1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * IIO DAC driver for Analog Devices AD8801 DAC
4 *
5 * Copyright (C) 2016 Gwenhael Goavec-Merou
6 */
7
8 #include <linux/iio/iio.h>
9 #include <linux/module.h>
10 #include <linux/regulator/consumer.h>
11 #include <linux/spi/spi.h>
12 #include <linux/sysfs.h>
13
14 #define AD8801_CFG_ADDR_OFFSET 8
15
16 enum ad8801_device_ids {
17 ID_AD8801,
18 ID_AD8803,
19 };
20
21 struct ad8801_state {
22 struct spi_device *spi;
23 unsigned char dac_cache[8]; /* Value write on each channel */
24 unsigned int vrefh_mv;
25 unsigned int vrefl_mv;
26 struct regulator *vrefh_reg;
27 struct regulator *vrefl_reg;
28
29 __be16 data ____cacheline_aligned;
30 };
31
ad8801_spi_write(struct ad8801_state * state,u8 channel,unsigned char value)32 static int ad8801_spi_write(struct ad8801_state *state,
33 u8 channel, unsigned char value)
34 {
35 state->data = cpu_to_be16((channel << AD8801_CFG_ADDR_OFFSET) | value);
36 return spi_write(state->spi, &state->data, sizeof(state->data));
37 }
38
ad8801_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)39 static int ad8801_write_raw(struct iio_dev *indio_dev,
40 struct iio_chan_spec const *chan, int val, int val2, long mask)
41 {
42 struct ad8801_state *state = iio_priv(indio_dev);
43 int ret;
44
45 switch (mask) {
46 case IIO_CHAN_INFO_RAW:
47 if (val >= 256 || val < 0)
48 return -EINVAL;
49
50 ret = ad8801_spi_write(state, chan->channel, val);
51 if (ret == 0)
52 state->dac_cache[chan->channel] = val;
53 break;
54 default:
55 ret = -EINVAL;
56 }
57
58 return ret;
59 }
60
ad8801_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long info)61 static int ad8801_read_raw(struct iio_dev *indio_dev,
62 struct iio_chan_spec const *chan, int *val, int *val2, long info)
63 {
64 struct ad8801_state *state = iio_priv(indio_dev);
65
66 switch (info) {
67 case IIO_CHAN_INFO_RAW:
68 *val = state->dac_cache[chan->channel];
69 return IIO_VAL_INT;
70 case IIO_CHAN_INFO_SCALE:
71 *val = state->vrefh_mv - state->vrefl_mv;
72 *val2 = 8;
73 return IIO_VAL_FRACTIONAL_LOG2;
74 case IIO_CHAN_INFO_OFFSET:
75 *val = state->vrefl_mv;
76 return IIO_VAL_INT;
77 default:
78 return -EINVAL;
79 }
80
81 return -EINVAL;
82 }
83
84 static const struct iio_info ad8801_info = {
85 .read_raw = ad8801_read_raw,
86 .write_raw = ad8801_write_raw,
87 };
88
89 #define AD8801_CHANNEL(chan) { \
90 .type = IIO_VOLTAGE, \
91 .indexed = 1, \
92 .output = 1, \
93 .channel = chan, \
94 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
95 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
96 BIT(IIO_CHAN_INFO_OFFSET), \
97 }
98
99 static const struct iio_chan_spec ad8801_channels[] = {
100 AD8801_CHANNEL(0),
101 AD8801_CHANNEL(1),
102 AD8801_CHANNEL(2),
103 AD8801_CHANNEL(3),
104 AD8801_CHANNEL(4),
105 AD8801_CHANNEL(5),
106 AD8801_CHANNEL(6),
107 AD8801_CHANNEL(7),
108 };
109
ad8801_probe(struct spi_device * spi)110 static int ad8801_probe(struct spi_device *spi)
111 {
112 struct iio_dev *indio_dev;
113 struct ad8801_state *state;
114 const struct spi_device_id *id;
115 int ret;
116
117 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
118 if (indio_dev == NULL)
119 return -ENOMEM;
120
121 state = iio_priv(indio_dev);
122 state->spi = spi;
123 id = spi_get_device_id(spi);
124
125 state->vrefh_reg = devm_regulator_get(&spi->dev, "vrefh");
126 if (IS_ERR(state->vrefh_reg)) {
127 dev_err(&spi->dev, "Vrefh regulator not specified\n");
128 return PTR_ERR(state->vrefh_reg);
129 }
130
131 ret = regulator_enable(state->vrefh_reg);
132 if (ret) {
133 dev_err(&spi->dev, "Failed to enable vrefh regulator: %d\n",
134 ret);
135 return ret;
136 }
137
138 ret = regulator_get_voltage(state->vrefh_reg);
139 if (ret < 0) {
140 dev_err(&spi->dev, "Failed to read vrefh regulator: %d\n",
141 ret);
142 goto error_disable_vrefh_reg;
143 }
144 state->vrefh_mv = ret / 1000;
145
146 if (id->driver_data == ID_AD8803) {
147 state->vrefl_reg = devm_regulator_get(&spi->dev, "vrefl");
148 if (IS_ERR(state->vrefl_reg)) {
149 dev_err(&spi->dev, "Vrefl regulator not specified\n");
150 ret = PTR_ERR(state->vrefl_reg);
151 goto error_disable_vrefh_reg;
152 }
153
154 ret = regulator_enable(state->vrefl_reg);
155 if (ret) {
156 dev_err(&spi->dev, "Failed to enable vrefl regulator: %d\n",
157 ret);
158 goto error_disable_vrefh_reg;
159 }
160
161 ret = regulator_get_voltage(state->vrefl_reg);
162 if (ret < 0) {
163 dev_err(&spi->dev, "Failed to read vrefl regulator: %d\n",
164 ret);
165 goto error_disable_vrefl_reg;
166 }
167 state->vrefl_mv = ret / 1000;
168 } else {
169 state->vrefl_mv = 0;
170 state->vrefl_reg = NULL;
171 }
172
173 spi_set_drvdata(spi, indio_dev);
174 indio_dev->info = &ad8801_info;
175 indio_dev->modes = INDIO_DIRECT_MODE;
176 indio_dev->channels = ad8801_channels;
177 indio_dev->num_channels = ARRAY_SIZE(ad8801_channels);
178 indio_dev->name = id->name;
179
180 ret = iio_device_register(indio_dev);
181 if (ret) {
182 dev_err(&spi->dev, "Failed to register iio device: %d\n",
183 ret);
184 goto error_disable_vrefl_reg;
185 }
186
187 return 0;
188
189 error_disable_vrefl_reg:
190 if (state->vrefl_reg)
191 regulator_disable(state->vrefl_reg);
192 error_disable_vrefh_reg:
193 regulator_disable(state->vrefh_reg);
194 return ret;
195 }
196
ad8801_remove(struct spi_device * spi)197 static int ad8801_remove(struct spi_device *spi)
198 {
199 struct iio_dev *indio_dev = spi_get_drvdata(spi);
200 struct ad8801_state *state = iio_priv(indio_dev);
201
202 iio_device_unregister(indio_dev);
203 if (state->vrefl_reg)
204 regulator_disable(state->vrefl_reg);
205 regulator_disable(state->vrefh_reg);
206
207 return 0;
208 }
209
210 static const struct spi_device_id ad8801_ids[] = {
211 {"ad8801", ID_AD8801},
212 {"ad8803", ID_AD8803},
213 {}
214 };
215 MODULE_DEVICE_TABLE(spi, ad8801_ids);
216
217 static struct spi_driver ad8801_driver = {
218 .driver = {
219 .name = "ad8801",
220 },
221 .probe = ad8801_probe,
222 .remove = ad8801_remove,
223 .id_table = ad8801_ids,
224 };
225 module_spi_driver(ad8801_driver);
226
227 MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>");
228 MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC");
229 MODULE_LICENSE("GPL v2");
230
