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
24 struct ad7766_chip_info {
25 unsigned int decimation_factor;
26 };
27
28 enum {
29 AD7766_SUPPLY_AVDD = 0,
30 AD7766_SUPPLY_DVDD = 1,
31 AD7766_SUPPLY_VREF = 2,
32 AD7766_NUM_SUPPLIES = 3
33 };
34
35 struct 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 */
60 enum ad7766_device_ids {
61 ID_AD7766,
62 ID_AD7766_1,
63 ID_AD7766_2,
64 };
65
ad7766_trigger_handler(int irq,void * p)66 static 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);
79 done:
80 iio_trigger_notify_done(indio_dev->trig);
81
82 return IRQ_HANDLED;
83 }
84
ad7766_preenable(struct iio_dev * indio_dev)85 static 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
ad7766_postdisable(struct iio_dev * indio_dev)109 static 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
ad7766_read_raw(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,int * val,int * val2,long info)127 static 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
150 static 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
166 static 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
178 static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = {
179 .preenable = &ad7766_preenable,
180 .postdisable = &ad7766_postdisable,
181 };
182
183 static const struct iio_info ad7766_info = {
184 .read_raw = &ad7766_read_raw,
185 };
186
ad7766_irq(int irq,void * private)187 static irqreturn_t ad7766_irq(int irq, void *private)
188 {
189 iio_trigger_poll(private);
190 return IRQ_HANDLED;
191 }
192
ad7766_set_trigger_state(struct iio_trigger * trig,bool enable)193 static 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
205 static 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
ad7766_probe(struct spi_device * spi)210 static 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
293 static 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 };
302 MODULE_DEVICE_TABLE(spi, ad7766_id);
303
304 static struct spi_driver ad7766_driver = {
305 .driver = {
306 .name = "ad7766",
307 },
308 .probe = ad7766_probe,
309 .id_table = ad7766_id,
310 };
311 module_spi_driver(ad7766_driver);
312
313 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
314 MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support");
315 MODULE_LICENSE("GPL v2");
316