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1/*
2 * AD7280A Lithium Ion Battery Monitoring System
3 *
4 * Copyright 2011 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2.
7 */
8
9#include <linux/device.h>
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <linux/sysfs.h>
13#include <linux/spi/spi.h>
14#include <linux/err.h>
15#include <linux/delay.h>
16#include <linux/interrupt.h>
17#include <linux/module.h>
18
19#include <linux/iio/iio.h>
20#include <linux/iio/sysfs.h>
21#include <linux/iio/events.h>
22
23#include "ad7280a.h"
24
25/* Registers */
26#define AD7280A_CELL_VOLTAGE_1		0x0  /* D11 to D0, Read only */
27#define AD7280A_CELL_VOLTAGE_2		0x1  /* D11 to D0, Read only */
28#define AD7280A_CELL_VOLTAGE_3		0x2  /* D11 to D0, Read only */
29#define AD7280A_CELL_VOLTAGE_4		0x3  /* D11 to D0, Read only */
30#define AD7280A_CELL_VOLTAGE_5		0x4  /* D11 to D0, Read only */
31#define AD7280A_CELL_VOLTAGE_6		0x5  /* D11 to D0, Read only */
32#define AD7280A_AUX_ADC_1		0x6  /* D11 to D0, Read only */
33#define AD7280A_AUX_ADC_2		0x7  /* D11 to D0, Read only */
34#define AD7280A_AUX_ADC_3		0x8  /* D11 to D0, Read only */
35#define AD7280A_AUX_ADC_4		0x9  /* D11 to D0, Read only */
36#define AD7280A_AUX_ADC_5		0xA  /* D11 to D0, Read only */
37#define AD7280A_AUX_ADC_6		0xB  /* D11 to D0, Read only */
38#define AD7280A_SELF_TEST		0xC  /* D11 to D0, Read only */
39#define AD7280A_CONTROL_HB		0xD  /* D15 to D8, Read/write */
40#define AD7280A_CONTROL_LB		0xE  /* D7 to D0, Read/write */
41#define AD7280A_CELL_OVERVOLTAGE	0xF  /* D7 to D0, Read/write */
42#define AD7280A_CELL_UNDERVOLTAGE	0x10 /* D7 to D0, Read/write */
43#define AD7280A_AUX_ADC_OVERVOLTAGE	0x11 /* D7 to D0, Read/write */
44#define AD7280A_AUX_ADC_UNDERVOLTAGE	0x12 /* D7 to D0, Read/write */
45#define AD7280A_ALERT			0x13 /* D7 to D0, Read/write */
46#define AD7280A_CELL_BALANCE		0x14 /* D7 to D0, Read/write */
47#define AD7280A_CB1_TIMER		0x15 /* D7 to D0, Read/write */
48#define AD7280A_CB2_TIMER		0x16 /* D7 to D0, Read/write */
49#define AD7280A_CB3_TIMER		0x17 /* D7 to D0, Read/write */
50#define AD7280A_CB4_TIMER		0x18 /* D7 to D0, Read/write */
51#define AD7280A_CB5_TIMER		0x19 /* D7 to D0, Read/write */
52#define AD7280A_CB6_TIMER		0x1A /* D7 to D0, Read/write */
53#define AD7280A_PD_TIMER		0x1B /* D7 to D0, Read/write */
54#define AD7280A_READ			0x1C /* D7 to D0, Read/write */
55#define AD7280A_CNVST_CONTROL		0x1D /* D7 to D0, Read/write */
56
57/* Bits and Masks */
58#define AD7280A_CTRL_HB_CONV_INPUT_ALL			(0 << 6)
59#define AD7280A_CTRL_HB_CONV_INPUT_6CELL_AUX1_3_4	(1 << 6)
60#define AD7280A_CTRL_HB_CONV_INPUT_6CELL		(2 << 6)
61#define AD7280A_CTRL_HB_CONV_INPUT_SELF_TEST		(3 << 6)
62#define AD7280A_CTRL_HB_CONV_RES_READ_ALL		(0 << 4)
63#define AD7280A_CTRL_HB_CONV_RES_READ_6CELL_AUX1_3_4	(1 << 4)
64#define AD7280A_CTRL_HB_CONV_RES_READ_6CELL		(2 << 4)
65#define AD7280A_CTRL_HB_CONV_RES_READ_NO		(3 << 4)
66#define AD7280A_CTRL_HB_CONV_START_CNVST		(0 << 3)
67#define AD7280A_CTRL_HB_CONV_START_CS			(1 << 3)
68#define AD7280A_CTRL_HB_CONV_AVG_DIS			(0 << 1)
69#define AD7280A_CTRL_HB_CONV_AVG_2			(1 << 1)
70#define AD7280A_CTRL_HB_CONV_AVG_4			(2 << 1)
71#define AD7280A_CTRL_HB_CONV_AVG_8			(3 << 1)
72#define AD7280A_CTRL_HB_CONV_AVG(x)			((x) << 1)
73#define AD7280A_CTRL_HB_PWRDN_SW			(1 << 0)
74
75#define AD7280A_CTRL_LB_SWRST				(1 << 7)
76#define AD7280A_CTRL_LB_ACQ_TIME_400ns			(0 << 5)
77#define AD7280A_CTRL_LB_ACQ_TIME_800ns			(1 << 5)
78#define AD7280A_CTRL_LB_ACQ_TIME_1200ns			(2 << 5)
79#define AD7280A_CTRL_LB_ACQ_TIME_1600ns			(3 << 5)
80#define AD7280A_CTRL_LB_ACQ_TIME(x)			((x) << 5)
81#define AD7280A_CTRL_LB_MUST_SET			(1 << 4)
82#define AD7280A_CTRL_LB_THERMISTOR_EN			(1 << 3)
83#define AD7280A_CTRL_LB_LOCK_DEV_ADDR			(1 << 2)
84#define AD7280A_CTRL_LB_INC_DEV_ADDR			(1 << 1)
85#define AD7280A_CTRL_LB_DAISY_CHAIN_RB_EN		(1 << 0)
86
87#define AD7280A_ALERT_GEN_STATIC_HIGH			(1 << 6)
88#define AD7280A_ALERT_RELAY_SIG_CHAIN_DOWN		(3 << 6)
89
90#define AD7280A_ALL_CELLS				(0xAD << 16)
91
92#define AD7280A_MAX_SPI_CLK_Hz		700000 /* < 1MHz */
93#define AD7280A_MAX_CHAIN		8
94#define AD7280A_CELLS_PER_DEV		6
95#define AD7280A_BITS			12
96#define AD7280A_NUM_CH			(AD7280A_AUX_ADC_6 - \
97					AD7280A_CELL_VOLTAGE_1 + 1)
98
99#define AD7280A_DEVADDR_MASTER		0
100#define AD7280A_DEVADDR_ALL		0x1F
101/* 5-bit device address is sent LSB first */
102#define AD7280A_DEVADDR(addr)	(((addr & 0x1) << 4) | ((addr & 0x2) << 3) | \
103				(addr & 0x4) | ((addr & 0x8) >> 3) | \
104				((addr & 0x10) >> 4))
105
106/* During a read a valid write is mandatory.
107 * So writing to the highest available address (Address 0x1F)
108 * and setting the address all parts bit to 0 is recommended
109 * So the TXVAL is AD7280A_DEVADDR_ALL + CRC
110 */
111#define AD7280A_READ_TXVAL	0xF800030A
112
113/*
114 * AD7280 CRC
115 *
116 * P(x) = x^8 + x^5 + x^3 + x^2 + x^1 + x^0 = 0b100101111 => 0x2F
117 */
118#define POLYNOM		0x2F
119#define POLYNOM_ORDER	8
120#define HIGHBIT		(1 << (POLYNOM_ORDER - 1))
121
122struct ad7280_state {
123	struct spi_device		*spi;
124	struct iio_chan_spec		*channels;
125	struct iio_dev_attr		*iio_attr;
126	int				slave_num;
127	int				scan_cnt;
128	int				readback_delay_us;
129	unsigned char			crc_tab[256];
130	unsigned char			ctrl_hb;
131	unsigned char			ctrl_lb;
132	unsigned char			cell_threshhigh;
133	unsigned char			cell_threshlow;
134	unsigned char			aux_threshhigh;
135	unsigned char			aux_threshlow;
136	unsigned char			cb_mask[AD7280A_MAX_CHAIN];
137
138	__be32				buf[2] ____cacheline_aligned;
139};
140
141static void ad7280_crc8_build_table(unsigned char *crc_tab)
142{
143	unsigned char bit, crc;
144	int cnt, i;
145
146	for (cnt = 0; cnt < 256; cnt++) {
147		crc = cnt;
148		for (i = 0; i < 8; i++) {
149			bit = crc & HIGHBIT;
150			crc <<= 1;
151			if (bit)
152				crc ^= POLYNOM;
153		}
154		crc_tab[cnt] = crc;
155	}
156}
157
158static unsigned char ad7280_calc_crc8(unsigned char *crc_tab, unsigned val)
159{
160	unsigned char crc;
161
162	crc = crc_tab[val >> 16 & 0xFF];
163	crc = crc_tab[crc ^ (val >> 8 & 0xFF)];
164
165	return  crc ^ (val & 0xFF);
166}
167
168static int ad7280_check_crc(struct ad7280_state *st, unsigned val)
169{
170	unsigned char crc = ad7280_calc_crc8(st->crc_tab, val >> 10);
171
172	if (crc != ((val >> 2) & 0xFF))
173		return -EIO;
174
175	return 0;
176}
177
178/* After initiating a conversion sequence we need to wait until the
179 * conversion is done. The delay is typically in the range of 15..30 us
180 * however depending an the number of devices in the daisy chain and the
181 * number of averages taken, conversion delays and acquisition time options
182 * it may take up to 250us, in this case we better sleep instead of busy
183 * wait.
184 */
185
186static void ad7280_delay(struct ad7280_state *st)
187{
188	if (st->readback_delay_us < 50)
189		udelay(st->readback_delay_us);
190	else
191		msleep(1);
192}
193
194static int __ad7280_read32(struct ad7280_state *st, unsigned *val)
195{
196	int ret;
197	struct spi_transfer t = {
198		.tx_buf	= &st->buf[0],
199		.rx_buf = &st->buf[1],
200		.len = 4,
201	};
202
203	st->buf[0] = cpu_to_be32(AD7280A_READ_TXVAL);
204
205	ret = spi_sync_transfer(st->spi, &t, 1);
206	if (ret)
207		return ret;
208
209	*val = be32_to_cpu(st->buf[1]);
210
211	return 0;
212}
213
214static int ad7280_write(struct ad7280_state *st, unsigned devaddr,
215			unsigned addr, bool all, unsigned val)
216{
217	unsigned reg = (devaddr << 27 | addr << 21 |
218			(val & 0xFF) << 13 | all << 12);
219
220	reg |= ad7280_calc_crc8(st->crc_tab, reg >> 11) << 3 | 0x2;
221	st->buf[0] = cpu_to_be32(reg);
222
223	return spi_write(st->spi, &st->buf[0], 4);
224}
225
226static int ad7280_read(struct ad7280_state *st, unsigned devaddr,
227			unsigned addr)
228{
229	int ret;
230	unsigned tmp;
231
232	/* turns off the read operation on all parts */
233	ret = ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CONTROL_HB, 1,
234			AD7280A_CTRL_HB_CONV_INPUT_ALL |
235			AD7280A_CTRL_HB_CONV_RES_READ_NO |
236			st->ctrl_hb);
237	if (ret)
238		return ret;
239
240	/* turns on the read operation on the addressed part */
241	ret = ad7280_write(st, devaddr, AD7280A_CONTROL_HB, 0,
242			AD7280A_CTRL_HB_CONV_INPUT_ALL |
243			AD7280A_CTRL_HB_CONV_RES_READ_ALL |
244			st->ctrl_hb);
245	if (ret)
246		return ret;
247
248	/* Set register address on the part to be read from */
249	ret = ad7280_write(st, devaddr, AD7280A_READ, 0, addr << 2);
250	if (ret)
251		return ret;
252
253	__ad7280_read32(st, &tmp);
254
255	if (ad7280_check_crc(st, tmp))
256		return -EIO;
257
258	if (((tmp >> 27) != devaddr) || (((tmp >> 21) & 0x3F) != addr))
259		return -EFAULT;
260
261	return (tmp >> 13) & 0xFF;
262}
263
264static int ad7280_read_channel(struct ad7280_state *st, unsigned devaddr,
265			       unsigned addr)
266{
267	int ret;
268	unsigned tmp;
269
270	ret = ad7280_write(st, devaddr, AD7280A_READ, 0, addr << 2);
271	if (ret)
272		return ret;
273
274	ret = ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CONTROL_HB, 1,
275			AD7280A_CTRL_HB_CONV_INPUT_ALL |
276			AD7280A_CTRL_HB_CONV_RES_READ_NO |
277			st->ctrl_hb);
278	if (ret)
279		return ret;
280
281	ret = ad7280_write(st, devaddr, AD7280A_CONTROL_HB, 0,
282			AD7280A_CTRL_HB_CONV_INPUT_ALL |
283			AD7280A_CTRL_HB_CONV_RES_READ_ALL |
284			AD7280A_CTRL_HB_CONV_START_CS |
285			st->ctrl_hb);
286	if (ret)
287		return ret;
288
289	ad7280_delay(st);
290
291	__ad7280_read32(st, &tmp);
292
293	if (ad7280_check_crc(st, tmp))
294		return -EIO;
295
296	if (((tmp >> 27) != devaddr) || (((tmp >> 23) & 0xF) != addr))
297		return -EFAULT;
298
299	return (tmp >> 11) & 0xFFF;
300}
301
302static int ad7280_read_all_channels(struct ad7280_state *st, unsigned cnt,
303			     unsigned *array)
304{
305	int i, ret;
306	unsigned tmp, sum = 0;
307
308	ret = ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_READ, 1,
309			   AD7280A_CELL_VOLTAGE_1 << 2);
310	if (ret)
311		return ret;
312
313	ret = ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CONTROL_HB, 1,
314			AD7280A_CTRL_HB_CONV_INPUT_ALL |
315			AD7280A_CTRL_HB_CONV_RES_READ_ALL |
316			AD7280A_CTRL_HB_CONV_START_CS |
317			st->ctrl_hb);
318	if (ret)
319		return ret;
320
321	ad7280_delay(st);
322
323	for (i = 0; i < cnt; i++) {
324		__ad7280_read32(st, &tmp);
325
326		if (ad7280_check_crc(st, tmp))
327			return -EIO;
328
329		if (array)
330			array[i] = tmp;
331		/* only sum cell voltages */
332		if (((tmp >> 23) & 0xF) <= AD7280A_CELL_VOLTAGE_6)
333			sum += ((tmp >> 11) & 0xFFF);
334	}
335
336	return sum;
337}
338
339static int ad7280_chain_setup(struct ad7280_state *st)
340{
341	unsigned val, n;
342	int ret;
343
344	ret = ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CONTROL_LB, 1,
345			AD7280A_CTRL_LB_DAISY_CHAIN_RB_EN |
346			AD7280A_CTRL_LB_LOCK_DEV_ADDR |
347			AD7280A_CTRL_LB_MUST_SET |
348			AD7280A_CTRL_LB_SWRST |
349			st->ctrl_lb);
350	if (ret)
351		return ret;
352
353	ret = ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CONTROL_LB, 1,
354			AD7280A_CTRL_LB_DAISY_CHAIN_RB_EN |
355			AD7280A_CTRL_LB_LOCK_DEV_ADDR |
356			AD7280A_CTRL_LB_MUST_SET |
357			st->ctrl_lb);
358	if (ret)
359		return ret;
360
361	ret = ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_READ, 1,
362			AD7280A_CONTROL_LB << 2);
363	if (ret)
364		return ret;
365
366	for (n = 0; n <= AD7280A_MAX_CHAIN; n++) {
367		__ad7280_read32(st, &val);
368		if (val == 0)
369			return n - 1;
370
371		if (ad7280_check_crc(st, val))
372			return -EIO;
373
374		if (n != AD7280A_DEVADDR(val >> 27))
375			return -EIO;
376	}
377
378	return -EFAULT;
379}
380
381static ssize_t ad7280_show_balance_sw(struct device *dev,
382					struct device_attribute *attr,
383					char *buf)
384{
385	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
386	struct ad7280_state *st = iio_priv(indio_dev);
387	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
388
389	return sprintf(buf, "%d\n",
390		       !!(st->cb_mask[this_attr->address >> 8] &
391		       (1 << ((this_attr->address & 0xFF) + 2))));
392}
393
394static ssize_t ad7280_store_balance_sw(struct device *dev,
395					 struct device_attribute *attr,
396					 const char *buf,
397					 size_t len)
398{
399	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
400	struct ad7280_state *st = iio_priv(indio_dev);
401	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
402	bool readin;
403	int ret;
404	unsigned devaddr, ch;
405
406	ret = strtobool(buf, &readin);
407	if (ret)
408		return ret;
409
410	devaddr = this_attr->address >> 8;
411	ch = this_attr->address & 0xFF;
412
413	mutex_lock(&indio_dev->mlock);
414	if (readin)
415		st->cb_mask[devaddr] |= 1 << (ch + 2);
416	else
417		st->cb_mask[devaddr] &= ~(1 << (ch + 2));
418
419	ret = ad7280_write(st, devaddr, AD7280A_CELL_BALANCE,
420			   0, st->cb_mask[devaddr]);
421	mutex_unlock(&indio_dev->mlock);
422
423	return ret ? ret : len;
424}
425
426static ssize_t ad7280_show_balance_timer(struct device *dev,
427					struct device_attribute *attr,
428					char *buf)
429{
430	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
431	struct ad7280_state *st = iio_priv(indio_dev);
432	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
433	int ret;
434	unsigned msecs;
435
436	mutex_lock(&indio_dev->mlock);
437	ret = ad7280_read(st, this_attr->address >> 8,
438			this_attr->address & 0xFF);
439	mutex_unlock(&indio_dev->mlock);
440
441	if (ret < 0)
442		return ret;
443
444	msecs = (ret >> 3) * 71500;
445
446	return sprintf(buf, "%u\n", msecs);
447}
448
449static ssize_t ad7280_store_balance_timer(struct device *dev,
450					 struct device_attribute *attr,
451					 const char *buf,
452					 size_t len)
453{
454	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
455	struct ad7280_state *st = iio_priv(indio_dev);
456	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
457	unsigned long val;
458	int ret;
459
460	ret = kstrtoul(buf, 10, &val);
461	if (ret)
462		return ret;
463
464	val /= 71500;
465
466	if (val > 31)
467		return -EINVAL;
468
469	mutex_lock(&indio_dev->mlock);
470	ret = ad7280_write(st, this_attr->address >> 8,
471			   this_attr->address & 0xFF,
472			   0, (val & 0x1F) << 3);
473	mutex_unlock(&indio_dev->mlock);
474
475	return ret ? ret : len;
476}
477
478static struct attribute *ad7280_attributes[AD7280A_MAX_CHAIN *
479					   AD7280A_CELLS_PER_DEV * 2 + 1];
480
481static struct attribute_group ad7280_attrs_group = {
482	.attrs = ad7280_attributes,
483};
484
485static int ad7280_channel_init(struct ad7280_state *st)
486{
487	int dev, ch, cnt;
488
489	st->channels = kcalloc((st->slave_num + 1) * 12 + 2,
490			       sizeof(*st->channels), GFP_KERNEL);
491	if (st->channels == NULL)
492		return -ENOMEM;
493
494	for (dev = 0, cnt = 0; dev <= st->slave_num; dev++)
495		for (ch = AD7280A_CELL_VOLTAGE_1; ch <= AD7280A_AUX_ADC_6; ch++,
496			cnt++) {
497			if (ch < AD7280A_AUX_ADC_1) {
498				st->channels[cnt].type = IIO_VOLTAGE;
499				st->channels[cnt].differential = 1;
500				st->channels[cnt].channel = (dev * 6) + ch;
501				st->channels[cnt].channel2 =
502					st->channels[cnt].channel + 1;
503			} else {
504				st->channels[cnt].type = IIO_TEMP;
505				st->channels[cnt].channel = (dev * 6) + ch - 6;
506			}
507			st->channels[cnt].indexed = 1;
508			st->channels[cnt].info_mask_separate =
509				BIT(IIO_CHAN_INFO_RAW);
510			st->channels[cnt].info_mask_shared_by_type =
511				BIT(IIO_CHAN_INFO_SCALE);
512			st->channels[cnt].address =
513				AD7280A_DEVADDR(dev) << 8 | ch;
514			st->channels[cnt].scan_index = cnt;
515			st->channels[cnt].scan_type.sign = 'u';
516			st->channels[cnt].scan_type.realbits = 12;
517			st->channels[cnt].scan_type.storagebits = 32;
518			st->channels[cnt].scan_type.shift = 0;
519		}
520
521	st->channels[cnt].type = IIO_VOLTAGE;
522	st->channels[cnt].differential = 1;
523	st->channels[cnt].channel = 0;
524	st->channels[cnt].channel2 = dev * 6;
525	st->channels[cnt].address = AD7280A_ALL_CELLS;
526	st->channels[cnt].indexed = 1;
527	st->channels[cnt].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
528	st->channels[cnt].info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
529	st->channels[cnt].scan_index = cnt;
530	st->channels[cnt].scan_type.sign = 'u';
531	st->channels[cnt].scan_type.realbits = 32;
532	st->channels[cnt].scan_type.storagebits = 32;
533	st->channels[cnt].scan_type.shift = 0;
534	cnt++;
535	st->channels[cnt].type = IIO_TIMESTAMP;
536	st->channels[cnt].channel = -1;
537	st->channels[cnt].scan_index = cnt;
538	st->channels[cnt].scan_type.sign = 's';
539	st->channels[cnt].scan_type.realbits = 64;
540	st->channels[cnt].scan_type.storagebits = 64;
541	st->channels[cnt].scan_type.shift = 0;
542
543	return cnt + 1;
544}
545
546static int ad7280_attr_init(struct ad7280_state *st)
547{
548	int dev, ch, cnt;
549
550	st->iio_attr = kzalloc(sizeof(*st->iio_attr) * (st->slave_num + 1) *
551				AD7280A_CELLS_PER_DEV * 2, GFP_KERNEL);
552	if (st->iio_attr == NULL)
553		return -ENOMEM;
554
555	for (dev = 0, cnt = 0; dev <= st->slave_num; dev++)
556		for (ch = AD7280A_CELL_VOLTAGE_1; ch <= AD7280A_CELL_VOLTAGE_6;
557			ch++, cnt++) {
558			st->iio_attr[cnt].address =
559				AD7280A_DEVADDR(dev) << 8 | ch;
560			st->iio_attr[cnt].dev_attr.attr.mode =
561				S_IWUSR | S_IRUGO;
562			st->iio_attr[cnt].dev_attr.show =
563				ad7280_show_balance_sw;
564			st->iio_attr[cnt].dev_attr.store =
565				ad7280_store_balance_sw;
566			st->iio_attr[cnt].dev_attr.attr.name =
567				kasprintf(GFP_KERNEL,
568					"in%d-in%d_balance_switch_en",
569					(dev * AD7280A_CELLS_PER_DEV) + ch,
570					(dev * AD7280A_CELLS_PER_DEV) + ch + 1);
571			ad7280_attributes[cnt] =
572				&st->iio_attr[cnt].dev_attr.attr;
573			cnt++;
574			st->iio_attr[cnt].address =
575				AD7280A_DEVADDR(dev) << 8 |
576				(AD7280A_CB1_TIMER + ch);
577			st->iio_attr[cnt].dev_attr.attr.mode =
578				S_IWUSR | S_IRUGO;
579			st->iio_attr[cnt].dev_attr.show =
580				ad7280_show_balance_timer;
581			st->iio_attr[cnt].dev_attr.store =
582				ad7280_store_balance_timer;
583			st->iio_attr[cnt].dev_attr.attr.name =
584				kasprintf(GFP_KERNEL, "in%d-in%d_balance_timer",
585					(dev * AD7280A_CELLS_PER_DEV) + ch,
586					(dev * AD7280A_CELLS_PER_DEV) + ch + 1);
587			ad7280_attributes[cnt] =
588				&st->iio_attr[cnt].dev_attr.attr;
589		}
590
591	ad7280_attributes[cnt] = NULL;
592
593	return 0;
594}
595
596static ssize_t ad7280_read_channel_config(struct device *dev,
597					struct device_attribute *attr,
598					char *buf)
599{
600	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
601	struct ad7280_state *st = iio_priv(indio_dev);
602	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
603	unsigned val;
604
605	switch ((u32) this_attr->address) {
606	case AD7280A_CELL_OVERVOLTAGE:
607		val = 1000 + (st->cell_threshhigh * 1568) / 100;
608		break;
609	case AD7280A_CELL_UNDERVOLTAGE:
610		val = 1000 + (st->cell_threshlow * 1568) / 100;
611		break;
612	case AD7280A_AUX_ADC_OVERVOLTAGE:
613		val = (st->aux_threshhigh * 196) / 10;
614		break;
615	case AD7280A_AUX_ADC_UNDERVOLTAGE:
616		val = (st->aux_threshlow * 196) / 10;
617		break;
618	default:
619		return -EINVAL;
620	}
621
622	return sprintf(buf, "%u\n", val);
623}
624
625static ssize_t ad7280_write_channel_config(struct device *dev,
626					 struct device_attribute *attr,
627					 const char *buf,
628					 size_t len)
629{
630	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
631	struct ad7280_state *st = iio_priv(indio_dev);
632	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
633
634	long val;
635	int ret;
636
637	ret = kstrtol(buf, 10, &val);
638	if (ret)
639		return ret;
640
641	switch ((u32) this_attr->address) {
642	case AD7280A_CELL_OVERVOLTAGE:
643	case AD7280A_CELL_UNDERVOLTAGE:
644		val = ((val - 1000) * 100) / 1568; /* LSB 15.68mV */
645		break;
646	case AD7280A_AUX_ADC_OVERVOLTAGE:
647	case AD7280A_AUX_ADC_UNDERVOLTAGE:
648		val = (val * 10) / 196; /* LSB 19.6mV */
649		break;
650	default:
651		return -EFAULT;
652	}
653
654	val = clamp(val, 0L, 0xFFL);
655
656	mutex_lock(&indio_dev->mlock);
657	switch ((u32) this_attr->address) {
658	case AD7280A_CELL_OVERVOLTAGE:
659		st->cell_threshhigh = val;
660		break;
661	case AD7280A_CELL_UNDERVOLTAGE:
662		st->cell_threshlow = val;
663		break;
664	case AD7280A_AUX_ADC_OVERVOLTAGE:
665		st->aux_threshhigh = val;
666		break;
667	case AD7280A_AUX_ADC_UNDERVOLTAGE:
668		st->aux_threshlow = val;
669		break;
670	}
671
672	ret = ad7280_write(st, AD7280A_DEVADDR_MASTER,
673			   this_attr->address, 1, val);
674
675	mutex_unlock(&indio_dev->mlock);
676
677	return ret ? ret : len;
678}
679
680static irqreturn_t ad7280_event_handler(int irq, void *private)
681{
682	struct iio_dev *indio_dev = private;
683	struct ad7280_state *st = iio_priv(indio_dev);
684	unsigned *channels;
685	int i, ret;
686
687	channels = kcalloc(st->scan_cnt, sizeof(*channels), GFP_KERNEL);
688	if (channels == NULL)
689		return IRQ_HANDLED;
690
691	ret = ad7280_read_all_channels(st, st->scan_cnt, channels);
692	if (ret < 0)
693		goto out;
694
695	for (i = 0; i < st->scan_cnt; i++) {
696		if (((channels[i] >> 23) & 0xF) <= AD7280A_CELL_VOLTAGE_6) {
697			if (((channels[i] >> 11) & 0xFFF) >=
698				st->cell_threshhigh)
699				iio_push_event(indio_dev,
700					IIO_EVENT_CODE(IIO_VOLTAGE,
701						       1,
702						       0,
703						       IIO_EV_DIR_RISING,
704						       IIO_EV_TYPE_THRESH,
705						       0, 0, 0),
706					iio_get_time_ns());
707			else if (((channels[i] >> 11) & 0xFFF) <=
708				st->cell_threshlow)
709				iio_push_event(indio_dev,
710					IIO_EVENT_CODE(IIO_VOLTAGE,
711						       1,
712						       0,
713						       IIO_EV_DIR_FALLING,
714						       IIO_EV_TYPE_THRESH,
715						       0, 0, 0),
716					iio_get_time_ns());
717		} else {
718			if (((channels[i] >> 11) & 0xFFF) >= st->aux_threshhigh)
719				iio_push_event(indio_dev,
720					IIO_UNMOD_EVENT_CODE(IIO_TEMP,
721					0,
722					IIO_EV_TYPE_THRESH,
723					IIO_EV_DIR_RISING),
724					iio_get_time_ns());
725			else if (((channels[i] >> 11) & 0xFFF) <=
726				st->aux_threshlow)
727				iio_push_event(indio_dev,
728					IIO_UNMOD_EVENT_CODE(IIO_TEMP,
729					0,
730					IIO_EV_TYPE_THRESH,
731					IIO_EV_DIR_FALLING),
732					iio_get_time_ns());
733		}
734	}
735
736out:
737	kfree(channels);
738
739	return IRQ_HANDLED;
740}
741
742static IIO_DEVICE_ATTR_NAMED(in_thresh_low_value,
743		in_voltage-voltage_thresh_low_value,
744		S_IRUGO | S_IWUSR,
745		ad7280_read_channel_config,
746		ad7280_write_channel_config,
747		AD7280A_CELL_UNDERVOLTAGE);
748
749static IIO_DEVICE_ATTR_NAMED(in_thresh_high_value,
750		in_voltage-voltage_thresh_high_value,
751		S_IRUGO | S_IWUSR,
752		ad7280_read_channel_config,
753		ad7280_write_channel_config,
754		AD7280A_CELL_OVERVOLTAGE);
755
756static IIO_DEVICE_ATTR(in_temp_thresh_low_value,
757		S_IRUGO | S_IWUSR,
758		ad7280_read_channel_config,
759		ad7280_write_channel_config,
760		AD7280A_AUX_ADC_UNDERVOLTAGE);
761
762static IIO_DEVICE_ATTR(in_temp_thresh_high_value,
763		S_IRUGO | S_IWUSR,
764		ad7280_read_channel_config,
765		ad7280_write_channel_config,
766		AD7280A_AUX_ADC_OVERVOLTAGE);
767
768
769static struct attribute *ad7280_event_attributes[] = {
770	&iio_dev_attr_in_thresh_low_value.dev_attr.attr,
771	&iio_dev_attr_in_thresh_high_value.dev_attr.attr,
772	&iio_dev_attr_in_temp_thresh_low_value.dev_attr.attr,
773	&iio_dev_attr_in_temp_thresh_high_value.dev_attr.attr,
774	NULL,
775};
776
777static struct attribute_group ad7280_event_attrs_group = {
778	.attrs = ad7280_event_attributes,
779};
780
781static int ad7280_read_raw(struct iio_dev *indio_dev,
782			   struct iio_chan_spec const *chan,
783			   int *val,
784			   int *val2,
785			   long m)
786{
787	struct ad7280_state *st = iio_priv(indio_dev);
788	int ret;
789
790	switch (m) {
791	case IIO_CHAN_INFO_RAW:
792		mutex_lock(&indio_dev->mlock);
793		if (chan->address == AD7280A_ALL_CELLS)
794			ret = ad7280_read_all_channels(st, st->scan_cnt, NULL);
795		else
796			ret = ad7280_read_channel(st, chan->address >> 8,
797						  chan->address & 0xFF);
798		mutex_unlock(&indio_dev->mlock);
799
800		if (ret < 0)
801			return ret;
802
803		*val = ret;
804
805		return IIO_VAL_INT;
806	case IIO_CHAN_INFO_SCALE:
807		if ((chan->address & 0xFF) <= AD7280A_CELL_VOLTAGE_6)
808			*val = 4000;
809		else
810			*val = 5000;
811
812		*val2 = AD7280A_BITS;
813		return IIO_VAL_FRACTIONAL_LOG2;
814	}
815	return -EINVAL;
816}
817
818static const struct iio_info ad7280_info = {
819	.read_raw = &ad7280_read_raw,
820	.event_attrs = &ad7280_event_attrs_group,
821	.attrs = &ad7280_attrs_group,
822	.driver_module = THIS_MODULE,
823};
824
825static const struct ad7280_platform_data ad7793_default_pdata = {
826	.acquisition_time = AD7280A_ACQ_TIME_400ns,
827	.conversion_averaging = AD7280A_CONV_AVG_DIS,
828	.thermistor_term_en = true,
829};
830
831static int ad7280_probe(struct spi_device *spi)
832{
833	const struct ad7280_platform_data *pdata = spi->dev.platform_data;
834	struct ad7280_state *st;
835	int ret;
836	const unsigned short tACQ_ns[4] = {465, 1010, 1460, 1890};
837	const unsigned short nAVG[4] = {1, 2, 4, 8};
838	struct iio_dev *indio_dev;
839
840	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
841	if (indio_dev == NULL)
842		return -ENOMEM;
843
844	st = iio_priv(indio_dev);
845	spi_set_drvdata(spi, indio_dev);
846	st->spi = spi;
847
848	if (!pdata)
849		pdata = &ad7793_default_pdata;
850
851	ad7280_crc8_build_table(st->crc_tab);
852
853	st->spi->max_speed_hz = AD7280A_MAX_SPI_CLK_Hz;
854	st->spi->mode = SPI_MODE_1;
855	spi_setup(st->spi);
856
857	st->ctrl_lb = AD7280A_CTRL_LB_ACQ_TIME(pdata->acquisition_time & 0x3);
858	st->ctrl_hb = AD7280A_CTRL_HB_CONV_AVG(pdata->conversion_averaging
859			& 0x3) | (pdata->thermistor_term_en ?
860			AD7280A_CTRL_LB_THERMISTOR_EN : 0);
861
862	ret = ad7280_chain_setup(st);
863	if (ret < 0)
864		return ret;
865
866	st->slave_num = ret;
867	st->scan_cnt = (st->slave_num + 1) * AD7280A_NUM_CH;
868	st->cell_threshhigh = 0xFF;
869	st->aux_threshhigh = 0xFF;
870
871	/*
872	 * Total Conversion Time = ((tACQ + tCONV) *
873	 *			   (Number of Conversions per Part)) −
874	 *			   tACQ + ((N - 1) * tDELAY)
875	 *
876	 * Readback Delay = Total Conversion Time + tWAIT
877	 */
878
879	st->readback_delay_us =
880		((tACQ_ns[pdata->acquisition_time & 0x3] + 695) *
881		(AD7280A_NUM_CH * nAVG[pdata->conversion_averaging & 0x3]))
882		- tACQ_ns[pdata->acquisition_time & 0x3] +
883		st->slave_num * 250;
884
885	/* Convert to usecs */
886	st->readback_delay_us = DIV_ROUND_UP(st->readback_delay_us, 1000);
887	st->readback_delay_us += 5; /* Add tWAIT */
888
889	indio_dev->name = spi_get_device_id(spi)->name;
890	indio_dev->dev.parent = &spi->dev;
891	indio_dev->modes = INDIO_DIRECT_MODE;
892
893	ret = ad7280_channel_init(st);
894	if (ret < 0)
895		return ret;
896
897	indio_dev->num_channels = ret;
898	indio_dev->channels = st->channels;
899	indio_dev->info = &ad7280_info;
900
901	ret = ad7280_attr_init(st);
902	if (ret < 0)
903		goto error_free_channels;
904
905	ret = iio_device_register(indio_dev);
906	if (ret)
907		goto error_free_attr;
908
909	if (spi->irq > 0) {
910		ret = ad7280_write(st, AD7280A_DEVADDR_MASTER,
911				   AD7280A_ALERT, 1,
912				   AD7280A_ALERT_RELAY_SIG_CHAIN_DOWN);
913		if (ret)
914			goto error_unregister;
915
916		ret = ad7280_write(st, AD7280A_DEVADDR(st->slave_num),
917				   AD7280A_ALERT, 0,
918				   AD7280A_ALERT_GEN_STATIC_HIGH |
919				   (pdata->chain_last_alert_ignore & 0xF));
920		if (ret)
921			goto error_unregister;
922
923		ret = request_threaded_irq(spi->irq,
924					   NULL,
925					   ad7280_event_handler,
926					   IRQF_TRIGGER_FALLING |
927					   IRQF_ONESHOT,
928					   indio_dev->name,
929					   indio_dev);
930		if (ret)
931			goto error_unregister;
932	}
933
934	return 0;
935error_unregister:
936	iio_device_unregister(indio_dev);
937
938error_free_attr:
939	kfree(st->iio_attr);
940
941error_free_channels:
942	kfree(st->channels);
943
944	return ret;
945}
946
947static int ad7280_remove(struct spi_device *spi)
948{
949	struct iio_dev *indio_dev = spi_get_drvdata(spi);
950	struct ad7280_state *st = iio_priv(indio_dev);
951
952	if (spi->irq > 0)
953		free_irq(spi->irq, indio_dev);
954	iio_device_unregister(indio_dev);
955
956	ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CONTROL_HB, 1,
957			AD7280A_CTRL_HB_PWRDN_SW | st->ctrl_hb);
958
959	kfree(st->channels);
960	kfree(st->iio_attr);
961
962	return 0;
963}
964
965static const struct spi_device_id ad7280_id[] = {
966	{"ad7280a", 0},
967	{}
968};
969MODULE_DEVICE_TABLE(spi, ad7280_id);
970
971static struct spi_driver ad7280_driver = {
972	.driver = {
973		.name	= "ad7280",
974		.owner	= THIS_MODULE,
975	},
976	.probe		= ad7280_probe,
977	.remove		= ad7280_remove,
978	.id_table	= ad7280_id,
979};
980module_spi_driver(ad7280_driver);
981
982MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
983MODULE_DESCRIPTION("Analog Devices AD7280A");
984MODULE_LICENSE("GPL v2");
985