Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
/*
 *
 * TWL4030 MADC module driver-This driver monitors the real time
 * conversion of analog signals like battery temperature,
 * battery type, battery level etc.
 *
 * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
 * J Keerthy <j-keerthy@ti.com>
 *
 * Based on twl4030-madc.c
 * Copyright (C) 2008 Nokia Corporation
 * Mikko Ylinen <mikko.k.ylinen@nokia.com>
 *
 * Amit Kucheria <amit.kucheria@canonical.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/init.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/i2c/twl.h>
#include <linux/i2c/twl4030-madc.h>
#include <linux/module.h>
#include <linux/stddef.h>
#include <linux/mutex.h>
#include <linux/bitops.h>
#include <linux/jiffies.h>
#include <linux/types.h>
#include <linux/gfp.h>
#include <linux/err.h>

/*
 * struct twl4030_madc_data - a container for madc info
 * @dev - pointer to device structure for madc
 * @lock - mutex protecting this data structure
 * @requests - Array of request struct corresponding to SW1, SW2 and RT
 * @imr - Interrupt mask register of MADC
 * @isr - Interrupt status register of MADC
 */
struct twl4030_madc_data {
	struct device *dev;
	struct mutex lock;	/* mutex protecting this data structure */
	struct twl4030_madc_request requests[TWL4030_MADC_NUM_METHODS];
	int imr;
	int isr;
};

static struct twl4030_madc_data *twl4030_madc;

struct twl4030_prescale_divider_ratios {
	s16 numerator;
	s16 denominator;
};

static const struct twl4030_prescale_divider_ratios
twl4030_divider_ratios[16] = {
	{1, 1},		/* CHANNEL 0 No Prescaler */
	{1, 1},		/* CHANNEL 1 No Prescaler */
	{6, 10},	/* CHANNEL 2 */
	{6, 10},	/* CHANNEL 3 */
	{6, 10},	/* CHANNEL 4 */
	{6, 10},	/* CHANNEL 5 */
	{6, 10},	/* CHANNEL 6 */
	{6, 10},	/* CHANNEL 7 */
	{3, 14},	/* CHANNEL 8 */
	{1, 3},		/* CHANNEL 9 */
	{1, 1},		/* CHANNEL 10 No Prescaler */
	{15, 100},	/* CHANNEL 11 */
	{1, 4},		/* CHANNEL 12 */
	{1, 1},		/* CHANNEL 13 Reserved channels */
	{1, 1},		/* CHANNEL 14 Reseved channels */
	{5, 11},	/* CHANNEL 15 */
};


/*
 * Conversion table from -3 to 55 degree Celcius
 */
static int therm_tbl[] = {
30800,	29500,	28300,	27100,
26000,	24900,	23900,	22900,	22000,	21100,	20300,	19400,	18700,	17900,
17200,	16500,	15900,	15300,	14700,	14100,	13600,	13100,	12600,	12100,
11600,	11200,	10800,	10400,	10000,	9630,	9280,	8950,	8620,	8310,
8020,	7730,	7460,	7200,	6950,	6710,	6470,	6250,	6040,	5830,
5640,	5450,	5260,	5090,	4920,	4760,	4600,	4450,	4310,	4170,
4040,	3910,	3790,	3670,	3550
};

/*
 * Structure containing the registers
 * of different conversion methods supported by MADC.
 * Hardware or RT real time conversion request initiated by external host
 * processor for RT Signal conversions.
 * External host processors can also request for non RT conversions
 * SW1 and SW2 software conversions also called asynchronous or GPC request.
 */
static
const struct twl4030_madc_conversion_method twl4030_conversion_methods[] = {
	[TWL4030_MADC_RT] = {
			     .sel = TWL4030_MADC_RTSELECT_LSB,
			     .avg = TWL4030_MADC_RTAVERAGE_LSB,
			     .rbase = TWL4030_MADC_RTCH0_LSB,
			     },
	[TWL4030_MADC_SW1] = {
			      .sel = TWL4030_MADC_SW1SELECT_LSB,
			      .avg = TWL4030_MADC_SW1AVERAGE_LSB,
			      .rbase = TWL4030_MADC_GPCH0_LSB,
			      .ctrl = TWL4030_MADC_CTRL_SW1,
			      },
	[TWL4030_MADC_SW2] = {
			      .sel = TWL4030_MADC_SW2SELECT_LSB,
			      .avg = TWL4030_MADC_SW2AVERAGE_LSB,
			      .rbase = TWL4030_MADC_GPCH0_LSB,
			      .ctrl = TWL4030_MADC_CTRL_SW2,
			      },
};

/*
 * Function to read a particular channel value.
 * @madc - pointer to struct twl4030_madc_data
 * @reg - lsb of ADC Channel
 * If the i2c read fails it returns an error else returns 0.
 */
static int twl4030_madc_channel_raw_read(struct twl4030_madc_data *madc, u8 reg)
{
	u8 msb, lsb;
	int ret;
	/*
	 * For each ADC channel, we have MSB and LSB register pair. MSB address
	 * is always LSB address+1. reg parameter is the address of LSB register
	 */
	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &msb, reg + 1);
	if (ret) {
		dev_err(madc->dev, "unable to read MSB register 0x%X\n",
			reg + 1);
		return ret;
	}
	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &lsb, reg);
	if (ret) {
		dev_err(madc->dev, "unable to read LSB register 0x%X\n", reg);
		return ret;
	}

	return (int)(((msb << 8) | lsb) >> 6);
}

/*
 * Return battery temperature
 * Or < 0 on failure.
 */
static int twl4030battery_temperature(int raw_volt)
{
	u8 val;
	int temp, curr, volt, res, ret;

	volt = (raw_volt * TEMP_STEP_SIZE) / TEMP_PSR_R;
	/* Getting and calculating the supply current in micro ampers */
	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &val,
		REG_BCICTL2);
	if (ret < 0)
		return ret;
	curr = ((val & TWL4030_BCI_ITHEN) + 1) * 10;
	/* Getting and calculating the thermistor resistance in ohms */
	res = volt * 1000 / curr;
	/* calculating temperature */
	for (temp = 58; temp >= 0; temp--) {
		int actual = therm_tbl[temp];

		if ((actual - res) >= 0)
			break;
	}

	return temp + 1;
}

static int twl4030battery_current(int raw_volt)
{
	int ret;
	u8 val;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE, &val,
		TWL4030_BCI_BCICTL1);
	if (ret)
		return ret;
	if (val & TWL4030_BCI_CGAIN) /* slope of 0.44 mV/mA */
		return (raw_volt * CURR_STEP_SIZE) / CURR_PSR_R1;
	else /* slope of 0.88 mV/mA */
		return (raw_volt * CURR_STEP_SIZE) / CURR_PSR_R2;
}
/*
 * Function to read channel values
 * @madc - pointer to twl4030_madc_data struct
 * @reg_base - Base address of the first channel
 * @Channels - 16 bit bitmap. If the bit is set, channel value is read
 * @buf - The channel values are stored here. if read fails error
 * value is stored
 * Returns the number of successfully read channels.
 */
static int twl4030_madc_read_channels(struct twl4030_madc_data *madc,
				      u8 reg_base, unsigned
						long channels, int *buf)
{
	int count = 0, count_req = 0, i;
	u8 reg;

	for_each_set_bit(i, &channels, TWL4030_MADC_MAX_CHANNELS) {
		reg = reg_base + 2 * i;
		buf[i] = twl4030_madc_channel_raw_read(madc, reg);
		if (buf[i] < 0) {
			dev_err(madc->dev,
				"Unable to read register 0x%X\n", reg);
			count_req++;
			continue;
		}
		switch (i) {
		case 10:
			buf[i] = twl4030battery_current(buf[i]);
			if (buf[i] < 0) {
				dev_err(madc->dev, "err reading current\n");
				count_req++;
			} else {
				count++;
				buf[i] = buf[i] - 750;
			}
			break;
		case 1:
			buf[i] = twl4030battery_temperature(buf[i]);
			if (buf[i] < 0) {
				dev_err(madc->dev, "err reading temperature\n");
				count_req++;
			} else {
				buf[i] -= 3;
				count++;
			}
			break;
		default:
			count++;
			/* Analog Input (V) = conv_result * step_size / R
			 * conv_result = decimal value of 10-bit conversion
			 *		 result
			 * step size = 1.5 / (2 ^ 10 -1)
			 * R = Prescaler ratio for input channels.
			 * Result given in mV hence multiplied by 1000.
			 */
			buf[i] = (buf[i] * 3 * 1000 *
				 twl4030_divider_ratios[i].denominator)
				/ (2 * 1023 *
				twl4030_divider_ratios[i].numerator);
		}
	}
	if (count_req)
		dev_err(madc->dev, "%d channel conversion failed\n", count_req);

	return count;
}

/*
 * Enables irq.
 * @madc - pointer to twl4030_madc_data struct
 * @id - irq number to be enabled
 * can take one of TWL4030_MADC_RT, TWL4030_MADC_SW1, TWL4030_MADC_SW2
 * corresponding to RT, SW1, SW2 conversion requests.
 * If the i2c read fails it returns an error else returns 0.
 */
static int twl4030_madc_enable_irq(struct twl4030_madc_data *madc, u8 id)
{
	u8 val;
	int ret;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &val, madc->imr);
	if (ret) {
		dev_err(madc->dev, "unable to read imr register 0x%X\n",
			madc->imr);
		return ret;
	}
	val &= ~(1 << id);
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, val, madc->imr);
	if (ret) {
		dev_err(madc->dev,
			"unable to write imr register 0x%X\n", madc->imr);
		return ret;

	}

	return 0;
}

/*
 * Disables irq.
 * @madc - pointer to twl4030_madc_data struct
 * @id - irq number to be disabled
 * can take one of TWL4030_MADC_RT, TWL4030_MADC_SW1, TWL4030_MADC_SW2
 * corresponding to RT, SW1, SW2 conversion requests.
 * Returns error if i2c read/write fails.
 */
static int twl4030_madc_disable_irq(struct twl4030_madc_data *madc, u8 id)
{
	u8 val;
	int ret;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &val, madc->imr);
	if (ret) {
		dev_err(madc->dev, "unable to read imr register 0x%X\n",
			madc->imr);
		return ret;
	}
	val |= (1 << id);
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, val, madc->imr);
	if (ret) {
		dev_err(madc->dev,
			"unable to write imr register 0x%X\n", madc->imr);
		return ret;
	}

	return 0;
}

static irqreturn_t twl4030_madc_threaded_irq_handler(int irq, void *_madc)
{
	struct twl4030_madc_data *madc = _madc;
	const struct twl4030_madc_conversion_method *method;
	u8 isr_val, imr_val;
	int i, len, ret;
	struct twl4030_madc_request *r;

	mutex_lock(&madc->lock);
	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &isr_val, madc->isr);
	if (ret) {
		dev_err(madc->dev, "unable to read isr register 0x%X\n",
			madc->isr);
		goto err_i2c;
	}
	ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &imr_val, madc->imr);
	if (ret) {
		dev_err(madc->dev, "unable to read imr register 0x%X\n",
			madc->imr);
		goto err_i2c;
	}
	isr_val &= ~imr_val;
	for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
		if (!(isr_val & (1 << i)))
			continue;
		ret = twl4030_madc_disable_irq(madc, i);
		if (ret < 0)
			dev_dbg(madc->dev, "Disable interrupt failed%d\n", i);
		madc->requests[i].result_pending = 1;
	}
	for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
		r = &madc->requests[i];
		/* No pending results for this method, move to next one */
		if (!r->result_pending)
			continue;
		method = &twl4030_conversion_methods[r->method];
		/* Read results */
		len = twl4030_madc_read_channels(madc, method->rbase,
						 r->channels, r->rbuf);
		/* Return results to caller */
		if (r->func_cb != NULL) {
			r->func_cb(len, r->channels, r->rbuf);
			r->func_cb = NULL;
		}
		/* Free request */
		r->result_pending = 0;
		r->active = 0;
	}
	mutex_unlock(&madc->lock);

	return IRQ_HANDLED;

err_i2c:
	/*
	 * In case of error check whichever request is active
	 * and service the same.
	 */
	for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
		r = &madc->requests[i];
		if (r->active == 0)
			continue;
		method = &twl4030_conversion_methods[r->method];
		/* Read results */
		len = twl4030_madc_read_channels(madc, method->rbase,
						 r->channels, r->rbuf);
		/* Return results to caller */
		if (r->func_cb != NULL) {
			r->func_cb(len, r->channels, r->rbuf);
			r->func_cb = NULL;
		}
		/* Free request */
		r->result_pending = 0;
		r->active = 0;
	}
	mutex_unlock(&madc->lock);

	return IRQ_HANDLED;
}

static int twl4030_madc_set_irq(struct twl4030_madc_data *madc,
				struct twl4030_madc_request *req)
{
	struct twl4030_madc_request *p;
	int ret;

	p = &madc->requests[req->method];
	memcpy(p, req, sizeof(*req));
	ret = twl4030_madc_enable_irq(madc, req->method);
	if (ret < 0) {
		dev_err(madc->dev, "enable irq failed!!\n");
		return ret;
	}

	return 0;
}

/*
 * Function which enables the madc conversion
 * by writing to the control register.
 * @madc - pointer to twl4030_madc_data struct
 * @conv_method - can be TWL4030_MADC_RT, TWL4030_MADC_SW2, TWL4030_MADC_SW1
 * corresponding to RT SW1 or SW2 conversion methods.
 * Returns 0 if succeeds else a negative error value
 */
static int twl4030_madc_start_conversion(struct twl4030_madc_data *madc,
					 int conv_method)
{
	const struct twl4030_madc_conversion_method *method;
	int ret = 0;
	method = &twl4030_conversion_methods[conv_method];
	switch (conv_method) {
	case TWL4030_MADC_SW1:
	case TWL4030_MADC_SW2:
		ret = twl_i2c_write_u8(TWL4030_MODULE_MADC,
				       TWL4030_MADC_SW_START, method->ctrl);
		if (ret) {
			dev_err(madc->dev,
				"unable to write ctrl register 0x%X\n",
				method->ctrl);
			return ret;
		}
		break;
	default:
		break;
	}

	return 0;
}

/*
 * Function that waits for conversion to be ready
 * @madc - pointer to twl4030_madc_data struct
 * @timeout_ms - timeout value in milliseconds
 * @status_reg - ctrl register
 * returns 0 if succeeds else a negative error value
 */
static int twl4030_madc_wait_conversion_ready(struct twl4030_madc_data *madc,
					      unsigned int timeout_ms,
					      u8 status_reg)
{
	unsigned long timeout;
	int ret;

	timeout = jiffies + msecs_to_jiffies(timeout_ms);
	do {
		u8 reg;

		ret = twl_i2c_read_u8(TWL4030_MODULE_MADC, &reg, status_reg);
		if (ret) {
			dev_err(madc->dev,
				"unable to read status register 0x%X\n",
				status_reg);
			return ret;
		}
		if (!(reg & TWL4030_MADC_BUSY) && (reg & TWL4030_MADC_EOC_SW))
			return 0;
		usleep_range(500, 2000);
	} while (!time_after(jiffies, timeout));
	dev_err(madc->dev, "conversion timeout!\n");

	return -EAGAIN;
}

/*
 * An exported function which can be called from other kernel drivers.
 * @req twl4030_madc_request structure
 * req->rbuf will be filled with read values of channels based on the
 * channel index. If a particular channel reading fails there will
 * be a negative error value in the corresponding array element.
 * returns 0 if succeeds else error value
 */
int twl4030_madc_conversion(struct twl4030_madc_request *req)
{
	const struct twl4030_madc_conversion_method *method;
	u8 ch_msb, ch_lsb;
	int ret;

	if (!req || !twl4030_madc)
		return -EINVAL;

	mutex_lock(&twl4030_madc->lock);
	if (req->method < TWL4030_MADC_RT || req->method > TWL4030_MADC_SW2) {
		ret = -EINVAL;
		goto out;
	}
	/* Do we have a conversion request ongoing */
	if (twl4030_madc->requests[req->method].active) {
		ret = -EBUSY;
		goto out;
	}
	ch_msb = (req->channels >> 8) & 0xff;
	ch_lsb = req->channels & 0xff;
	method = &twl4030_conversion_methods[req->method];
	/* Select channels to be converted */
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, ch_msb, method->sel + 1);
	if (ret) {
		dev_err(twl4030_madc->dev,
			"unable to write sel register 0x%X\n", method->sel + 1);
		goto out;
	}
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, ch_lsb, method->sel);
	if (ret) {
		dev_err(twl4030_madc->dev,
			"unable to write sel register 0x%X\n", method->sel + 1);
		goto out;
	}
	/* Select averaging for all channels if do_avg is set */
	if (req->do_avg) {
		ret = twl_i2c_write_u8(TWL4030_MODULE_MADC,
				       ch_msb, method->avg + 1);
		if (ret) {
			dev_err(twl4030_madc->dev,
				"unable to write avg register 0x%X\n",
				method->avg + 1);
			goto out;
		}
		ret = twl_i2c_write_u8(TWL4030_MODULE_MADC,
				       ch_lsb, method->avg);
		if (ret) {
			dev_err(twl4030_madc->dev,
				"unable to write sel reg 0x%X\n",
				method->sel + 1);
			goto out;
		}
	}
	if (req->type == TWL4030_MADC_IRQ_ONESHOT && req->func_cb != NULL) {
		ret = twl4030_madc_set_irq(twl4030_madc, req);
		if (ret < 0)
			goto out;
		ret = twl4030_madc_start_conversion(twl4030_madc, req->method);
		if (ret < 0)
			goto out;
		twl4030_madc->requests[req->method].active = 1;
		ret = 0;
		goto out;
	}
	/* With RT method we should not be here anymore */
	if (req->method == TWL4030_MADC_RT) {
		ret = -EINVAL;
		goto out;
	}
	ret = twl4030_madc_start_conversion(twl4030_madc, req->method);
	if (ret < 0)
		goto out;
	twl4030_madc->requests[req->method].active = 1;
	/* Wait until conversion is ready (ctrl register returns EOC) */
	ret = twl4030_madc_wait_conversion_ready(twl4030_madc, 5, method->ctrl);
	if (ret) {
		twl4030_madc->requests[req->method].active = 0;
		goto out;
	}
	ret = twl4030_madc_read_channels(twl4030_madc, method->rbase,
					 req->channels, req->rbuf);
	twl4030_madc->requests[req->method].active = 0;

out:
	mutex_unlock(&twl4030_madc->lock);

	return ret;
}
EXPORT_SYMBOL_GPL(twl4030_madc_conversion);

/*
 * Return channel value
 * Or < 0 on failure.
 */
int twl4030_get_madc_conversion(int channel_no)
{
	struct twl4030_madc_request req;
	int temp = 0;
	int ret;

	req.channels = (1 << channel_no);
	req.method = TWL4030_MADC_SW2;
	req.active = 0;
	req.func_cb = NULL;
	ret = twl4030_madc_conversion(&req);
	if (ret < 0)
		return ret;
	if (req.rbuf[channel_no] > 0)
		temp = req.rbuf[channel_no];

	return temp;
}
EXPORT_SYMBOL_GPL(twl4030_get_madc_conversion);

/*
 * Function to enable or disable bias current for
 * main battery type reading or temperature sensing
 * @madc - pointer to twl4030_madc_data struct
 * @chan - can be one of the two values
 * TWL4030_BCI_ITHEN - Enables bias current for main battery type reading
 * TWL4030_BCI_TYPEN - Enables bias current for main battery temperature
 * sensing
 * @on - enable or disable chan.
 */
static int twl4030_madc_set_current_generator(struct twl4030_madc_data *madc,
					      int chan, int on)
{
	int ret;
	u8 regval;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
			      &regval, TWL4030_BCI_BCICTL1);
	if (ret) {
		dev_err(madc->dev, "unable to read BCICTL1 reg 0x%X",
			TWL4030_BCI_BCICTL1);
		return ret;
	}
	if (on)
		regval |= chan ? TWL4030_BCI_ITHEN : TWL4030_BCI_TYPEN;
	else
		regval &= chan ? ~TWL4030_BCI_ITHEN : ~TWL4030_BCI_TYPEN;
	ret = twl_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE,
			       regval, TWL4030_BCI_BCICTL1);
	if (ret) {
		dev_err(madc->dev, "unable to write BCICTL1 reg 0x%X\n",
			TWL4030_BCI_BCICTL1);
		return ret;
	}

	return 0;
}

/*
 * Function that sets MADC software power on bit to enable MADC
 * @madc - pointer to twl4030_madc_data struct
 * @on - Enable or disable MADC software powen on bit.
 * returns error if i2c read/write fails else 0
 */
static int twl4030_madc_set_power(struct twl4030_madc_data *madc, int on)
{
	u8 regval;
	int ret;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
			      &regval, TWL4030_MADC_CTRL1);
	if (ret) {
		dev_err(madc->dev, "unable to read madc ctrl1 reg 0x%X\n",
			TWL4030_MADC_CTRL1);
		return ret;
	}
	if (on)
		regval |= TWL4030_MADC_MADCON;
	else
		regval &= ~TWL4030_MADC_MADCON;
	ret = twl_i2c_write_u8(TWL4030_MODULE_MADC, regval, TWL4030_MADC_CTRL1);
	if (ret) {
		dev_err(madc->dev, "unable to write madc ctrl1 reg 0x%X\n",
			TWL4030_MADC_CTRL1);
		return ret;
	}

	return 0;
}

/*
 * Initialize MADC and request for threaded irq
 */
static int __devinit twl4030_madc_probe(struct platform_device *pdev)
{
	struct twl4030_madc_data *madc;
	struct twl4030_madc_platform_data *pdata = pdev->dev.platform_data;
	int ret;
	u8 regval;

	if (!pdata) {
		dev_err(&pdev->dev, "platform_data not available\n");
		return -EINVAL;
	}
	madc = kzalloc(sizeof(*madc), GFP_KERNEL);
	if (!madc)
		return -ENOMEM;

	madc->dev = &pdev->dev;

	/*
	 * Phoenix provides 2 interrupt lines. The first one is connected to
	 * the OMAP. The other one can be connected to the other processor such
	 * as modem. Hence two separate ISR and IMR registers.
	 */
	madc->imr = (pdata->irq_line == 1) ?
	    TWL4030_MADC_IMR1 : TWL4030_MADC_IMR2;
	madc->isr = (pdata->irq_line == 1) ?
	    TWL4030_MADC_ISR1 : TWL4030_MADC_ISR2;
	ret = twl4030_madc_set_power(madc, 1);
	if (ret < 0)
		goto err_power;
	ret = twl4030_madc_set_current_generator(madc, 0, 1);
	if (ret < 0)
		goto err_current_generator;

	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
			      &regval, TWL4030_BCI_BCICTL1);
	if (ret) {
		dev_err(&pdev->dev, "unable to read reg BCI CTL1 0x%X\n",
			TWL4030_BCI_BCICTL1);
		goto err_i2c;
	}
	regval |= TWL4030_BCI_MESBAT;
	ret = twl_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE,
			       regval, TWL4030_BCI_BCICTL1);
	if (ret) {
		dev_err(&pdev->dev, "unable to write reg BCI Ctl1 0x%X\n",
			TWL4030_BCI_BCICTL1);
		goto err_i2c;
	}

	/* Check that MADC clock is on */
	ret = twl_i2c_read_u8(TWL4030_MODULE_INTBR, &regval, TWL4030_REG_GPBR1);
	if (ret) {
		dev_err(&pdev->dev, "unable to read reg GPBR1 0x%X\n",
				TWL4030_REG_GPBR1);
		goto err_i2c;
	}

	/* If MADC clk is not on, turn it on */
	if (!(regval & TWL4030_GPBR1_MADC_HFCLK_EN)) {
		dev_info(&pdev->dev, "clk disabled, enabling\n");
		regval |= TWL4030_GPBR1_MADC_HFCLK_EN;
		ret = twl_i2c_write_u8(TWL4030_MODULE_INTBR, regval,
				       TWL4030_REG_GPBR1);
		if (ret) {
			dev_err(&pdev->dev, "unable to write reg GPBR1 0x%X\n",
					TWL4030_REG_GPBR1);
			goto err_i2c;
		}
	}

	platform_set_drvdata(pdev, madc);
	mutex_init(&madc->lock);
	ret = request_threaded_irq(platform_get_irq(pdev, 0), NULL,
				   twl4030_madc_threaded_irq_handler,
				   IRQF_TRIGGER_RISING, "twl4030_madc", madc);
	if (ret) {
		dev_dbg(&pdev->dev, "could not request irq\n");
		goto err_irq;
	}
	twl4030_madc = madc;
	return 0;
err_irq:
	platform_set_drvdata(pdev, NULL);
err_i2c:
	twl4030_madc_set_current_generator(madc, 0, 0);
err_current_generator:
	twl4030_madc_set_power(madc, 0);
err_power:
	kfree(madc);

	return ret;
}

static int __devexit twl4030_madc_remove(struct platform_device *pdev)
{
	struct twl4030_madc_data *madc = platform_get_drvdata(pdev);

	free_irq(platform_get_irq(pdev, 0), madc);
	platform_set_drvdata(pdev, NULL);
	twl4030_madc_set_current_generator(madc, 0, 0);
	twl4030_madc_set_power(madc, 0);
	kfree(madc);

	return 0;
}

static struct platform_driver twl4030_madc_driver = {
	.probe = twl4030_madc_probe,
	.remove = __exit_p(twl4030_madc_remove),
	.driver = {
		   .name = "twl4030_madc",
		   .owner = THIS_MODULE,
		   },
};

module_platform_driver(twl4030_madc_driver);

MODULE_DESCRIPTION("TWL4030 ADC driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("J Keerthy");
MODULE_ALIAS("platform:twl4030_madc");