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 | |
34 | ||
35 | #define MCP3021_OUTPUT_RES 10 /* 10-bit resolution */ | |
36 | #define MCP3021_OUTPUT_SCALE 4 | |
37 | ||
592758b1 SS |
38 | #define MCP3221_SAR_SHIFT 0 |
39 | #define MCP3221_SAR_MASK 0xfff | |
40 | #define MCP3221_OUTPUT_RES 12 /* 12-bit resolution */ | |
41 | #define MCP3221_OUTPUT_SCALE 1 | |
42 | ||
8b662f38 | 43 | enum chips { |
592758b1 SS |
44 | mcp3021, |
45 | mcp3221 | |
8b662f38 | 46 | }; |
592758b1 | 47 | |
5510e62a XX |
48 | /* |
49 | * Client data (each client gets its own) | |
50 | */ | |
51 | struct mcp3021_data { | |
52 | struct device *hwmon_dev; | |
53 | u32 vdd; /* device power supply */ | |
8b662f38 SS |
54 | u16 sar_shift; |
55 | u16 sar_mask; | |
56 | u8 output_res; | |
57 | u8 output_scale; | |
5510e62a XX |
58 | }; |
59 | ||
60 | static int mcp3021_read16(struct i2c_client *client) | |
61 | { | |
8b662f38 | 62 | struct mcp3021_data *data = i2c_get_clientdata(client); |
5510e62a XX |
63 | int ret; |
64 | u16 reg; | |
65 | __be16 buf; | |
66 | ||
67 | ret = i2c_master_recv(client, (char *)&buf, 2); | |
68 | if (ret < 0) | |
69 | return ret; | |
70 | if (ret != 2) | |
71 | return -EIO; | |
72 | ||
73 | /* The output code of the MCP3021 is transmitted with MSB first. */ | |
74 | reg = be16_to_cpu(buf); | |
75 | ||
76 | /* | |
77 | * The ten-bit output code is composed of the lower 4-bit of the | |
78 | * first byte and the upper 6-bit of the second byte. | |
79 | */ | |
8b662f38 | 80 | reg = (reg >> data->sar_shift) & data->sar_mask; |
5510e62a XX |
81 | |
82 | return reg; | |
83 | } | |
84 | ||
8b662f38 | 85 | static inline u16 volts_from_reg(struct mcp3021_data *data, u16 val) |
5510e62a XX |
86 | { |
87 | if (val == 0) | |
88 | return 0; | |
89 | ||
8b662f38 | 90 | val = val * data->output_scale - data->output_scale / 2; |
5510e62a | 91 | |
8b662f38 SS |
92 | return val * DIV_ROUND_CLOSEST(data->vdd, |
93 | (1 << data->output_res) * data->output_scale); | |
5510e62a XX |
94 | } |
95 | ||
96 | static ssize_t show_in_input(struct device *dev, struct device_attribute *attr, | |
97 | char *buf) | |
98 | { | |
99 | struct i2c_client *client = to_i2c_client(dev); | |
100 | struct mcp3021_data *data = i2c_get_clientdata(client); | |
101 | int reg, in_input; | |
102 | ||
103 | reg = mcp3021_read16(client); | |
104 | if (reg < 0) | |
105 | return reg; | |
106 | ||
8b662f38 SS |
107 | in_input = volts_from_reg(data, reg); |
108 | ||
5510e62a XX |
109 | return sprintf(buf, "%d\n", in_input); |
110 | } | |
111 | ||
112 | static DEVICE_ATTR(in0_input, S_IRUGO, show_in_input, NULL); | |
113 | ||
114 | static int mcp3021_probe(struct i2c_client *client, | |
115 | const struct i2c_device_id *id) | |
116 | { | |
117 | int err; | |
118 | struct mcp3021_data *data = NULL; | |
119 | ||
120 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) | |
121 | return -ENODEV; | |
122 | ||
79831fd4 GR |
123 | data = devm_kzalloc(&client->dev, sizeof(struct mcp3021_data), |
124 | GFP_KERNEL); | |
5510e62a XX |
125 | if (!data) |
126 | return -ENOMEM; | |
127 | ||
128 | i2c_set_clientdata(client, data); | |
129 | ||
8b662f38 SS |
130 | switch (id->driver_data) { |
131 | case mcp3021: | |
132 | data->sar_shift = MCP3021_SAR_SHIFT; | |
133 | data->sar_mask = MCP3021_SAR_MASK; | |
134 | data->output_res = MCP3021_OUTPUT_RES; | |
135 | data->output_scale = MCP3021_OUTPUT_SCALE; | |
136 | break; | |
592758b1 SS |
137 | |
138 | case mcp3221: | |
139 | data->sar_shift = MCP3221_SAR_SHIFT; | |
140 | data->sar_mask = MCP3221_SAR_MASK; | |
141 | data->output_res = MCP3221_OUTPUT_RES; | |
142 | data->output_scale = MCP3221_OUTPUT_SCALE; | |
143 | break; | |
8b662f38 SS |
144 | } |
145 | ||
a8b3a3a5 JH |
146 | if (dev_get_platdata(&client->dev)) { |
147 | data->vdd = *(u32 *)dev_get_platdata(&client->dev); | |
79831fd4 GR |
148 | if (data->vdd > MCP3021_VDD_MAX || data->vdd < MCP3021_VDD_MIN) |
149 | return -EINVAL; | |
a8b3a3a5 | 150 | } else { |
5510e62a | 151 | data->vdd = MCP3021_VDD_REF; |
a8b3a3a5 | 152 | } |
5510e62a XX |
153 | |
154 | err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr); | |
155 | if (err) | |
79831fd4 | 156 | return err; |
5510e62a XX |
157 | |
158 | data->hwmon_dev = hwmon_device_register(&client->dev); | |
159 | if (IS_ERR(data->hwmon_dev)) { | |
160 | err = PTR_ERR(data->hwmon_dev); | |
161 | goto exit_remove; | |
162 | } | |
163 | ||
164 | return 0; | |
165 | ||
166 | exit_remove: | |
167 | sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr); | |
5510e62a XX |
168 | return err; |
169 | } | |
170 | ||
171 | static int mcp3021_remove(struct i2c_client *client) | |
172 | { | |
173 | struct mcp3021_data *data = i2c_get_clientdata(client); | |
174 | ||
175 | hwmon_device_unregister(data->hwmon_dev); | |
176 | sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr); | |
5510e62a XX |
177 | |
178 | return 0; | |
179 | } | |
180 | ||
181 | static const struct i2c_device_id mcp3021_id[] = { | |
8b662f38 | 182 | { "mcp3021", mcp3021 }, |
592758b1 | 183 | { "mcp3221", mcp3221 }, |
5510e62a XX |
184 | { } |
185 | }; | |
186 | MODULE_DEVICE_TABLE(i2c, mcp3021_id); | |
187 | ||
188 | static struct i2c_driver mcp3021_driver = { | |
189 | .driver = { | |
190 | .name = "mcp3021", | |
191 | }, | |
192 | .probe = mcp3021_probe, | |
193 | .remove = mcp3021_remove, | |
194 | .id_table = mcp3021_id, | |
195 | }; | |
196 | ||
197 | module_i2c_driver(mcp3021_driver); | |
198 | ||
199 | MODULE_AUTHOR("Mingkai Hu <Mingkai.hu@freescale.com>"); | |
592758b1 | 200 | MODULE_DESCRIPTION("Microchip MCP3021/MCP3221 driver"); |
5510e62a | 201 | MODULE_LICENSE("GPL"); |