xref: /kernel/linux/linux-6.6/drivers/iio/dac/ad7303.c (revision 62306a36) 
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#define AD7303_CFG_EXTERNAL_VREF BIT(15)
21#define AD7303_CFG_POWER_DOWN(ch) BIT(11 + (ch))
22#define AD7303_CFG_ADDR_OFFSET	10
23
24#define AD7303_CMD_UPDATE_DAC	(0x3 << 8)
25
26/**
27 * struct ad7303_state - driver instance specific data
28 * @spi:		the device for this driver instance
29 * @config:		cached config register value
30 * @dac_cache:		current DAC raw value (chip does not support readback)
31 * @vdd_reg:		reference to VDD regulator
32 * @vref_reg:		reference to VREF regulator
33 * @lock:		protect writes and cache updates
34 * @data:		spi transfer buffer
35 */
36
37struct ad7303_state {
38	struct spi_device *spi;
39	uint16_t config;
40	uint8_t dac_cache[2];
41
42	struct regulator *vdd_reg;
43	struct regulator *vref_reg;
44
45	struct mutex lock;
46	/*
47	 * DMA (thus cache coherency maintenance) may require the
48	 * transfer buffers to live in their own cache lines.
49	 */
50	__be16 data __aligned(IIO_DMA_MINALIGN);
51};
52
53static int ad7303_write(struct ad7303_state *st, unsigned int chan,
54	uint8_t val)
55{
56	st->data = cpu_to_be16(AD7303_CMD_UPDATE_DAC |
57		(chan << AD7303_CFG_ADDR_OFFSET) |
58		st->config | val);
59
60	return spi_write(st->spi, &st->data, sizeof(st->data));
61}
62
63static ssize_t ad7303_read_dac_powerdown(struct iio_dev *indio_dev,
64	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
65{
66	struct ad7303_state *st = iio_priv(indio_dev);
67
68	return sysfs_emit(buf, "%d\n", (bool)(st->config &
69		AD7303_CFG_POWER_DOWN(chan->channel)));
70}
71
72static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
73	 uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
74	 size_t len)
75{
76	struct ad7303_state *st = iio_priv(indio_dev);
77	bool pwr_down;
78	int ret;
79
80	ret = kstrtobool(buf, &pwr_down);
81	if (ret)
82		return ret;
83
84	mutex_lock(&st->lock);
85
86	if (pwr_down)
87		st->config |= AD7303_CFG_POWER_DOWN(chan->channel);
88	else
89		st->config &= ~AD7303_CFG_POWER_DOWN(chan->channel);
90
91	/* There is no noop cmd which allows us to only update the powerdown
92	 * mode, so just write one of the DAC channels again */
93	ad7303_write(st, chan->channel, st->dac_cache[chan->channel]);
94
95	mutex_unlock(&st->lock);
96	return len;
97}
98
99static int ad7303_get_vref(struct ad7303_state *st,
100	struct iio_chan_spec const *chan)
101{
102	int ret;
103
104	if (st->config & AD7303_CFG_EXTERNAL_VREF)
105		return regulator_get_voltage(st->vref_reg);
106
107	ret = regulator_get_voltage(st->vdd_reg);
108	if (ret < 0)
109		return ret;
110	return ret / 2;
111}
112
113static int ad7303_read_raw(struct iio_dev *indio_dev,
114	struct iio_chan_spec const *chan, int *val, int *val2, long info)
115{
116	struct ad7303_state *st = iio_priv(indio_dev);
117	int vref_uv;
118
119	switch (info) {
120	case IIO_CHAN_INFO_RAW:
121		mutex_lock(&st->lock);
122		*val = st->dac_cache[chan->channel];
123		mutex_unlock(&st->lock);
124		return IIO_VAL_INT;
125	case IIO_CHAN_INFO_SCALE:
126		vref_uv = ad7303_get_vref(st, chan);
127		if (vref_uv < 0)
128			return vref_uv;
129
130		*val = 2 * vref_uv / 1000;
131		*val2 = chan->scan_type.realbits;
132
133		return IIO_VAL_FRACTIONAL_LOG2;
134	default:
135		break;
136	}
137	return -EINVAL;
138}
139
140static int ad7303_write_raw(struct iio_dev *indio_dev,
141	struct iio_chan_spec const *chan, int val, int val2, long mask)
142{
143	struct ad7303_state *st = iio_priv(indio_dev);
144	int ret;
145
146	switch (mask) {
147	case IIO_CHAN_INFO_RAW:
148		if (val >= (1 << chan->scan_type.realbits) || val < 0)
149			return -EINVAL;
150
151		mutex_lock(&st->lock);
152		ret = ad7303_write(st, chan->address, val);
153		if (ret == 0)
154			st->dac_cache[chan->channel] = val;
155		mutex_unlock(&st->lock);
156		break;
157	default:
158		ret = -EINVAL;
159	}
160
161	return ret;
162}
163
164static const struct iio_info ad7303_info = {
165	.read_raw = ad7303_read_raw,
166	.write_raw = ad7303_write_raw,
167};
168
169static const struct iio_chan_spec_ext_info ad7303_ext_info[] = {
170	{
171		.name = "powerdown",
172		.read = ad7303_read_dac_powerdown,
173		.write = ad7303_write_dac_powerdown,
174		.shared = IIO_SEPARATE,
175	},
176	{ },
177};
178
179#define AD7303_CHANNEL(chan) {					\
180	.type = IIO_VOLTAGE,					\
181	.indexed = 1,						\
182	.output = 1,						\
183	.channel = (chan),					\
184	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
185	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
186	.address = (chan),					\
187	.scan_type = {						\
188		.sign = 'u',					\
189		.realbits = 8,					\
190		.storagebits = 8,				\
191		.shift = 0,					\
192	},							\
193	.ext_info = ad7303_ext_info,				\
194}
195
196static const struct iio_chan_spec ad7303_channels[] = {
197	AD7303_CHANNEL(0),
198	AD7303_CHANNEL(1),
199};
200
201static void ad7303_reg_disable(void *reg)
202{
203	regulator_disable(reg);
204}
205
206static int ad7303_probe(struct spi_device *spi)
207{
208	const struct spi_device_id *id = spi_get_device_id(spi);
209	struct iio_dev *indio_dev;
210	struct ad7303_state *st;
211	int ret;
212
213	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
214	if (indio_dev == NULL)
215		return -ENOMEM;
216
217	st = iio_priv(indio_dev);
218
219	st->spi = spi;
220
221	mutex_init(&st->lock);
222
223	st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd");
224	if (IS_ERR(st->vdd_reg))
225		return PTR_ERR(st->vdd_reg);
226
227	ret = regulator_enable(st->vdd_reg);
228	if (ret)
229		return ret;
230
231	ret = devm_add_action_or_reset(&spi->dev, ad7303_reg_disable, st->vdd_reg);
232	if (ret)
233		return ret;
234
235	st->vref_reg = devm_regulator_get_optional(&spi->dev, "REF");
236	if (IS_ERR(st->vref_reg)) {
237		ret = PTR_ERR(st->vref_reg);
238		if (ret != -ENODEV)
239			return ret;
240		st->vref_reg = NULL;
241	}
242
243	if (st->vref_reg) {
244		ret = regulator_enable(st->vref_reg);
245		if (ret)
246			return ret;
247
248		ret = devm_add_action_or_reset(&spi->dev, ad7303_reg_disable,
249					       st->vref_reg);
250		if (ret)
251			return ret;
252
253		st->config |= AD7303_CFG_EXTERNAL_VREF;
254	}
255
256	indio_dev->name = id->name;
257	indio_dev->info = &ad7303_info;
258	indio_dev->modes = INDIO_DIRECT_MODE;
259	indio_dev->channels = ad7303_channels;
260	indio_dev->num_channels = ARRAY_SIZE(ad7303_channels);
261
262	return devm_iio_device_register(&spi->dev, indio_dev);
263}
264
265static const struct of_device_id ad7303_spi_of_match[] = {
266	{ .compatible = "adi,ad7303", },
267	{ /* sentinel */ },
268};
269MODULE_DEVICE_TABLE(of, ad7303_spi_of_match);
270
271static const struct spi_device_id ad7303_spi_ids[] = {
272	{ "ad7303", 0 },
273	{}
274};
275MODULE_DEVICE_TABLE(spi, ad7303_spi_ids);
276
277static struct spi_driver ad7303_driver = {
278	.driver = {
279		.name = "ad7303",
280		.of_match_table = ad7303_spi_of_match,
281	},
282	.probe = ad7303_probe,
283	.id_table = ad7303_spi_ids,
284};
285module_spi_driver(ad7303_driver);
286
287MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
288MODULE_DESCRIPTION("Analog Devices AD7303 DAC driver");
289MODULE_LICENSE("GPL v2");
290