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
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* mcp3021.c - driver for Microchip MCP3021 and MCP3221
*
* Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc.
* Author: Mingkai Hu <Mingkai.hu@freescale.com>
* Reworked by Sven Schuchmann <schuchmann@schleissheimer.de>
* DT support added by Clemens Gruber <clemens.gruber@pqgruber.com>
*
* This driver exports the value of analog input voltage to sysfs, the
* voltage unit is mV. Through the sysfs interface, lm-sensors tool
* can also display the input voltage.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/hwmon.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_device.h>
/* Vdd / reference voltage in millivolt */
#define MCP3021_VDD_REF_MAX 5500
#define MCP3021_VDD_REF_MIN 2700
#define MCP3021_VDD_REF_DEFAULT 3300
/* output format */
#define MCP3021_SAR_SHIFT 2
#define MCP3021_SAR_MASK 0x3ff
#define MCP3021_OUTPUT_RES 10 /* 10-bit resolution */
#define MCP3221_SAR_SHIFT 0
#define MCP3221_SAR_MASK 0xfff
#define MCP3221_OUTPUT_RES 12 /* 12-bit resolution */
enum chips {
mcp3021,
mcp3221
};
/*
* Client data (each client gets its own)
*/
struct mcp3021_data {
struct i2c_client *client;
u32 vdd; /* supply and reference voltage in millivolt */
u16 sar_shift;
u16 sar_mask;
u8 output_res;
};
static inline u16 volts_from_reg(struct mcp3021_data *data, u16 val)
{
return DIV_ROUND_CLOSEST(data->vdd * val, 1 << data->output_res);
}
static int mcp3021_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
struct mcp3021_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
__be16 buf;
u16 reg;
int ret;
if (type != hwmon_in)
return -EOPNOTSUPP;
ret = i2c_master_recv(client, (char *)&buf, 2);
if (ret < 0)
return ret;
if (ret != 2)
return -EIO;
/* The output code of the MCP3021 is transmitted with MSB first. */
reg = be16_to_cpu(buf);
/*
* The ten-bit output code is composed of the lower 4-bit of the
* first byte and the upper 6-bit of the second byte.
*/
reg = (reg >> data->sar_shift) & data->sar_mask;
*val = volts_from_reg(data, reg);
return 0;
}
static umode_t mcp3021_is_visible(const void *_data,
enum hwmon_sensor_types type,
u32 attr, int channel)
{
if (type != hwmon_in)
return 0;
if (attr != hwmon_in_input)
return 0;
return 0444;
}
static const struct hwmon_channel_info * const mcp3021_info[] = {
HWMON_CHANNEL_INFO(in, HWMON_I_INPUT),
NULL
};
static const struct hwmon_ops mcp3021_hwmon_ops = {
.is_visible = mcp3021_is_visible,
.read = mcp3021_read,
};
static const struct hwmon_chip_info mcp3021_chip_info = {
.ops = &mcp3021_hwmon_ops,
.info = mcp3021_info,
};
static const struct i2c_device_id mcp3021_id[];
static int mcp3021_probe(struct i2c_client *client)
{
struct mcp3021_data *data = NULL;
struct device_node *np = client->dev.of_node;
struct device *hwmon_dev;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
data = devm_kzalloc(&client->dev, sizeof(struct mcp3021_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
i2c_set_clientdata(client, data);
if (np) {
if (!of_property_read_u32(np, "reference-voltage-microvolt",
&data->vdd))
data->vdd /= 1000;
else
data->vdd = MCP3021_VDD_REF_DEFAULT;
} else {
u32 *pdata = dev_get_platdata(&client->dev);
if (pdata)
data->vdd = *pdata;
else
data->vdd = MCP3021_VDD_REF_DEFAULT;
}
switch (i2c_match_id(mcp3021_id, client)->driver_data) {
case mcp3021:
data->sar_shift = MCP3021_SAR_SHIFT;
data->sar_mask = MCP3021_SAR_MASK;
data->output_res = MCP3021_OUTPUT_RES;
break;
case mcp3221:
data->sar_shift = MCP3221_SAR_SHIFT;
data->sar_mask = MCP3221_SAR_MASK;
data->output_res = MCP3221_OUTPUT_RES;
break;
}
data->client = client;
if (data->vdd > MCP3021_VDD_REF_MAX || data->vdd < MCP3021_VDD_REF_MIN)
return -EINVAL;
hwmon_dev = devm_hwmon_device_register_with_info(&client->dev,
client->name,
data,
&mcp3021_chip_info,
NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id mcp3021_id[] = {
{ "mcp3021", mcp3021 },
{ "mcp3221", mcp3221 },
{ }
};
MODULE_DEVICE_TABLE(i2c, mcp3021_id);
#ifdef CONFIG_OF
static const struct of_device_id of_mcp3021_match[] = {
{ .compatible = "microchip,mcp3021", .data = (void *)mcp3021 },
{ .compatible = "microchip,mcp3221", .data = (void *)mcp3221 },
{ }
};
MODULE_DEVICE_TABLE(of, of_mcp3021_match);
#endif
static struct i2c_driver mcp3021_driver = {
.driver = {
.name = "mcp3021",
.of_match_table = of_match_ptr(of_mcp3021_match),
},
.probe = mcp3021_probe,
.id_table = mcp3021_id,
};
module_i2c_driver(mcp3021_driver);
MODULE_AUTHOR("Mingkai Hu <Mingkai.hu@freescale.com>");
MODULE_DESCRIPTION("Microchip MCP3021/MCP3221 driver");
MODULE_LICENSE("GPL");
|
