2 * IIO DAC driver for Analog Devices AD8801 DAC
4 * Copyright (C) 2016 Gwenhael Goavec-Merou
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2, as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
16 #include <linux/iio/iio.h>
17 #include <linux/module.h>
18 #include <linux/regulator/consumer.h>
19 #include <linux/spi/spi.h>
20 #include <linux/sysfs.h>
22 #define AD8801_CFG_ADDR_OFFSET 8
24 enum ad8801_device_ids {
30 struct spi_device *spi;
31 unsigned char dac_cache[8]; /* Value write on each channel */
32 unsigned int vrefh_mv;
33 unsigned int vrefl_mv;
34 struct regulator *vrefh_reg;
35 struct regulator *vrefl_reg;
37 __be16 data ____cacheline_aligned;
40 static int ad8801_spi_write(struct ad8801_state *state,
41 u8 channel, unsigned char value)
43 state->data = cpu_to_be16((channel << AD8801_CFG_ADDR_OFFSET) | value);
44 return spi_write(state->spi, &state->data, sizeof(state->data));
47 static int ad8801_write_raw(struct iio_dev *indio_dev,
48 struct iio_chan_spec const *chan, int val, int val2, long mask)
50 struct ad8801_state *state = iio_priv(indio_dev);
54 case IIO_CHAN_INFO_RAW:
55 if (val >= 256 || val < 0)
58 ret = ad8801_spi_write(state, chan->channel, val);
60 state->dac_cache[chan->channel] = val;
69 static int ad8801_read_raw(struct iio_dev *indio_dev,
70 struct iio_chan_spec const *chan, int *val, int *val2, long info)
72 struct ad8801_state *state = iio_priv(indio_dev);
75 case IIO_CHAN_INFO_RAW:
76 *val = state->dac_cache[chan->channel];
78 case IIO_CHAN_INFO_SCALE:
79 *val = state->vrefh_mv - state->vrefl_mv;
81 return IIO_VAL_FRACTIONAL_LOG2;
82 case IIO_CHAN_INFO_OFFSET:
83 *val = state->vrefl_mv;
92 static const struct iio_info ad8801_info = {
93 .read_raw = ad8801_read_raw,
94 .write_raw = ad8801_write_raw,
95 .driver_module = THIS_MODULE,
98 #define AD8801_CHANNEL(chan) { \
99 .type = IIO_VOLTAGE, \
103 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
104 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
105 BIT(IIO_CHAN_INFO_OFFSET), \
108 static const struct iio_chan_spec ad8801_channels[] = {
119 static int ad8801_probe(struct spi_device *spi)
121 struct iio_dev *indio_dev;
122 struct ad8801_state *state;
123 const struct spi_device_id *id;
126 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
127 if (indio_dev == NULL)
130 state = iio_priv(indio_dev);
132 id = spi_get_device_id(spi);
134 state->vrefh_reg = devm_regulator_get(&spi->dev, "vrefh");
135 if (IS_ERR(state->vrefh_reg)) {
136 dev_err(&spi->dev, "Vrefh regulator not specified\n");
137 return PTR_ERR(state->vrefh_reg);
140 ret = regulator_enable(state->vrefh_reg);
142 dev_err(&spi->dev, "Failed to enable vrefh regulator: %d\n",
147 ret = regulator_get_voltage(state->vrefh_reg);
149 dev_err(&spi->dev, "Failed to read vrefh regulator: %d\n",
151 goto error_disable_vrefh_reg;
153 state->vrefh_mv = ret / 1000;
155 if (id->driver_data == ID_AD8803) {
156 state->vrefl_reg = devm_regulator_get(&spi->dev, "vrefl");
157 if (IS_ERR(state->vrefl_reg)) {
158 dev_err(&spi->dev, "Vrefl regulator not specified\n");
159 ret = PTR_ERR(state->vrefl_reg);
160 goto error_disable_vrefh_reg;
163 ret = regulator_enable(state->vrefl_reg);
165 dev_err(&spi->dev, "Failed to enable vrefl regulator: %d\n",
167 goto error_disable_vrefh_reg;
170 ret = regulator_get_voltage(state->vrefl_reg);
172 dev_err(&spi->dev, "Failed to read vrefl regulator: %d\n",
174 goto error_disable_vrefl_reg;
176 state->vrefl_mv = ret / 1000;
179 state->vrefl_reg = NULL;
182 spi_set_drvdata(spi, indio_dev);
183 indio_dev->dev.parent = &spi->dev;
184 indio_dev->info = &ad8801_info;
185 indio_dev->modes = INDIO_DIRECT_MODE;
186 indio_dev->channels = ad8801_channels;
187 indio_dev->num_channels = ARRAY_SIZE(ad8801_channels);
188 indio_dev->name = id->name;
190 ret = iio_device_register(indio_dev);
192 dev_err(&spi->dev, "Failed to register iio device: %d\n",
194 goto error_disable_vrefl_reg;
199 error_disable_vrefl_reg:
200 if (state->vrefl_reg)
201 regulator_disable(state->vrefl_reg);
202 error_disable_vrefh_reg:
203 regulator_disable(state->vrefh_reg);
207 static int ad8801_remove(struct spi_device *spi)
209 struct iio_dev *indio_dev = spi_get_drvdata(spi);
210 struct ad8801_state *state = iio_priv(indio_dev);
212 iio_device_unregister(indio_dev);
213 if (state->vrefl_reg)
214 regulator_disable(state->vrefl_reg);
215 regulator_disable(state->vrefh_reg);
220 static const struct spi_device_id ad8801_ids[] = {
221 {"ad8801", ID_AD8801},
222 {"ad8803", ID_AD8803},
225 MODULE_DEVICE_TABLE(spi, ad8801_ids);
227 static struct spi_driver ad8801_driver = {
231 .probe = ad8801_probe,
232 .remove = ad8801_remove,
233 .id_table = ad8801_ids,
235 module_spi_driver(ad8801_driver);
237 MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>");
238 MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC");
239 MODULE_LICENSE("GPL v2");