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 __aligned(IIO_DMA_MINALIGN);
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 		return dev_err_probe(&spi->dev, PTR_ERR(state->vrefh_reg),
128 				     "Vrefh regulator not specified\n");
129 
130 	ret = regulator_enable(state->vrefh_reg);
131 	if (ret) {
132 		dev_err(&spi->dev, "Failed to enable vrefh regulator: %d\n",
133 				ret);
134 		return ret;
135 	}
136 
137 	ret = regulator_get_voltage(state->vrefh_reg);
138 	if (ret < 0) {
139 		dev_err(&spi->dev, "Failed to read vrefh regulator: %d\n",
140 				ret);
141 		goto error_disable_vrefh_reg;
142 	}
143 	state->vrefh_mv = ret / 1000;
144 
145 	if (id->driver_data == ID_AD8803) {
146 		state->vrefl_reg = devm_regulator_get(&spi->dev, "vrefl");
147 		if (IS_ERR(state->vrefl_reg)) {
148 			ret = dev_err_probe(&spi->dev, PTR_ERR(state->vrefl_reg),
149 					    "Vrefl regulator not specified\n");
150 			goto error_disable_vrefh_reg;
151 		}
152 
153 		ret = regulator_enable(state->vrefl_reg);
154 		if (ret) {
155 			dev_err(&spi->dev, "Failed to enable vrefl regulator: %d\n",
156 					ret);
157 			goto error_disable_vrefh_reg;
158 		}
159 
160 		ret = regulator_get_voltage(state->vrefl_reg);
161 		if (ret < 0) {
162 			dev_err(&spi->dev, "Failed to read vrefl regulator: %d\n",
163 					ret);
164 			goto error_disable_vrefl_reg;
165 		}
166 		state->vrefl_mv = ret / 1000;
167 	} else {
168 		state->vrefl_mv = 0;
169 		state->vrefl_reg = NULL;
170 	}
171 
172 	spi_set_drvdata(spi, indio_dev);
173 	indio_dev->info = &ad8801_info;
174 	indio_dev->modes = INDIO_DIRECT_MODE;
175 	indio_dev->channels = ad8801_channels;
176 	indio_dev->num_channels = ARRAY_SIZE(ad8801_channels);
177 	indio_dev->name = id->name;
178 
179 	ret = iio_device_register(indio_dev);
180 	if (ret) {
181 		dev_err(&spi->dev, "Failed to register iio device: %d\n",
182 				ret);
183 		goto error_disable_vrefl_reg;
184 	}
185 
186 	return 0;
187 
188 error_disable_vrefl_reg:
189 	if (state->vrefl_reg)
190 		regulator_disable(state->vrefl_reg);
191 error_disable_vrefh_reg:
192 	regulator_disable(state->vrefh_reg);
193 	return ret;
194 }
195 
ad8801_remove(struct spi_device * spi)196 static void ad8801_remove(struct spi_device *spi)
197 {
198 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
199 	struct ad8801_state *state = iio_priv(indio_dev);
200 
201 	iio_device_unregister(indio_dev);
202 	if (state->vrefl_reg)
203 		regulator_disable(state->vrefl_reg);
204 	regulator_disable(state->vrefh_reg);
205 }
206 
207 static const struct spi_device_id ad8801_ids[] = {
208 	{"ad8801", ID_AD8801},
209 	{"ad8803", ID_AD8803},
210 	{}
211 };
212 MODULE_DEVICE_TABLE(spi, ad8801_ids);
213 
214 static struct spi_driver ad8801_driver = {
215 	.driver = {
216 		.name	= "ad8801",
217 	},
218 	.probe		= ad8801_probe,
219 	.remove		= ad8801_remove,
220 	.id_table	= ad8801_ids,
221 };
222 module_spi_driver(ad8801_driver);
223 
224 MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>");
225 MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC");
226 MODULE_LICENSE("GPL v2");
227