aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/hwmon/ltc4260.c
blob: 453a250d9df5c8eaa9e51fcbb8b76ce5dc200d5a (plain) (blame)
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
/*
 * Driver for Linear Technology LTC4260 I2C Positive Voltage Hot Swap Controller
 *
 * Copyright (c) 2014 Guenter Roeck
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/module.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>
#include <linux/regmap.h>

/* chip registers */
#define LTC4260_CONTROL	0x00
#define LTC4260_ALERT	0x01
#define LTC4260_STATUS	0x02
#define LTC4260_FAULT	0x03
#define LTC4260_SENSE	0x04
#define LTC4260_SOURCE	0x05
#define LTC4260_ADIN	0x06

/*
 * Fault register bits
 */
#define FAULT_OV	(1 << 0)
#define FAULT_UV	(1 << 1)
#define FAULT_OC	(1 << 2)
#define FAULT_POWER_BAD	(1 << 3)
#define FAULT_FET_SHORT	(1 << 5)

/* Return the voltage from the given register in mV or mA */
static int ltc4260_get_value(struct device *dev, u8 reg)
{
	struct regmap *regmap = dev_get_drvdata(dev);
	unsigned int val;
	int ret;

	ret = regmap_read(regmap, reg, &val);
	if (ret < 0)
		return ret;

	switch (reg) {
	case LTC4260_ADIN:
		/* 10 mV resolution. Convert to mV. */
		val = val * 10;
		break;
	case LTC4260_SOURCE:
		/* 400 mV resolution. Convert to mV. */
		val = val * 400;
		break;
	case LTC4260_SENSE:
		/*
		 * 300 uV 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 * 300;
		break;
	default:
		return -EINVAL;
	}

	return val;
}

static ssize_t ltc4260_show_value(struct device *dev,
				  struct device_attribute *da, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	int value;

	value = ltc4260_get_value(dev, attr->index);
	if (value < 0)
		return value;
	return snprintf(buf, PAGE_SIZE, "%d\n", value);
}

static ssize_t ltc4260_show_bool(struct device *dev,
				 struct device_attribute *da, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct regmap *regmap = dev_get_drvdata(dev);
	unsigned int fault;
	int ret;

	ret = regmap_read(regmap, LTC4260_FAULT, &fault);
	if (ret < 0)
		return ret;

	fault &= attr->index;
	if (fault)		/* Clear reported faults in chip register */
		regmap_update_bits(regmap, LTC4260_FAULT, attr->index, 0);

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

/* Voltages */
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4260_show_value, NULL,
			  LTC4260_SOURCE);
static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4260_show_value, NULL,
			  LTC4260_ADIN);

/*
 * Voltage alarms
 * UV/OV faults are associated with the input voltage, and the POWER BAD and
 * FET SHORT faults are associated with the output voltage.
 */
static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ltc4260_show_bool, NULL,
			  FAULT_UV);
static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ltc4260_show_bool, NULL,
			  FAULT_OV);
static SENSOR_DEVICE_ATTR(in2_alarm, S_IRUGO, ltc4260_show_bool, NULL,
			  FAULT_POWER_BAD | FAULT_FET_SHORT);

/* Current (via sense resistor) */
static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4260_show_value, NULL,
			  LTC4260_SENSE);

/* Overcurrent alarm */
static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO, ltc4260_show_bool, NULL,
			  FAULT_OC);

static struct attribute *ltc4260_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_alarm.dev_attr.attr,

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

	NULL,
};
ATTRIBUTE_GROUPS(ltc4260);

static struct regmap_config ltc4260_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = LTC4260_ADIN,
};

static int ltc4260_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct device *dev = &client->dev;
	struct device *hwmon_dev;
	struct regmap *regmap;

	regmap = devm_regmap_init_i2c(client, &ltc4260_regmap_config);
	if (IS_ERR(regmap)) {
		dev_err(dev, "failed to allocate register map\n");
		return PTR_ERR(regmap);
	}

	/* Clear faults */
	regmap_write(regmap, LTC4260_FAULT, 0x00);

	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
							   regmap,
							   ltc4260_groups);
	return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct i2c_device_id ltc4260_id[] = {
	{"ltc4260", 0},
	{ }
};

MODULE_DEVICE_TABLE(i2c, ltc4260_id);

static struct i2c_driver ltc4260_driver = {
	.driver = {
		   .name = "ltc4260",
		   },
	.probe = ltc4260_probe,
	.id_table = ltc4260_id,
};

module_i2c_driver(ltc4260_driver);

MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("LTC4260 driver");
MODULE_LICENSE("GPL");