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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
31enum mcp4922_supported_device_ids {
32 ID_MCP4902,
33 ID_MCP4912,
34 ID_MCP4922,
35};
36
37struct 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
60static 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
69static 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
90static 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
113static 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
119static const struct iio_info mcp4922_info = {
120 .read_raw = &mcp4922_read_raw,
121 .write_raw = &mcp4922_write_raw,
122 .driver_module = THIS_MODULE,
123};
124
125static int mcp4922_probe(struct spi_device *spi)
126{
127 struct iio_dev *indio_dev;
128 struct mcp4922_state *state;
129 const struct spi_device_id *id;
130 int ret;
131
132 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
133 if (indio_dev == NULL)
134 return -ENOMEM;
135
136 state = iio_priv(indio_dev);
137 state->spi = spi;
138 state->vref_reg = devm_regulator_get(&spi->dev, "vref");
139 if (IS_ERR(state->vref_reg)) {
140 dev_err(&spi->dev, "Vref regulator not specified\n");
141 return PTR_ERR(state->vref_reg);
142 }
143
144 ret = regulator_enable(state->vref_reg);
145 if (ret) {
146 dev_err(&spi->dev, "Failed to enable vref regulator: %d\n",
147 ret);
148 return ret;
149 }
150
151 ret = regulator_get_voltage(state->vref_reg);
152 if (ret < 0) {
153 dev_err(&spi->dev, "Failed to read vref regulator: %d\n",
154 ret);
155 goto error_disable_reg;
156 }
157 state->vref_mv = ret / 1000;
158
159 spi_set_drvdata(spi, indio_dev);
160 id = spi_get_device_id(spi);
161 indio_dev->dev.parent = &spi->dev;
162 indio_dev->info = &mcp4922_info;
163 indio_dev->modes = INDIO_DIRECT_MODE;
164 indio_dev->channels = mcp4922_channels[id->driver_data];
165 indio_dev->num_channels = MCP4922_NUM_CHANNELS;
166 indio_dev->name = id->name;
167
168 ret = iio_device_register(indio_dev);
169 if (ret) {
170 dev_err(&spi->dev, "Failed to register iio device: %d\n",
171 ret);
172 goto error_disable_reg;
173 }
174
175 return 0;
176
177error_disable_reg:
178 regulator_disable(state->vref_reg);
179
180 return ret;
181}
182
183static int mcp4922_remove(struct spi_device *spi)
184{
185 struct iio_dev *indio_dev = spi_get_drvdata(spi);
186 struct mcp4922_state *state;
187
188 iio_device_unregister(indio_dev);
189 state = iio_priv(indio_dev);
190 regulator_disable(state->vref_reg);
191
192 return 0;
193}
194
195static const struct spi_device_id mcp4922_id[] = {
196 {"mcp4902", ID_MCP4902},
197 {"mcp4912", ID_MCP4912},
198 {"mcp4922", ID_MCP4922},
199 {}
200};
201MODULE_DEVICE_TABLE(spi, mcp4922_id);
202
203static struct spi_driver mcp4922_driver = {
204 .driver = {
205 .name = "mcp4922",
206 },
207 .probe = mcp4922_probe,
208 .remove = mcp4922_remove,
209 .id_table = mcp4922_id,
210};
211module_spi_driver(mcp4922_driver);
212
213MODULE_AUTHOR("Michael Welling <mwelling@ieee.org>");
214MODULE_DESCRIPTION("Microchip MCP4902, MCP4912, MCP4922 DAC");
215MODULE_LICENSE("GPL v2");
216
