1/*
2 * ad2s1210.c support for the ADI Resolver to Digital Converters: AD2S1210
3 *
4 * Copyright (c) 2010-2010 Analog Devices Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11#include <linux/types.h>
12#include <linux/mutex.h>
13#include <linux/device.h>
14#include <linux/spi/spi.h>
15#include <linux/slab.h>
16#include <linux/sysfs.h>
17#include <linux/delay.h>
18#include <linux/gpio.h>
19#include <linux/module.h>
20
21#include <linux/iio/iio.h>
22#include <linux/iio/sysfs.h>
23#include "ad2s1210.h"
24
25#define DRV_NAME "ad2s1210"
26
27#define AD2S1210_DEF_CONTROL		0x7E
28
29#define AD2S1210_MSB_IS_HIGH		0x80
30#define AD2S1210_MSB_IS_LOW		0x7F
31#define AD2S1210_PHASE_LOCK_RANGE_44	0x20
32#define AD2S1210_ENABLE_HYSTERESIS	0x10
33#define AD2S1210_SET_ENRES1		0x08
34#define AD2S1210_SET_ENRES0		0x04
35#define AD2S1210_SET_RES1		0x02
36#define AD2S1210_SET_RES0		0x01
37
38#define AD2S1210_SET_ENRESOLUTION	(AD2S1210_SET_ENRES1 |	\
39					 AD2S1210_SET_ENRES0)
40#define AD2S1210_SET_RESOLUTION		(AD2S1210_SET_RES1 | AD2S1210_SET_RES0)
41
42#define AD2S1210_REG_POSITION		0x80
43#define AD2S1210_REG_VELOCITY		0x82
44#define AD2S1210_REG_LOS_THRD		0x88
45#define AD2S1210_REG_DOS_OVR_THRD	0x89
46#define AD2S1210_REG_DOS_MIS_THRD	0x8A
47#define AD2S1210_REG_DOS_RST_MAX_THRD	0x8B
48#define AD2S1210_REG_DOS_RST_MIN_THRD	0x8C
49#define AD2S1210_REG_LOT_HIGH_THRD	0x8D
50#define AD2S1210_REG_LOT_LOW_THRD	0x8E
51#define AD2S1210_REG_EXCIT_FREQ		0x91
52#define AD2S1210_REG_CONTROL		0x92
53#define AD2S1210_REG_SOFT_RESET		0xF0
54#define AD2S1210_REG_FAULT		0xFF
55
56/* pin SAMPLE, A0, A1, RES0, RES1, is controlled by driver */
57#define AD2S1210_SAA		3
58#define AD2S1210_PN		(AD2S1210_SAA + AD2S1210_RES)
59
60#define AD2S1210_MIN_CLKIN	6144000
61#define AD2S1210_MAX_CLKIN	10240000
62#define AD2S1210_MIN_EXCIT	2000
63#define AD2S1210_MAX_EXCIT	20000
64#define AD2S1210_MIN_FCW	0x4
65#define AD2S1210_MAX_FCW	0x50
66
67/* default input clock on serial interface */
68#define AD2S1210_DEF_CLKIN	8192000
69/* clock period in nano second */
70#define AD2S1210_DEF_TCK	(1000000000/AD2S1210_DEF_CLKIN)
71#define AD2S1210_DEF_EXCIT	10000
72
73enum ad2s1210_mode {
74	MOD_POS = 0,
75	MOD_VEL,
76	MOD_CONFIG,
77	MOD_RESERVED,
78};
79
80static const unsigned int ad2s1210_resolution_value[] = { 10, 12, 14, 16 };
81
82struct ad2s1210_state {
83	const struct ad2s1210_platform_data *pdata;
84	struct mutex lock;
85	struct spi_device *sdev;
86	unsigned int fclkin;
87	unsigned int fexcit;
88	bool hysteresis;
89	bool old_data;
90	u8 resolution;
91	enum ad2s1210_mode mode;
92	u8 rx[2] ____cacheline_aligned;
93	u8 tx[2] ____cacheline_aligned;
94};
95
96static const int ad2s1210_mode_vals[4][2] = {
97	[MOD_POS] = { 0, 0 },
98	[MOD_VEL] = { 0, 1 },
99	[MOD_CONFIG] = { 1, 0 },
100};
101static inline void ad2s1210_set_mode(enum ad2s1210_mode mode,
102				     struct ad2s1210_state *st)
103{
104	gpio_set_value(st->pdata->a[0], ad2s1210_mode_vals[mode][0]);
105	gpio_set_value(st->pdata->a[1], ad2s1210_mode_vals[mode][1]);
106	st->mode = mode;
107}
108
109/* write 1 bytes (address or data) to the chip */
110static int ad2s1210_config_write(struct ad2s1210_state *st, u8 data)
111{
112	int ret;
113
114	ad2s1210_set_mode(MOD_CONFIG, st);
115	st->tx[0] = data;
116	ret = spi_write(st->sdev, st->tx, 1);
117	if (ret < 0)
118		return ret;
119	st->old_data = true;
120
121	return 0;
122}
123
124/* read value from one of the registers */
125static int ad2s1210_config_read(struct ad2s1210_state *st,
126		       unsigned char address)
127{
128	struct spi_transfer xfer = {
129		.len = 2,
130		.rx_buf = st->rx,
131		.tx_buf = st->tx,
132	};
133	int ret = 0;
134
135	ad2s1210_set_mode(MOD_CONFIG, st);
136	st->tx[0] = address | AD2S1210_MSB_IS_HIGH;
137	st->tx[1] = AD2S1210_REG_FAULT;
138	ret = spi_sync_transfer(st->sdev, &xfer, 1);
139	if (ret < 0)
140		return ret;
141	st->old_data = true;
142
143	return st->rx[1];
144}
145
146static inline
147int ad2s1210_update_frequency_control_word(struct ad2s1210_state *st)
148{
149	int ret;
150	unsigned char fcw;
151
152	fcw = (unsigned char)(st->fexcit * (1 << 15) / st->fclkin);
153	if (fcw < AD2S1210_MIN_FCW || fcw > AD2S1210_MAX_FCW) {
154		dev_err(&st->sdev->dev, "ad2s1210: FCW out of range\n");
155		return -ERANGE;
156	}
157
158	ret = ad2s1210_config_write(st, AD2S1210_REG_EXCIT_FREQ);
159	if (ret < 0)
160		return ret;
161
162	return ad2s1210_config_write(st, fcw);
163}
164
165static unsigned char ad2s1210_read_resolution_pin(struct ad2s1210_state *st)
166{
167	return ad2s1210_resolution_value[
168		(gpio_get_value(st->pdata->res[0]) << 1) |
169		gpio_get_value(st->pdata->res[1])];
170}
171
172static const int ad2s1210_res_pins[4][2] = {
173	{ 0, 0 }, {0, 1}, {1, 0}, {1, 1}
174};
175
176static inline void ad2s1210_set_resolution_pin(struct ad2s1210_state *st)
177{
178	gpio_set_value(st->pdata->res[0],
179		       ad2s1210_res_pins[(st->resolution - 10)/2][0]);
180	gpio_set_value(st->pdata->res[1],
181		       ad2s1210_res_pins[(st->resolution - 10)/2][1]);
182}
183
184static inline int ad2s1210_soft_reset(struct ad2s1210_state *st)
185{
186	int ret;
187
188	ret = ad2s1210_config_write(st, AD2S1210_REG_SOFT_RESET);
189	if (ret < 0)
190		return ret;
191
192	return ad2s1210_config_write(st, 0x0);
193}
194
195static ssize_t ad2s1210_show_fclkin(struct device *dev,
196				    struct device_attribute *attr,
197				    char *buf)
198{
199	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
200
201	return sprintf(buf, "%u\n", st->fclkin);
202}
203
204static ssize_t ad2s1210_store_fclkin(struct device *dev,
205				     struct device_attribute *attr,
206				     const char *buf,
207				     size_t len)
208{
209	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
210	unsigned int fclkin;
211	int ret;
212
213	ret = kstrtouint(buf, 10, &fclkin);
214	if (ret)
215		return ret;
216	if (fclkin < AD2S1210_MIN_CLKIN || fclkin > AD2S1210_MAX_CLKIN) {
217		dev_err(dev, "ad2s1210: fclkin out of range\n");
218		return -EINVAL;
219	}
220
221	mutex_lock(&st->lock);
222	st->fclkin = fclkin;
223
224	ret = ad2s1210_update_frequency_control_word(st);
225	if (ret < 0)
226		goto error_ret;
227	ret = ad2s1210_soft_reset(st);
228error_ret:
229	mutex_unlock(&st->lock);
230
231	return ret < 0 ? ret : len;
232}
233
234static ssize_t ad2s1210_show_fexcit(struct device *dev,
235				    struct device_attribute *attr,
236				    char *buf)
237{
238	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
239
240	return sprintf(buf, "%u\n", st->fexcit);
241}
242
243static ssize_t ad2s1210_store_fexcit(struct device *dev,
244				     struct device_attribute *attr,
245				     const char *buf, size_t len)
246{
247	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
248	unsigned int fexcit;
249	int ret;
250
251	ret = kstrtouint(buf, 10, &fexcit);
252	if (ret < 0)
253		return ret;
254	if (fexcit < AD2S1210_MIN_EXCIT || fexcit > AD2S1210_MAX_EXCIT) {
255		dev_err(dev,
256			"ad2s1210: excitation frequency out of range\n");
257		return -EINVAL;
258	}
259	mutex_lock(&st->lock);
260	st->fexcit = fexcit;
261	ret = ad2s1210_update_frequency_control_word(st);
262	if (ret < 0)
263		goto error_ret;
264	ret = ad2s1210_soft_reset(st);
265error_ret:
266	mutex_unlock(&st->lock);
267
268	return ret < 0 ? ret : len;
269}
270
271static ssize_t ad2s1210_show_control(struct device *dev,
272				     struct device_attribute *attr,
273				     char *buf)
274{
275	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
276	int ret;
277
278	mutex_lock(&st->lock);
279	ret = ad2s1210_config_read(st, AD2S1210_REG_CONTROL);
280	mutex_unlock(&st->lock);
281	return ret < 0 ? ret : sprintf(buf, "0x%x\n", ret);
282}
283
284static ssize_t ad2s1210_store_control(struct device *dev,
285			struct device_attribute *attr,
286			const char *buf, size_t len)
287{
288	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
289	unsigned char udata;
290	unsigned char data;
291	int ret;
292
293	ret = kstrtou8(buf, 16, &udata);
294	if (ret)
295		return -EINVAL;
296
297	mutex_lock(&st->lock);
298	ret = ad2s1210_config_write(st, AD2S1210_REG_CONTROL);
299	if (ret < 0)
300		goto error_ret;
301	data = udata & AD2S1210_MSB_IS_LOW;
302	ret = ad2s1210_config_write(st, data);
303	if (ret < 0)
304		goto error_ret;
305
306	ret = ad2s1210_config_read(st, AD2S1210_REG_CONTROL);
307	if (ret < 0)
308		goto error_ret;
309	if (ret & AD2S1210_MSB_IS_HIGH) {
310		ret = -EIO;
311		dev_err(dev,
312			"ad2s1210: write control register fail\n");
313		goto error_ret;
314	}
315	st->resolution
316		= ad2s1210_resolution_value[data & AD2S1210_SET_RESOLUTION];
317	if (st->pdata->gpioin) {
318		data = ad2s1210_read_resolution_pin(st);
319		if (data != st->resolution)
320			dev_warn(dev, "ad2s1210: resolution settings not match\n");
321	} else
322		ad2s1210_set_resolution_pin(st);
323
324	ret = len;
325	st->hysteresis = !!(data & AD2S1210_ENABLE_HYSTERESIS);
326
327error_ret:
328	mutex_unlock(&st->lock);
329	return ret;
330}
331
332static ssize_t ad2s1210_show_resolution(struct device *dev,
333			struct device_attribute *attr, char *buf)
334{
335	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
336
337	return sprintf(buf, "%d\n", st->resolution);
338}
339
340static ssize_t ad2s1210_store_resolution(struct device *dev,
341			struct device_attribute *attr,
342			const char *buf, size_t len)
343{
344	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
345	unsigned char data;
346	unsigned char udata;
347	int ret;
348
349	ret = kstrtou8(buf, 10, &udata);
350	if (ret || udata < 10 || udata > 16) {
351		dev_err(dev, "ad2s1210: resolution out of range\n");
352		return -EINVAL;
353	}
354	mutex_lock(&st->lock);
355	ret = ad2s1210_config_read(st, AD2S1210_REG_CONTROL);
356	if (ret < 0)
357		goto error_ret;
358	data = ret;
359	data &= ~AD2S1210_SET_RESOLUTION;
360	data |= (udata - 10) >> 1;
361	ret = ad2s1210_config_write(st, AD2S1210_REG_CONTROL);
362	if (ret < 0)
363		goto error_ret;
364	ret = ad2s1210_config_write(st, data & AD2S1210_MSB_IS_LOW);
365	if (ret < 0)
366		goto error_ret;
367	ret = ad2s1210_config_read(st, AD2S1210_REG_CONTROL);
368	if (ret < 0)
369		goto error_ret;
370	data = ret;
371	if (data & AD2S1210_MSB_IS_HIGH) {
372		ret = -EIO;
373		dev_err(dev, "ad2s1210: setting resolution fail\n");
374		goto error_ret;
375	}
376	st->resolution
377		= ad2s1210_resolution_value[data & AD2S1210_SET_RESOLUTION];
378	if (st->pdata->gpioin) {
379		data = ad2s1210_read_resolution_pin(st);
380		if (data != st->resolution)
381			dev_warn(dev, "ad2s1210: resolution settings not match\n");
382	} else
383		ad2s1210_set_resolution_pin(st);
384	ret = len;
385error_ret:
386	mutex_unlock(&st->lock);
387	return ret;
388}
389
390/* read the fault register since last sample */
391static ssize_t ad2s1210_show_fault(struct device *dev,
392			struct device_attribute *attr, char *buf)
393{
394	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
395	int ret;
396
397	mutex_lock(&st->lock);
398	ret = ad2s1210_config_read(st, AD2S1210_REG_FAULT);
399	mutex_unlock(&st->lock);
400
401	return ret ? ret : sprintf(buf, "0x%x\n", ret);
402}
403
404static ssize_t ad2s1210_clear_fault(struct device *dev,
405				    struct device_attribute *attr,
406				    const char *buf,
407				    size_t len)
408{
409	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
410	int ret;
411
412	mutex_lock(&st->lock);
413	gpio_set_value(st->pdata->sample, 0);
414	/* delay (2 * tck + 20) nano seconds */
415	udelay(1);
416	gpio_set_value(st->pdata->sample, 1);
417	ret = ad2s1210_config_read(st, AD2S1210_REG_FAULT);
418	if (ret < 0)
419		goto error_ret;
420	gpio_set_value(st->pdata->sample, 0);
421	gpio_set_value(st->pdata->sample, 1);
422error_ret:
423	mutex_unlock(&st->lock);
424
425	return ret < 0 ? ret : len;
426}
427
428static ssize_t ad2s1210_show_reg(struct device *dev,
429				 struct device_attribute *attr,
430				 char *buf)
431{
432	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
433	struct iio_dev_attr *iattr = to_iio_dev_attr(attr);
434	int ret;
435
436	mutex_lock(&st->lock);
437	ret = ad2s1210_config_read(st, iattr->address);
438	mutex_unlock(&st->lock);
439
440	return ret < 0 ? ret : sprintf(buf, "%d\n", ret);
441}
442
443static ssize_t ad2s1210_store_reg(struct device *dev,
444		struct device_attribute *attr, const char *buf, size_t len)
445{
446	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
447	unsigned char data;
448	int ret;
449	struct iio_dev_attr *iattr = to_iio_dev_attr(attr);
450
451	ret = kstrtou8(buf, 10, &data);
452	if (ret)
453		return -EINVAL;
454	mutex_lock(&st->lock);
455	ret = ad2s1210_config_write(st, iattr->address);
456	if (ret < 0)
457		goto error_ret;
458	ret = ad2s1210_config_write(st, data & AD2S1210_MSB_IS_LOW);
459error_ret:
460	mutex_unlock(&st->lock);
461	return ret < 0 ? ret : len;
462}
463
464static int ad2s1210_read_raw(struct iio_dev *indio_dev,
465			     struct iio_chan_spec const *chan,
466			     int *val,
467			     int *val2,
468			     long m)
469{
470	struct ad2s1210_state *st = iio_priv(indio_dev);
471	bool negative;
472	int ret = 0;
473	u16 pos;
474	s16 vel;
475
476	mutex_lock(&st->lock);
477	gpio_set_value(st->pdata->sample, 0);
478	/* delay (6 * tck + 20) nano seconds */
479	udelay(1);
480
481	switch (chan->type) {
482	case IIO_ANGL:
483		ad2s1210_set_mode(MOD_POS, st);
484		break;
485	case IIO_ANGL_VEL:
486		ad2s1210_set_mode(MOD_VEL, st);
487		break;
488	default:
489	       ret = -EINVAL;
490	       break;
491	}
492	if (ret < 0)
493		goto error_ret;
494	ret = spi_read(st->sdev, st->rx, 2);
495	if (ret < 0)
496		goto error_ret;
497
498	switch (chan->type) {
499	case IIO_ANGL:
500		pos = be16_to_cpup((__be16 *) st->rx);
501		if (st->hysteresis)
502			pos >>= 16 - st->resolution;
503		*val = pos;
504		ret = IIO_VAL_INT;
505		break;
506	case IIO_ANGL_VEL:
507		negative = st->rx[0] & 0x80;
508		vel = be16_to_cpup((__be16 *) st->rx);
509		vel >>= 16 - st->resolution;
510		if (vel & 0x8000) {
511			negative = (0xffff >> st->resolution) << st->resolution;
512			vel |= negative;
513		}
514		*val = vel;
515		ret = IIO_VAL_INT;
516		break;
517	default:
518		mutex_unlock(&st->lock);
519		return -EINVAL;
520	}
521
522error_ret:
523	gpio_set_value(st->pdata->sample, 1);
524	/* delay (2 * tck + 20) nano seconds */
525	udelay(1);
526	mutex_unlock(&st->lock);
527	return ret;
528}
529
530static IIO_DEVICE_ATTR(fclkin, S_IRUGO | S_IWUSR,
531		       ad2s1210_show_fclkin, ad2s1210_store_fclkin, 0);
532static IIO_DEVICE_ATTR(fexcit, S_IRUGO | S_IWUSR,
533		       ad2s1210_show_fexcit,	ad2s1210_store_fexcit, 0);
534static IIO_DEVICE_ATTR(control, S_IRUGO | S_IWUSR,
535		       ad2s1210_show_control, ad2s1210_store_control, 0);
536static IIO_DEVICE_ATTR(bits, S_IRUGO | S_IWUSR,
537		       ad2s1210_show_resolution, ad2s1210_store_resolution, 0);
538static IIO_DEVICE_ATTR(fault, S_IRUGO | S_IWUSR,
539		       ad2s1210_show_fault, ad2s1210_clear_fault, 0);
540
541static IIO_DEVICE_ATTR(los_thrd, S_IRUGO | S_IWUSR,
542		       ad2s1210_show_reg, ad2s1210_store_reg,
543		       AD2S1210_REG_LOS_THRD);
544static IIO_DEVICE_ATTR(dos_ovr_thrd, S_IRUGO | S_IWUSR,
545		       ad2s1210_show_reg, ad2s1210_store_reg,
546		       AD2S1210_REG_DOS_OVR_THRD);
547static IIO_DEVICE_ATTR(dos_mis_thrd, S_IRUGO | S_IWUSR,
548		       ad2s1210_show_reg, ad2s1210_store_reg,
549		       AD2S1210_REG_DOS_MIS_THRD);
550static IIO_DEVICE_ATTR(dos_rst_max_thrd, S_IRUGO | S_IWUSR,
551		       ad2s1210_show_reg, ad2s1210_store_reg,
552		       AD2S1210_REG_DOS_RST_MAX_THRD);
553static IIO_DEVICE_ATTR(dos_rst_min_thrd, S_IRUGO | S_IWUSR,
554		       ad2s1210_show_reg, ad2s1210_store_reg,
555		       AD2S1210_REG_DOS_RST_MIN_THRD);
556static IIO_DEVICE_ATTR(lot_high_thrd, S_IRUGO | S_IWUSR,
557		       ad2s1210_show_reg, ad2s1210_store_reg,
558		       AD2S1210_REG_LOT_HIGH_THRD);
559static IIO_DEVICE_ATTR(lot_low_thrd, S_IRUGO | S_IWUSR,
560		       ad2s1210_show_reg, ad2s1210_store_reg,
561		       AD2S1210_REG_LOT_LOW_THRD);
562
563
564static const struct iio_chan_spec ad2s1210_channels[] = {
565	{
566		.type = IIO_ANGL,
567		.indexed = 1,
568		.channel = 0,
569		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
570	}, {
571		.type = IIO_ANGL_VEL,
572		.indexed = 1,
573		.channel = 0,
574		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
575	}
576};
577
578static struct attribute *ad2s1210_attributes[] = {
579	&iio_dev_attr_fclkin.dev_attr.attr,
580	&iio_dev_attr_fexcit.dev_attr.attr,
581	&iio_dev_attr_control.dev_attr.attr,
582	&iio_dev_attr_bits.dev_attr.attr,
583	&iio_dev_attr_fault.dev_attr.attr,
584	&iio_dev_attr_los_thrd.dev_attr.attr,
585	&iio_dev_attr_dos_ovr_thrd.dev_attr.attr,
586	&iio_dev_attr_dos_mis_thrd.dev_attr.attr,
587	&iio_dev_attr_dos_rst_max_thrd.dev_attr.attr,
588	&iio_dev_attr_dos_rst_min_thrd.dev_attr.attr,
589	&iio_dev_attr_lot_high_thrd.dev_attr.attr,
590	&iio_dev_attr_lot_low_thrd.dev_attr.attr,
591	NULL,
592};
593
594static const struct attribute_group ad2s1210_attribute_group = {
595	.attrs = ad2s1210_attributes,
596};
597
598static int ad2s1210_initial(struct ad2s1210_state *st)
599{
600	unsigned char data;
601	int ret;
602
603	mutex_lock(&st->lock);
604	if (st->pdata->gpioin)
605		st->resolution = ad2s1210_read_resolution_pin(st);
606	else
607		ad2s1210_set_resolution_pin(st);
608
609	ret = ad2s1210_config_write(st, AD2S1210_REG_CONTROL);
610	if (ret < 0)
611		goto error_ret;
612	data = AD2S1210_DEF_CONTROL & ~(AD2S1210_SET_RESOLUTION);
613	data |= (st->resolution - 10) >> 1;
614	ret = ad2s1210_config_write(st, data);
615	if (ret < 0)
616		goto error_ret;
617	ret = ad2s1210_config_read(st, AD2S1210_REG_CONTROL);
618	if (ret < 0)
619		goto error_ret;
620
621	if (ret & AD2S1210_MSB_IS_HIGH) {
622		ret = -EIO;
623		goto error_ret;
624	}
625
626	ret = ad2s1210_update_frequency_control_word(st);
627	if (ret < 0)
628		goto error_ret;
629	ret = ad2s1210_soft_reset(st);
630error_ret:
631	mutex_unlock(&st->lock);
632	return ret;
633}
634
635static const struct iio_info ad2s1210_info = {
636	.read_raw = &ad2s1210_read_raw,
637	.attrs = &ad2s1210_attribute_group,
638	.driver_module = THIS_MODULE,
639};
640
641static int ad2s1210_setup_gpios(struct ad2s1210_state *st)
642{
643	unsigned long flags = st->pdata->gpioin ? GPIOF_DIR_IN : GPIOF_DIR_OUT;
644	struct gpio ad2s1210_gpios[] = {
645		{ st->pdata->sample, GPIOF_DIR_IN, "sample" },
646		{ st->pdata->a[0], flags, "a0" },
647		{ st->pdata->a[1], flags, "a1" },
648		{ st->pdata->res[0], flags, "res0" },
649		{ st->pdata->res[0], flags, "res1" },
650	};
651
652	return gpio_request_array(ad2s1210_gpios, ARRAY_SIZE(ad2s1210_gpios));
653}
654
655static void ad2s1210_free_gpios(struct ad2s1210_state *st)
656{
657	unsigned long flags = st->pdata->gpioin ? GPIOF_DIR_IN : GPIOF_DIR_OUT;
658	struct gpio ad2s1210_gpios[] = {
659		{ st->pdata->sample, GPIOF_DIR_IN, "sample" },
660		{ st->pdata->a[0], flags, "a0" },
661		{ st->pdata->a[1], flags, "a1" },
662		{ st->pdata->res[0], flags, "res0" },
663		{ st->pdata->res[0], flags, "res1" },
664	};
665
666	gpio_free_array(ad2s1210_gpios, ARRAY_SIZE(ad2s1210_gpios));
667}
668
669static int ad2s1210_probe(struct spi_device *spi)
670{
671	struct iio_dev *indio_dev;
672	struct ad2s1210_state *st;
673	int ret;
674
675	if (spi->dev.platform_data == NULL)
676		return -EINVAL;
677
678	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
679	if (!indio_dev)
680		return -ENOMEM;
681	st = iio_priv(indio_dev);
682	st->pdata = spi->dev.platform_data;
683	ret = ad2s1210_setup_gpios(st);
684	if (ret < 0)
685		return ret;
686
687	spi_set_drvdata(spi, indio_dev);
688
689	mutex_init(&st->lock);
690	st->sdev = spi;
691	st->hysteresis = true;
692	st->mode = MOD_CONFIG;
693	st->resolution = 12;
694	st->fexcit = AD2S1210_DEF_EXCIT;
695
696	indio_dev->dev.parent = &spi->dev;
697	indio_dev->info = &ad2s1210_info;
698	indio_dev->modes = INDIO_DIRECT_MODE;
699	indio_dev->channels = ad2s1210_channels;
700	indio_dev->num_channels = ARRAY_SIZE(ad2s1210_channels);
701	indio_dev->name = spi_get_device_id(spi)->name;
702
703	ret = iio_device_register(indio_dev);
704	if (ret)
705		goto error_free_gpios;
706
707	st->fclkin = spi->max_speed_hz;
708	spi->mode = SPI_MODE_3;
709	spi_setup(spi);
710	ad2s1210_initial(st);
711
712	return 0;
713
714error_free_gpios:
715	ad2s1210_free_gpios(st);
716	return ret;
717}
718
719static int ad2s1210_remove(struct spi_device *spi)
720{
721	struct iio_dev *indio_dev = spi_get_drvdata(spi);
722
723	iio_device_unregister(indio_dev);
724	ad2s1210_free_gpios(iio_priv(indio_dev));
725
726	return 0;
727}
728
729static const struct spi_device_id ad2s1210_id[] = {
730	{ "ad2s1210" },
731	{}
732};
733MODULE_DEVICE_TABLE(spi, ad2s1210_id);
734
735static struct spi_driver ad2s1210_driver = {
736	.driver = {
737		.name = DRV_NAME,
738		.owner = THIS_MODULE,
739	},
740	.probe = ad2s1210_probe,
741	.remove = ad2s1210_remove,
742	.id_table = ad2s1210_id,
743};
744module_spi_driver(ad2s1210_driver);
745
746MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
747MODULE_DESCRIPTION("Analog Devices AD2S1210 Resolver to Digital SPI driver");
748MODULE_LICENSE("GPL v2");
749