/*
   * 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
  ", 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
  ",
  					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
  ",
  						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
  ",
  					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
  ", __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
  ", __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
  ", __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
  ",
  			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
  ",
  				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
  ",
  					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
  ", 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
  ", "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
  ", 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
  ", 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?
  ");
  		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;
  }