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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for Linear Technology LTC4260 I2C Positive Voltage Hot Swap Controller
4 *
5 * Copyright (c) 2014 Guenter Roeck
6 */
7
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/err.h>
11#include <linux/slab.h>
12#include <linux/i2c.h>
13#include <linux/hwmon.h>
14#include <linux/hwmon-sysfs.h>
15#include <linux/jiffies.h>
16#include <linux/regmap.h>
17
18/* chip registers */
19#define LTC4260_CONTROL 0x00
20#define LTC4260_ALERT 0x01
21#define LTC4260_STATUS 0x02
22#define LTC4260_FAULT 0x03
23#define LTC4260_SENSE 0x04
24#define LTC4260_SOURCE 0x05
25#define LTC4260_ADIN 0x06
26
27/*
28 * Fault register bits
29 */
30#define FAULT_OV (1 << 0)
31#define FAULT_UV (1 << 1)
32#define FAULT_OC (1 << 2)
33#define FAULT_POWER_BAD (1 << 3)
34#define FAULT_FET_SHORT (1 << 5)
35
36/* Return the voltage from the given register in mV or mA */
37static int ltc4260_get_value(struct device *dev, u8 reg)
38{
39 struct regmap *regmap = dev_get_drvdata(dev);
40 unsigned int val;
41 int ret;
42
43 ret = regmap_read(regmap, reg, &val);
44 if (ret < 0)
45 return ret;
46
47 switch (reg) {
48 case LTC4260_ADIN:
49 /* 10 mV resolution. Convert to mV. */
50 val = val * 10;
51 break;
52 case LTC4260_SOURCE:
53 /* 400 mV resolution. Convert to mV. */
54 val = val * 400;
55 break;
56 case LTC4260_SENSE:
57 /*
58 * 300 uV resolution. Convert to current as measured with
59 * an 1 mOhm sense resistor, in mA. If a different sense
60 * resistor is installed, calculate the actual current by
61 * dividing the reported current by the sense resistor value
62 * in mOhm.
63 */
64 val = val * 300;
65 break;
66 default:
67 return -EINVAL;
68 }
69
70 return val;
71}
72
73static ssize_t ltc4260_value_show(struct device *dev,
74 struct device_attribute *da, char *buf)
75{
76 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
77 int value;
78
79 value = ltc4260_get_value(dev, attr->index);
80 if (value < 0)
81 return value;
82 return sysfs_emit(buf, "%d\n", value);
83}
84
85static ssize_t ltc4260_bool_show(struct device *dev,
86 struct device_attribute *da, char *buf)
87{
88 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
89 struct regmap *regmap = dev_get_drvdata(dev);
90 unsigned int fault;
91 int ret;
92
93 ret = regmap_read(regmap, LTC4260_FAULT, &fault);
94 if (ret < 0)
95 return ret;
96
97 fault &= attr->index;
98 if (fault) /* Clear reported faults in chip register */
99 regmap_update_bits(regmap, LTC4260_FAULT, attr->index, 0);
100
101 return sysfs_emit(buf, "%d\n", !!fault);
102}
103
104/* Voltages */
105static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4260_value, LTC4260_SOURCE);
106static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4260_value, LTC4260_ADIN);
107
108/*
109 * Voltage alarms
110 * UV/OV faults are associated with the input voltage, and the POWER BAD and
111 * FET SHORT faults are associated with the output voltage.
112 */
113static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc4260_bool, FAULT_UV);
114static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc4260_bool, FAULT_OV);
115static SENSOR_DEVICE_ATTR_RO(in2_alarm, ltc4260_bool,
116 FAULT_POWER_BAD | FAULT_FET_SHORT);
117
118/* Current (via sense resistor) */
119static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4260_value, LTC4260_SENSE);
120
121/* Overcurrent alarm */
122static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc4260_bool, FAULT_OC);
123
124static struct attribute *ltc4260_attrs[] = {
125 &sensor_dev_attr_in1_input.dev_attr.attr,
126 &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
127 &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
128 &sensor_dev_attr_in2_input.dev_attr.attr,
129 &sensor_dev_attr_in2_alarm.dev_attr.attr,
130
131 &sensor_dev_attr_curr1_input.dev_attr.attr,
132 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
133
134 NULL,
135};
136ATTRIBUTE_GROUPS(ltc4260);
137
138static const struct regmap_config ltc4260_regmap_config = {
139 .reg_bits = 8,
140 .val_bits = 8,
141 .max_register = LTC4260_ADIN,
142};
143
144static int ltc4260_probe(struct i2c_client *client)
145{
146 struct device *dev = &client->dev;
147 struct device *hwmon_dev;
148 struct regmap *regmap;
149
150 regmap = devm_regmap_init_i2c(client, <c4260_regmap_config);
151 if (IS_ERR(regmap)) {
152 dev_err(dev, "failed to allocate register map\n");
153 return PTR_ERR(regmap);
154 }
155
156 /* Clear faults */
157 regmap_write(regmap, LTC4260_FAULT, 0x00);
158
159 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
160 regmap,
161 ltc4260_groups);
162 return PTR_ERR_OR_ZERO(hwmon_dev);
163}
164
165static const struct i2c_device_id ltc4260_id[] = {
166 {"ltc4260", 0},
167 { }
168};
169
170MODULE_DEVICE_TABLE(i2c, ltc4260_id);
171
172static struct i2c_driver ltc4260_driver = {
173 .driver = {
174 .name = "ltc4260",
175 },
176 .probe = ltc4260_probe,
177 .id_table = ltc4260_id,
178};
179
180module_i2c_driver(ltc4260_driver);
181
182MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
183MODULE_DESCRIPTION("LTC4260 driver");
184MODULE_LICENSE("GPL");
1/*
2 * Driver for Linear Technology LTC4260 I2C Positive Voltage Hot Swap Controller
3 *
4 * Copyright (c) 2014 Guenter Roeck
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/err.h>
20#include <linux/slab.h>
21#include <linux/i2c.h>
22#include <linux/hwmon.h>
23#include <linux/hwmon-sysfs.h>
24#include <linux/jiffies.h>
25#include <linux/regmap.h>
26
27/* chip registers */
28#define LTC4260_CONTROL 0x00
29#define LTC4260_ALERT 0x01
30#define LTC4260_STATUS 0x02
31#define LTC4260_FAULT 0x03
32#define LTC4260_SENSE 0x04
33#define LTC4260_SOURCE 0x05
34#define LTC4260_ADIN 0x06
35
36/*
37 * Fault register bits
38 */
39#define FAULT_OV (1 << 0)
40#define FAULT_UV (1 << 1)
41#define FAULT_OC (1 << 2)
42#define FAULT_POWER_BAD (1 << 3)
43#define FAULT_FET_SHORT (1 << 5)
44
45/* Return the voltage from the given register in mV or mA */
46static int ltc4260_get_value(struct device *dev, u8 reg)
47{
48 struct regmap *regmap = dev_get_drvdata(dev);
49 unsigned int val;
50 int ret;
51
52 ret = regmap_read(regmap, reg, &val);
53 if (ret < 0)
54 return ret;
55
56 switch (reg) {
57 case LTC4260_ADIN:
58 /* 10 mV resolution. Convert to mV. */
59 val = val * 10;
60 break;
61 case LTC4260_SOURCE:
62 /* 400 mV resolution. Convert to mV. */
63 val = val * 400;
64 break;
65 case LTC4260_SENSE:
66 /*
67 * 300 uV resolution. Convert to current as measured with
68 * an 1 mOhm sense resistor, in mA. If a different sense
69 * resistor is installed, calculate the actual current by
70 * dividing the reported current by the sense resistor value
71 * in mOhm.
72 */
73 val = val * 300;
74 break;
75 default:
76 return -EINVAL;
77 }
78
79 return val;
80}
81
82static ssize_t ltc4260_show_value(struct device *dev,
83 struct device_attribute *da, char *buf)
84{
85 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
86 int value;
87
88 value = ltc4260_get_value(dev, attr->index);
89 if (value < 0)
90 return value;
91 return snprintf(buf, PAGE_SIZE, "%d\n", value);
92}
93
94static ssize_t ltc4260_show_bool(struct device *dev,
95 struct device_attribute *da, char *buf)
96{
97 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
98 struct regmap *regmap = dev_get_drvdata(dev);
99 unsigned int fault;
100 int ret;
101
102 ret = regmap_read(regmap, LTC4260_FAULT, &fault);
103 if (ret < 0)
104 return ret;
105
106 fault &= attr->index;
107 if (fault) /* Clear reported faults in chip register */
108 regmap_update_bits(regmap, LTC4260_FAULT, attr->index, 0);
109
110 return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
111}
112
113/* Voltages */
114static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4260_show_value, NULL,
115 LTC4260_SOURCE);
116static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4260_show_value, NULL,
117 LTC4260_ADIN);
118
119/*
120 * Voltage alarms
121 * UV/OV faults are associated with the input voltage, and the POWER BAD and
122 * FET SHORT faults are associated with the output voltage.
123 */
124static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ltc4260_show_bool, NULL,
125 FAULT_UV);
126static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ltc4260_show_bool, NULL,
127 FAULT_OV);
128static SENSOR_DEVICE_ATTR(in2_alarm, S_IRUGO, ltc4260_show_bool, NULL,
129 FAULT_POWER_BAD | FAULT_FET_SHORT);
130
131/* Current (via sense resistor) */
132static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4260_show_value, NULL,
133 LTC4260_SENSE);
134
135/* Overcurrent alarm */
136static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO, ltc4260_show_bool, NULL,
137 FAULT_OC);
138
139static struct attribute *ltc4260_attrs[] = {
140 &sensor_dev_attr_in1_input.dev_attr.attr,
141 &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
142 &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
143 &sensor_dev_attr_in2_input.dev_attr.attr,
144 &sensor_dev_attr_in2_alarm.dev_attr.attr,
145
146 &sensor_dev_attr_curr1_input.dev_attr.attr,
147 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
148
149 NULL,
150};
151ATTRIBUTE_GROUPS(ltc4260);
152
153static struct regmap_config ltc4260_regmap_config = {
154 .reg_bits = 8,
155 .val_bits = 8,
156 .max_register = LTC4260_ADIN,
157};
158
159static int ltc4260_probe(struct i2c_client *client,
160 const struct i2c_device_id *id)
161{
162 struct device *dev = &client->dev;
163 struct device *hwmon_dev;
164 struct regmap *regmap;
165
166 regmap = devm_regmap_init_i2c(client, <c4260_regmap_config);
167 if (IS_ERR(regmap)) {
168 dev_err(dev, "failed to allocate register map\n");
169 return PTR_ERR(regmap);
170 }
171
172 /* Clear faults */
173 regmap_write(regmap, LTC4260_FAULT, 0x00);
174
175 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
176 regmap,
177 ltc4260_groups);
178 return PTR_ERR_OR_ZERO(hwmon_dev);
179}
180
181static const struct i2c_device_id ltc4260_id[] = {
182 {"ltc4260", 0},
183 { }
184};
185
186MODULE_DEVICE_TABLE(i2c, ltc4260_id);
187
188static struct i2c_driver ltc4260_driver = {
189 .driver = {
190 .name = "ltc4260",
191 },
192 .probe = ltc4260_probe,
193 .id_table = ltc4260_id,
194};
195
196module_i2c_driver(ltc4260_driver);
197
198MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
199MODULE_DESCRIPTION("LTC4260 driver");
200MODULE_LICENSE("GPL");