[linux.git] / drivers / hwmon / ltc4261.c

/*
 * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot Swap Controller
 *
 * Copyright (C) 2010 Ericsson AB.
 *
 * Derived from:
 *
 *  Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
 *  Copyright (C) 2008 Ira W. Snyder <[email protected]>
 *
 * Datasheet: http://cds.linear.com/docs/Datasheet/42612fb.pdf
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#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>
#include <linux/jiffies.h>

/* chip registers */
#define LTC4261_STATUS	0x00	/* readonly */
#define LTC4261_FAULT	0x01
#define LTC4261_ALERT	0x02
#define LTC4261_CONTROL	0x03
#define LTC4261_SENSE_H	0x04
#define LTC4261_SENSE_L	0x05
#define LTC4261_ADIN2_H	0x06
#define LTC4261_ADIN2_L	0x07
#define LTC4261_ADIN_H	0x08
#define LTC4261_ADIN_L	0x09

/*
 * Fault register bits
 */
#define FAULT_OV	(1<<0)
#define FAULT_UV	(1<<1)
#define FAULT_OC	(1<<2)

struct ltc4261_data {
	struct i2c_client *client;

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

	/* Registers */
	u8 regs[10];
};

static struct ltc4261_data *ltc4261_update_device(struct device *dev)
{
	struct ltc4261_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	struct ltc4261_data *ret = data;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ / 4) || !data->valid) {
		int i;

		/* Read registers -- 0x00 to 0x09 */
		for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
			int val;

			val = i2c_smbus_read_byte_data(client, i);
			if (unlikely(val < 0)) {
				dev_dbg(dev,
					"Failed to read ADC value: error %d\n",
					val);
				ret = ERR_PTR(val);
				data->valid = 0;
				goto abort;
			}
			data->regs[i] = val;
		}
		data->last_updated = jiffies;
		data->valid = 1;
	}
abort:
	mutex_unlock(&data->update_lock);
	return ret;
}

/* Return the voltage from the given register in mV or mA */
static int ltc4261_get_value(struct ltc4261_data *data, u8 reg)
{
	u32 val;

	val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6);

	switch (reg) {
	case LTC4261_ADIN_H:
	case LTC4261_ADIN2_H:
		/* 2.5mV resolution. Convert to mV. */
		val = val * 25 / 10;
		break;
	case LTC4261_SENSE_H:
		/*
		 * 62.5uV resolution. Convert to current as measured with
		 * an 1 mOhm sense resistor, in mA. If a different sense
		 * resistor is installed, calculate the actual current by
		 * dividing the reported current by the sense resistor value
		 * in mOhm.
		 */
		val = val * 625 / 10;
		break;
	default:
		/* If we get here, the developer messed up */
		WARN_ON_ONCE(1);
		val = 0;
		break;
	}

	return val;
}

static ssize_t ltc4261_show_value(struct device *dev,
				  struct device_attribute *da, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ltc4261_data *data = ltc4261_update_device(dev);
	int value;

	if (IS_ERR(data))
		return PTR_ERR(data);

	value = ltc4261_get_value(data, attr->index);
	return snprintf(buf, PAGE_SIZE, "%d\n", value);
}

static ssize_t ltc4261_show_bool(struct device *dev,
				 struct device_attribute *da, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ltc4261_data *data = ltc4261_update_device(dev);
	u8 fault;

	if (IS_ERR(data))
		return PTR_ERR(data);

	fault = data->regs[LTC4261_FAULT] & attr->index;
	if (fault)		/* Clear reported faults in chip register */
		i2c_smbus_write_byte_data(data->client, LTC4261_FAULT, ~fault);

	return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 1 : 0);
}

/*
 * Input voltages.
 */
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4261_show_value, NULL,
			  LTC4261_ADIN_H);
static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4261_show_value, NULL,
			  LTC4261_ADIN2_H);

/*
 * Voltage alarms. The chip has only one set of voltage alarm status bits,
 * triggered by input voltage alarms. In many designs, those alarms are
 * associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin
 * to the OV pin. ADIN2 is, however, not available on all chip variants.
 * To ensure that the alarm condition is reported to the user, report it
 * with both voltage sensors.
 */
static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ltc4261_show_bool, NULL,
			  FAULT_UV);
static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ltc4261_show_bool, NULL,
			  FAULT_OV);
static SENSOR_DEVICE_ATTR(in2_min_alarm, S_IRUGO, ltc4261_show_bool, NULL,
			  FAULT_UV);
static SENSOR_DEVICE_ATTR(in2_max_alarm, S_IRUGO, ltc4261_show_bool, NULL,
			  FAULT_OV);

/* Currents (via sense resistor) */
static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4261_show_value, NULL,
			  LTC4261_SENSE_H);

/* Overcurrent alarm */
static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO, ltc4261_show_bool, NULL,
			  FAULT_OC);

static struct attribute *ltc4261_attrs[] = {
	&sensor_dev_attr_in1_input.dev_attr.attr,
	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
	&sensor_dev_attr_in2_input.dev_attr.attr,
	&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in2_max_alarm.dev_attr.attr,

	&sensor_dev_attr_curr1_input.dev_attr.attr,
	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,

	NULL,
};
ATTRIBUTE_GROUPS(ltc4261);

static int ltc4261_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct i2c_adapter *adapter = client->adapter;
	struct device *dev = &client->dev;
	struct ltc4261_data *data;
	struct device *hwmon_dev;

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

	if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) {
		dev_err(dev, "Failed to read status register\n");
		return -ENODEV;
	}

	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->client = client;
	mutex_init(&data->update_lock);

	/* Clear faults */
	i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00);

	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
							   data,
							   ltc4261_groups);
	return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct i2c_device_id ltc4261_id[] = {
	{"ltc4261", 0},
	{}
};

MODULE_DEVICE_TABLE(i2c, ltc4261_id);

/* This is the driver that will be inserted */
static struct i2c_driver ltc4261_driver = {
	.driver = {
		   .name = "ltc4261",
		   },
	.probe = ltc4261_probe,
	.id_table = ltc4261_id,
};

module_i2c_driver(ltc4261_driver);

MODULE_AUTHOR("Guenter Roeck <[email protected]>");
MODULE_DESCRIPTION("LTC4261 driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
e5f5c99a GR	1	/*
	2	* Driver for Linear Technology LTC4261 I2C Negative Voltage Hot Swap Controller
	3	*
	4	* Copyright (C) 2010 Ericsson AB.
	5	*
	6	* Derived from:
	7	*
	8	* Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
	9	* Copyright (C) 2008 Ira W. Snyder <[email protected]>
	10	*
	11	* Datasheet: http://cds.linear.com/docs/Datasheet/42612fb.pdf
	12	*
	13	* This program is free software; you can redistribute it and/or modify
	14	* it under the terms of the GNU General Public License as published by
	15	* the Free Software Foundation; either version 2 of the License, or
	16	* (at your option) any later version.
	17	*
	18	* This program is distributed in the hope that it will be useful,
	19	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	20	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	21	* GNU General Public License for more details.
	22	*
	23	* You should have received a copy of the GNU General Public License
	24	* along with this program; if not, write to the Free Software
	25	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	26	*/
	27
	28	#include <linux/kernel.h>
	29	#include <linux/module.h>
	30	#include <linux/init.h>
	31	#include <linux/err.h>
	32	#include <linux/slab.h>
	33	#include <linux/i2c.h>
	34	#include <linux/hwmon.h>
	35	#include <linux/hwmon-sysfs.h>
dcd8f392	36	#include <linux/jiffies.h>
e5f5c99a GR	37
	38	/* chip registers */
	39	#define LTC4261_STATUS 0x00 /* readonly */
	40	#define LTC4261_FAULT 0x01
	41	#define LTC4261_ALERT 0x02
	42	#define LTC4261_CONTROL 0x03
	43	#define LTC4261_SENSE_H 0x04
	44	#define LTC4261_SENSE_L 0x05
	45	#define LTC4261_ADIN2_H 0x06
	46	#define LTC4261_ADIN2_L 0x07
	47	#define LTC4261_ADIN_H 0x08
	48	#define LTC4261_ADIN_L 0x09
	49
	50	/*
	51	* Fault register bits
	52	*/
	53	#define FAULT_OV (1<<0)
	54	#define FAULT_UV (1<<1)
	55	#define FAULT_OC (1<<2)
	56
	57	struct ltc4261_data {
38f150fe	58	struct i2c_client *client;
e5f5c99a GR	59
	60	struct mutex update_lock;
	61	bool valid;
	62	unsigned long last_updated; /* in jiffies */
	63
	64	/* Registers */
	65	u8 regs[10];
	66	};
	67
	68	static struct ltc4261_data ltc4261_update_device(struct device dev)
	69	{
38f150fe GR	70	struct ltc4261_data *data = dev_get_drvdata(dev);
38f150fe GR	71	struct i2c_client *client = data->client;
e5f5c99a GR	72	struct ltc4261_data *ret = data;
	73
	74	mutex_lock(&data->update_lock);
	75
	76	if (time_after(jiffies, data->last_updated + HZ / 4) \|\| !data->valid) {
	77	int i;
	78
	79	/* Read registers -- 0x00 to 0x09 */
	80	for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
	81	int val;
	82
	83	val = i2c_smbus_read_byte_data(client, i);
	84	if (unlikely(val < 0)) {
	85	dev_dbg(dev,
69f8b741	86	"Failed to read ADC value: error %d\n",
e5f5c99a GR	87	val);
e5f5c99a GR	88	ret = ERR_PTR(val);
aac9fe9b	89	data->valid = 0;
e5f5c99a GR	90	goto abort;
	91	}
	92	data->regs[i] = val;
	93	}
	94	data->last_updated = jiffies;
	95	data->valid = 1;
	96	}
	97	abort:
	98	mutex_unlock(&data->update_lock);
	99	return ret;
	100	}
	101
	102	/* Return the voltage from the given register in mV or mA */
	103	static int ltc4261_get_value(struct ltc4261_data *data, u8 reg)
	104	{
	105	u32 val;
	106
	107	val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6);
	108
	109	switch (reg) {
	110	case LTC4261_ADIN_H:
	111	case LTC4261_ADIN2_H:
	112	/* 2.5mV resolution. Convert to mV. */
	113	val = val * 25 / 10;
	114	break;
	115	case LTC4261_SENSE_H:
	116	/*
	117	* 62.5uV resolution. Convert to current as measured with
	118	* an 1 mOhm sense resistor, in mA. If a different sense
	119	* resistor is installed, calculate the actual current by
	120	* dividing the reported current by the sense resistor value
	121	* in mOhm.
	122	*/
	123	val = val * 625 / 10;
	124	break;
	125	default:
	126	/* If we get here, the developer messed up */
	127	WARN_ON_ONCE(1);
	128	val = 0;
	129	break;
	130	}
	131
	132	return val;
	133	}
	134
	135	static ssize_t ltc4261_show_value(struct device *dev,
	136	struct device_attribute da, char buf)
	137	{
	138	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	139	struct ltc4261_data *data = ltc4261_update_device(dev);
	140	int value;
	141
	142	if (IS_ERR(data))
	143	return PTR_ERR(data);
	144
	145	value = ltc4261_get_value(data, attr->index);
	146	return snprintf(buf, PAGE_SIZE, "%d\n", value);
	147	}
	148
	149	static ssize_t ltc4261_show_bool(struct device *dev,
	150	struct device_attribute da, char buf)
	151	{
	152	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
e5f5c99a GR	153	struct ltc4261_data *data = ltc4261_update_device(dev);
	154	u8 fault;
	155
	156	if (IS_ERR(data))
	157	return PTR_ERR(data);
	158
	159	fault = data->regs[LTC4261_FAULT] & attr->index;
	160	if (fault) /* Clear reported faults in chip register */
38f150fe	161	i2c_smbus_write_byte_data(data->client, LTC4261_FAULT, ~fault);
e5f5c99a GR	162
	163	return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 1 : 0);
	164	}
	165
e5f5c99a GR	166	/*
	167	* Input voltages.
	168	*/
bec24b74 GR	169	static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4261_show_value, NULL,
	170	LTC4261_ADIN_H);
	171	static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4261_show_value, NULL,
	172	LTC4261_ADIN2_H);
e5f5c99a GR	173
	174	/*
	175	* Voltage alarms. The chip has only one set of voltage alarm status bits,
	176	* triggered by input voltage alarms. In many designs, those alarms are
	177	* associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin
	178	* to the OV pin. ADIN2 is, however, not available on all chip variants.
	179	* To ensure that the alarm condition is reported to the user, report it
	180	* with both voltage sensors.
	181	*/
bec24b74 GR	182	static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ltc4261_show_bool, NULL,
	183	FAULT_UV);
	184	static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ltc4261_show_bool, NULL,
	185	FAULT_OV);
	186	static SENSOR_DEVICE_ATTR(in2_min_alarm, S_IRUGO, ltc4261_show_bool, NULL,
	187	FAULT_UV);
	188	static SENSOR_DEVICE_ATTR(in2_max_alarm, S_IRUGO, ltc4261_show_bool, NULL,
	189	FAULT_OV);
e5f5c99a GR	190
e5f5c99a GR	191	/* Currents (via sense resistor) */
bec24b74 GR	192	static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4261_show_value, NULL,
bec24b74 GR	193	LTC4261_SENSE_H);
e5f5c99a GR	194
e5f5c99a GR	195	/* Overcurrent alarm */
bec24b74 GR	196	static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO, ltc4261_show_bool, NULL,
bec24b74 GR	197	FAULT_OC);
e5f5c99a	198
38f150fe	199	static struct attribute *ltc4261_attrs[] = {
e5f5c99a GR	200	&sensor_dev_attr_in1_input.dev_attr.attr,
	201	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
	202	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
	203	&sensor_dev_attr_in2_input.dev_attr.attr,
	204	&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
	205	&sensor_dev_attr_in2_max_alarm.dev_attr.attr,
	206
	207	&sensor_dev_attr_curr1_input.dev_attr.attr,
	208	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
	209
	210	NULL,
	211	};
38f150fe	212	ATTRIBUTE_GROUPS(ltc4261);
e5f5c99a GR	213
	214	static int ltc4261_probe(struct i2c_client *client,
	215	const struct i2c_device_id *id)
	216	{
	217	struct i2c_adapter *adapter = client->adapter;
38f150fe	218	struct device *dev = &client->dev;
e5f5c99a	219	struct ltc4261_data *data;
38f150fe	220	struct device *hwmon_dev;
e5f5c99a GR	221
	222	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
	223	return -ENODEV;
	224
	225	if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) {
38f150fe	226	dev_err(dev, "Failed to read status register\n");
e5f5c99a GR	227	return -ENODEV;
	228	}
	229
38f150fe	230	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
36839287 GR	231	if (!data)
36839287 GR	232	return -ENOMEM;
e5f5c99a	233
38f150fe	234	data->client = client;
e5f5c99a GR	235	mutex_init(&data->update_lock);
	236
	237	/* Clear faults */
	238	i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00);
	239
38f150fe GR	240	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
	241	data,
	242	ltc4261_groups);
2a253c47	243	return PTR_ERR_OR_ZERO(hwmon_dev);
e5f5c99a GR	244	}
	245
	246	static const struct i2c_device_id ltc4261_id[] = {
	247	{"ltc4261", 0},
	248	{}
	249	};
	250
	251	MODULE_DEVICE_TABLE(i2c, ltc4261_id);
	252
	253	/* This is the driver that will be inserted */
	254	static struct i2c_driver ltc4261_driver = {
	255	.driver = {
	256	.name = "ltc4261",
	257	},
	258	.probe = ltc4261_probe,
e5f5c99a GR	259	.id_table = ltc4261_id,
	260	};
	261
f0967eea	262	module_i2c_driver(ltc4261_driver);
e5f5c99a	263
bb9a80e5	264	MODULE_AUTHOR("Guenter Roeck <[email protected]>");
e5f5c99a GR	265	MODULE_DESCRIPTION("LTC4261 driver");
e5f5c99a GR	266	MODULE_LICENSE("GPL");