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1 | /* |
2 | * Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com> | |
3 | * | |
4 | * Driver for Microchip Technology's MCP3204 and MCP3208 ADC chips. | |
5 | * Datasheet can be found here: | |
6 | * http://ww1.microchip.com/downloads/en/devicedoc/21298c.pdf | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/err.h> | |
14 | #include <linux/spi/spi.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/iio/iio.h> | |
17 | #include <linux/regulator/consumer.h> | |
18 | ||
19 | #define MCP_SINGLE_ENDED (1 << 3) | |
20 | #define MCP_START_BIT (1 << 4) | |
21 | ||
22 | enum { | |
23 | mcp3204, | |
24 | mcp3208, | |
25 | }; | |
26 | ||
27 | struct mcp320x { | |
28 | struct spi_device *spi; | |
29 | struct spi_message msg; | |
30 | struct spi_transfer transfer[2]; | |
31 | ||
32 | u8 tx_buf; | |
33 | u8 rx_buf[2]; | |
34 | ||
35 | struct regulator *reg; | |
36 | struct mutex lock; | |
37 | }; | |
38 | ||
39 | static int mcp320x_adc_conversion(struct mcp320x *adc, u8 msg) | |
40 | { | |
41 | int ret; | |
42 | ||
43 | adc->tx_buf = msg; | |
44 | ret = spi_sync(adc->spi, &adc->msg); | |
45 | if (ret < 0) | |
46 | return ret; | |
47 | ||
48 | return ((adc->rx_buf[0] & 0x3f) << 6) | | |
49 | (adc->rx_buf[1] >> 2); | |
50 | } | |
51 | ||
52 | static int mcp320x_read_raw(struct iio_dev *indio_dev, | |
53 | struct iio_chan_spec const *channel, int *val, | |
54 | int *val2, long mask) | |
55 | { | |
56 | struct mcp320x *adc = iio_priv(indio_dev); | |
57 | int ret = -EINVAL; | |
58 | ||
59 | mutex_lock(&adc->lock); | |
60 | ||
61 | switch (mask) { | |
62 | case IIO_CHAN_INFO_RAW: | |
63 | if (channel->differential) | |
64 | ret = mcp320x_adc_conversion(adc, | |
65 | MCP_START_BIT | channel->address); | |
66 | else | |
67 | ret = mcp320x_adc_conversion(adc, | |
68 | MCP_START_BIT | MCP_SINGLE_ENDED | | |
69 | channel->address); | |
70 | if (ret < 0) | |
71 | goto out; | |
72 | ||
73 | *val = ret; | |
74 | ret = IIO_VAL_INT; | |
75 | break; | |
76 | ||
77 | case IIO_CHAN_INFO_SCALE: | |
78 | /* Digital output code = (4096 * Vin) / Vref */ | |
79 | ret = regulator_get_voltage(adc->reg); | |
80 | if (ret < 0) | |
81 | goto out; | |
82 | ||
83 | *val = ret / 1000; | |
84 | *val2 = 12; | |
85 | ret = IIO_VAL_FRACTIONAL_LOG2; | |
86 | break; | |
87 | ||
88 | default: | |
89 | break; | |
90 | } | |
91 | ||
92 | out: | |
93 | mutex_unlock(&adc->lock); | |
94 | ||
95 | return ret; | |
96 | } | |
97 | ||
98 | #define MCP320X_VOLTAGE_CHANNEL(num) \ | |
99 | { \ | |
100 | .type = IIO_VOLTAGE, \ | |
101 | .indexed = 1, \ | |
102 | .channel = (num), \ | |
103 | .address = (num), \ | |
104 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ | |
105 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ | |
106 | } | |
107 | ||
108 | #define MCP320X_VOLTAGE_CHANNEL_DIFF(num) \ | |
109 | { \ | |
110 | .type = IIO_VOLTAGE, \ | |
111 | .indexed = 1, \ | |
112 | .channel = (num * 2), \ | |
113 | .channel2 = (num * 2 + 1), \ | |
114 | .address = (num * 2), \ | |
115 | .differential = 1, \ | |
116 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ | |
117 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ | |
118 | } | |
119 | ||
120 | static const struct iio_chan_spec mcp3204_channels[] = { | |
121 | MCP320X_VOLTAGE_CHANNEL(0), | |
122 | MCP320X_VOLTAGE_CHANNEL(1), | |
123 | MCP320X_VOLTAGE_CHANNEL(2), | |
124 | MCP320X_VOLTAGE_CHANNEL(3), | |
125 | MCP320X_VOLTAGE_CHANNEL_DIFF(0), | |
126 | MCP320X_VOLTAGE_CHANNEL_DIFF(1), | |
127 | }; | |
128 | ||
129 | static const struct iio_chan_spec mcp3208_channels[] = { | |
130 | MCP320X_VOLTAGE_CHANNEL(0), | |
131 | MCP320X_VOLTAGE_CHANNEL(1), | |
132 | MCP320X_VOLTAGE_CHANNEL(2), | |
133 | MCP320X_VOLTAGE_CHANNEL(3), | |
134 | MCP320X_VOLTAGE_CHANNEL(4), | |
135 | MCP320X_VOLTAGE_CHANNEL(5), | |
136 | MCP320X_VOLTAGE_CHANNEL(6), | |
137 | MCP320X_VOLTAGE_CHANNEL(7), | |
138 | MCP320X_VOLTAGE_CHANNEL_DIFF(0), | |
139 | MCP320X_VOLTAGE_CHANNEL_DIFF(1), | |
140 | MCP320X_VOLTAGE_CHANNEL_DIFF(2), | |
141 | MCP320X_VOLTAGE_CHANNEL_DIFF(3), | |
142 | }; | |
143 | ||
144 | static const struct iio_info mcp320x_info = { | |
145 | .read_raw = mcp320x_read_raw, | |
146 | .driver_module = THIS_MODULE, | |
147 | }; | |
148 | ||
149 | struct mcp3208_chip_info { | |
150 | const struct iio_chan_spec *channels; | |
151 | unsigned int num_channels; | |
152 | }; | |
153 | ||
154 | static const struct mcp3208_chip_info mcp3208_chip_infos[] = { | |
155 | [mcp3204] = { | |
156 | .channels = mcp3204_channels, | |
157 | .num_channels = ARRAY_SIZE(mcp3204_channels) | |
158 | }, | |
159 | [mcp3208] = { | |
160 | .channels = mcp3208_channels, | |
161 | .num_channels = ARRAY_SIZE(mcp3208_channels) | |
162 | }, | |
163 | }; | |
164 | ||
165 | static int mcp320x_probe(struct spi_device *spi) | |
166 | { | |
167 | struct iio_dev *indio_dev; | |
168 | struct mcp320x *adc; | |
169 | const struct mcp3208_chip_info *chip_info; | |
170 | int ret; | |
171 | ||
a726dea5 | 172 | indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); |
f5ce4a7a OA |
173 | if (!indio_dev) |
174 | return -ENOMEM; | |
175 | ||
176 | adc = iio_priv(indio_dev); | |
177 | adc->spi = spi; | |
178 | ||
179 | indio_dev->dev.parent = &spi->dev; | |
180 | indio_dev->name = spi_get_device_id(spi)->name; | |
181 | indio_dev->modes = INDIO_DIRECT_MODE; | |
182 | indio_dev->info = &mcp320x_info; | |
183 | ||
184 | chip_info = &mcp3208_chip_infos[spi_get_device_id(spi)->driver_data]; | |
185 | indio_dev->channels = chip_info->channels; | |
186 | indio_dev->num_channels = chip_info->num_channels; | |
187 | ||
188 | adc->transfer[0].tx_buf = &adc->tx_buf; | |
189 | adc->transfer[0].len = sizeof(adc->tx_buf); | |
190 | adc->transfer[1].rx_buf = adc->rx_buf; | |
191 | adc->transfer[1].len = sizeof(adc->rx_buf); | |
192 | ||
193 | spi_message_init_with_transfers(&adc->msg, adc->transfer, | |
194 | ARRAY_SIZE(adc->transfer)); | |
195 | ||
a726dea5 SK |
196 | adc->reg = devm_regulator_get(&spi->dev, "vref"); |
197 | if (IS_ERR(adc->reg)) | |
198 | return PTR_ERR(adc->reg); | |
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199 | |
200 | ret = regulator_enable(adc->reg); | |
201 | if (ret < 0) | |
a726dea5 | 202 | return ret; |
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203 | |
204 | mutex_init(&adc->lock); | |
205 | ||
206 | ret = iio_device_register(indio_dev); | |
207 | if (ret < 0) | |
208 | goto reg_disable; | |
209 | ||
210 | return 0; | |
211 | ||
212 | reg_disable: | |
213 | regulator_disable(adc->reg); | |
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214 | |
215 | return ret; | |
216 | } | |
217 | ||
218 | static int mcp320x_remove(struct spi_device *spi) | |
219 | { | |
220 | struct iio_dev *indio_dev = spi_get_drvdata(spi); | |
221 | struct mcp320x *adc = iio_priv(indio_dev); | |
222 | ||
223 | iio_device_unregister(indio_dev); | |
224 | regulator_disable(adc->reg); | |
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225 | |
226 | return 0; | |
227 | } | |
228 | ||
229 | static const struct spi_device_id mcp320x_id[] = { | |
230 | { "mcp3204", mcp3204 }, | |
231 | { "mcp3208", mcp3208 }, | |
232 | { } | |
233 | }; | |
234 | MODULE_DEVICE_TABLE(spi, mcp320x_id); | |
235 | ||
236 | static struct spi_driver mcp320x_driver = { | |
237 | .driver = { | |
238 | .name = "mcp320x", | |
239 | .owner = THIS_MODULE, | |
240 | }, | |
241 | .probe = mcp320x_probe, | |
242 | .remove = mcp320x_remove, | |
243 | .id_table = mcp320x_id, | |
244 | }; | |
245 | module_spi_driver(mcp320x_driver); | |
246 | ||
247 | MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>"); | |
248 | MODULE_DESCRIPTION("Microchip Technology MCP3204/08"); | |
249 | MODULE_LICENSE("GPL v2"); |