1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * mcp3021.c - driver for Microchip MCP3021 and MCP3221 |
4 | * |
5 | * Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc. |
6 | * Author: Mingkai Hu <Mingkai.hu@freescale.com> |
7 | * Reworked by Sven Schuchmann <schuchmann@schleissheimer.de> |
8 | * DT support added by Clemens Gruber <clemens.gruber@pqgruber.com> |
9 | * |
10 | * This driver exports the value of analog input voltage to sysfs, the |
11 | * voltage unit is mV. Through the sysfs interface, lm-sensors tool |
12 | * can also display the input voltage. |
13 | */ |
14 | |
15 | #include <linux/kernel.h> |
16 | #include <linux/module.h> |
17 | #include <linux/hwmon.h> |
18 | #include <linux/slab.h> |
19 | #include <linux/i2c.h> |
20 | #include <linux/err.h> |
21 | #include <linux/device.h> |
22 | #include <linux/of.h> |
23 | |
24 | /* Vdd / reference voltage in millivolt */ |
25 | #define MCP3021_VDD_REF_MAX 5500 |
26 | #define MCP3021_VDD_REF_MIN 2700 |
27 | #define MCP3021_VDD_REF_DEFAULT 3300 |
28 | |
29 | /* output format */ |
30 | #define MCP3021_SAR_SHIFT 2 |
31 | #define MCP3021_SAR_MASK 0x3ff |
32 | #define MCP3021_OUTPUT_RES 10 /* 10-bit resolution */ |
33 | |
34 | #define MCP3221_SAR_SHIFT 0 |
35 | #define MCP3221_SAR_MASK 0xfff |
36 | #define MCP3221_OUTPUT_RES 12 /* 12-bit resolution */ |
37 | |
38 | enum chips { |
39 | mcp3021, |
40 | mcp3221 |
41 | }; |
42 | |
43 | /* |
44 | * Client data (each client gets its own) |
45 | */ |
46 | struct mcp3021_data { |
47 | struct i2c_client *client; |
48 | u32 vdd; /* supply and reference voltage in millivolt */ |
49 | u16 sar_shift; |
50 | u16 sar_mask; |
51 | u8 output_res; |
52 | }; |
53 | |
54 | static inline u16 volts_from_reg(struct mcp3021_data *data, u16 val) |
55 | { |
56 | return DIV_ROUND_CLOSEST(data->vdd * val, 1 << data->output_res); |
57 | } |
58 | |
59 | static int mcp3021_read(struct device *dev, enum hwmon_sensor_types type, |
60 | u32 attr, int channel, long *val) |
61 | { |
62 | struct mcp3021_data *data = dev_get_drvdata(dev); |
63 | struct i2c_client *client = data->client; |
64 | __be16 buf; |
65 | u16 reg; |
66 | int ret; |
67 | |
68 | if (type != hwmon_in) |
69 | return -EOPNOTSUPP; |
70 | |
71 | ret = i2c_master_recv(client, buf: (char *)&buf, count: 2); |
72 | if (ret < 0) |
73 | return ret; |
74 | if (ret != 2) |
75 | return -EIO; |
76 | |
77 | /* The output code of the MCP3021 is transmitted with MSB first. */ |
78 | reg = be16_to_cpu(buf); |
79 | |
80 | /* |
81 | * The ten-bit output code is composed of the lower 4-bit of the |
82 | * first byte and the upper 6-bit of the second byte. |
83 | */ |
84 | reg = (reg >> data->sar_shift) & data->sar_mask; |
85 | |
86 | *val = volts_from_reg(data, val: reg); |
87 | |
88 | return 0; |
89 | } |
90 | |
91 | static umode_t mcp3021_is_visible(const void *_data, |
92 | enum hwmon_sensor_types type, |
93 | u32 attr, int channel) |
94 | { |
95 | if (type != hwmon_in) |
96 | return 0; |
97 | |
98 | if (attr != hwmon_in_input) |
99 | return 0; |
100 | |
101 | return 0444; |
102 | } |
103 | |
104 | static const struct hwmon_channel_info * const mcp3021_info[] = { |
105 | HWMON_CHANNEL_INFO(in, HWMON_I_INPUT), |
106 | NULL |
107 | }; |
108 | |
109 | static const struct hwmon_ops mcp3021_hwmon_ops = { |
110 | .is_visible = mcp3021_is_visible, |
111 | .read = mcp3021_read, |
112 | }; |
113 | |
114 | static const struct hwmon_chip_info mcp3021_chip_info = { |
115 | .ops = &mcp3021_hwmon_ops, |
116 | .info = mcp3021_info, |
117 | }; |
118 | |
119 | static const struct i2c_device_id mcp3021_id[]; |
120 | |
121 | static int mcp3021_probe(struct i2c_client *client) |
122 | { |
123 | struct mcp3021_data *data = NULL; |
124 | struct device_node *np = client->dev.of_node; |
125 | struct device *hwmon_dev; |
126 | |
127 | if (!i2c_check_functionality(adap: client->adapter, I2C_FUNC_I2C)) |
128 | return -ENODEV; |
129 | |
130 | data = devm_kzalloc(dev: &client->dev, size: sizeof(struct mcp3021_data), |
131 | GFP_KERNEL); |
132 | if (!data) |
133 | return -ENOMEM; |
134 | |
135 | i2c_set_clientdata(client, data); |
136 | |
137 | if (np) { |
138 | if (!of_property_read_u32(np, propname: "reference-voltage-microvolt" , |
139 | out_value: &data->vdd)) |
140 | data->vdd /= 1000; |
141 | else |
142 | data->vdd = MCP3021_VDD_REF_DEFAULT; |
143 | } else { |
144 | u32 *pdata = dev_get_platdata(dev: &client->dev); |
145 | |
146 | if (pdata) |
147 | data->vdd = *pdata; |
148 | else |
149 | data->vdd = MCP3021_VDD_REF_DEFAULT; |
150 | } |
151 | |
152 | switch (i2c_match_id(id: mcp3021_id, client)->driver_data) { |
153 | case mcp3021: |
154 | data->sar_shift = MCP3021_SAR_SHIFT; |
155 | data->sar_mask = MCP3021_SAR_MASK; |
156 | data->output_res = MCP3021_OUTPUT_RES; |
157 | break; |
158 | |
159 | case mcp3221: |
160 | data->sar_shift = MCP3221_SAR_SHIFT; |
161 | data->sar_mask = MCP3221_SAR_MASK; |
162 | data->output_res = MCP3221_OUTPUT_RES; |
163 | break; |
164 | } |
165 | |
166 | data->client = client; |
167 | |
168 | if (data->vdd > MCP3021_VDD_REF_MAX || data->vdd < MCP3021_VDD_REF_MIN) |
169 | return -EINVAL; |
170 | |
171 | hwmon_dev = devm_hwmon_device_register_with_info(dev: &client->dev, |
172 | name: client->name, |
173 | drvdata: data, |
174 | info: &mcp3021_chip_info, |
175 | NULL); |
176 | return PTR_ERR_OR_ZERO(ptr: hwmon_dev); |
177 | } |
178 | |
179 | static const struct i2c_device_id mcp3021_id[] = { |
180 | { "mcp3021" , mcp3021 }, |
181 | { "mcp3221" , mcp3221 }, |
182 | { } |
183 | }; |
184 | MODULE_DEVICE_TABLE(i2c, mcp3021_id); |
185 | |
186 | #ifdef CONFIG_OF |
187 | static const struct of_device_id of_mcp3021_match[] = { |
188 | { .compatible = "microchip,mcp3021" , .data = (void *)mcp3021 }, |
189 | { .compatible = "microchip,mcp3221" , .data = (void *)mcp3221 }, |
190 | { } |
191 | }; |
192 | MODULE_DEVICE_TABLE(of, of_mcp3021_match); |
193 | #endif |
194 | |
195 | static struct i2c_driver mcp3021_driver = { |
196 | .driver = { |
197 | .name = "mcp3021" , |
198 | .of_match_table = of_match_ptr(of_mcp3021_match), |
199 | }, |
200 | .probe = mcp3021_probe, |
201 | .id_table = mcp3021_id, |
202 | }; |
203 | |
204 | module_i2c_driver(mcp3021_driver); |
205 | |
206 | MODULE_AUTHOR("Mingkai Hu <Mingkai.hu@freescale.com>" ); |
207 | MODULE_DESCRIPTION("Microchip MCP3021/MCP3221 driver" ); |
208 | MODULE_LICENSE("GPL" ); |
209 | |