[net-next-2.6.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 <iws@ovro.caltech.edu>
 *
 * 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>

/* 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 device *hwmon_dev;

	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 i2c_client *client = to_i2c_client(dev);
	struct ltc4261_data *data = i2c_get_clientdata(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);
				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 i2c_client *client = to_i2c_client(dev);
	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(client, LTC4261_FAULT, ~fault);

	return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 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 LTC4261_VALUE(name, ltc4261_cmd_idx) \
	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
	ltc4261_show_value, NULL, ltc4261_cmd_idx)

#define LTC4261_BOOL(name, mask) \
	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
	ltc4261_show_bool, NULL, (mask))

/*
 * Input voltages.
 */
LTC4261_VALUE(in1_input, LTC4261_ADIN_H);
LTC4261_VALUE(in2_input, 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.
 */
LTC4261_BOOL(in1_min_alarm, FAULT_UV);
LTC4261_BOOL(in1_max_alarm, FAULT_OV);
LTC4261_BOOL(in2_min_alarm, FAULT_UV);
LTC4261_BOOL(in2_max_alarm, FAULT_OV);

/* Currents (via sense resistor) */
LTC4261_VALUE(curr1_input, LTC4261_SENSE_H);

/* Overcurrent alarm */
LTC4261_BOOL(curr1_max_alarm, FAULT_OC);

static struct attribute *ltc4261_attributes[] = {
	&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,
};

static const struct attribute_group ltc4261_group = {
	.attrs = ltc4261_attributes,
};

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

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

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

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

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

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

	/* Register sysfs hooks */
	ret = sysfs_create_group(&client->dev.kobj, &ltc4261_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, &ltc4261_group);
out_sysfs_create_group:
	kfree(data);
out_kzalloc:
	return ret;
}

static int ltc4261_remove(struct i2c_client *client)
{
	struct ltc4261_data *data = i2c_get_clientdata(client);

	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&client->dev.kobj, &ltc4261_group);

	kfree(data);

	return 0;
}

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,
	.remove = ltc4261_remove,
	.id_table = ltc4261_id,
};

static int __init ltc4261_init(void)
{
	return i2c_add_driver(&ltc4261_driver);
}

static void __exit ltc4261_exit(void)
{
	i2c_del_driver(&ltc4261_driver);
}

MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
MODULE_DESCRIPTION("LTC4261 driver");
MODULE_LICENSE("GPL");

module_init(ltc4261_init);
module_exit(ltc4261_exit);
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 <iws@ovro.caltech.edu>
	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>
	36
	37	/* chip registers */
	38	#define LTC4261_STATUS 0x00 /* readonly */
	39	#define LTC4261_FAULT 0x01
	40	#define LTC4261_ALERT 0x02
	41	#define LTC4261_CONTROL 0x03
	42	#define LTC4261_SENSE_H 0x04
	43	#define LTC4261_SENSE_L 0x05
	44	#define LTC4261_ADIN2_H 0x06
	45	#define LTC4261_ADIN2_L 0x07
	46	#define LTC4261_ADIN_H 0x08
	47	#define LTC4261_ADIN_L 0x09
	48
	49	/*
	50	* Fault register bits
	51	*/
	52	#define FAULT_OV (1<<0)
	53	#define FAULT_UV (1<<1)
	54	#define FAULT_OC (1<<2)
	55
	56	struct ltc4261_data {
	57	struct device *hwmon_dev;
	58
	59	struct mutex update_lock;
	60	bool valid;
	61	unsigned long last_updated; /* in jiffies */
	62
	63	/* Registers */
	64	u8 regs[10];
65	};
66
67	static struct ltc4261_data ltc4261_update_device(struct device dev)
68	{
69	struct i2c_client *client = to_i2c_client(dev);
70	struct ltc4261_data *data = i2c_get_clientdata(client);
71	struct ltc4261_data *ret = data;
72
73	mutex_lock(&data->update_lock);
74
75	if (time_after(jiffies, data->last_updated + HZ / 4) \|\| !data->valid) {
76	int i;
77
78	/* Read registers -- 0x00 to 0x09 */
79	for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
80	int val;
81
82	val = i2c_smbus_read_byte_data(client, i);
83	if (unlikely(val < 0)) {
84	dev_dbg(dev,
69f8b741	85	"Failed to read ADC value: error %d\n",
e5f5c99a GR	86	val);
	87	ret = ERR_PTR(val);
	88	goto abort;
	89	}
	90	data->regs[i] = val;
	91	}
	92	data->last_updated = jiffies;
	93	data->valid = 1;
	94	}
	95	abort:
	96	mutex_unlock(&data->update_lock);
	97	return ret;
	98	}
	99
	100	/* Return the voltage from the given register in mV or mA */
	101	static int ltc4261_get_value(struct ltc4261_data *data, u8 reg)
	102	{
	103	u32 val;
	104
	105	val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6);
	106
	107	switch (reg) {
	108	case LTC4261_ADIN_H:
	109	case LTC4261_ADIN2_H:
	110	/* 2.5mV resolution. Convert to mV. */
	111	val = val * 25 / 10;
	112	break;
	113	case LTC4261_SENSE_H:
	114	/*
	115	* 62.5uV resolution. Convert to current as measured with
	116	* an 1 mOhm sense resistor, in mA. If a different sense
	117	* resistor is installed, calculate the actual current by
	118	* dividing the reported current by the sense resistor value
	119	* in mOhm.
	120	*/
	121	val = val * 625 / 10;
	122	break;
	123	default:
	124	/* If we get here, the developer messed up */
	125	WARN_ON_ONCE(1);
	126	val = 0;
	127	break;
	128	}
	129
	130	return val;
	131	}
	132
	133	static ssize_t ltc4261_show_value(struct device *dev,
	134	struct device_attribute da, char buf)
	135	{
	136	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	137	struct ltc4261_data *data = ltc4261_update_device(dev);
	138	int value;
	139
	140	if (IS_ERR(data))
	141	return PTR_ERR(data);
	142
	143	value = ltc4261_get_value(data, attr->index);
	144	return snprintf(buf, PAGE_SIZE, "%d\n", value);
	145	}
	146
	147	static ssize_t ltc4261_show_bool(struct device *dev,
	148	struct device_attribute da, char buf)
	149	{
150	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
151	struct i2c_client *client = to_i2c_client(dev);
152	struct ltc4261_data *data = ltc4261_update_device(dev);
153	u8 fault;
154
155	if (IS_ERR(data))
156	return PTR_ERR(data);
157
158	fault = data->regs[LTC4261_FAULT] & attr->index;
159	if (fault) /* Clear reported faults in chip register */
160	i2c_smbus_write_byte_data(client, LTC4261_FAULT, ~fault);
161
162	return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 1 : 0);
163	}
164
165	/*
166	* These macros are used below in constructing device attribute objects
167	* for use with sysfs_create_group() to make a sysfs device file
168	* for each register.
169	*/
170
171	#define LTC4261_VALUE(name, ltc4261_cmd_idx) \
172	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
173	ltc4261_show_value, NULL, ltc4261_cmd_idx)
174
175	#define LTC4261_BOOL(name, mask) \
176	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
177	ltc4261_show_bool, NULL, (mask))
178
179	/*
180	* Input voltages.
181	*/
182	LTC4261_VALUE(in1_input, LTC4261_ADIN_H);
183	LTC4261_VALUE(in2_input, LTC4261_ADIN2_H);
184
185	/*
186	* Voltage alarms. The chip has only one set of voltage alarm status bits,
187	* triggered by input voltage alarms. In many designs, those alarms are
188	* associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin
189	* to the OV pin. ADIN2 is, however, not available on all chip variants.
190	* To ensure that the alarm condition is reported to the user, report it
191	* with both voltage sensors.
192	*/
193	LTC4261_BOOL(in1_min_alarm, FAULT_UV);
194	LTC4261_BOOL(in1_max_alarm, FAULT_OV);
195	LTC4261_BOOL(in2_min_alarm, FAULT_UV);
196	LTC4261_BOOL(in2_max_alarm, FAULT_OV);
197
198	/* Currents (via sense resistor) */
199	LTC4261_VALUE(curr1_input, LTC4261_SENSE_H);
200
201	/* Overcurrent alarm */
202	LTC4261_BOOL(curr1_max_alarm, FAULT_OC);
203
204	static struct attribute *ltc4261_attributes[] = {
205	&sensor_dev_attr_in1_input.dev_attr.attr,
206	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
207	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
208	&sensor_dev_attr_in2_input.dev_attr.attr,
209	&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
210	&sensor_dev_attr_in2_max_alarm.dev_attr.attr,
211
212	&sensor_dev_attr_curr1_input.dev_attr.attr,
213	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
214
215	NULL,
216	};
217
218	static const struct attribute_group ltc4261_group = {
219	.attrs = ltc4261_attributes,
220	};
221
222	static int ltc4261_probe(struct i2c_client *client,
223	const struct i2c_device_id *id)
224	{
225	struct i2c_adapter *adapter = client->adapter;
226	struct ltc4261_data *data;
227	int ret;
228
229	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
230	return -ENODEV;
231
232	if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) {
475200c0	233	dev_err(&client->dev, "Failed to read status register\n");
e5f5c99a GR	234	return -ENODEV;
	235	}
	236
	237	data = kzalloc(sizeof(*data), GFP_KERNEL);
	238	if (!data) {
	239	ret = -ENOMEM;
	240	goto out_kzalloc;
	241	}
	242
	243	i2c_set_clientdata(client, data);
	244	mutex_init(&data->update_lock);
	245
	246	/* Clear faults */
	247	i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00);
	248
	249	/* Register sysfs hooks */
	250	ret = sysfs_create_group(&client->dev.kobj, &ltc4261_group);
	251	if (ret)
	252	goto out_sysfs_create_group;
	253
	254	data->hwmon_dev = hwmon_device_register(&client->dev);
	255	if (IS_ERR(data->hwmon_dev)) {
	256	ret = PTR_ERR(data->hwmon_dev);
	257	goto out_hwmon_device_register;
	258	}
	259
	260	return 0;
	261
	262	out_hwmon_device_register:
	263	sysfs_remove_group(&client->dev.kobj, &ltc4261_group);
	264	out_sysfs_create_group:
	265	kfree(data);
	266	out_kzalloc:
	267	return ret;
	268	}
	269
	270	static int ltc4261_remove(struct i2c_client *client)
	271	{
	272	struct ltc4261_data *data = i2c_get_clientdata(client);
	273
	274	hwmon_device_unregister(data->hwmon_dev);
	275	sysfs_remove_group(&client->dev.kobj, &ltc4261_group);
	276
	277	kfree(data);
	278
	279	return 0;
	280	}
	281
	282	static const struct i2c_device_id ltc4261_id[] = {
	283	{"ltc4261", 0},
	284	{}
	285	};
	286
	287	MODULE_DEVICE_TABLE(i2c, ltc4261_id);
	288
	289	/* This is the driver that will be inserted */
	290	static struct i2c_driver ltc4261_driver = {
	291	.driver = {
	292	.name = "ltc4261",
	293	},
	294	.probe = ltc4261_probe,
	295	.remove = ltc4261_remove,
	296	.id_table = ltc4261_id,
	297	};
298
299	static int __init ltc4261_init(void)
300	{
301	return i2c_add_driver(&ltc4261_driver);
302	}
303
304	static void __exit ltc4261_exit(void)
305	{
306	i2c_del_driver(&ltc4261_driver);
307	}
308
309	MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
310	MODULE_DESCRIPTION("LTC4261 driver");
311	MODULE_LICENSE("GPL");
312
313	module_init(ltc4261_init);
314	module_exit(ltc4261_exit);