1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Analog Devices ADF4371 SPI Wideband Synthesizer driver
4 *
5 * Copyright 2019 Analog Devices Inc.
6 */
7#include <linux/bitfield.h>
8#include <linux/clk.h>
9#include <linux/device.h>
10#include <linux/err.h>
11#include <linux/gcd.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/regmap.h>
15#include <linux/sysfs.h>
16#include <linux/spi/spi.h>
17
18#include <linux/iio/iio.h>
19
20/* Registers address macro */
21#define ADF4371_REG(x) (x)
22
23/* ADF4371_REG0 */
24#define ADF4371_ADDR_ASC_MSK BIT(2)
25#define ADF4371_ADDR_ASC(x) FIELD_PREP(ADF4371_ADDR_ASC_MSK, x)
26#define ADF4371_ADDR_ASC_R_MSK BIT(5)
27#define ADF4371_ADDR_ASC_R(x) FIELD_PREP(ADF4371_ADDR_ASC_R_MSK, x)
28#define ADF4371_RESET_CMD 0x81
29
30/* ADF4371_REG17 */
31#define ADF4371_FRAC2WORD_L_MSK GENMASK(7, 1)
32#define ADF4371_FRAC2WORD_L(x) FIELD_PREP(ADF4371_FRAC2WORD_L_MSK, x)
33#define ADF4371_FRAC1WORD_MSK BIT(0)
34#define ADF4371_FRAC1WORD(x) FIELD_PREP(ADF4371_FRAC1WORD_MSK, x)
35
36/* ADF4371_REG18 */
37#define ADF4371_FRAC2WORD_H_MSK GENMASK(6, 0)
38#define ADF4371_FRAC2WORD_H(x) FIELD_PREP(ADF4371_FRAC2WORD_H_MSK, x)
39
40/* ADF4371_REG1A */
41#define ADF4371_MOD2WORD_MSK GENMASK(5, 0)
42#define ADF4371_MOD2WORD(x) FIELD_PREP(ADF4371_MOD2WORD_MSK, x)
43
44/* ADF4371_REG24 */
45#define ADF4371_RF_DIV_SEL_MSK GENMASK(6, 4)
46#define ADF4371_RF_DIV_SEL(x) FIELD_PREP(ADF4371_RF_DIV_SEL_MSK, x)
47
48/* ADF4371_REG25 */
49#define ADF4371_MUTE_LD_MSK BIT(7)
50#define ADF4371_MUTE_LD(x) FIELD_PREP(ADF4371_MUTE_LD_MSK, x)
51
52/* ADF4371_REG32 */
53#define ADF4371_TIMEOUT_MSK GENMASK(1, 0)
54#define ADF4371_TIMEOUT(x) FIELD_PREP(ADF4371_TIMEOUT_MSK, x)
55
56/* ADF4371_REG34 */
57#define ADF4371_VCO_ALC_TOUT_MSK GENMASK(4, 0)
58#define ADF4371_VCO_ALC_TOUT(x) FIELD_PREP(ADF4371_VCO_ALC_TOUT_MSK, x)
59
60/* Specifications */
61#define ADF4371_MIN_VCO_FREQ 4000000000ULL /* 4000 MHz */
62#define ADF4371_MAX_VCO_FREQ 8000000000ULL /* 8000 MHz */
63#define ADF4371_MAX_OUT_RF8_FREQ ADF4371_MAX_VCO_FREQ /* Hz */
64#define ADF4371_MIN_OUT_RF8_FREQ (ADF4371_MIN_VCO_FREQ / 64) /* Hz */
65#define ADF4371_MAX_OUT_RF16_FREQ (ADF4371_MAX_VCO_FREQ * 2) /* Hz */
66#define ADF4371_MIN_OUT_RF16_FREQ (ADF4371_MIN_VCO_FREQ * 2) /* Hz */
67#define ADF4371_MAX_OUT_RF32_FREQ (ADF4371_MAX_VCO_FREQ * 4) /* Hz */
68#define ADF4371_MIN_OUT_RF32_FREQ (ADF4371_MIN_VCO_FREQ * 4) /* Hz */
69
70#define ADF4371_MAX_FREQ_PFD 250000000UL /* Hz */
71#define ADF4371_MAX_FREQ_REFIN 600000000UL /* Hz */
72
73/* MOD1 is a 24-bit primary modulus with fixed value of 2^25 */
74#define ADF4371_MODULUS1 33554432ULL
75/* MOD2 is the programmable, 14-bit auxiliary fractional modulus */
76#define ADF4371_MAX_MODULUS2 BIT(14)
77
78#define ADF4371_CHECK_RANGE(freq, range) \
79 ((freq > ADF4371_MAX_ ## range) || (freq < ADF4371_MIN_ ## range))
80
81enum {
82 ADF4371_FREQ,
83 ADF4371_POWER_DOWN,
84 ADF4371_CHANNEL_NAME
85};
86
87enum {
88 ADF4371_CH_RF8,
89 ADF4371_CH_RFAUX8,
90 ADF4371_CH_RF16,
91 ADF4371_CH_RF32
92};
93
94enum adf4371_variant {
95 ADF4371,
96 ADF4372
97};
98
99struct adf4371_pwrdown {
100 unsigned int reg;
101 unsigned int bit;
102};
103
104static const char * const adf4371_ch_names[] = {
105 "RF8x", "RFAUX8x", "RF16x", "RF32x"
106};
107
108static const struct adf4371_pwrdown adf4371_pwrdown_ch[4] = {
109 [ADF4371_CH_RF8] = { ADF4371_REG(0x25), 2 },
110 [ADF4371_CH_RFAUX8] = { ADF4371_REG(0x72), .bit: 3 },
111 [ADF4371_CH_RF16] = { ADF4371_REG(0x25), .bit: 3 },
112 [ADF4371_CH_RF32] = { ADF4371_REG(0x25), .bit: 4 },
113};
114
115static const struct reg_sequence adf4371_reg_defaults[] = {
116 { ADF4371_REG(0x0), 0x18 },
117 { ADF4371_REG(0x12), 0x40 },
118 { ADF4371_REG(0x1E), 0x48 },
119 { ADF4371_REG(0x20), 0x14 },
120 { ADF4371_REG(0x22), 0x00 },
121 { ADF4371_REG(0x23), 0x00 },
122 { ADF4371_REG(0x24), 0x80 },
123 { ADF4371_REG(0x25), 0x07 },
124 { ADF4371_REG(0x27), 0xC5 },
125 { ADF4371_REG(0x28), 0x83 },
126 { ADF4371_REG(0x2C), 0x44 },
127 { ADF4371_REG(0x2D), 0x11 },
128 { ADF4371_REG(0x2E), 0x12 },
129 { ADF4371_REG(0x2F), 0x94 },
130 { ADF4371_REG(0x32), 0x04 },
131 { ADF4371_REG(0x35), 0xFA },
132 { ADF4371_REG(0x36), 0x30 },
133 { ADF4371_REG(0x39), 0x07 },
134 { ADF4371_REG(0x3A), 0x55 },
135 { ADF4371_REG(0x3E), 0x0C },
136 { ADF4371_REG(0x3F), 0x80 },
137 { ADF4371_REG(0x40), 0x50 },
138 { ADF4371_REG(0x41), 0x28 },
139 { ADF4371_REG(0x47), 0xC0 },
140 { ADF4371_REG(0x52), 0xF4 },
141 { ADF4371_REG(0x70), 0x03 },
142 { ADF4371_REG(0x71), 0x60 },
143 { ADF4371_REG(0x72), 0x32 },
144};
145
146static const struct regmap_config adf4371_regmap_config = {
147 .reg_bits = 16,
148 .val_bits = 8,
149 .read_flag_mask = BIT(7),
150};
151
152struct adf4371_chip_info {
153 unsigned int num_channels;
154 const struct iio_chan_spec *channels;
155};
156
157struct adf4371_state {
158 struct spi_device *spi;
159 struct regmap *regmap;
160 struct clk *clkin;
161 /*
162 * Lock for accessing device registers. Some operations require
163 * multiple consecutive R/W operations, during which the device
164 * shouldn't be interrupted. The buffers are also shared across
165 * all operations so need to be protected on stand alone reads and
166 * writes.
167 */
168 struct mutex lock;
169 const struct adf4371_chip_info *chip_info;
170 unsigned long clkin_freq;
171 unsigned long fpfd;
172 unsigned int integer;
173 unsigned int fract1;
174 unsigned int fract2;
175 unsigned int mod2;
176 unsigned int rf_div_sel;
177 unsigned int ref_div_factor;
178 u8 buf[10] __aligned(IIO_DMA_MINALIGN);
179};
180
181static unsigned long long adf4371_pll_fract_n_get_rate(struct adf4371_state *st,
182 u32 channel)
183{
184 unsigned long long val, tmp;
185 unsigned int ref_div_sel;
186
187 val = (((u64)st->integer * ADF4371_MODULUS1) + st->fract1) * st->fpfd;
188 tmp = (u64)st->fract2 * st->fpfd;
189 do_div(tmp, st->mod2);
190 val += tmp + ADF4371_MODULUS1 / 2;
191
192 if (channel == ADF4371_CH_RF8 || channel == ADF4371_CH_RFAUX8)
193 ref_div_sel = st->rf_div_sel;
194 else
195 ref_div_sel = 0;
196
197 do_div(val, ADF4371_MODULUS1 * (1 << ref_div_sel));
198
199 if (channel == ADF4371_CH_RF16)
200 val <<= 1;
201 else if (channel == ADF4371_CH_RF32)
202 val <<= 2;
203
204 return val;
205}
206
207static void adf4371_pll_fract_n_compute(unsigned long long vco,
208 unsigned long long pfd,
209 unsigned int *integer,
210 unsigned int *fract1,
211 unsigned int *fract2,
212 unsigned int *mod2)
213{
214 unsigned long long tmp;
215 u32 gcd_div;
216
217 tmp = do_div(vco, pfd);
218 tmp = tmp * ADF4371_MODULUS1;
219 *fract2 = do_div(tmp, pfd);
220
221 *integer = vco;
222 *fract1 = tmp;
223
224 *mod2 = pfd;
225
226 while (*mod2 > ADF4371_MAX_MODULUS2) {
227 *mod2 >>= 1;
228 *fract2 >>= 1;
229 }
230
231 gcd_div = gcd(a: *fract2, b: *mod2);
232 *mod2 /= gcd_div;
233 *fract2 /= gcd_div;
234}
235
236static int adf4371_set_freq(struct adf4371_state *st, unsigned long long freq,
237 unsigned int channel)
238{
239 u32 cp_bleed;
240 u8 int_mode = 0;
241 int ret;
242
243 switch (channel) {
244 case ADF4371_CH_RF8:
245 case ADF4371_CH_RFAUX8:
246 if (ADF4371_CHECK_RANGE(freq, OUT_RF8_FREQ))
247 return -EINVAL;
248
249 st->rf_div_sel = 0;
250
251 while (freq < ADF4371_MIN_VCO_FREQ) {
252 freq <<= 1;
253 st->rf_div_sel++;
254 }
255 break;
256 case ADF4371_CH_RF16:
257 /* ADF4371 RF16 8000...16000 MHz */
258 if (ADF4371_CHECK_RANGE(freq, OUT_RF16_FREQ))
259 return -EINVAL;
260
261 freq >>= 1;
262 break;
263 case ADF4371_CH_RF32:
264 /* ADF4371 RF32 16000...32000 MHz */
265 if (ADF4371_CHECK_RANGE(freq, OUT_RF32_FREQ))
266 return -EINVAL;
267
268 freq >>= 2;
269 break;
270 default:
271 return -EINVAL;
272 }
273
274 adf4371_pll_fract_n_compute(vco: freq, pfd: st->fpfd, integer: &st->integer, fract1: &st->fract1,
275 fract2: &st->fract2, mod2: &st->mod2);
276 st->buf[0] = st->integer >> 8;
277 st->buf[1] = 0x40; /* REG12 default */
278 st->buf[2] = 0x00;
279 st->buf[3] = st->fract1 & 0xFF;
280 st->buf[4] = st->fract1 >> 8;
281 st->buf[5] = st->fract1 >> 16;
282 st->buf[6] = ADF4371_FRAC2WORD_L(st->fract2 & 0x7F) |
283 ADF4371_FRAC1WORD(st->fract1 >> 24);
284 st->buf[7] = ADF4371_FRAC2WORD_H(st->fract2 >> 7);
285 st->buf[8] = st->mod2 & 0xFF;
286 st->buf[9] = ADF4371_MOD2WORD(st->mod2 >> 8);
287
288 ret = regmap_bulk_write(map: st->regmap, ADF4371_REG(0x11), val: st->buf, val_count: 10);
289 if (ret < 0)
290 return ret;
291 /*
292 * The R counter allows the input reference frequency to be
293 * divided down to produce the reference clock to the PFD
294 */
295 ret = regmap_write(map: st->regmap, ADF4371_REG(0x1F), val: st->ref_div_factor);
296 if (ret < 0)
297 return ret;
298
299 ret = regmap_update_bits(map: st->regmap, ADF4371_REG(0x24),
300 ADF4371_RF_DIV_SEL_MSK,
301 ADF4371_RF_DIV_SEL(st->rf_div_sel));
302 if (ret < 0)
303 return ret;
304
305 cp_bleed = DIV_ROUND_UP(400 * 1750, st->integer * 375);
306 cp_bleed = clamp(cp_bleed, 1U, 255U);
307 ret = regmap_write(map: st->regmap, ADF4371_REG(0x26), val: cp_bleed);
308 if (ret < 0)
309 return ret;
310 /*
311 * Set to 1 when in INT mode (when FRAC1 = FRAC2 = 0),
312 * and set to 0 when in FRAC mode.
313 */
314 if (st->fract1 == 0 && st->fract2 == 0)
315 int_mode = 0x01;
316
317 ret = regmap_write(map: st->regmap, ADF4371_REG(0x2B), val: int_mode);
318 if (ret < 0)
319 return ret;
320
321 return regmap_write(map: st->regmap, ADF4371_REG(0x10), val: st->integer & 0xFF);
322}
323
324static ssize_t adf4371_read(struct iio_dev *indio_dev,
325 uintptr_t private,
326 const struct iio_chan_spec *chan,
327 char *buf)
328{
329 struct adf4371_state *st = iio_priv(indio_dev);
330 unsigned long long val = 0;
331 unsigned int readval, reg, bit;
332 int ret;
333
334 switch ((u32)private) {
335 case ADF4371_FREQ:
336 val = adf4371_pll_fract_n_get_rate(st, channel: chan->channel);
337 ret = regmap_read(map: st->regmap, ADF4371_REG(0x7C), val: &readval);
338 if (ret < 0)
339 break;
340
341 if (readval == 0x00) {
342 dev_dbg(&st->spi->dev, "PLL un-locked\n");
343 ret = -EBUSY;
344 }
345 break;
346 case ADF4371_POWER_DOWN:
347 reg = adf4371_pwrdown_ch[chan->channel].reg;
348 bit = adf4371_pwrdown_ch[chan->channel].bit;
349
350 ret = regmap_read(map: st->regmap, reg, val: &readval);
351 if (ret < 0)
352 break;
353
354 val = !(readval & BIT(bit));
355 break;
356 case ADF4371_CHANNEL_NAME:
357 return sprintf(buf, fmt: "%s\n", adf4371_ch_names[chan->channel]);
358 default:
359 ret = -EINVAL;
360 val = 0;
361 break;
362 }
363
364 return ret < 0 ? ret : sprintf(buf, fmt: "%llu\n", val);
365}
366
367static ssize_t adf4371_write(struct iio_dev *indio_dev,
368 uintptr_t private,
369 const struct iio_chan_spec *chan,
370 const char *buf, size_t len)
371{
372 struct adf4371_state *st = iio_priv(indio_dev);
373 unsigned long long freq;
374 bool power_down;
375 unsigned int bit, readval, reg;
376 int ret;
377
378 mutex_lock(&st->lock);
379 switch ((u32)private) {
380 case ADF4371_FREQ:
381 ret = kstrtoull(s: buf, base: 10, res: &freq);
382 if (ret)
383 break;
384
385 ret = adf4371_set_freq(st, freq, channel: chan->channel);
386 break;
387 case ADF4371_POWER_DOWN:
388 ret = kstrtobool(s: buf, res: &power_down);
389 if (ret)
390 break;
391
392 reg = adf4371_pwrdown_ch[chan->channel].reg;
393 bit = adf4371_pwrdown_ch[chan->channel].bit;
394 ret = regmap_read(map: st->regmap, reg, val: &readval);
395 if (ret < 0)
396 break;
397
398 readval &= ~BIT(bit);
399 readval |= (!power_down << bit);
400
401 ret = regmap_write(map: st->regmap, reg, val: readval);
402 break;
403 default:
404 ret = -EINVAL;
405 break;
406 }
407 mutex_unlock(lock: &st->lock);
408
409 return ret ? ret : len;
410}
411
412#define _ADF4371_EXT_INFO(_name, _ident) { \
413 .name = _name, \
414 .read = adf4371_read, \
415 .write = adf4371_write, \
416 .private = _ident, \
417 .shared = IIO_SEPARATE, \
418}
419
420static const struct iio_chan_spec_ext_info adf4371_ext_info[] = {
421 /*
422 * Ideally we use IIO_CHAN_INFO_FREQUENCY, but there are
423 * values > 2^32 in order to support the entire frequency range
424 * in Hz. Using scale is a bit ugly.
425 */
426 _ADF4371_EXT_INFO("frequency", ADF4371_FREQ),
427 _ADF4371_EXT_INFO("powerdown", ADF4371_POWER_DOWN),
428 _ADF4371_EXT_INFO("name", ADF4371_CHANNEL_NAME),
429 { },
430};
431
432#define ADF4371_CHANNEL(index) { \
433 .type = IIO_ALTVOLTAGE, \
434 .output = 1, \
435 .channel = index, \
436 .ext_info = adf4371_ext_info, \
437 .indexed = 1, \
438 }
439
440static const struct iio_chan_spec adf4371_chan[] = {
441 ADF4371_CHANNEL(ADF4371_CH_RF8),
442 ADF4371_CHANNEL(ADF4371_CH_RFAUX8),
443 ADF4371_CHANNEL(ADF4371_CH_RF16),
444 ADF4371_CHANNEL(ADF4371_CH_RF32),
445};
446
447static const struct adf4371_chip_info adf4371_chip_info[] = {
448 [ADF4371] = {
449 .channels = adf4371_chan,
450 .num_channels = 4,
451 },
452 [ADF4372] = {
453 .channels = adf4371_chan,
454 .num_channels = 3,
455 }
456};
457
458static int adf4371_reg_access(struct iio_dev *indio_dev,
459 unsigned int reg,
460 unsigned int writeval,
461 unsigned int *readval)
462{
463 struct adf4371_state *st = iio_priv(indio_dev);
464
465 if (readval)
466 return regmap_read(map: st->regmap, reg, val: readval);
467 else
468 return regmap_write(map: st->regmap, reg, val: writeval);
469}
470
471static const struct iio_info adf4371_info = {
472 .debugfs_reg_access = &adf4371_reg_access,
473};
474
475static int adf4371_setup(struct adf4371_state *st)
476{
477 unsigned int synth_timeout = 2, timeout = 1, vco_alc_timeout = 1;
478 unsigned int vco_band_div, tmp;
479 int ret;
480
481 /* Perform a software reset */
482 ret = regmap_write(map: st->regmap, ADF4371_REG(0x0), ADF4371_RESET_CMD);
483 if (ret < 0)
484 return ret;
485
486 ret = regmap_multi_reg_write(map: st->regmap, regs: adf4371_reg_defaults,
487 ARRAY_SIZE(adf4371_reg_defaults));
488 if (ret < 0)
489 return ret;
490
491 /* Mute to Lock Detect */
492 if (device_property_read_bool(dev: &st->spi->dev, propname: "adi,mute-till-lock-en")) {
493 ret = regmap_update_bits(map: st->regmap, ADF4371_REG(0x25),
494 ADF4371_MUTE_LD_MSK,
495 ADF4371_MUTE_LD(1));
496 if (ret < 0)
497 return ret;
498 }
499
500 /* Set address in ascending order, so the bulk_write() will work */
501 ret = regmap_update_bits(map: st->regmap, ADF4371_REG(0x0),
502 ADF4371_ADDR_ASC_MSK | ADF4371_ADDR_ASC_R_MSK,
503 ADF4371_ADDR_ASC(1) | ADF4371_ADDR_ASC_R(1));
504 if (ret < 0)
505 return ret;
506 /*
507 * Calculate and maximize PFD frequency
508 * fPFD = REFIN × ((1 + D)/(R × (1 + T)))
509 * Where D is the REFIN doubler bit, T is the reference divide by 2,
510 * R is the reference division factor
511 * TODO: it is assumed D and T equal 0.
512 */
513 do {
514 st->ref_div_factor++;
515 st->fpfd = st->clkin_freq / st->ref_div_factor;
516 } while (st->fpfd > ADF4371_MAX_FREQ_PFD);
517
518 /* Calculate Timeouts */
519 vco_band_div = DIV_ROUND_UP(st->fpfd, 2400000U);
520
521 tmp = DIV_ROUND_CLOSEST(st->fpfd, 1000000U);
522 do {
523 timeout++;
524 if (timeout > 1023) {
525 timeout = 2;
526 synth_timeout++;
527 }
528 } while (synth_timeout * 1024 + timeout <= 20 * tmp);
529
530 do {
531 vco_alc_timeout++;
532 } while (vco_alc_timeout * 1024 - timeout <= 50 * tmp);
533
534 st->buf[0] = vco_band_div;
535 st->buf[1] = timeout & 0xFF;
536 st->buf[2] = ADF4371_TIMEOUT(timeout >> 8) | 0x04;
537 st->buf[3] = synth_timeout;
538 st->buf[4] = ADF4371_VCO_ALC_TOUT(vco_alc_timeout);
539
540 return regmap_bulk_write(map: st->regmap, ADF4371_REG(0x30), val: st->buf, val_count: 5);
541}
542
543static int adf4371_probe(struct spi_device *spi)
544{
545 const struct spi_device_id *id = spi_get_device_id(sdev: spi);
546 struct iio_dev *indio_dev;
547 struct adf4371_state *st;
548 struct regmap *regmap;
549 int ret;
550
551 indio_dev = devm_iio_device_alloc(parent: &spi->dev, sizeof_priv: sizeof(*st));
552 if (!indio_dev)
553 return -ENOMEM;
554
555 regmap = devm_regmap_init_spi(spi, &adf4371_regmap_config);
556 if (IS_ERR(ptr: regmap)) {
557 dev_err(&spi->dev, "Error initializing spi regmap: %ld\n",
558 PTR_ERR(regmap));
559 return PTR_ERR(ptr: regmap);
560 }
561
562 st = iio_priv(indio_dev);
563 spi_set_drvdata(spi, data: indio_dev);
564 st->spi = spi;
565 st->regmap = regmap;
566 mutex_init(&st->lock);
567
568 st->chip_info = &adf4371_chip_info[id->driver_data];
569 indio_dev->name = id->name;
570 indio_dev->info = &adf4371_info;
571 indio_dev->modes = INDIO_DIRECT_MODE;
572 indio_dev->channels = st->chip_info->channels;
573 indio_dev->num_channels = st->chip_info->num_channels;
574
575 st->clkin = devm_clk_get_enabled(dev: &spi->dev, id: "clkin");
576 if (IS_ERR(ptr: st->clkin))
577 return PTR_ERR(ptr: st->clkin);
578
579 st->clkin_freq = clk_get_rate(clk: st->clkin);
580
581 ret = adf4371_setup(st);
582 if (ret < 0) {
583 dev_err(&spi->dev, "ADF4371 setup failed\n");
584 return ret;
585 }
586
587 return devm_iio_device_register(&spi->dev, indio_dev);
588}
589
590static const struct spi_device_id adf4371_id_table[] = {
591 { "adf4371", ADF4371 },
592 { "adf4372", ADF4372 },
593 {}
594};
595MODULE_DEVICE_TABLE(spi, adf4371_id_table);
596
597static const struct of_device_id adf4371_of_match[] = {
598 { .compatible = "adi,adf4371" },
599 { .compatible = "adi,adf4372" },
600 { },
601};
602MODULE_DEVICE_TABLE(of, adf4371_of_match);
603
604static struct spi_driver adf4371_driver = {
605 .driver = {
606 .name = "adf4371",
607 .of_match_table = adf4371_of_match,
608 },
609 .probe = adf4371_probe,
610 .id_table = adf4371_id_table,
611};
612module_spi_driver(adf4371_driver);
613
614MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
615MODULE_DESCRIPTION("Analog Devices ADF4371 SPI PLL");
616MODULE_LICENSE("GPL");
617

source code of linux/drivers/iio/frequency/adf4371.c