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
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
/*
* Driver for Linear Technology LTC4151 High Voltage I2C Current
* and Voltage Monitor
*
* Copyright (C) 2011 AppearTV AS
*
* Derived from:
*
* Driver for Linear Technology LTC4261 I2C Negative Voltage Hot
* Swap Controller
* Copyright (C) 2010 Ericsson AB.
*
* Datasheet: http://www.linear.com/docs/Datasheet/4151fc.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/of.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>
#include <linux/jiffies.h>
/* chip registers */
#define LTC4151_SENSE_H 0x00
#define LTC4151_SENSE_L 0x01
#define LTC4151_VIN_H 0x02
#define LTC4151_VIN_L 0x03
#define LTC4151_ADIN_H 0x04
#define LTC4151_ADIN_L 0x05
struct ltc4151_data {
struct i2c_client *client;
struct mutex update_lock;
bool valid;
unsigned long last_updated; /* in jiffies */
unsigned int shunt; /* in micro ohms */
/* Registers */
u8 regs[6];
};
static struct ltc4151_data *ltc4151_update_device(struct device *dev)
{
struct ltc4151_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
struct ltc4151_data *ret = data;
mutex_lock(&data->update_lock);
/*
* The chip's A/D updates 6 times per second
* (Conversion Rate 6 - 9 Hz)
*/
if (time_after(jiffies, data->last_updated + HZ / 6) || !data->valid) {
int i;
dev_dbg(&client->dev, "Starting ltc4151 update\n");
/* Read all registers */
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 */
static int ltc4151_get_value(struct ltc4151_data *data, u8 reg)
{
u32 val;
val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4);
switch (reg) {
case LTC4151_ADIN_H:
/* 500uV resolution. Convert to mV. */
val = val * 500 / 1000;
break;
case LTC4151_SENSE_H:
/*
* 20uV resolution. Convert to current as measured with
* a given sense resistor, in mA.
*/
val = val * 20 * 1000 / data->shunt;
break;
case LTC4151_VIN_H:
/* 25 mV per increment */
val = val * 25;
break;
default:
/* If we get here, the developer messed up */
WARN_ON_ONCE(1);
val = 0;
break;
}
return val;
}
static ssize_t ltc4151_value_show(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ltc4151_data *data = ltc4151_update_device(dev);
int value;
if (IS_ERR(data))
return PTR_ERR(data);
value = ltc4151_get_value(data, attr->index);
return snprintf(buf, PAGE_SIZE, "%d\n", value);
}
/*
* Input voltages.
*/
static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4151_value, LTC4151_VIN_H);
static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4151_value, LTC4151_ADIN_H);
/* Currents (via sense resistor) */
static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4151_value, LTC4151_SENSE_H);
/*
* Finally, construct an array of pointers to members of the above objects,
* as required for sysfs_create_group()
*/
static struct attribute *ltc4151_attrs[] = {
&sensor_dev_attr_in1_input.dev_attr.attr,
&sensor_dev_attr_in2_input.dev_attr.attr,
&sensor_dev_attr_curr1_input.dev_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(ltc4151);
static int ltc4151_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = client->adapter;
struct device *dev = &client->dev;
struct ltc4151_data *data;
struct device *hwmon_dev;
u32 shunt;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
if (of_property_read_u32(client->dev.of_node,
"shunt-resistor-micro-ohms", &shunt))
shunt = 1000; /* 1 mOhm if not set via DT */
if (shunt == 0)
return -EINVAL;
data->shunt = shunt;
data->client = client;
mutex_init(&data->update_lock);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
data,
ltc4151_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id ltc4151_id[] = {
{ "ltc4151", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ltc4151_id);
static const struct of_device_id __maybe_unused ltc4151_match[] = {
{ .compatible = "lltc,ltc4151" },
{},
};
MODULE_DEVICE_TABLE(of, ltc4151_match);
/* This is the driver that will be inserted */
static struct i2c_driver ltc4151_driver = {
.driver = {
.name = "ltc4151",
.of_match_table = of_match_ptr(ltc4151_match),
},
.probe = ltc4151_probe,
.id_table = ltc4151_id,
};
module_i2c_driver(ltc4151_driver);
MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
MODULE_DESCRIPTION("LTC4151 driver");
MODULE_LICENSE("GPL");
|
