xref: /kernel/linux/linux-5.10/drivers/iio/dac/ad7303.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * AD7303 Digital to analog converters driver
4 *
5 * Copyright 2013 Analog Devices Inc.
6 */
7
8#include <linux/err.h>
9#include <linux/module.h>
10#include <linux/mod_devicetable.h>
11#include <linux/kernel.h>
12#include <linux/spi/spi.h>
13#include <linux/slab.h>
14#include <linux/sysfs.h>
15#include <linux/regulator/consumer.h>
16
17#include <linux/iio/iio.h>
18#include <linux/iio/sysfs.h>
19
20#include <linux/platform_data/ad7303.h>
21
22#define AD7303_CFG_EXTERNAL_VREF BIT(15)
23#define AD7303_CFG_POWER_DOWN(ch) BIT(11 + (ch))
24#define AD7303_CFG_ADDR_OFFSET	10
25
26#define AD7303_CMD_UPDATE_DAC	(0x3 << 8)
27
28/**
29 * struct ad7303_state - driver instance specific data
30 * @spi:		the device for this driver instance
31 * @config:		cached config register value
32 * @dac_cache:		current DAC raw value (chip does not support readback)
33 * @vdd_reg:		reference to VDD regulator
34 * @vref_reg:		reference to VREF regulator
35 * @lock:		protect writes and cache updates
36 * @data:		spi transfer buffer
37 */
38
39struct ad7303_state {
40	struct spi_device *spi;
41	uint16_t config;
42	uint8_t dac_cache[2];
43
44	struct regulator *vdd_reg;
45	struct regulator *vref_reg;
46
47	struct mutex lock;
48	/*
49	 * DMA (thus cache coherency maintenance) requires the
50	 * transfer buffers to live in their own cache lines.
51	 */
52	__be16 data ____cacheline_aligned;
53};
54
55static int ad7303_write(struct ad7303_state *st, unsigned int chan,
56	uint8_t val)
57{
58	st->data = cpu_to_be16(AD7303_CMD_UPDATE_DAC |
59		(chan << AD7303_CFG_ADDR_OFFSET) |
60		st->config | val);
61
62	return spi_write(st->spi, &st->data, sizeof(st->data));
63}
64
65static ssize_t ad7303_read_dac_powerdown(struct iio_dev *indio_dev,
66	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
67{
68	struct ad7303_state *st = iio_priv(indio_dev);
69
70	return sprintf(buf, "%d\n", (bool)(st->config &
71		AD7303_CFG_POWER_DOWN(chan->channel)));
72}
73
74static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
75	 uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
76	 size_t len)
77{
78	struct ad7303_state *st = iio_priv(indio_dev);
79	bool pwr_down;
80	int ret;
81
82	ret = strtobool(buf, &pwr_down);
83	if (ret)
84		return ret;
85
86	mutex_lock(&st->lock);
87
88	if (pwr_down)
89		st->config |= AD7303_CFG_POWER_DOWN(chan->channel);
90	else
91		st->config &= ~AD7303_CFG_POWER_DOWN(chan->channel);
92
93	/* There is no noop cmd which allows us to only update the powerdown
94	 * mode, so just write one of the DAC channels again */
95	ad7303_write(st, chan->channel, st->dac_cache[chan->channel]);
96
97	mutex_unlock(&st->lock);
98	return len;
99}
100
101static int ad7303_get_vref(struct ad7303_state *st,
102	struct iio_chan_spec const *chan)
103{
104	int ret;
105
106	if (st->config & AD7303_CFG_EXTERNAL_VREF)
107		return regulator_get_voltage(st->vref_reg);
108
109	ret = regulator_get_voltage(st->vdd_reg);
110	if (ret < 0)
111		return ret;
112	return ret / 2;
113}
114
115static int ad7303_read_raw(struct iio_dev *indio_dev,
116	struct iio_chan_spec const *chan, int *val, int *val2, long info)
117{
118	struct ad7303_state *st = iio_priv(indio_dev);
119	int vref_uv;
120
121	switch (info) {
122	case IIO_CHAN_INFO_RAW:
123		mutex_lock(&st->lock);
124		*val = st->dac_cache[chan->channel];
125		mutex_unlock(&st->lock);
126		return IIO_VAL_INT;
127	case IIO_CHAN_INFO_SCALE:
128		vref_uv = ad7303_get_vref(st, chan);
129		if (vref_uv < 0)
130			return vref_uv;
131
132		*val = 2 * vref_uv / 1000;
133		*val2 = chan->scan_type.realbits;
134
135		return IIO_VAL_FRACTIONAL_LOG2;
136	default:
137		break;
138	}
139	return -EINVAL;
140}
141
142static int ad7303_write_raw(struct iio_dev *indio_dev,
143	struct iio_chan_spec const *chan, int val, int val2, long mask)
144{
145	struct ad7303_state *st = iio_priv(indio_dev);
146	int ret;
147
148	switch (mask) {
149	case IIO_CHAN_INFO_RAW:
150		if (val >= (1 << chan->scan_type.realbits) || val < 0)
151			return -EINVAL;
152
153		mutex_lock(&st->lock);
154		ret = ad7303_write(st, chan->address, val);
155		if (ret == 0)
156			st->dac_cache[chan->channel] = val;
157		mutex_unlock(&st->lock);
158		break;
159	default:
160		ret = -EINVAL;
161	}
162
163	return ret;
164}
165
166static const struct iio_info ad7303_info = {
167	.read_raw = ad7303_read_raw,
168	.write_raw = ad7303_write_raw,
169};
170
171static const struct iio_chan_spec_ext_info ad7303_ext_info[] = {
172	{
173		.name = "powerdown",
174		.read = ad7303_read_dac_powerdown,
175		.write = ad7303_write_dac_powerdown,
176		.shared = IIO_SEPARATE,
177	},
178	{ },
179};
180
181#define AD7303_CHANNEL(chan) {					\
182	.type = IIO_VOLTAGE,					\
183	.indexed = 1,						\
184	.output = 1,						\
185	.channel = (chan),					\
186	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
187	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
188	.address = (chan),					\
189	.scan_type = {						\
190		.sign = 'u',					\
191		.realbits = 8,					\
192		.storagebits = 8,				\
193		.shift = 0,					\
194	},							\
195	.ext_info = ad7303_ext_info,				\
196}
197
198static const struct iio_chan_spec ad7303_channels[] = {
199	AD7303_CHANNEL(0),
200	AD7303_CHANNEL(1),
201};
202
203static int ad7303_probe(struct spi_device *spi)
204{
205	const struct spi_device_id *id = spi_get_device_id(spi);
206	struct iio_dev *indio_dev;
207	struct ad7303_state *st;
208	int ret;
209
210	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
211	if (indio_dev == NULL)
212		return -ENOMEM;
213
214	st = iio_priv(indio_dev);
215	spi_set_drvdata(spi, indio_dev);
216
217	st->spi = spi;
218
219	mutex_init(&st->lock);
220
221	st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd");
222	if (IS_ERR(st->vdd_reg))
223		return PTR_ERR(st->vdd_reg);
224
225	ret = regulator_enable(st->vdd_reg);
226	if (ret)
227		return ret;
228
229	st->vref_reg = devm_regulator_get_optional(&spi->dev, "REF");
230	if (IS_ERR(st->vref_reg)) {
231		ret = PTR_ERR(st->vref_reg);
232		if (ret != -ENODEV)
233			goto err_disable_vdd_reg;
234		st->vref_reg = NULL;
235	}
236
237	if (st->vref_reg) {
238		ret = regulator_enable(st->vref_reg);
239		if (ret)
240			goto err_disable_vdd_reg;
241
242		st->config |= AD7303_CFG_EXTERNAL_VREF;
243	}
244
245	indio_dev->name = id->name;
246	indio_dev->info = &ad7303_info;
247	indio_dev->modes = INDIO_DIRECT_MODE;
248	indio_dev->channels = ad7303_channels;
249	indio_dev->num_channels = ARRAY_SIZE(ad7303_channels);
250
251	ret = iio_device_register(indio_dev);
252	if (ret)
253		goto err_disable_vref_reg;
254
255	return 0;
256
257err_disable_vref_reg:
258	if (st->vref_reg)
259		regulator_disable(st->vref_reg);
260err_disable_vdd_reg:
261	regulator_disable(st->vdd_reg);
262	return ret;
263}
264
265static int ad7303_remove(struct spi_device *spi)
266{
267	struct iio_dev *indio_dev = spi_get_drvdata(spi);
268	struct ad7303_state *st = iio_priv(indio_dev);
269
270	iio_device_unregister(indio_dev);
271
272	if (st->vref_reg)
273		regulator_disable(st->vref_reg);
274	regulator_disable(st->vdd_reg);
275
276	return 0;
277}
278
279static const struct of_device_id ad7303_spi_of_match[] = {
280	{ .compatible = "adi,ad7303", },
281	{ /* sentinel */ },
282};
283MODULE_DEVICE_TABLE(of, ad7303_spi_of_match);
284
285static const struct spi_device_id ad7303_spi_ids[] = {
286	{ "ad7303", 0 },
287	{}
288};
289MODULE_DEVICE_TABLE(spi, ad7303_spi_ids);
290
291static struct spi_driver ad7303_driver = {
292	.driver = {
293		.name = "ad7303",
294		.of_match_table = ad7303_spi_of_match,
295	},
296	.probe = ad7303_probe,
297	.remove = ad7303_remove,
298	.id_table = ad7303_spi_ids,
299};
300module_spi_driver(ad7303_driver);
301
302MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
303MODULE_DESCRIPTION("Analog Devices AD7303 DAC driver");
304MODULE_LICENSE("GPL v2");
305