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1b791fad MW |
1 | /* |
2 | * mcp4922.c | |
3 | * | |
4 | * Driver for Microchip Digital to Analog Converters. | |
5 | * Supports MCP4902, MCP4912, and MCP4922. | |
6 | * | |
7 | * Copyright (c) 2014 EMAC Inc. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | */ | |
20 | ||
21 | #include <linux/module.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/spi/spi.h> | |
24 | #include <linux/iio/iio.h> | |
25 | #include <linux/iio/sysfs.h> | |
26 | #include <linux/regulator/consumer.h> | |
27 | #include <linux/bitops.h> | |
28 | ||
29 | #define MCP4922_NUM_CHANNELS 2 | |
30 | ||
31 | enum mcp4922_supported_device_ids { | |
32 | ID_MCP4902, | |
33 | ID_MCP4912, | |
34 | ID_MCP4922, | |
35 | }; | |
36 | ||
37 | struct mcp4922_state { | |
38 | struct spi_device *spi; | |
39 | unsigned int value[MCP4922_NUM_CHANNELS]; | |
40 | unsigned int vref_mv; | |
41 | struct regulator *vref_reg; | |
42 | u8 mosi[2] ____cacheline_aligned; | |
43 | }; | |
44 | ||
45 | #define MCP4922_CHAN(chan, bits) { \ | |
46 | .type = IIO_VOLTAGE, \ | |
47 | .output = 1, \ | |
48 | .indexed = 1, \ | |
49 | .channel = chan, \ | |
50 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ | |
51 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ | |
52 | .scan_type = { \ | |
53 | .sign = 'u', \ | |
54 | .realbits = (bits), \ | |
55 | .storagebits = 16, \ | |
56 | .shift = 12 - (bits), \ | |
57 | }, \ | |
58 | } | |
59 | ||
60 | static int mcp4922_spi_write(struct mcp4922_state *state, u8 addr, u32 val) | |
61 | { | |
62 | state->mosi[1] = val & 0xff; | |
63 | state->mosi[0] = (addr == 0) ? 0x00 : 0x80; | |
64 | state->mosi[0] |= 0x30 | ((val >> 8) & 0x0f); | |
65 | ||
66 | return spi_write(state->spi, state->mosi, 2); | |
67 | } | |
68 | ||
69 | static int mcp4922_read_raw(struct iio_dev *indio_dev, | |
70 | struct iio_chan_spec const *chan, | |
71 | int *val, | |
72 | int *val2, | |
73 | long mask) | |
74 | { | |
75 | struct mcp4922_state *state = iio_priv(indio_dev); | |
76 | ||
77 | switch (mask) { | |
78 | case IIO_CHAN_INFO_RAW: | |
79 | *val = state->value[chan->channel]; | |
80 | return IIO_VAL_INT; | |
81 | case IIO_CHAN_INFO_SCALE: | |
82 | *val = state->vref_mv; | |
83 | *val2 = chan->scan_type.realbits; | |
84 | return IIO_VAL_FRACTIONAL_LOG2; | |
85 | default: | |
86 | return -EINVAL; | |
87 | } | |
88 | } | |
89 | ||
90 | static int mcp4922_write_raw(struct iio_dev *indio_dev, | |
91 | struct iio_chan_spec const *chan, | |
92 | int val, | |
93 | int val2, | |
94 | long mask) | |
95 | { | |
96 | struct mcp4922_state *state = iio_priv(indio_dev); | |
97 | ||
98 | if (val2 != 0) | |
99 | return -EINVAL; | |
100 | ||
101 | switch (mask) { | |
102 | case IIO_CHAN_INFO_RAW: | |
103 | if (val > GENMASK(chan->scan_type.realbits-1, 0)) | |
104 | return -EINVAL; | |
105 | val <<= chan->scan_type.shift; | |
106 | state->value[chan->channel] = val; | |
107 | return mcp4922_spi_write(state, chan->channel, val); | |
108 | default: | |
109 | return -EINVAL; | |
110 | } | |
111 | } | |
112 | ||
113 | static const struct iio_chan_spec mcp4922_channels[3][MCP4922_NUM_CHANNELS] = { | |
114 | [ID_MCP4902] = { MCP4922_CHAN(0, 8), MCP4922_CHAN(1, 8) }, | |
115 | [ID_MCP4912] = { MCP4922_CHAN(0, 10), MCP4922_CHAN(1, 10) }, | |
116 | [ID_MCP4922] = { MCP4922_CHAN(0, 12), MCP4922_CHAN(1, 12) }, | |
117 | }; | |
118 | ||
119 | static const struct iio_info mcp4922_info = { | |
120 | .read_raw = &mcp4922_read_raw, | |
121 | .write_raw = &mcp4922_write_raw, | |
1b791fad MW |
122 | }; |
123 | ||
124 | static int mcp4922_probe(struct spi_device *spi) | |
125 | { | |
126 | struct iio_dev *indio_dev; | |
127 | struct mcp4922_state *state; | |
128 | const struct spi_device_id *id; | |
129 | int ret; | |
130 | ||
131 | indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state)); | |
132 | if (indio_dev == NULL) | |
133 | return -ENOMEM; | |
134 | ||
135 | state = iio_priv(indio_dev); | |
136 | state->spi = spi; | |
137 | state->vref_reg = devm_regulator_get(&spi->dev, "vref"); | |
138 | if (IS_ERR(state->vref_reg)) { | |
139 | dev_err(&spi->dev, "Vref regulator not specified\n"); | |
140 | return PTR_ERR(state->vref_reg); | |
141 | } | |
142 | ||
143 | ret = regulator_enable(state->vref_reg); | |
144 | if (ret) { | |
145 | dev_err(&spi->dev, "Failed to enable vref regulator: %d\n", | |
146 | ret); | |
147 | return ret; | |
148 | } | |
149 | ||
150 | ret = regulator_get_voltage(state->vref_reg); | |
151 | if (ret < 0) { | |
152 | dev_err(&spi->dev, "Failed to read vref regulator: %d\n", | |
153 | ret); | |
154 | goto error_disable_reg; | |
155 | } | |
156 | state->vref_mv = ret / 1000; | |
157 | ||
158 | spi_set_drvdata(spi, indio_dev); | |
159 | id = spi_get_device_id(spi); | |
160 | indio_dev->dev.parent = &spi->dev; | |
161 | indio_dev->info = &mcp4922_info; | |
162 | indio_dev->modes = INDIO_DIRECT_MODE; | |
163 | indio_dev->channels = mcp4922_channels[id->driver_data]; | |
164 | indio_dev->num_channels = MCP4922_NUM_CHANNELS; | |
165 | indio_dev->name = id->name; | |
166 | ||
167 | ret = iio_device_register(indio_dev); | |
168 | if (ret) { | |
169 | dev_err(&spi->dev, "Failed to register iio device: %d\n", | |
170 | ret); | |
171 | goto error_disable_reg; | |
172 | } | |
173 | ||
174 | return 0; | |
175 | ||
176 | error_disable_reg: | |
177 | regulator_disable(state->vref_reg); | |
178 | ||
179 | return ret; | |
180 | } | |
181 | ||
182 | static int mcp4922_remove(struct spi_device *spi) | |
183 | { | |
184 | struct iio_dev *indio_dev = spi_get_drvdata(spi); | |
185 | struct mcp4922_state *state; | |
186 | ||
187 | iio_device_unregister(indio_dev); | |
188 | state = iio_priv(indio_dev); | |
189 | regulator_disable(state->vref_reg); | |
190 | ||
191 | return 0; | |
192 | } | |
193 | ||
194 | static const struct spi_device_id mcp4922_id[] = { | |
195 | {"mcp4902", ID_MCP4902}, | |
196 | {"mcp4912", ID_MCP4912}, | |
197 | {"mcp4922", ID_MCP4922}, | |
198 | {} | |
199 | }; | |
200 | MODULE_DEVICE_TABLE(spi, mcp4922_id); | |
201 | ||
202 | static struct spi_driver mcp4922_driver = { | |
203 | .driver = { | |
204 | .name = "mcp4922", | |
1b791fad MW |
205 | }, |
206 | .probe = mcp4922_probe, | |
207 | .remove = mcp4922_remove, | |
208 | .id_table = mcp4922_id, | |
209 | }; | |
210 | module_spi_driver(mcp4922_driver); | |
211 | ||
212 | MODULE_AUTHOR("Michael Welling <mwelling@ieee.org>"); | |
213 | MODULE_DESCRIPTION("Microchip MCP4902, MCP4912, MCP4922 DAC"); | |
214 | MODULE_LICENSE("GPL v2"); |