1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * mcp4922.c |
4 | * |
5 | * Driver for Microchip Digital to Analog Converters. |
6 | * Supports MCP4902, MCP4912, and MCP4922. |
7 | * |
8 | * Copyright (c) 2014 EMAC Inc. |
9 | */ |
10 | |
11 | #include <linux/module.h> |
12 | #include <linux/init.h> |
13 | #include <linux/spi/spi.h> |
14 | #include <linux/iio/iio.h> |
15 | #include <linux/iio/sysfs.h> |
16 | #include <linux/regulator/consumer.h> |
17 | #include <linux/bitops.h> |
18 | |
19 | #define MCP4922_NUM_CHANNELS 2 |
20 | #define MCP4921_NUM_CHANNELS 1 |
21 | |
22 | enum mcp4922_supported_device_ids { |
23 | ID_MCP4902, |
24 | ID_MCP4912, |
25 | ID_MCP4921, |
26 | ID_MCP4922, |
27 | }; |
28 | |
29 | struct mcp4922_state { |
30 | struct spi_device *spi; |
31 | unsigned int value[MCP4922_NUM_CHANNELS]; |
32 | unsigned int vref_mv; |
33 | struct regulator *vref_reg; |
34 | u8 mosi[2] __aligned(IIO_DMA_MINALIGN); |
35 | }; |
36 | |
37 | #define MCP4922_CHAN(chan, bits) { \ |
38 | .type = IIO_VOLTAGE, \ |
39 | .output = 1, \ |
40 | .indexed = 1, \ |
41 | .channel = chan, \ |
42 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
43 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ |
44 | .scan_type = { \ |
45 | .sign = 'u', \ |
46 | .realbits = (bits), \ |
47 | .storagebits = 16, \ |
48 | .shift = 12 - (bits), \ |
49 | }, \ |
50 | } |
51 | |
52 | static int mcp4922_spi_write(struct mcp4922_state *state, u8 addr, u32 val) |
53 | { |
54 | state->mosi[1] = val & 0xff; |
55 | state->mosi[0] = (addr == 0) ? 0x00 : 0x80; |
56 | state->mosi[0] |= 0x30 | ((val >> 8) & 0x0f); |
57 | |
58 | return spi_write(spi: state->spi, buf: state->mosi, len: 2); |
59 | } |
60 | |
61 | static int mcp4922_read_raw(struct iio_dev *indio_dev, |
62 | struct iio_chan_spec const *chan, |
63 | int *val, |
64 | int *val2, |
65 | long mask) |
66 | { |
67 | struct mcp4922_state *state = iio_priv(indio_dev); |
68 | |
69 | switch (mask) { |
70 | case IIO_CHAN_INFO_RAW: |
71 | *val = state->value[chan->channel]; |
72 | return IIO_VAL_INT; |
73 | case IIO_CHAN_INFO_SCALE: |
74 | *val = state->vref_mv; |
75 | *val2 = chan->scan_type.realbits; |
76 | return IIO_VAL_FRACTIONAL_LOG2; |
77 | default: |
78 | return -EINVAL; |
79 | } |
80 | } |
81 | |
82 | static int mcp4922_write_raw(struct iio_dev *indio_dev, |
83 | struct iio_chan_spec const *chan, |
84 | int val, |
85 | int val2, |
86 | long mask) |
87 | { |
88 | struct mcp4922_state *state = iio_priv(indio_dev); |
89 | int ret; |
90 | |
91 | if (val2 != 0) |
92 | return -EINVAL; |
93 | |
94 | switch (mask) { |
95 | case IIO_CHAN_INFO_RAW: |
96 | if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0)) |
97 | return -EINVAL; |
98 | val <<= chan->scan_type.shift; |
99 | |
100 | ret = mcp4922_spi_write(state, addr: chan->channel, val); |
101 | if (!ret) |
102 | state->value[chan->channel] = val; |
103 | return ret; |
104 | |
105 | default: |
106 | return -EINVAL; |
107 | } |
108 | } |
109 | |
110 | static const struct iio_chan_spec mcp4922_channels[4][MCP4922_NUM_CHANNELS] = { |
111 | [ID_MCP4902] = { MCP4922_CHAN(0, 8), MCP4922_CHAN(1, 8) }, |
112 | [ID_MCP4912] = { MCP4922_CHAN(0, 10), MCP4922_CHAN(1, 10) }, |
113 | [ID_MCP4921] = { MCP4922_CHAN(0, 12), {} }, |
114 | [ID_MCP4922] = { MCP4922_CHAN(0, 12), MCP4922_CHAN(1, 12) }, |
115 | }; |
116 | |
117 | static const struct iio_info mcp4922_info = { |
118 | .read_raw = &mcp4922_read_raw, |
119 | .write_raw = &mcp4922_write_raw, |
120 | }; |
121 | |
122 | static int mcp4922_probe(struct spi_device *spi) |
123 | { |
124 | struct iio_dev *indio_dev; |
125 | struct mcp4922_state *state; |
126 | const struct spi_device_id *id; |
127 | int ret; |
128 | |
129 | indio_dev = devm_iio_device_alloc(parent: &spi->dev, sizeof_priv: sizeof(*state)); |
130 | if (indio_dev == NULL) |
131 | return -ENOMEM; |
132 | |
133 | state = iio_priv(indio_dev); |
134 | state->spi = spi; |
135 | state->vref_reg = devm_regulator_get(dev: &spi->dev, id: "vref" ); |
136 | if (IS_ERR(ptr: state->vref_reg)) |
137 | return dev_err_probe(dev: &spi->dev, err: PTR_ERR(ptr: state->vref_reg), |
138 | fmt: "Vref regulator not specified\n" ); |
139 | |
140 | ret = regulator_enable(regulator: state->vref_reg); |
141 | if (ret) { |
142 | dev_err(&spi->dev, "Failed to enable vref regulator: %d\n" , |
143 | ret); |
144 | return ret; |
145 | } |
146 | |
147 | ret = regulator_get_voltage(regulator: state->vref_reg); |
148 | if (ret < 0) { |
149 | dev_err(&spi->dev, "Failed to read vref regulator: %d\n" , |
150 | ret); |
151 | goto error_disable_reg; |
152 | } |
153 | state->vref_mv = ret / 1000; |
154 | |
155 | spi_set_drvdata(spi, data: indio_dev); |
156 | id = spi_get_device_id(sdev: spi); |
157 | indio_dev->info = &mcp4922_info; |
158 | indio_dev->modes = INDIO_DIRECT_MODE; |
159 | indio_dev->channels = mcp4922_channels[id->driver_data]; |
160 | if (id->driver_data == ID_MCP4921) |
161 | indio_dev->num_channels = MCP4921_NUM_CHANNELS; |
162 | else |
163 | indio_dev->num_channels = MCP4922_NUM_CHANNELS; |
164 | indio_dev->name = id->name; |
165 | |
166 | ret = iio_device_register(indio_dev); |
167 | if (ret) { |
168 | dev_err(&spi->dev, "Failed to register iio device: %d\n" , |
169 | ret); |
170 | goto error_disable_reg; |
171 | } |
172 | |
173 | return 0; |
174 | |
175 | error_disable_reg: |
176 | regulator_disable(regulator: state->vref_reg); |
177 | |
178 | return ret; |
179 | } |
180 | |
181 | static void mcp4922_remove(struct spi_device *spi) |
182 | { |
183 | struct iio_dev *indio_dev = spi_get_drvdata(spi); |
184 | struct mcp4922_state *state; |
185 | |
186 | iio_device_unregister(indio_dev); |
187 | state = iio_priv(indio_dev); |
188 | regulator_disable(regulator: state->vref_reg); |
189 | } |
190 | |
191 | static const struct spi_device_id mcp4922_id[] = { |
192 | {"mcp4902" , ID_MCP4902}, |
193 | {"mcp4912" , ID_MCP4912}, |
194 | {"mcp4921" , ID_MCP4921}, |
195 | {"mcp4922" , ID_MCP4922}, |
196 | {} |
197 | }; |
198 | MODULE_DEVICE_TABLE(spi, mcp4922_id); |
199 | |
200 | static struct spi_driver mcp4922_driver = { |
201 | .driver = { |
202 | .name = "mcp4922" , |
203 | }, |
204 | .probe = mcp4922_probe, |
205 | .remove = mcp4922_remove, |
206 | .id_table = mcp4922_id, |
207 | }; |
208 | module_spi_driver(mcp4922_driver); |
209 | |
210 | MODULE_AUTHOR("Michael Welling <mwelling@ieee.org>" ); |
211 | MODULE_DESCRIPTION("Microchip MCP4902, MCP4912, MCP4922 DAC" ); |
212 | MODULE_LICENSE("GPL v2" ); |
213 | |