static int __init ltc4245_init(void)
{
	return i2c_add_driver(&ltc4245_driver);
}

static void __exit ltc4245_exit(void)
{
	i2c_del_driver(&ltc4245_driver);
}

MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
MODULE_DESCRIPTION("LTC4245 driver");
MODULE_LICENSE("GPL");

module_init(ltc4245_init);
module_exit(ltc4245_exit);