summaryrefslogtreecommitdiff
path: root/drivers/mfd/twl4030-irq.c
blob: b31f920feb5104f498097353fb6056a3186cf43d (plain)
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
/*
 * twl4030-irq.c - TWL4030/TPS659x0 irq support
 *
 * Copyright (C) 2005-2006 Texas Instruments, Inc.
 *
 * Modifications to defer interrupt handling to a kernel thread:
 * Copyright (C) 2006 MontaVista Software, Inc.
 *
 * Based on tlv320aic23.c:
 * Copyright (c) by Kai Svahn <kai.svahn@nokia.com>
 *
 * Code cleanup and modifications to IRQ handler.
 * by syed khasim <x0khasim@ti.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/slab.h>

#include <linux/i2c/twl.h>

#include "twl-core.h"

/*
 * TWL4030 IRQ handling has two stages in hardware, and thus in software.
 * The Primary Interrupt Handler (PIH) stage exposes status bits saying
 * which Secondary Interrupt Handler (SIH) stage is raising an interrupt.
 * SIH modules are more traditional IRQ components, which support per-IRQ
 * enable/disable and trigger controls; they do most of the work.
 *
 * These chips are designed to support IRQ handling from two different
 * I2C masters.  Each has a dedicated IRQ line, and dedicated IRQ status
 * and mask registers in the PIH and SIH modules.
 *
 * We set up IRQs starting at a platform-specified base, always starting
 * with PIH and the SIH for PWR_INT and then usually adding GPIO:
 *	base + 0  .. base + 7	PIH
 *	base + 8  .. base + 15	SIH for PWR_INT
 *	base + 16 .. base + 33	SIH for GPIO
 */

/* PIH register offsets */
#define REG_PIH_ISR_P1			0x01
#define REG_PIH_ISR_P2			0x02
#define REG_PIH_SIR			0x03	/* for testing */

/* Linux could (eventually) use either IRQ line */
static int irq_line;

struct sih {
	char	name[8];
	u8	module;			/* module id */
	u8	control_offset;		/* for SIH_CTRL */
	bool	set_cor;

	u8	bits;			/* valid in isr/imr */
	u8	bytes_ixr;		/* bytelen of ISR/IMR/SIR */

	u8	edr_offset;
	u8	bytes_edr;		/* bytelen of EDR */

	u8	irq_lines;		/* number of supported irq lines */

	/* SIR ignored -- set interrupt, for testing only */
	struct sih_irq_data {
		u8	isr_offset;
		u8	imr_offset;
	} mask[2];
	/* + 2 bytes padding */
};

static const struct sih *sih_modules;
static int nr_sih_modules;

#define SIH_INITIALIZER(modname, nbits) \
	.module		= TWL4030_MODULE_ ## modname, \
	.control_offset = TWL4030_ ## modname ## _SIH_CTRL, \
	.bits		= nbits, \
	.bytes_ixr	= DIV_ROUND_UP(nbits, 8), \
	.edr_offset	= TWL4030_ ## modname ## _EDR, \
	.bytes_edr	= DIV_ROUND_UP((2*(nbits)), 8), \
	.irq_lines	= 2, \
	.mask = { { \
		.isr_offset	= TWL4030_ ## modname ## _ISR1, \
		.imr_offset	= TWL4030_ ## modname ## _IMR1, \
	}, \
	{ \
		.isr_offset	= TWL4030_ ## modname ## _ISR2, \
		.imr_offset	= TWL4030_ ## modname ## _IMR2, \
	}, },

/* register naming policies are inconsistent ... */
#define TWL4030_INT_PWR_EDR		TWL4030_INT_PWR_EDR1
#define TWL4030_MODULE_KEYPAD_KEYP	TWL4030_MODULE_KEYPAD
#define TWL4030_MODULE_INT_PWR		TWL4030_MODULE_INT


/*
 * Order in this table matches order in PIH_ISR.  That is,
 * BIT(n) in PIH_ISR is sih_modules[n].
 */
/* sih_modules_twl4030 is used both in twl4030 and twl5030 */
static const struct sih sih_modules_twl4030[6] = {
	[0] = {
		.name		= "gpio",
		.module		= TWL4030_MODULE_GPIO,
		.control_offset	= REG_GPIO_SIH_CTRL,
		.set_cor	= true,
		.bits		= TWL4030_GPIO_MAX,
		.bytes_ixr	= 3,
		/* Note: *all* of these IRQs default to no-trigger */
		.edr_offset	= REG_GPIO_EDR1,
		.bytes_edr	= 5,
		.irq_lines	= 2,
		.mask = { {
			.isr_offset	= REG_GPIO_ISR1A,
			.imr_offset	= REG_GPIO_IMR1A,
		}, {
			.isr_offset	= REG_GPIO_ISR1B,
			.imr_offset	= REG_GPIO_IMR1B,
		}, },
	},
	[1] = {
		.name		= "keypad",
		.set_cor	= true,
		SIH_INITIALIZER(KEYPAD_KEYP, 4)
	},
	[2] = {
		.name		= "bci",
		.module		= TWL4030_MODULE_INTERRUPTS,
		.control_offset	= TWL4030_INTERRUPTS_BCISIHCTRL,
		.set_cor	= true,
		.bits		= 12,
		.bytes_ixr	= 2,
		.edr_offset	= TWL4030_INTERRUPTS_BCIEDR1,
		/* Note: most of these IRQs default to no-trigger */
		.bytes_edr	= 3,
		.irq_lines	= 2,
		.mask = { {
			.isr_offset	= TWL4030_INTERRUPTS_BCIISR1A,
			.imr_offset	= TWL4030_INTERRUPTS_BCIIMR1A,
		}, {
			.isr_offset	= TWL4030_INTERRUPTS_BCIISR1B,
			.imr_offset	= TWL4030_INTERRUPTS_BCIIMR1B,
		}, },
	},
	[3] = {
		.name		= "madc",
		SIH_INITIALIZER(MADC, 4)
	},
	[4] = {
		/* USB doesn't use the same SIH organization */
		.name		= "usb",
	},
	[5] = {
		.name		= "power",
		.set_cor	= true,
		SIH_INITIALIZER(INT_PWR, 8)
	},
		/* there are no SIH modules #6 or #7 ... */
};

static const struct sih sih_modules_twl5031[8] = {
	[0] = {
		.name		= "gpio",
		.module		= TWL4030_MODULE_GPIO,
		.control_offset	= REG_GPIO_SIH_CTRL,
		.set_cor	= true,
		.bits		= TWL4030_GPIO_MAX,
		.bytes_ixr	= 3,
		/* Note: *all* of these IRQs default to no-trigger */
		.edr_offset	= REG_GPIO_EDR1,
		.bytes_edr	= 5,
		.irq_lines	= 2,
		.mask = { {
			.isr_offset	= REG_GPIO_ISR1A,
			.imr_offset	= REG_GPIO_IMR1A,
		}, {
			.isr_offset	= REG_GPIO_ISR1B,
			.imr_offset	= REG_GPIO_IMR1B,
		}, },
	},
	[1] = {
		.name		= "keypad",
		.set_cor	= true,
		SIH_INITIALIZER(KEYPAD_KEYP, 4)
	},
	[2] = {
		.name		= "bci",
		.module		= TWL5031_MODULE_INTERRUPTS,
		.control_offset	= TWL5031_INTERRUPTS_BCISIHCTRL,
		.bits		= 7,
		.bytes_ixr	= 1,
		.edr_offset	= TWL5031_INTERRUPTS_BCIEDR1,
		/* Note: most of these IRQs default to no-trigger */
		.bytes_edr	= 2,
		.irq_lines	= 2,
		.mask = { {
			.isr_offset	= TWL5031_INTERRUPTS_BCIISR1,
			.imr_offset	= TWL5031_INTERRUPTS_BCIIMR1,
		}, {
			.isr_offset	= TWL5031_INTERRUPTS_BCIISR2,
			.imr_offset	= TWL5031_INTERRUPTS_BCIIMR2,
		}, },
	},
	[3] = {
		.name		= "madc",
		SIH_INITIALIZER(MADC, 4)
	},
	[4] = {
		/* USB doesn't use the same SIH organization */
		.name		= "usb",
	},
	[5] = {
		.name		= "power",
		.set_cor	= true,
		SIH_INITIALIZER(INT_PWR, 8)
	},
	[6] = {
		/*
		 * ECI/DBI doesn't use the same SIH organization.
		 * For example, it supports only one interrupt output line.
		 * That is, the interrupts are seen on both INT1 and INT2 lines.
		 */
		.name		= "eci_dbi",
		.module		= TWL5031_MODULE_ACCESSORY,
		.bits		= 9,
		.bytes_ixr	= 2,
		.irq_lines	= 1,
		.mask = { {
			.isr_offset	= TWL5031_ACIIDR_LSB,
			.imr_offset	= TWL5031_ACIIMR_LSB,
		}, },

	},
	[7] = {
		/* Audio accessory */
		.name		= "audio",
		.module		= TWL5031_MODULE_ACCESSORY,
		.control_offset	= TWL5031_ACCSIHCTRL,
		.bits		= 2,
		.bytes_ixr	= 1,
		.edr_offset	= TWL5031_ACCEDR1,
		/* Note: most of these IRQs default to no-trigger */
		.bytes_edr	= 1,
		.irq_lines	= 2,
		.mask = { {
			.isr_offset	= TWL5031_ACCISR1,
			.imr_offset	= TWL5031_ACCIMR1,
		}, {
			.isr_offset	= TWL5031_ACCISR2,
			.imr_offset	= TWL5031_ACCIMR2,
		}, },
	},
};

#undef TWL4030_MODULE_KEYPAD_KEYP
#undef TWL4030_MODULE_INT_PWR
#undef TWL4030_INT_PWR_EDR

/*----------------------------------------------------------------------*/

static unsigned twl4030_irq_base;

/*
 * handle_twl4030_pih() is the desc->handle method for the twl4030 interrupt.
 * This is a chained interrupt, so there is no desc->action method for it.
 * Now we need to query the interrupt controller in the twl4030 to determine
 * which module is generating the interrupt request.  However, we can't do i2c
 * transactions in interrupt context, so we must defer that work to a kernel
 * thread.  All we do here is acknowledge and mask the interrupt and wakeup
 * the kernel thread.
 */
static irqreturn_t handle_twl4030_pih(int irq, void *devid)
{
	int		module_irq;
	irqreturn_t	ret;
	u8		pih_isr;

	ret = twl_i2c_read_u8(TWL4030_MODULE_PIH, &pih_isr,
			REG_PIH_ISR_P1);
	if (ret) {
		pr_warning("twl4030: I2C error %d reading PIH ISR\n", ret);
		return IRQ_NONE;
	}

	/* these handlers deal with the relevant SIH irq status */
	for (module_irq = twl4030_irq_base;
			pih_isr;
			pih_isr >>= 1, module_irq++) {
		if (pih_isr & 0x1)
			handle_nested_irq(module_irq);
	}

	return IRQ_HANDLED;
}

/*----------------------------------------------------------------------*/

/*
 * twl4030_init_sih_modules() ... start from a known state where no
 * IRQs will be coming in, and where we can quickly enable them then
 * handle them as they arrive.  Mask all IRQs: maybe init SIH_CTRL.
 *
 * NOTE:  we don't touch EDR registers here; they stay with hardware
 * defaults or whatever the last value was.  Note that when both EDR
 * bits for an IRQ are clear, that's as if its IMR bit is set...
 */
static int twl4030_init_sih_modules(unsigned line)
{
	const struct sih *sih;
	u8 buf[4];
	int i;
	int status;

	/* line 0 == int1_n signal; line 1 == int2_n signal */
	if (line > 1)
		return -EINVAL;

	irq_line = line;

	/* disable all interrupts on our line */
	memset(buf, 0xff, sizeof buf);
	sih = sih_modules;
	for (i = 0; i < nr_sih_modules; i++, sih++) {
		/* skip USB -- it's funky */
		if (!sih->bytes_ixr)
			continue;

		/* Not all the SIH modules support multiple interrupt lines */
		if (sih->irq_lines <= line)
			continue;

		status = twl_i2c_write(sih->module, buf,
				sih->mask[line].imr_offset, sih->bytes_ixr);
		if (status < 0)
			pr_err("twl4030: err %d initializing %s %s\n",
					status, sih->name, "IMR");

		/*
		 * Maybe disable "exclusive" mode; buffer second pending irq;
		 * set Clear-On-Read (COR) bit.
		 *
		 * NOTE that sometimes COR polarity is documented as being
		 * inverted:  for MADC, COR=1 means "clear on write".
		 * And for PWR_INT it's not documented...
		 */
		if (sih->set_cor) {
			status = twl_i2c_write_u8(sih->module,
					TWL4030_SIH_CTRL_COR_MASK,
					sih->control_offset);
			if (status < 0)
				pr_err("twl4030: err %d initializing %s %s\n",
						status, sih->name, "SIH_CTRL");
		}
	}

	sih = sih_modules;
	for (i = 0; i < nr_sih_modules; i++, sih++) {
		u8 rxbuf[4];
		int j;

		/* skip USB */
		if (!sih->bytes_ixr)
			continue;

		/* Not all the SIH modules support multiple interrupt lines */
		if (sih->irq_lines <= line)
			continue;

		/*
		 * Clear pending interrupt status.  Either the read was
		 * enough, or we need to write those bits.  Repeat, in
		 * case an IRQ is pending (PENDDIS=0) ... that's not
		 * uncommon with PWR_INT.PWRON.
		 */
		for (j = 0; j < 2; j++) {
			status = twl_i2c_read(sih->module, rxbuf,
				sih->mask[line].isr_offset, sih->bytes_ixr);
			if (status < 0)
				pr_err("twl4030: err %d initializing %s %s\n",
					status, sih->name, "ISR");

			if (!sih->set_cor)
				status = twl_i2c_write(sih->module, buf,
					sih->mask[line].isr_offset,
					sih->bytes_ixr);
			/*
			 * else COR=1 means read sufficed.
			 * (for most SIH modules...)
			 */
		}
	}

	return 0;
}

static inline void activate_irq(int irq)
{
#ifdef CONFIG_ARM
	/*
	 * ARM requires an extra step to clear IRQ_NOREQUEST, which it
	 * sets on behalf of every irq_chip.  Also sets IRQ_NOPROBE.
	 */
	set_irq_flags(irq, IRQF_VALID);
#else
	/* same effect on other architectures */
	irq_set_noprobe(irq);
#endif
}

/*----------------------------------------------------------------------*/

struct sih_agent {
	int			irq_base;
	const struct sih	*sih;

	u32			imr;
	bool			imr_change_pending;

	u32			edge_change;

	struct mutex		irq_lock;
	char			*irq_name;
};

/*----------------------------------------------------------------------*/

/*
 * All irq_chip methods get issued from code holding irq_desc[irq].lock,
 * which can't perform the underlying I2C operations (because they sleep).
 * So we must hand them off to a thread (workqueue) and cope with asynch
 * completion, potentially including some re-ordering, of these requests.
 */

static void twl4030_sih_mask(struct irq_data *data)
{
	struct sih_agent *agent = irq_data_get_irq_chip_data(data);

	agent->imr |= BIT(data->irq - agent->irq_base);
	agent->imr_change_pending = true;
}

static void twl4030_sih_unmask(struct irq_data *data)
{
	struct sih_agent *agent = irq_data_get_irq_chip_data(data);

	agent->imr &= ~BIT(data->irq - agent->irq_base);
	agent->imr_change_pending = true;
}

static int twl4030_sih_set_type(struct irq_data *data, unsigned trigger)
{
	struct sih_agent *agent = irq_data_get_irq_chip_data(data);

	if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
		return -EINVAL;

	if (irqd_get_trigger_type(data) != trigger)
		agent->edge_change |= BIT(data->irq - agent->irq_base);

	return 0;
}

static void twl4030_sih_bus_lock(struct irq_data *data)
{
	struct sih_agent	*agent = irq_data_get_irq_chip_data(data);

	mutex_lock(&agent->irq_lock);
}

static void twl4030_sih_bus_sync_unlock(struct irq_data *data)
{
	struct sih_agent	*agent = irq_data_get_irq_chip_data(data);
	const struct sih	*sih = agent->sih;
	int			status;

	if (agent->imr_change_pending) {
		union {
			u32	word;
			u8	bytes[4];
		} imr;

		/* byte[0] gets overwritten as we write ... */
		imr.word = cpu_to_le32(agent->imr << 8);
		agent->imr_change_pending = false;

		/* write the whole mask ... simpler than subsetting it */
		status = twl_i2c_write(sih->module, imr.bytes,
				sih->mask[irq_line].imr_offset,
				sih->bytes_ixr);
		if (status)
			pr_err("twl4030: %s, %s --> %d\n", __func__,
					"write", status);
	}

	if (agent->edge_change) {
		u32		edge_change;
		u8		bytes[6];

		edge_change = agent->edge_change;
		agent->edge_change = 0;

		/*
		 * Read, reserving first byte for write scratch.  Yes, this
		 * could be cached for some speedup ... but be careful about
		 * any processor on the other IRQ line, EDR registers are
		 * shared.
		 */
		status = twl_i2c_read(sih->module, bytes + 1,
				sih->edr_offset, sih->bytes_edr);
		if (status) {
			pr_err("twl4030: %s, %s --> %d\n", __func__,
					"read", status);
			return;
		}

		/* Modify only the bits we know must change */
		while (edge_change) {
			int		i = fls(edge_change) - 1;
			struct irq_data	*idata;
			int		byte = 1 + (i >> 2);
			int		off = (i & 0x3) * 2;
			unsigned int	type;

			idata = irq_get_irq_data(i + agent->irq_base);

			bytes[byte] &= ~(0x03 << off);

			type = irqd_get_trigger_type(idata);
			if (type & IRQ_TYPE_EDGE_RISING)
				bytes[byte] |= BIT(off + 1);
			if (type & IRQ_TYPE_EDGE_FALLING)
				bytes[byte] |= BIT(off + 0);

			edge_change &= ~BIT(i);
		}

		/* Write */
		status = twl_i2c_write(sih->module, bytes,
				sih->edr_offset, sih->bytes_edr);
		if (status)
			pr_err("twl4030: %s, %s --> %d\n", __func__,
					"write", status);
	}

	mutex_unlock(&agent->irq_lock);
}

static struct irq_chip twl4030_sih_irq_chip = {
	.name		= "twl4030",
	.irq_mask	= twl4030_sih_mask,
	.irq_unmask	= twl4030_sih_unmask,
	.irq_set_type	= twl4030_sih_set_type,
	.irq_bus_lock	= twl4030_sih_bus_lock,
	.irq_bus_sync_unlock = twl4030_sih_bus_sync_unlock,
};

/*----------------------------------------------------------------------*/

static inline int sih_read_isr(const struct sih *sih)
{
	int status;
	union {
		u8 bytes[4];
		u32 word;
	} isr;

	/* FIXME need retry-on-error ... */

	isr.word = 0;
	status = twl_i2c_read(sih->module, isr.bytes,
			sih->mask[irq_line].isr_offset, sih->bytes_ixr);

	return (status < 0) ? status : le32_to_cpu(isr.word);
}

/*
 * Generic handler for SIH interrupts ... we "know" this is called
 * in task context, with IRQs enabled.
 */
static irqreturn_t handle_twl4030_sih(int irq, void *data)
{
	struct sih_agent *agent = irq_get_handler_data(irq);
	const struct sih *sih = agent->sih;
	int isr;

	/* reading ISR acks the IRQs, using clear-on-read mode */
	isr = sih_read_isr(sih);

	if (isr < 0) {
		pr_err("twl4030: %s SIH, read ISR error %d\n",
			sih->name, isr);
		/* REVISIT:  recover; eventually mask it all, etc */
		return IRQ_HANDLED;
	}

	while (isr) {
		irq = fls(isr);
		irq--;
		isr &= ~BIT(irq);

		if (irq < sih->bits)
			handle_nested_irq(agent->irq_base + irq);
		else
			pr_err("twl4030: %s SIH, invalid ISR bit %d\n",
				sih->name, irq);
	}
	return IRQ_HANDLED;
}

static unsigned twl4030_irq_next;

/* returns the first IRQ used by this SIH bank, or negative errno */
int twl4030_sih_setup(int module)
{
	int			sih_mod;
	const struct sih	*sih = NULL;
	struct sih_agent	*agent;
	int			i, irq;
	int			status = -EINVAL;
	unsigned		irq_base = twl4030_irq_next;

	/* only support modules with standard clear-on-read for now */
	for (sih_mod = 0, sih = sih_modules;
			sih_mod < nr_sih_modules;
			sih_mod++, sih++) {
		if (sih->module == module && sih->set_cor) {
			if (!WARN((irq_base + sih->bits) > NR_IRQS,
					"irq %d for %s too big\n",
					irq_base + sih->bits,
					sih->name))
				status = 0;
			break;
		}
	}
	if (status < 0)
		return status;

	agent = kzalloc(sizeof *agent, GFP_KERNEL);
	if (!agent)
		return -ENOMEM;

	status = 0;

	agent->irq_base = irq_base;
	agent->sih = sih;
	agent->imr = ~0;
	mutex_init(&agent->irq_lock);

	for (i = 0; i < sih->bits; i++) {
		irq = irq_base + i;

		irq_set_chip_data(irq, agent);
		irq_set_chip_and_handler(irq, &twl4030_sih_irq_chip,
					 handle_edge_irq);
		irq_set_nested_thread(irq, 1);
		activate_irq(irq);
	}

	twl4030_irq_next += i;

	/* replace generic PIH handler (handle_simple_irq) */
	irq = sih_mod + twl4030_irq_base;
	irq_set_handler_data(irq, agent);
	agent->irq_name = kasprintf(GFP_KERNEL, "twl4030_%s", sih->name);
	status = request_threaded_irq(irq, NULL, handle_twl4030_sih, 0,
				      agent->irq_name ?: sih->name, NULL);

	pr_info("twl4030: %s (irq %d) chaining IRQs %d..%d\n", sih->name,
			irq, irq_base, twl4030_irq_next - 1);

	return status < 0 ? status : irq_base;
}

/* FIXME need a call to reverse twl4030_sih_setup() ... */

/*----------------------------------------------------------------------*/

/* FIXME pass in which interrupt line we'll use ... */
#define twl_irq_line	0

int twl4030_init_irq(int irq_num, unsigned irq_base, unsigned irq_end)
{
	static struct irq_chip	twl4030_irq_chip;

	int			status;
	int			i;

	/*
	 * Mask and clear all TWL4030 interrupts since initially we do
	 * not have any TWL4030 module interrupt handlers present
	 */
	status = twl4030_init_sih_modules(twl_irq_line);
	if (status < 0)
		return status;

	twl4030_irq_base = irq_base;

	/*
	 * install an irq handler for each of the SIH modules;
	 * clone dummy irq_chip since PIH can't *do* anything
	 */
	twl4030_irq_chip = dummy_irq_chip;
	twl4030_irq_chip.name = "twl4030";

	twl4030_sih_irq_chip.irq_ack = dummy_irq_chip.irq_ack;

	for (i = irq_base; i < irq_end; i++) {
		irq_set_chip_and_handler(i, &twl4030_irq_chip,
					 handle_simple_irq);
		irq_set_nested_thread(i, 1);
		activate_irq(i);
	}
	twl4030_irq_next = i;
	pr_info("twl4030: %s (irq %d) chaining IRQs %d..%d\n", "PIH",
			irq_num, irq_base, twl4030_irq_next - 1);

	/* ... and the PWR_INT module ... */
	status = twl4030_sih_setup(TWL4030_MODULE_INT);
	if (status < 0) {
		pr_err("twl4030: sih_setup PWR INT --> %d\n", status);
		goto fail;
	}

	/* install an irq handler to demultiplex the TWL4030 interrupt */
	status = request_threaded_irq(irq_num, NULL, handle_twl4030_pih,
				      IRQF_ONESHOT,
				      "TWL4030-PIH", NULL);
	if (status < 0) {
		pr_err("twl4030: could not claim irq%d: %d\n", irq_num, status);
		goto fail_rqirq;
	}

	return status;
fail_rqirq:
	/* clean up twl4030_sih_setup */
fail:
	for (i = irq_base; i < irq_end; i++) {
		irq_set_nested_thread(i, 0);
		irq_set_chip_and_handler(i, NULL, NULL);
	}

	return status;
}

int twl4030_exit_irq(void)
{
	/* FIXME undo twl_init_irq() */
	if (twl4030_irq_base) {
		pr_err("twl4030: can't yet clean up IRQs?\n");
		return -ENOSYS;
	}
	return 0;
}

int twl4030_init_chip_irq(const char *chip)
{
	if (!strcmp(chip, "twl5031")) {
		sih_modules = sih_modules_twl5031;
		nr_sih_modules = ARRAY_SIZE(sih_modules_twl5031);
	} else {
		sih_modules = sih_modules_twl4030;
		nr_sih_modules = ARRAY_SIZE(sih_modules_twl4030);
	}

	return 0;
}