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1/*
2 * Driver for Linear Technology LTC4151 High Voltage I2C Current
3 * and Voltage Monitor
4 *
5 * Copyright (C) 2011 AppearTV AS
6 *
7 * Derived from:
8 *
9 * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot
10 * Swap Controller
11 * Copyright (C) 2010 Ericsson AB.
12 *
13 * Datasheet: http://www.linear.com/docs/Datasheet/4151fc.pdf
14 *
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2 of the License, or
18 * (at your option) any later version.
19 *
20 * This program is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 * GNU General Public License for more details.
24 *
25 * You should have received a copy of the GNU General Public License
26 * along with this program; if not, write to the Free Software
27 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28 *
29 */
30
31#include <linux/kernel.h>
32#include <linux/module.h>
33#include <linux/init.h>
34#include <linux/err.h>
35#include <linux/slab.h>
36#include <linux/i2c.h>
37#include <linux/hwmon.h>
38#include <linux/hwmon-sysfs.h>
39
40/* chip registers */
41#define LTC4151_SENSE_H 0x00
42#define LTC4151_SENSE_L 0x01
43#define LTC4151_VIN_H 0x02
44#define LTC4151_VIN_L 0x03
45#define LTC4151_ADIN_H 0x04
46#define LTC4151_ADIN_L 0x05
47
48struct ltc4151_data {
49 struct device *hwmon_dev;
50
51 struct mutex update_lock;
52 bool valid;
53 unsigned long last_updated; /* in jiffies */
54
55 /* Registers */
56 u8 regs[6];
57};
58
59static struct ltc4151_data *ltc4151_update_device(struct device *dev)
60{
61 struct i2c_client *client = to_i2c_client(dev);
62 struct ltc4151_data *data = i2c_get_clientdata(client);
63 struct ltc4151_data *ret = data;
64
65 mutex_lock(&data->update_lock);
66
67 /*
68 * The chip's A/D updates 6 times per second
69 * (Conversion Rate 6 - 9 Hz)
70 */
71 if (time_after(jiffies, data->last_updated + HZ / 6) || !data->valid) {
72 int i;
73
74 dev_dbg(&client->dev, "Starting ltc4151 update\n");
75
76 /* Read all registers */
77 for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
78 int val;
79
80 val = i2c_smbus_read_byte_data(client, i);
81 if (unlikely(val < 0)) {
82 dev_dbg(dev,
83 "Failed to read ADC value: error %d\n",
84 val);
85 ret = ERR_PTR(val);
86 goto abort;
87 }
88 data->regs[i] = val;
89 }
90 data->last_updated = jiffies;
91 data->valid = 1;
92 }
93abort:
94 mutex_unlock(&data->update_lock);
95 return ret;
96}
97
98/* Return the voltage from the given register in mV */
99static int ltc4151_get_value(struct ltc4151_data *data, u8 reg)
100{
101 u32 val;
102
103 val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4);
104
105 switch (reg) {
106 case LTC4151_ADIN_H:
107 /* 500uV resolution. Convert to mV. */
108 val = val * 500 / 1000;
109 break;
110 case LTC4151_SENSE_H:
111 /*
112 * 20uV resolution. Convert to current as measured with
113 * an 1 mOhm sense resistor, in mA.
114 */
115 val = val * 20;
116 break;
117 case LTC4151_VIN_H:
118 /* 25 mV per increment */
119 val = val * 25;
120 break;
121 default:
122 /* If we get here, the developer messed up */
123 WARN_ON_ONCE(1);
124 val = 0;
125 break;
126 }
127
128 return val;
129}
130
131static ssize_t ltc4151_show_value(struct device *dev,
132 struct device_attribute *da, char *buf)
133{
134 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
135 struct ltc4151_data *data = ltc4151_update_device(dev);
136 int value;
137
138 if (IS_ERR(data))
139 return PTR_ERR(data);
140
141 value = ltc4151_get_value(data, attr->index);
142 return snprintf(buf, PAGE_SIZE, "%d\n", value);
143}
144
145/*
146 * Input voltages.
147 */
148static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \
149 ltc4151_show_value, NULL, LTC4151_VIN_H);
150static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, \
151 ltc4151_show_value, NULL, LTC4151_ADIN_H);
152
153/* Currents (via sense resistor) */
154static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \
155 ltc4151_show_value, NULL, LTC4151_SENSE_H);
156
157/* Finally, construct an array of pointers to members of the above objects,
158 * as required for sysfs_create_group()
159 */
160static struct attribute *ltc4151_attributes[] = {
161 &sensor_dev_attr_in1_input.dev_attr.attr,
162 &sensor_dev_attr_in2_input.dev_attr.attr,
163
164 &sensor_dev_attr_curr1_input.dev_attr.attr,
165
166 NULL,
167};
168
169static const struct attribute_group ltc4151_group = {
170 .attrs = ltc4151_attributes,
171};
172
173static int ltc4151_probe(struct i2c_client *client,
174 const struct i2c_device_id *id)
175{
176 struct i2c_adapter *adapter = client->adapter;
177 struct ltc4151_data *data;
178 int ret;
179
180 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
181 return -ENODEV;
182
183 data = kzalloc(sizeof(*data), GFP_KERNEL);
184 if (!data) {
185 ret = -ENOMEM;
186 goto out_kzalloc;
187 }
188
189 i2c_set_clientdata(client, data);
190 mutex_init(&data->update_lock);
191
192 /* Register sysfs hooks */
193 ret = sysfs_create_group(&client->dev.kobj, <c4151_group);
194 if (ret)
195 goto out_sysfs_create_group;
196
197 data->hwmon_dev = hwmon_device_register(&client->dev);
198 if (IS_ERR(data->hwmon_dev)) {
199 ret = PTR_ERR(data->hwmon_dev);
200 goto out_hwmon_device_register;
201 }
202
203 return 0;
204
205out_hwmon_device_register:
206 sysfs_remove_group(&client->dev.kobj, <c4151_group);
207out_sysfs_create_group:
208 kfree(data);
209out_kzalloc:
210 return ret;
211}
212
213static int ltc4151_remove(struct i2c_client *client)
214{
215 struct ltc4151_data *data = i2c_get_clientdata(client);
216
217 hwmon_device_unregister(data->hwmon_dev);
218 sysfs_remove_group(&client->dev.kobj, <c4151_group);
219
220 kfree(data);
221
222 return 0;
223}
224
225static const struct i2c_device_id ltc4151_id[] = {
226 { "ltc4151", 0 },
227 { }
228};
229MODULE_DEVICE_TABLE(i2c, ltc4151_id);
230
231/* This is the driver that will be inserted */
232static struct i2c_driver ltc4151_driver = {
233 .driver = {
234 .name = "ltc4151",
235 },
236 .probe = ltc4151_probe,
237 .remove = ltc4151_remove,
238 .id_table = ltc4151_id,
239};
240
241static int __init ltc4151_init(void)
242{
243 return i2c_add_driver(<c4151_driver);
244}
245
246static void __exit ltc4151_exit(void)
247{
248 i2c_del_driver(<c4151_driver);
249}
250
251MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
252MODULE_DESCRIPTION("LTC4151 driver");
253MODULE_LICENSE("GPL");
254
255module_init(ltc4151_init);
256module_exit(ltc4151_exit);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for Linear Technology LTC4151 High Voltage I2C Current
4 * and Voltage Monitor
5 *
6 * Copyright (C) 2011 AppearTV AS
7 *
8 * Derived from:
9 *
10 * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot
11 * Swap Controller
12 * Copyright (C) 2010 Ericsson AB.
13 *
14 * Datasheet: http://www.linear.com/docs/Datasheet/4151fc.pdf
15 */
16
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/of.h>
20#include <linux/init.h>
21#include <linux/err.h>
22#include <linux/slab.h>
23#include <linux/i2c.h>
24#include <linux/hwmon.h>
25#include <linux/hwmon-sysfs.h>
26#include <linux/jiffies.h>
27
28/* chip registers */
29#define LTC4151_SENSE_H 0x00
30#define LTC4151_SENSE_L 0x01
31#define LTC4151_VIN_H 0x02
32#define LTC4151_VIN_L 0x03
33#define LTC4151_ADIN_H 0x04
34#define LTC4151_ADIN_L 0x05
35
36struct ltc4151_data {
37 struct i2c_client *client;
38
39 struct mutex update_lock;
40 bool valid;
41 unsigned long last_updated; /* in jiffies */
42 unsigned int shunt; /* in micro ohms */
43
44 /* Registers */
45 u8 regs[6];
46};
47
48static struct ltc4151_data *ltc4151_update_device(struct device *dev)
49{
50 struct ltc4151_data *data = dev_get_drvdata(dev);
51 struct i2c_client *client = data->client;
52 struct ltc4151_data *ret = data;
53
54 mutex_lock(&data->update_lock);
55
56 /*
57 * The chip's A/D updates 6 times per second
58 * (Conversion Rate 6 - 9 Hz)
59 */
60 if (time_after(jiffies, data->last_updated + HZ / 6) || !data->valid) {
61 int i;
62
63 dev_dbg(&client->dev, "Starting ltc4151 update\n");
64
65 /* Read all registers */
66 for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
67 int val;
68
69 val = i2c_smbus_read_byte_data(client, i);
70 if (unlikely(val < 0)) {
71 dev_dbg(dev,
72 "Failed to read ADC value: error %d\n",
73 val);
74 ret = ERR_PTR(val);
75 goto abort;
76 }
77 data->regs[i] = val;
78 }
79 data->last_updated = jiffies;
80 data->valid = true;
81 }
82abort:
83 mutex_unlock(&data->update_lock);
84 return ret;
85}
86
87/* Return the voltage from the given register in mV */
88static int ltc4151_get_value(struct ltc4151_data *data, u8 reg)
89{
90 u32 val;
91
92 val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4);
93
94 switch (reg) {
95 case LTC4151_ADIN_H:
96 /* 500uV resolution. Convert to mV. */
97 val = val * 500 / 1000;
98 break;
99 case LTC4151_SENSE_H:
100 /*
101 * 20uV resolution. Convert to current as measured with
102 * a given sense resistor, in mA.
103 */
104 val = val * 20 * 1000 / data->shunt;
105 break;
106 case LTC4151_VIN_H:
107 /* 25 mV per increment */
108 val = val * 25;
109 break;
110 default:
111 /* If we get here, the developer messed up */
112 WARN_ON_ONCE(1);
113 val = 0;
114 break;
115 }
116
117 return val;
118}
119
120static ssize_t ltc4151_value_show(struct device *dev,
121 struct device_attribute *da, char *buf)
122{
123 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
124 struct ltc4151_data *data = ltc4151_update_device(dev);
125 int value;
126
127 if (IS_ERR(data))
128 return PTR_ERR(data);
129
130 value = ltc4151_get_value(data, attr->index);
131 return sysfs_emit(buf, "%d\n", value);
132}
133
134/*
135 * Input voltages.
136 */
137static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4151_value, LTC4151_VIN_H);
138static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4151_value, LTC4151_ADIN_H);
139
140/* Currents (via sense resistor) */
141static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4151_value, LTC4151_SENSE_H);
142
143/*
144 * Finally, construct an array of pointers to members of the above objects,
145 * as required for sysfs_create_group()
146 */
147static struct attribute *ltc4151_attrs[] = {
148 &sensor_dev_attr_in1_input.dev_attr.attr,
149 &sensor_dev_attr_in2_input.dev_attr.attr,
150
151 &sensor_dev_attr_curr1_input.dev_attr.attr,
152
153 NULL,
154};
155ATTRIBUTE_GROUPS(ltc4151);
156
157static int ltc4151_probe(struct i2c_client *client)
158{
159 struct i2c_adapter *adapter = client->adapter;
160 struct device *dev = &client->dev;
161 struct ltc4151_data *data;
162 struct device *hwmon_dev;
163 u32 shunt;
164
165 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
166 return -ENODEV;
167
168 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
169 if (!data)
170 return -ENOMEM;
171
172 if (of_property_read_u32(client->dev.of_node,
173 "shunt-resistor-micro-ohms", &shunt))
174 shunt = 1000; /* 1 mOhm if not set via DT */
175
176 if (shunt == 0)
177 return -EINVAL;
178
179 data->shunt = shunt;
180
181 data->client = client;
182 mutex_init(&data->update_lock);
183
184 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
185 data,
186 ltc4151_groups);
187 return PTR_ERR_OR_ZERO(hwmon_dev);
188}
189
190static const struct i2c_device_id ltc4151_id[] = {
191 { "ltc4151", 0 },
192 { }
193};
194MODULE_DEVICE_TABLE(i2c, ltc4151_id);
195
196static const struct of_device_id __maybe_unused ltc4151_match[] = {
197 { .compatible = "lltc,ltc4151" },
198 {},
199};
200MODULE_DEVICE_TABLE(of, ltc4151_match);
201
202/* This is the driver that will be inserted */
203static struct i2c_driver ltc4151_driver = {
204 .driver = {
205 .name = "ltc4151",
206 .of_match_table = of_match_ptr(ltc4151_match),
207 },
208 .probe = ltc4151_probe,
209 .id_table = ltc4151_id,
210};
211
212module_i2c_driver(ltc4151_driver);
213
214MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
215MODULE_DESCRIPTION("LTC4151 driver");
216MODULE_LICENSE("GPL");