PM / sleep: Asynchronous threads for suspend_noirq

[linux/fpc-iii.git] / drivers / mfd / twl4030-irq.c

/*
 * 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/export.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/irqdomain.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
 */
#define TWL4030_CORE_NR_IRQS    8
#define TWL4030_PWR_NR_IRQS     8

/* 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)
{
        irqreturn_t     ret;
        u8              pih_isr;

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

        while (pih_isr) {
                unsigned long   pending = __ffs(pih_isr);
                unsigned int    irq;

                pih_isr &= ~BIT(pending);
                irq = pending + twl4030_irq_base;
                handle_nested_irq(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);
                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,
                                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;
                        int             byte = i >> 2;
                        int             off = (i & 0x3) * 2;
                        unsigned int    type;

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

                        type = irq_get_trigger_type(i + agent->irq_base);
                        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,
        .flags          = IRQCHIP_SKIP_SET_WAKE,
};

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

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;
}

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

        /* 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) {
                        status = 0;
                        break;
                }
        }

        if (status < 0)
                return status;

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

        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);
        }

        /* 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,
                                      IRQF_EARLY_RESUME,
                                      agent->irq_name ?: sih->name, NULL);

        dev_info(dev, "%s (irq %d) chaining IRQs %d..%d\n", sih->name,
                        irq, irq_base, irq_base + i - 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(struct device *dev, int irq_num)
{
        static struct irq_chip  twl4030_irq_chip;
        int                     status, i;
        int                     irq_base, irq_end, nr_irqs;
        struct                  device_node *node = dev->of_node;

        /*
         * TWL core and pwr interrupts must be contiguous because
         * the hwirqs numbers are defined contiguously from 1 to 15.
         * Create only one domain for both.
         */
        nr_irqs = TWL4030_PWR_NR_IRQS + TWL4030_CORE_NR_IRQS;

        irq_base = irq_alloc_descs(-1, 0, nr_irqs, 0);
        if (IS_ERR_VALUE(irq_base)) {
                dev_err(dev, "Fail to allocate IRQ descs\n");
                return irq_base;
        }

        irq_domain_add_legacy(node, nr_irqs, irq_base, 0,
                              &irq_domain_simple_ops, NULL);

        irq_end = irq_base + TWL4030_CORE_NR_IRQS;

        /*
         * 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);
        }

        dev_info(dev, "%s (irq %d) chaining IRQs %d..%d\n", "PIH",
                        irq_num, irq_base, irq_end);

        /* ... and the PWR_INT module ... */
        status = twl4030_sih_setup(dev, TWL4030_MODULE_INT, irq_end);
        if (status < 0) {
                dev_err(dev, "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) {
                dev_err(dev, "could not claim irq%d: %d\n", irq_num, status);
                goto fail_rqirq;
        }
        enable_irq_wake(irq_num);

        return irq_base;
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;
}