Commit | Line | Data |
---|---|---|
5510e62a | 1 | /* |
592758b1 | 2 | * mcp3021.c - driver for Microchip MCP3021 and MCP3221 |
5510e62a XX |
3 | * |
4 | * Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc. | |
5 | * Author: Mingkai Hu <Mingkai.hu@freescale.com> | |
8b662f38 | 6 | * Reworked by Sven Schuchmann <schuchmann@schleissheimer.de> |
5510e62a XX |
7 | * |
8 | * This driver export the value of analog input voltage to sysfs, the | |
9 | * voltage unit is mV. Through the sysfs interface, lm-sensors tool | |
10 | * can also display the input voltage. | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License as published by | |
14 | * the Free Software Foundation; either version 2 of the License, or | |
15 | * (at your option) any later version. | |
16 | */ | |
17 | ||
18 | #include <linux/kernel.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/hwmon.h> | |
21 | #include <linux/slab.h> | |
22 | #include <linux/i2c.h> | |
23 | #include <linux/err.h> | |
24 | #include <linux/device.h> | |
25 | ||
26 | /* Vdd info */ | |
27 | #define MCP3021_VDD_MAX 5500 | |
28 | #define MCP3021_VDD_MIN 2700 | |
29 | #define MCP3021_VDD_REF 3300 | |
30 | ||
31 | /* output format */ | |
32 | #define MCP3021_SAR_SHIFT 2 | |
33 | #define MCP3021_SAR_MASK 0x3ff | |
5510e62a | 34 | #define MCP3021_OUTPUT_RES 10 /* 10-bit resolution */ |
5510e62a | 35 | |
592758b1 SS |
36 | #define MCP3221_SAR_SHIFT 0 |
37 | #define MCP3221_SAR_MASK 0xfff | |
38 | #define MCP3221_OUTPUT_RES 12 /* 12-bit resolution */ | |
592758b1 | 39 | |
8b662f38 | 40 | enum chips { |
592758b1 SS |
41 | mcp3021, |
42 | mcp3221 | |
8b662f38 | 43 | }; |
592758b1 | 44 | |
5510e62a XX |
45 | /* |
46 | * Client data (each client gets its own) | |
47 | */ | |
48 | struct mcp3021_data { | |
49 | struct device *hwmon_dev; | |
50 | u32 vdd; /* device power supply */ | |
8b662f38 SS |
51 | u16 sar_shift; |
52 | u16 sar_mask; | |
53 | u8 output_res; | |
5510e62a XX |
54 | }; |
55 | ||
56 | static int mcp3021_read16(struct i2c_client *client) | |
57 | { | |
8b662f38 | 58 | struct mcp3021_data *data = i2c_get_clientdata(client); |
5510e62a XX |
59 | int ret; |
60 | u16 reg; | |
61 | __be16 buf; | |
62 | ||
63 | ret = i2c_master_recv(client, (char *)&buf, 2); | |
64 | if (ret < 0) | |
65 | return ret; | |
66 | if (ret != 2) | |
67 | return -EIO; | |
68 | ||
69 | /* The output code of the MCP3021 is transmitted with MSB first. */ | |
70 | reg = be16_to_cpu(buf); | |
71 | ||
72 | /* | |
73 | * The ten-bit output code is composed of the lower 4-bit of the | |
74 | * first byte and the upper 6-bit of the second byte. | |
75 | */ | |
8b662f38 | 76 | reg = (reg >> data->sar_shift) & data->sar_mask; |
5510e62a XX |
77 | |
78 | return reg; | |
79 | } | |
80 | ||
8b662f38 | 81 | static inline u16 volts_from_reg(struct mcp3021_data *data, u16 val) |
5510e62a | 82 | { |
347d7e45 | 83 | return DIV_ROUND_CLOSEST(data->vdd * val, 1 << data->output_res); |
5510e62a XX |
84 | } |
85 | ||
86 | static ssize_t show_in_input(struct device *dev, struct device_attribute *attr, | |
87 | char *buf) | |
88 | { | |
89 | struct i2c_client *client = to_i2c_client(dev); | |
90 | struct mcp3021_data *data = i2c_get_clientdata(client); | |
91 | int reg, in_input; | |
92 | ||
93 | reg = mcp3021_read16(client); | |
94 | if (reg < 0) | |
95 | return reg; | |
96 | ||
8b662f38 SS |
97 | in_input = volts_from_reg(data, reg); |
98 | ||
5510e62a XX |
99 | return sprintf(buf, "%d\n", in_input); |
100 | } | |
101 | ||
102 | static DEVICE_ATTR(in0_input, S_IRUGO, show_in_input, NULL); | |
103 | ||
104 | static int mcp3021_probe(struct i2c_client *client, | |
105 | const struct i2c_device_id *id) | |
106 | { | |
107 | int err; | |
108 | struct mcp3021_data *data = NULL; | |
109 | ||
110 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) | |
111 | return -ENODEV; | |
112 | ||
79831fd4 GR |
113 | data = devm_kzalloc(&client->dev, sizeof(struct mcp3021_data), |
114 | GFP_KERNEL); | |
5510e62a XX |
115 | if (!data) |
116 | return -ENOMEM; | |
117 | ||
118 | i2c_set_clientdata(client, data); | |
119 | ||
8b662f38 SS |
120 | switch (id->driver_data) { |
121 | case mcp3021: | |
122 | data->sar_shift = MCP3021_SAR_SHIFT; | |
123 | data->sar_mask = MCP3021_SAR_MASK; | |
124 | data->output_res = MCP3021_OUTPUT_RES; | |
8b662f38 | 125 | break; |
592758b1 SS |
126 | |
127 | case mcp3221: | |
128 | data->sar_shift = MCP3221_SAR_SHIFT; | |
129 | data->sar_mask = MCP3221_SAR_MASK; | |
130 | data->output_res = MCP3221_OUTPUT_RES; | |
592758b1 | 131 | break; |
8b662f38 SS |
132 | } |
133 | ||
a8b3a3a5 JH |
134 | if (dev_get_platdata(&client->dev)) { |
135 | data->vdd = *(u32 *)dev_get_platdata(&client->dev); | |
79831fd4 GR |
136 | if (data->vdd > MCP3021_VDD_MAX || data->vdd < MCP3021_VDD_MIN) |
137 | return -EINVAL; | |
a8b3a3a5 | 138 | } else { |
5510e62a | 139 | data->vdd = MCP3021_VDD_REF; |
a8b3a3a5 | 140 | } |
5510e62a XX |
141 | |
142 | err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr); | |
143 | if (err) | |
79831fd4 | 144 | return err; |
5510e62a XX |
145 | |
146 | data->hwmon_dev = hwmon_device_register(&client->dev); | |
147 | if (IS_ERR(data->hwmon_dev)) { | |
148 | err = PTR_ERR(data->hwmon_dev); | |
149 | goto exit_remove; | |
150 | } | |
151 | ||
152 | return 0; | |
153 | ||
154 | exit_remove: | |
155 | sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr); | |
5510e62a XX |
156 | return err; |
157 | } | |
158 | ||
159 | static int mcp3021_remove(struct i2c_client *client) | |
160 | { | |
161 | struct mcp3021_data *data = i2c_get_clientdata(client); | |
162 | ||
163 | hwmon_device_unregister(data->hwmon_dev); | |
164 | sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr); | |
5510e62a XX |
165 | |
166 | return 0; | |
167 | } | |
168 | ||
169 | static const struct i2c_device_id mcp3021_id[] = { | |
8b662f38 | 170 | { "mcp3021", mcp3021 }, |
592758b1 | 171 | { "mcp3221", mcp3221 }, |
5510e62a XX |
172 | { } |
173 | }; | |
174 | MODULE_DEVICE_TABLE(i2c, mcp3021_id); | |
175 | ||
176 | static struct i2c_driver mcp3021_driver = { | |
177 | .driver = { | |
178 | .name = "mcp3021", | |
179 | }, | |
180 | .probe = mcp3021_probe, | |
181 | .remove = mcp3021_remove, | |
182 | .id_table = mcp3021_id, | |
183 | }; | |
184 | ||
185 | module_i2c_driver(mcp3021_driver); | |
186 | ||
187 | MODULE_AUTHOR("Mingkai Hu <Mingkai.hu@freescale.com>"); | |
592758b1 | 188 | MODULE_DESCRIPTION("Microchip MCP3021/MCP3221 driver"); |
5510e62a | 189 | MODULE_LICENSE("GPL"); |