[mirror_ubuntu-bionic-kernel.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);
				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 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 = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	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)
		return ret;

	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);
	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);

	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,
};

module_i2c_driver(ltc4261_driver);

MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
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 <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);
e5f5c99a GR	87	ret = ERR_PTR(val);
aac9fe9b	88	data->valid = 0;
e5f5c99a GR	89	goto abort;
	90	}
	91	data->regs[i] = val;
	92	}
	93	data->last_updated = jiffies;
	94	data->valid = 1;
	95	}
	96	abort:
	97	mutex_unlock(&data->update_lock);
	98	return ret;
	99	}
	100
	101	/* Return the voltage from the given register in mV or mA */
	102	static int ltc4261_get_value(struct ltc4261_data *data, u8 reg)
	103	{
	104	u32 val;
	105
	106	val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6);
	107
	108	switch (reg) {
	109	case LTC4261_ADIN_H:
	110	case LTC4261_ADIN2_H:
	111	/* 2.5mV resolution. Convert to mV. */
	112	val = val * 25 / 10;
	113	break;
	114	case LTC4261_SENSE_H:
	115	/*
	116	* 62.5uV resolution. Convert to current as measured with
	117	* an 1 mOhm sense resistor, in mA. If a different sense
	118	* resistor is installed, calculate the actual current by
	119	* dividing the reported current by the sense resistor value
	120	* in mOhm.
	121	*/
	122	val = val * 625 / 10;
	123	break;
	124	default:
	125	/* If we get here, the developer messed up */
	126	WARN_ON_ONCE(1);
	127	val = 0;
	128	break;
	129	}
	130
	131	return val;
	132	}
	133
	134	static ssize_t ltc4261_show_value(struct device *dev,
	135	struct device_attribute da, char buf)
	136	{
	137	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	138	struct ltc4261_data *data = ltc4261_update_device(dev);
	139	int value;
	140
	141	if (IS_ERR(data))
	142	return PTR_ERR(data);
	143
	144	value = ltc4261_get_value(data, attr->index);
	145	return snprintf(buf, PAGE_SIZE, "%d\n", value);
	146	}
	147
	148	static ssize_t ltc4261_show_bool(struct device *dev,
	149	struct device_attribute da, char buf)
	150	{
	151	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	152	struct i2c_client *client = to_i2c_client(dev);
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 */
161	i2c_smbus_write_byte_data(client, LTC4261_FAULT, ~fault);
162
163	return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 1 : 0);
164	}
165
166	/*
167	* These macros are used below in constructing device attribute objects
168	* for use with sysfs_create_group() to make a sysfs device file
169	* for each register.
170	*/
171
172	#define LTC4261_VALUE(name, ltc4261_cmd_idx) \
173	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
174	ltc4261_show_value, NULL, ltc4261_cmd_idx)
175
176	#define LTC4261_BOOL(name, mask) \
177	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
178	ltc4261_show_bool, NULL, (mask))
179
180	/*
181	* Input voltages.
182	*/
183	LTC4261_VALUE(in1_input, LTC4261_ADIN_H);
184	LTC4261_VALUE(in2_input, LTC4261_ADIN2_H);
185
186	/*
187	* Voltage alarms. The chip has only one set of voltage alarm status bits,
188	* triggered by input voltage alarms. In many designs, those alarms are
189	* associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin
190	* to the OV pin. ADIN2 is, however, not available on all chip variants.
191	* To ensure that the alarm condition is reported to the user, report it
192	* with both voltage sensors.
193	*/
194	LTC4261_BOOL(in1_min_alarm, FAULT_UV);
195	LTC4261_BOOL(in1_max_alarm, FAULT_OV);
196	LTC4261_BOOL(in2_min_alarm, FAULT_UV);
197	LTC4261_BOOL(in2_max_alarm, FAULT_OV);
198
199	/* Currents (via sense resistor) */
200	LTC4261_VALUE(curr1_input, LTC4261_SENSE_H);
201
202	/* Overcurrent alarm */
203	LTC4261_BOOL(curr1_max_alarm, FAULT_OC);
204
205	static struct attribute *ltc4261_attributes[] = {
206	&sensor_dev_attr_in1_input.dev_attr.attr,
207	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
208	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
209	&sensor_dev_attr_in2_input.dev_attr.attr,
210	&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
211	&sensor_dev_attr_in2_max_alarm.dev_attr.attr,
212
213	&sensor_dev_attr_curr1_input.dev_attr.attr,
214	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
215
216	NULL,
217	};
218
219	static const struct attribute_group ltc4261_group = {
220	.attrs = ltc4261_attributes,
221	};
222
223	static int ltc4261_probe(struct i2c_client *client,
224	const struct i2c_device_id *id)
225	{
226	struct i2c_adapter *adapter = client->adapter;
227	struct ltc4261_data *data;
228	int ret;
229
230	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
231	return -ENODEV;
232
233	if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) {
475200c0	234	dev_err(&client->dev, "Failed to read status register\n");
e5f5c99a GR	235	return -ENODEV;
	236	}
	237
36839287 GR	238	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
	239	if (!data)
	240	return -ENOMEM;
e5f5c99a GR	241
	242	i2c_set_clientdata(client, data);
	243	mutex_init(&data->update_lock);
	244
	245	/* Clear faults */
	246	i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00);
	247
	248	/* Register sysfs hooks */
	249	ret = sysfs_create_group(&client->dev.kobj, &ltc4261_group);
	250	if (ret)
36839287	251	return ret;
e5f5c99a GR	252
	253	data->hwmon_dev = hwmon_device_register(&client->dev);
	254	if (IS_ERR(data->hwmon_dev)) {
	255	ret = PTR_ERR(data->hwmon_dev);
	256	goto out_hwmon_device_register;
	257	}
	258
	259	return 0;
	260
	261	out_hwmon_device_register:
	262	sysfs_remove_group(&client->dev.kobj, &ltc4261_group);
e5f5c99a GR	263	return ret;
	264	}
	265
	266	static int ltc4261_remove(struct i2c_client *client)
	267	{
	268	struct ltc4261_data *data = i2c_get_clientdata(client);
	269
	270	hwmon_device_unregister(data->hwmon_dev);
	271	sysfs_remove_group(&client->dev.kobj, &ltc4261_group);
	272
e5f5c99a GR	273	return 0;
	274	}
	275
	276	static const struct i2c_device_id ltc4261_id[] = {
	277	{"ltc4261", 0},
	278	{}
	279	};
	280
	281	MODULE_DEVICE_TABLE(i2c, ltc4261_id);
	282
	283	/* This is the driver that will be inserted */
	284	static struct i2c_driver ltc4261_driver = {
	285	.driver = {
	286	.name = "ltc4261",
	287	},
	288	.probe = ltc4261_probe,
	289	.remove = ltc4261_remove,
	290	.id_table = ltc4261_id,
	291	};
	292
f0967eea	293	module_i2c_driver(ltc4261_driver);
e5f5c99a GR	294
	295	MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
	296	MODULE_DESCRIPTION("LTC4261 driver");
	297	MODULE_LICENSE("GPL");