1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * AD7766/AD7767 SPI ADC driver
4 *
5 * Copyright 2016 Analog Devices Inc.
6 */
7
8#include <linux/clk.h>
9#include <linux/delay.h>
10#include <linux/device.h>
11#include <linux/err.h>
12#include <linux/gpio/consumer.h>
13#include <linux/module.h>
14#include <linux/regulator/consumer.h>
15#include <linux/slab.h>
16#include <linux/spi/spi.h>
17
18#include <linux/iio/iio.h>
19#include <linux/iio/buffer.h>
20#include <linux/iio/trigger.h>
21#include <linux/iio/trigger_consumer.h>
22#include <linux/iio/triggered_buffer.h>
23
24struct ad7766_chip_info {
25	unsigned int decimation_factor;
26};
27
28enum {
29	AD7766_SUPPLY_AVDD = 0,
30	AD7766_SUPPLY_DVDD = 1,
31	AD7766_SUPPLY_VREF = 2,
32	AD7766_NUM_SUPPLIES = 3
33};
34
35struct ad7766 {
36	const struct ad7766_chip_info *chip_info;
37	struct spi_device *spi;
38	struct clk *mclk;
39	struct gpio_desc *pd_gpio;
40	struct regulator_bulk_data reg[AD7766_NUM_SUPPLIES];
41
42	struct iio_trigger *trig;
43
44	struct spi_transfer xfer;
45	struct spi_message msg;
46
47	/*
48	 * DMA (thus cache coherency maintenance) may require the
49	 * transfer buffers to live in their own cache lines.
50	 * Make the buffer large enough for one 24 bit sample and one 64 bit
51	 * aligned 64 bit timestamp.
52	 */
53	unsigned char data[ALIGN(3, sizeof(s64)) + sizeof(s64)]	__aligned(IIO_DMA_MINALIGN);
54};
55
56/*
57 * AD7766 and AD7767 variations are interface compatible, the main difference is
58 * analog performance. Both parts will use the same ID.
59 */
60enum ad7766_device_ids {
61	ID_AD7766,
62	ID_AD7766_1,
63	ID_AD7766_2,
64};
65
66static irqreturn_t ad7766_trigger_handler(int irq, void *p)
67{
68	struct iio_poll_func *pf = p;
69	struct iio_dev *indio_dev = pf->indio_dev;
70	struct ad7766 *ad7766 = iio_priv(indio_dev);
71	int ret;
72
73	ret = spi_sync(ad7766->spi, &ad7766->msg);
74	if (ret < 0)
75		goto done;
76
77	iio_push_to_buffers_with_timestamp(indio_dev, ad7766->data,
78		pf->timestamp);
79done:
80	iio_trigger_notify_done(indio_dev->trig);
81
82	return IRQ_HANDLED;
83}
84
85static int ad7766_preenable(struct iio_dev *indio_dev)
86{
87	struct ad7766 *ad7766 = iio_priv(indio_dev);
88	int ret;
89
90	ret = regulator_bulk_enable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
91	if (ret < 0) {
92		dev_err(&ad7766->spi->dev, "Failed to enable supplies: %d\n",
93			ret);
94		return ret;
95	}
96
97	ret = clk_prepare_enable(ad7766->mclk);
98	if (ret < 0) {
99		dev_err(&ad7766->spi->dev, "Failed to enable MCLK: %d\n", ret);
100		regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
101		return ret;
102	}
103
104	gpiod_set_value(ad7766->pd_gpio, 0);
105
106	return 0;
107}
108
109static int ad7766_postdisable(struct iio_dev *indio_dev)
110{
111	struct ad7766 *ad7766 = iio_priv(indio_dev);
112
113	gpiod_set_value(ad7766->pd_gpio, 1);
114
115	/*
116	 * The PD pin is synchronous to the clock, so give it some time to
117	 * notice the change before we disable the clock.
118	 */
119	msleep(20);
120
121	clk_disable_unprepare(ad7766->mclk);
122	regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
123
124	return 0;
125}
126
127static int ad7766_read_raw(struct iio_dev *indio_dev,
128	const struct iio_chan_spec *chan, int *val, int *val2, long info)
129{
130	struct ad7766 *ad7766 = iio_priv(indio_dev);
131	struct regulator *vref = ad7766->reg[AD7766_SUPPLY_VREF].consumer;
132	int scale_uv;
133
134	switch (info) {
135	case IIO_CHAN_INFO_SCALE:
136		scale_uv = regulator_get_voltage(vref);
137		if (scale_uv < 0)
138			return scale_uv;
139		*val = scale_uv / 1000;
140		*val2 = chan->scan_type.realbits;
141		return IIO_VAL_FRACTIONAL_LOG2;
142	case IIO_CHAN_INFO_SAMP_FREQ:
143		*val = clk_get_rate(ad7766->mclk) /
144			ad7766->chip_info->decimation_factor;
145		return IIO_VAL_INT;
146	}
147	return -EINVAL;
148}
149
150static const struct iio_chan_spec ad7766_channels[] = {
151	{
152		.type = IIO_VOLTAGE,
153		.indexed = 1,
154		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
155		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
156		.scan_type = {
157			.sign = 's',
158			.realbits = 24,
159			.storagebits = 32,
160			.endianness = IIO_BE,
161		},
162	},
163	IIO_CHAN_SOFT_TIMESTAMP(1),
164};
165
166static const struct ad7766_chip_info ad7766_chip_info[] = {
167	[ID_AD7766] = {
168		.decimation_factor = 8,
169	},
170	[ID_AD7766_1] = {
171		.decimation_factor = 16,
172	},
173	[ID_AD7766_2] = {
174		.decimation_factor = 32,
175	},
176};
177
178static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = {
179	.preenable = &ad7766_preenable,
180	.postdisable = &ad7766_postdisable,
181};
182
183static const struct iio_info ad7766_info = {
184	.read_raw = &ad7766_read_raw,
185};
186
187static irqreturn_t ad7766_irq(int irq, void *private)
188{
189	iio_trigger_poll(private);
190	return IRQ_HANDLED;
191}
192
193static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable)
194{
195	struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig);
196
197	if (enable)
198		enable_irq(ad7766->spi->irq);
199	else
200		disable_irq(ad7766->spi->irq);
201
202	return 0;
203}
204
205static const struct iio_trigger_ops ad7766_trigger_ops = {
206	.set_trigger_state = ad7766_set_trigger_state,
207	.validate_device = iio_trigger_validate_own_device,
208};
209
210static int ad7766_probe(struct spi_device *spi)
211{
212	const struct spi_device_id *id = spi_get_device_id(spi);
213	struct iio_dev *indio_dev;
214	struct ad7766 *ad7766;
215	int ret;
216
217	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ad7766));
218	if (!indio_dev)
219		return -ENOMEM;
220
221	ad7766 = iio_priv(indio_dev);
222	ad7766->chip_info = &ad7766_chip_info[id->driver_data];
223
224	ad7766->mclk = devm_clk_get(&spi->dev, "mclk");
225	if (IS_ERR(ad7766->mclk))
226		return PTR_ERR(ad7766->mclk);
227
228	ad7766->reg[AD7766_SUPPLY_AVDD].supply = "avdd";
229	ad7766->reg[AD7766_SUPPLY_DVDD].supply = "dvdd";
230	ad7766->reg[AD7766_SUPPLY_VREF].supply = "vref";
231
232	ret = devm_regulator_bulk_get(&spi->dev, ARRAY_SIZE(ad7766->reg),
233		ad7766->reg);
234	if (ret)
235		return ret;
236
237	ad7766->pd_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown",
238		GPIOD_OUT_HIGH);
239	if (IS_ERR(ad7766->pd_gpio))
240		return PTR_ERR(ad7766->pd_gpio);
241
242	indio_dev->name = spi_get_device_id(spi)->name;
243	indio_dev->modes = INDIO_DIRECT_MODE;
244	indio_dev->channels = ad7766_channels;
245	indio_dev->num_channels = ARRAY_SIZE(ad7766_channels);
246	indio_dev->info = &ad7766_info;
247
248	if (spi->irq > 0) {
249		ad7766->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
250						      indio_dev->name,
251						      iio_device_id(indio_dev));
252		if (!ad7766->trig)
253			return -ENOMEM;
254
255		ad7766->trig->ops = &ad7766_trigger_ops;
256		iio_trigger_set_drvdata(ad7766->trig, ad7766);
257
258		/*
259		 * The device generates interrupts as long as it is powered up.
260		 * Some platforms might not allow the option to power it down so
261		 * don't enable the interrupt to avoid extra load on the system
262		 */
263		ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq,
264				       IRQF_TRIGGER_FALLING | IRQF_NO_AUTOEN,
265				       dev_name(&spi->dev),
266				       ad7766->trig);
267		if (ret < 0)
268			return ret;
269
270		ret = devm_iio_trigger_register(&spi->dev, ad7766->trig);
271		if (ret)
272			return ret;
273	}
274
275	ad7766->spi = spi;
276
277	/* First byte always 0 */
278	ad7766->xfer.rx_buf = &ad7766->data[1];
279	ad7766->xfer.len = 3;
280
281	spi_message_init(&ad7766->msg);
282	spi_message_add_tail(&ad7766->xfer, &ad7766->msg);
283
284	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
285		&iio_pollfunc_store_time, &ad7766_trigger_handler,
286		&ad7766_buffer_setup_ops);
287	if (ret)
288		return ret;
289
290	return devm_iio_device_register(&spi->dev, indio_dev);
291}
292
293static const struct spi_device_id ad7766_id[] = {
294	{"ad7766", ID_AD7766},
295	{"ad7766-1", ID_AD7766_1},
296	{"ad7766-2", ID_AD7766_2},
297	{"ad7767", ID_AD7766},
298	{"ad7767-1", ID_AD7766_1},
299	{"ad7767-2", ID_AD7766_2},
300	{}
301};
302MODULE_DEVICE_TABLE(spi, ad7766_id);
303
304static struct spi_driver ad7766_driver = {
305	.driver = {
306		.name	= "ad7766",
307	},
308	.probe		= ad7766_probe,
309	.id_table	= ad7766_id,
310};
311module_spi_driver(ad7766_driver);
312
313MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
314MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support");
315MODULE_LICENSE("GPL v2");
316