xref: /kernel/linux/linux-5.10/drivers/iio/adc/ad7766.c (revision 8c2ecf20) 
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) requires 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)]
54			____cacheline_aligned;
55};
56
57/*
58 * AD7766 and AD7767 variations are interface compatible, the main difference is
59 * analog performance. Both parts will use the same ID.
60 */
61enum ad7766_device_ids {
62	ID_AD7766,
63	ID_AD7766_1,
64	ID_AD7766_2,
65};
66
67static irqreturn_t ad7766_trigger_handler(int irq, void *p)
68{
69	struct iio_poll_func *pf = p;
70	struct iio_dev *indio_dev = pf->indio_dev;
71	struct ad7766 *ad7766 = iio_priv(indio_dev);
72	int ret;
73
74	ret = spi_sync(ad7766->spi, &ad7766->msg);
75	if (ret < 0)
76		goto done;
77
78	iio_push_to_buffers_with_timestamp(indio_dev, ad7766->data,
79		pf->timestamp);
80done:
81	iio_trigger_notify_done(indio_dev->trig);
82
83	return IRQ_HANDLED;
84}
85
86static int ad7766_preenable(struct iio_dev *indio_dev)
87{
88	struct ad7766 *ad7766 = iio_priv(indio_dev);
89	int ret;
90
91	ret = regulator_bulk_enable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
92	if (ret < 0) {
93		dev_err(&ad7766->spi->dev, "Failed to enable supplies: %d\n",
94			ret);
95		return ret;
96	}
97
98	ret = clk_prepare_enable(ad7766->mclk);
99	if (ret < 0) {
100		dev_err(&ad7766->spi->dev, "Failed to enable MCLK: %d\n", ret);
101		regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
102		return ret;
103	}
104
105	gpiod_set_value(ad7766->pd_gpio, 0);
106
107	return 0;
108}
109
110static int ad7766_postdisable(struct iio_dev *indio_dev)
111{
112	struct ad7766 *ad7766 = iio_priv(indio_dev);
113
114	gpiod_set_value(ad7766->pd_gpio, 1);
115
116	/*
117	 * The PD pin is synchronous to the clock, so give it some time to
118	 * notice the change before we disable the clock.
119	 */
120	msleep(20);
121
122	clk_disable_unprepare(ad7766->mclk);
123	regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
124
125	return 0;
126}
127
128static int ad7766_read_raw(struct iio_dev *indio_dev,
129	const struct iio_chan_spec *chan, int *val, int *val2, long info)
130{
131	struct ad7766 *ad7766 = iio_priv(indio_dev);
132	struct regulator *vref = ad7766->reg[AD7766_SUPPLY_VREF].consumer;
133	int scale_uv;
134
135	switch (info) {
136	case IIO_CHAN_INFO_SCALE:
137		scale_uv = regulator_get_voltage(vref);
138		if (scale_uv < 0)
139			return scale_uv;
140		*val = scale_uv / 1000;
141		*val2 = chan->scan_type.realbits;
142		return IIO_VAL_FRACTIONAL_LOG2;
143	case IIO_CHAN_INFO_SAMP_FREQ:
144		*val = clk_get_rate(ad7766->mclk) /
145			ad7766->chip_info->decimation_factor;
146		return IIO_VAL_INT;
147	}
148	return -EINVAL;
149}
150
151static const struct iio_chan_spec ad7766_channels[] = {
152	{
153		.type = IIO_VOLTAGE,
154		.indexed = 1,
155		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
156		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
157		.scan_type = {
158			.sign = 's',
159			.realbits = 24,
160			.storagebits = 32,
161			.endianness = IIO_BE,
162		},
163	},
164	IIO_CHAN_SOFT_TIMESTAMP(1),
165};
166
167static const struct ad7766_chip_info ad7766_chip_info[] = {
168	[ID_AD7766] = {
169		.decimation_factor = 8,
170	},
171	[ID_AD7766_1] = {
172		.decimation_factor = 16,
173	},
174	[ID_AD7766_2] = {
175		.decimation_factor = 32,
176	},
177};
178
179static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = {
180	.preenable = &ad7766_preenable,
181	.postdisable = &ad7766_postdisable,
182};
183
184static const struct iio_info ad7766_info = {
185	.read_raw = &ad7766_read_raw,
186};
187
188static irqreturn_t ad7766_irq(int irq, void *private)
189{
190	iio_trigger_poll(private);
191	return IRQ_HANDLED;
192}
193
194static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable)
195{
196	struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig);
197
198	if (enable)
199		enable_irq(ad7766->spi->irq);
200	else
201		disable_irq(ad7766->spi->irq);
202
203	return 0;
204}
205
206static const struct iio_trigger_ops ad7766_trigger_ops = {
207	.set_trigger_state = ad7766_set_trigger_state,
208	.validate_device = iio_trigger_validate_own_device,
209};
210
211static int ad7766_probe(struct spi_device *spi)
212{
213	const struct spi_device_id *id = spi_get_device_id(spi);
214	struct iio_dev *indio_dev;
215	struct ad7766 *ad7766;
216	int ret;
217
218	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ad7766));
219	if (!indio_dev)
220		return -ENOMEM;
221
222	ad7766 = iio_priv(indio_dev);
223	ad7766->chip_info = &ad7766_chip_info[id->driver_data];
224
225	ad7766->mclk = devm_clk_get(&spi->dev, "mclk");
226	if (IS_ERR(ad7766->mclk))
227		return PTR_ERR(ad7766->mclk);
228
229	ad7766->reg[AD7766_SUPPLY_AVDD].supply = "avdd";
230	ad7766->reg[AD7766_SUPPLY_DVDD].supply = "dvdd";
231	ad7766->reg[AD7766_SUPPLY_VREF].supply = "vref";
232
233	ret = devm_regulator_bulk_get(&spi->dev, ARRAY_SIZE(ad7766->reg),
234		ad7766->reg);
235	if (ret)
236		return ret;
237
238	ad7766->pd_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown",
239		GPIOD_OUT_HIGH);
240	if (IS_ERR(ad7766->pd_gpio))
241		return PTR_ERR(ad7766->pd_gpio);
242
243	indio_dev->name = spi_get_device_id(spi)->name;
244	indio_dev->modes = INDIO_DIRECT_MODE;
245	indio_dev->channels = ad7766_channels;
246	indio_dev->num_channels = ARRAY_SIZE(ad7766_channels);
247	indio_dev->info = &ad7766_info;
248
249	if (spi->irq > 0) {
250		ad7766->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
251			indio_dev->name, indio_dev->id);
252		if (!ad7766->trig)
253			return -ENOMEM;
254
255		ad7766->trig->ops = &ad7766_trigger_ops;
256		ad7766->trig->dev.parent = &spi->dev;
257		iio_trigger_set_drvdata(ad7766->trig, ad7766);
258
259		ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq,
260			IRQF_TRIGGER_FALLING, dev_name(&spi->dev),
261			ad7766->trig);
262		if (ret < 0)
263			return ret;
264
265		/*
266		 * The device generates interrupts as long as it is powered up.
267		 * Some platforms might not allow the option to power it down so
268		 * disable the interrupt to avoid extra load on the system
269		 */
270		disable_irq(spi->irq);
271
272		ret = devm_iio_trigger_register(&spi->dev, ad7766->trig);
273		if (ret)
274			return ret;
275	}
276
277	spi_set_drvdata(spi, indio_dev);
278
279	ad7766->spi = spi;
280
281	/* First byte always 0 */
282	ad7766->xfer.rx_buf = &ad7766->data[1];
283	ad7766->xfer.len = 3;
284
285	spi_message_init(&ad7766->msg);
286	spi_message_add_tail(&ad7766->xfer, &ad7766->msg);
287
288	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
289		&iio_pollfunc_store_time, &ad7766_trigger_handler,
290		&ad7766_buffer_setup_ops);
291	if (ret)
292		return ret;
293
294	ret = devm_iio_device_register(&spi->dev, indio_dev);
295	if (ret)
296		return ret;
297	return 0;
298}
299
300static const struct spi_device_id ad7766_id[] = {
301	{"ad7766", ID_AD7766},
302	{"ad7766-1", ID_AD7766_1},
303	{"ad7766-2", ID_AD7766_2},
304	{"ad7767", ID_AD7766},
305	{"ad7767-1", ID_AD7766_1},
306	{"ad7767-2", ID_AD7766_2},
307	{}
308};
309MODULE_DEVICE_TABLE(spi, ad7766_id);
310
311static struct spi_driver ad7766_driver = {
312	.driver = {
313		.name	= "ad7766",
314	},
315	.probe		= ad7766_probe,
316	.id_table	= ad7766_id,
317};
318module_spi_driver(ad7766_driver);
319
320MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
321MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support");
322MODULE_LICENSE("GPL v2");
323