]> www.pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - drivers/mfd/twl4030-irq.c
new sharable twl4030 SIH irq_chip
[linux-2.6-omap-h63xx.git] / drivers / mfd / twl4030-irq.c
index e849bc0c65c7ecd6d8633534db3331dab7aada6a..9b8d74422792939ce5b74d39c1f1d1bc7fc168b8 100644 (file)
 #include <linux/i2c/twl4030.h>
 
 
-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 */
-       set_irq_noprobe(irq);
-#endif
-}
+/*
+ * 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 */
 
-/*----------------------------------------------------------------------*/
 
-/**
- * struct twl4030_mod_iregs - TWL module IMR/ISR regs to mask/clear at init
- * @mod_no: TWL4030 module number (e.g., TWL4030_MODULE_GPIO)
- * @sih_ctrl: address of module SIH_CTRL register
- * @reg_cnt: number of IMR/ISR regs
- * @imrs: pointer to array of TWL module interrupt mask register indices
- * @isrs: pointer to array of TWL module interrupt status register indices
- *
- * Ties together TWL4030 modules and lists of IMR/ISR registers to mask/clear
- * during twl_init_irq().
- */
-struct twl4030_mod_iregs {
-       const u8 mod_no;
-       const u8 sih_ctrl;
-       const u8 reg_cnt;
-       const u8 *imrs;
-       const u8 *isrs;
-};
+/* Linux could (eventually) use either IRQ line */
+static int irq_line;
 
-/* TWL4030 INT module interrupt mask registers */
-static const u8 __initconst twl4030_int_imr_regs[] = {
-       TWL4030_INT_PWR_IMR1,
-       TWL4030_INT_PWR_IMR2,
-};
+struct sih {
+       char    name[8];
+       u8      module;                 /* module id */
+       u8      control_offset;         /* for SIH_CTRL */
+       bool    set_cor;
 
-/* TWL4030 INT module interrupt status registers */
-static const u8 __initconst twl4030_int_isr_regs[] = {
-       TWL4030_INT_PWR_ISR1,
-       TWL4030_INT_PWR_ISR2,
-};
+       u8      bits;                   /* valid in isr/imr */
+       u8      bytes_ixr;              /* bytelen of ISR/IMR/SIR */
 
-/* TWL4030 INTERRUPTS module interrupt mask registers */
-static const u8 __initconst twl4030_interrupts_imr_regs[] = {
-       TWL4030_INTERRUPTS_BCIIMR1A,
-       TWL4030_INTERRUPTS_BCIIMR1B,
-       TWL4030_INTERRUPTS_BCIIMR2A,
-       TWL4030_INTERRUPTS_BCIIMR2B,
-};
-
-/* TWL4030 INTERRUPTS module interrupt status registers */
-static const u8 __initconst twl4030_interrupts_isr_regs[] = {
-       TWL4030_INTERRUPTS_BCIISR1A,
-       TWL4030_INTERRUPTS_BCIISR1B,
-       TWL4030_INTERRUPTS_BCIISR2A,
-       TWL4030_INTERRUPTS_BCIISR2B,
-};
-
-/* TWL4030 MADC module interrupt mask registers */
-static const u8 __initconst twl4030_madc_imr_regs[] = {
-       TWL4030_MADC_IMR1,
-       TWL4030_MADC_IMR2,
-};
-
-/* TWL4030 MADC module interrupt status registers */
-static const u8 __initconst twl4030_madc_isr_regs[] = {
-       TWL4030_MADC_ISR1,
-       TWL4030_MADC_ISR2,
-};
-
-/* TWL4030 keypad module interrupt mask registers */
-static const u8 __initconst twl4030_keypad_imr_regs[] = {
-       TWL4030_KEYPAD_KEYP_IMR1,
-       TWL4030_KEYPAD_KEYP_IMR2,
-};
-
-/* TWL4030 keypad module interrupt status registers */
-static const u8 __initconst twl4030_keypad_isr_regs[] = {
-       TWL4030_KEYPAD_KEYP_ISR1,
-       TWL4030_KEYPAD_KEYP_ISR2,
-};
-
-/* TWL4030 GPIO module interrupt mask registers */
-static const u8 __initconst twl4030_gpio_imr_regs[] = {
-       REG_GPIO_IMR1A,
-       REG_GPIO_IMR1B,
-       REG_GPIO_IMR2A,
-       REG_GPIO_IMR2B,
-       REG_GPIO_IMR3A,
-       REG_GPIO_IMR3B,
-};
+       u8      edr_offset;
+       u8      bytes_edr;              /* bytelen of EDR */
 
-/* TWL4030 GPIO module interrupt status registers */
-static const u8 __initconst twl4030_gpio_isr_regs[] = {
-       REG_GPIO_ISR1A,
-       REG_GPIO_ISR1B,
-       REG_GPIO_ISR2A,
-       REG_GPIO_ISR2B,
-       REG_GPIO_ISR3A,
-       REG_GPIO_ISR3B,
+       /* SIR ignored -- set interrupt, for testing only */
+       struct irq_data {
+               u8      isr_offset;
+               u8      imr_offset;
+       } mask[2];
+       /* + 2 bytes padding */
 };
 
-/* TWL4030 modules that have IMR/ISR registers that must be masked/cleared */
-static const struct twl4030_mod_iregs __initconst twl4030_mod_regs[] = {
-       {
-               .mod_no   = TWL4030_MODULE_INT,
-               .sih_ctrl = TWL4030_INT_PWR_SIH_CTRL,
-               .reg_cnt  = ARRAY_SIZE(twl4030_int_imr_regs),
-               .imrs     = twl4030_int_imr_regs,
-               .isrs     = twl4030_int_isr_regs,
+#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), \
+       .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].
+ */
+static const struct sih sih_modules[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,
+               .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)
        },
-       {
-               .mod_no   = TWL4030_MODULE_INTERRUPTS,
-               .sih_ctrl = TWL4030_INTERRUPTS_BCISIHCTRL,
-               .reg_cnt  = ARRAY_SIZE(twl4030_interrupts_imr_regs),
-               .imrs     = twl4030_interrupts_imr_regs,
-               .isrs     = twl4030_interrupts_isr_regs,
+       [2] = {
+               .name           = "bci",
+               .module         = TWL4030_MODULE_INTERRUPTS,
+               .control_offset = TWL4030_INTERRUPTS_BCISIHCTRL,
+               .bits           = 12,
+               .bytes_ixr      = 2,
+               .edr_offset     = TWL4030_INTERRUPTS_BCIEDR1,
+               /* Note: most of these IRQs default to no-trigger */
+               .bytes_edr      = 3,
+               .mask = { {
+                       .isr_offset     = TWL4030_INTERRUPTS_BCIISR1A,
+                       .imr_offset     = TWL4030_INTERRUPTS_BCIIMR1A,
+               }, {
+                       .isr_offset     = TWL4030_INTERRUPTS_BCIISR1B,
+                       .imr_offset     = TWL4030_INTERRUPTS_BCIIMR1B,
+               }, },
        },
-       {
-               .mod_no   = TWL4030_MODULE_MADC,
-               .sih_ctrl = TWL4030_MADC_SIH_CTRL,
-               .reg_cnt  = ARRAY_SIZE(twl4030_madc_imr_regs),
-               .imrs     = twl4030_madc_imr_regs,
-               .isrs     = twl4030_madc_isr_regs,
+       [3] = {
+               .name           = "madc",
+               SIH_INITIALIZER(MADC, 4)
        },
-       {
-               .mod_no   = TWL4030_MODULE_KEYPAD,
-               .sih_ctrl = TWL4030_KEYPAD_KEYP_SIH_CTRL,
-               .reg_cnt  = ARRAY_SIZE(twl4030_keypad_imr_regs),
-               .imrs     = twl4030_keypad_imr_regs,
-               .isrs     = twl4030_keypad_isr_regs,
+       [4] = {
+               /* USB doesn't use the same SIH organization */
+               .name           = "usb",
        },
-       {
-               .mod_no   = TWL4030_MODULE_GPIO,
-               .sih_ctrl = REG_GPIO_SIH_CTRL,
-               .reg_cnt  = ARRAY_SIZE(twl4030_gpio_imr_regs),
-               .imrs     = twl4030_gpio_imr_regs,
-               .isrs     = twl4030_gpio_isr_regs,
+       [5] = {
+               .name           = "power",
+               .set_cor        = true,
+               SIH_INITIALIZER(INT_PWR, 8)
        },
+               /* there are no SIH modules #6 or #7 ... */
 };
 
+#undef TWL4030_MODULE_KEYPAD_KEYP
+#undef TWL4030_MODULE_INT_PWR
+#undef TWL4030_INT_PWR_EDR
+
 /*----------------------------------------------------------------------*/
 
 static unsigned twl4030_irq_base;
@@ -282,99 +265,425 @@ static struct task_struct *start_twl4030_irq_thread(long irq)
 
 /*----------------------------------------------------------------------*/
 
-/**
- * twl4030_i2c_clear_isr - clear TWL4030 SIH ISR regs via read + write
- * @mod_no: TWL4030 module number
- * @reg: register index to clear
- * @cor: value of the <module>_SIH_CTRL.COR bit (1 or 0)
+/*
+ * 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.
  *
- * Either reads (cor == 1) or writes (cor == 0) to a TWL4030 interrupt
- * status register to ensure that any prior interrupts are cleared.
- * Returns the status from the I2C read operation.
+ * 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 __init twl4030_i2c_clear_isr(u8 mod_no, u8 reg, u8 cor)
+static int twl4030_init_sih_modules(unsigned line)
 {
-       u8 tmp;
+       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 < ARRAY_SIZE(sih_modules); i++, sih++) {
+
+               /* skip USB -- it's funky */
+               if (!sih->bytes_ixr)
+                       continue;
+
+               status = twl4030_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 and BCI, COR=1 means "clear on write".
+                * And for PWR_INT it's not documented...
+                */
+               if (sih->set_cor) {
+                       status = twl4030_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 < ARRAY_SIZE(sih_modules); i++, sih++) {
+               u8 rxbuf[4];
+               int j;
+
+               /* skip USB */
+               if (!sih->bytes_ixr)
+                       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 = twl4030_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 = twl4030_i2c_write(sih->module, buf,
+                                       sih->mask[line].isr_offset,
+                                       sih->bytes_ixr);
+                       /* else COR=1 means read sufficed.
+                        * (for most SIH modules...)
+                        */
+               }
+       }
 
-       return (cor) ? twl4030_i2c_read_u8(mod_no, &tmp, reg) :
-               twl4030_i2c_write_u8(mod_no, 0xff, reg);
+       return 0;
 }
 
-/**
- * twl4030_read_cor_bit - are TWL module ISRs cleared by reads or writes?
- * @mod_no: TWL4030 module number
- * @reg: register index to clear
- *
- * Returns 1 if the TWL4030 SIH interrupt status registers (ISRs) for
- * the specified TWL module are cleared by reads, or 0 if cleared by
- * writes.
- */
-static int twl4030_read_cor_bit(u8 mod_no, u8 reg)
+static inline void activate_irq(int irq)
 {
-       u8 tmp = 0;
+#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 */
+       set_irq_noprobe(irq);
+#endif
+}
+
+/*----------------------------------------------------------------------*/
+
+static DEFINE_SPINLOCK(sih_agent_lock);
 
-       WARN_ON(twl4030_i2c_read_u8(mod_no, &tmp, reg) < 0);
+static struct workqueue_struct *wq;
 
-       tmp &= TWL4030_SIH_CTRL_COR_MASK;
-       tmp >>= __ffs(TWL4030_SIH_CTRL_COR_MASK);
+struct sih_agent {
+       int                     irq_base;
+       const struct sih        *sih;
 
-       return tmp;
+       u32                     imr;
+       bool                    imr_change_pending;
+       struct work_struct      mask_work;
+
+       u32                     edge_change;
+       struct work_struct      edge_work;
+};
+
+static void twl4030_sih_do_mask(struct work_struct *work)
+{
+       struct sih_agent        *agent;
+       const struct sih        *sih;
+       union {
+               u8      bytes[4];
+               u32     word;
+       }                       imr;
+       int                     status;
+
+       agent = container_of(work, struct sih_agent, mask_work);
+
+       /* see what work we have */
+       spin_lock_irq(&sih_agent_lock);
+       if (agent->imr_change_pending) {
+               sih = agent->sih;
+               /* byte[0] gets overwritten as we write ... */
+               imr.word = cpu_to_le32(agent->imr << 8);
+               agent->imr_change_pending = false;
+       } else
+               sih = NULL;
+       spin_unlock_irq(&sih_agent_lock);
+       if (!sih)
+               return;
+
+       /* write the whole mask ... simpler than subsetting it */
+       status = twl4030_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);
 }
 
-/**
- * twl4030_mask_clear_intrs - mask and clear all TWL4030 interrupts
- * @t: pointer to twl4030_mod_iregs array
- * @t_sz: ARRAY_SIZE(t) (starting at 1)
- *
- * Mask all TWL4030 interrupt mask registers (IMRs) and clear all
- * interrupt status registers (ISRs).  No return value, but will WARN if
- * any I2C operations fail.
+static void twl4030_sih_do_edge(struct work_struct *work)
+{
+       struct sih_agent        *agent;
+       const struct sih        *sih;
+       u8                      bytes[6];
+       u32                     edge_change;
+       int                     status;
+
+       agent = container_of(work, struct sih_agent, edge_work);
+
+       /* see what work we have */
+       spin_lock_irq(&sih_agent_lock);
+       edge_change = agent->edge_change;
+       agent->edge_change = 0;;
+       sih = edge_change ? agent->sih : NULL;
+       spin_unlock_irq(&sih_agent_lock);
+       if (!sih)
+               return;
+
+       /* 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 = twl4030_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_desc *d = irq_desc + i + agent->irq_base;
+               int             byte = 1 + (i >> 2);
+               int             off = (i & 0x3) * 2;
+
+               bytes[byte] &= ~(0x03 << off);
+
+               spin_lock_irq(&d->lock);
+               if (d->status & IRQ_TYPE_EDGE_RISING)
+                       bytes[byte] |= BIT(off + 1);
+               if (d->status & IRQ_TYPE_EDGE_FALLING)
+                       bytes[byte] |= BIT(off + 0);
+               spin_unlock_irq(&d->lock);
+
+               edge_change &= ~BIT(i);
+       }
+
+       /* Write */
+       status = twl4030_i2c_write(sih->module, bytes,
+                       sih->edr_offset, sih->bytes_edr);
+       if (status)
+               pr_err("twl4030: %s, %s --> %d\n", __func__,
+                               "write", status);
+}
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * 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 __init twl4030_mask_clear_intrs(const struct twl4030_mod_iregs *t,
-                                           const u8 t_sz)
+
+static void twl4030_sih_mask(unsigned irq)
 {
-       int i, j;
+       struct sih_agent *sih = get_irq_chip_data(irq);
+       unsigned long flags;
+
+       spin_lock_irqsave(&sih_agent_lock, flags);
+       sih->imr |= BIT(irq - sih->irq_base);
+       sih->imr_change_pending = true;
+       queue_work(wq, &sih->mask_work);
+       spin_unlock_irqrestore(&sih_agent_lock, flags);
+}
 
-       /*
-        * N.B. - further efficiency is possible here.  Eight I2C
-        * operations on BCI and GPIO modules are avoidable if I2C
-        * burst read/write transactions were implemented.  Would
-        * probably save about 1ms of boot time and a small amount of
-        * power.
-        */
-       for (i = 0; i < t_sz; i++) {
-               const struct twl4030_mod_iregs tmr = t[i];
-               int cor;
+static void twl4030_sih_unmask(unsigned irq)
+{
+       struct sih_agent *sih = get_irq_chip_data(irq);
+       unsigned long flags;
+
+       spin_lock_irqsave(&sih_agent_lock, flags);
+       sih->imr &= ~BIT(irq - sih->irq_base);
+       sih->imr_change_pending = true;
+       queue_work(wq, &sih->mask_work);
+       spin_unlock_irqrestore(&sih_agent_lock, flags);
+}
 
-               /* Are ISRs cleared by reads or writes? */
-               cor = twl4030_read_cor_bit(tmr.mod_no, tmr.sih_ctrl);
+static int twl4030_sih_set_type(unsigned irq, unsigned trigger)
+{
+       struct sih_agent *sih = get_irq_chip_data(irq);
+       struct irq_desc *desc = irq_desc + irq;
+       unsigned long flags;
+
+       if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
+               return -EINVAL;
+
+       spin_lock_irqsave(&sih_agent_lock, flags);
+       if ((desc->status & IRQ_TYPE_SENSE_MASK) != trigger) {
+               desc->status &= ~IRQ_TYPE_SENSE_MASK;
+               desc->status |= trigger;
+               sih->edge_change |= BIT(irq - sih->irq_base);
+               queue_work(wq, &sih->edge_work);
+       }
+       spin_unlock_irqrestore(&sih_agent_lock, flags);
+       return 0;
+}
+
+static struct irq_chip twl4030_sih_irq_chip = {
+       .name           = "twl4030",
+       .mask           = twl4030_sih_mask,
+       .unmask         = twl4030_sih_unmask,
+       .set_type       = twl4030_sih_set_type,
+};
+
+/*----------------------------------------------------------------------*/
+
+static inline int sih_read_isr(const struct sih *sih)
+{
+       int status;
+       union {
+               u8 bytes[4];
+               u32 word;
+       } isr;
 
-               for (j = 0; j < tmr.reg_cnt; j++) {
+       /* FIXME need retry-on-error ... */
 
-                       /* Mask interrupts at the TWL4030 */
-                       WARN_ON(twl4030_i2c_write_u8(tmr.mod_no, 0xff,
-                                                    tmr.imrs[j]) < 0);
+       isr.word = 0;
+       status = twl4030_i2c_read(sih->module, isr.bytes,
+                       sih->mask[irq_line].isr_offset, sih->bytes_ixr);
 
-                       /* Clear TWL4030 ISRs */
-                       WARN_ON(twl4030_i2c_clear_isr(tmr.mod_no,
-                                                     tmr.isrs[j], cor) < 0);
+       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 void handle_twl4030_sih(unsigned irq, struct irq_desc *desc)
+{
+       struct sih_agent *agent = get_irq_data(irq);
+       const struct sih *sih = agent->sih;
+       int isr;
+
+       /* reading ISR acks the IRQs, using clear-on-read mode */
+       local_irq_enable();
+       isr = sih_read_isr(sih);
+       local_irq_disable();
+
+       if (isr < 0) {
+               pr_err("twl4030: %s SIH, read ISR error %d\n",
+                       sih->name, isr);
+               /* REVISIT:  recover; eventually mask it all, etc */
+               return;
+       }
+
+       while (isr) {
+               irq = fls(isr);
+               irq--;
+               isr &= ~BIT(irq);
+
+               if (irq < sih->bits)
+                       generic_handle_irq(agent->irq_base + irq);
+               else
+                       pr_err("twl4030: %s SIH, invalid ISR bit %d\n",
+                               sih->name, irq);
+       }
+}
+
+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 < ARRAY_SIZE(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;
+       INIT_WORK(&agent->mask_work, twl4030_sih_do_mask);
+       INIT_WORK(&agent->edge_work, twl4030_sih_do_edge);
+
+       for (i = 0; i < sih->bits; i++) {
+               irq = irq_base + i;
+
+               set_irq_chip_and_handler(irq, &twl4030_sih_irq_chip,
+                               handle_edge_irq);
+               set_irq_chip_data(irq, agent);
+               activate_irq(irq);
+       }
+
+       status = irq_base;
+       twl4030_irq_next += i;
+
+       /* replace generic PIH handler (handle_simple_irq) */
+       irq = sih_mod + twl4030_irq_base;
+       set_irq_data(irq, agent);
+       set_irq_chained_handler(irq, handle_twl4030_sih);
+
+       pr_info("twl4030: %s (irq %d) chaining IRQs %d..%d\n", sih->name,
+                       irq, irq_base, twl4030_irq_next - 1);
+
+       return status;
 }
 
+/* FIXME need a call to reverse twl4030_sih_setup() ... */
+
+
+/*----------------------------------------------------------------------*/
+
+/* FIXME pass in which interrupt line we'll use ... */
+#define twl_irq_line   0
 
 int twl_init_irq(int irq_num, unsigned irq_base, unsigned irq_end)
 {
        static struct irq_chip  twl4030_irq_chip;
 
+       int                     status;
        int                     i;
+       struct task_struct      *task;
 
        /*
         * Mask and clear all TWL4030 interrupts since initially we do
         * not have any TWL4030 module interrupt handlers present
         */
-       twl4030_mask_clear_intrs(twl4030_mod_regs,
-                                ARRAY_SIZE(twl4030_mod_regs));
+       status = twl4030_init_sih_modules(twl_irq_line);
+       if (status < 0)
+               return status;
+
+       wq = create_singlethread_workqueue("twl4030-irqchip");
+       if (!wq) {
+               pr_err("twl4030: workqueue FAIL\n");
+               return -ESRCH;
+       }
 
        twl4030_irq_base = irq_base;
 
@@ -384,17 +693,36 @@ int twl_init_irq(int irq_num, unsigned irq_base, unsigned irq_end)
        twl4030_irq_chip = dummy_irq_chip;
        twl4030_irq_chip.name = "twl4030";
 
+       twl4030_sih_irq_chip.ack = dummy_irq_chip.ack;
+
        for (i = irq_base; i < irq_end; i++) {
                set_irq_chip_and_handler(i, &twl4030_irq_chip,
                                handle_simple_irq);
                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);
 
        /* install an irq handler to demultiplex the TWL4030 interrupt */
-       set_irq_data(irq_num, start_twl4030_irq_thread(irq_num));
+       task = start_twl4030_irq_thread(irq_num);
+       if (!task) {
+               pr_err("twl4030: irq thread FAIL\n");
+               status = -ESRCH;
+               goto fail;
+       }
+
+       set_irq_data(irq_num, task);
        set_irq_chained_handler(irq_num, handle_twl4030_pih);
 
-       return 0;
+       return status;
+
+fail:
+       for (i = irq_base; i < irq_end; i++)
+               set_irq_chip_and_handler(i, NULL, NULL);
+       destroy_workqueue(wq);
+       wq = NULL;
+       return status;
 }
 
 int twl_exit_irq(void)