mfd: twl4030 IRQ handling update

- Move it into a separate file; clean and streamline it
 - Restructure the init code for reuse during secondary dispatch
 - Support both levels (primary, secondary) of IRQ dispatch
 - Use a workqueue for irq mask/unmask and trigger configuration

Code for two subchips currently share that secondary handler code.
One is the power subchip; its IRQs are now handled by this core,
courtesy of this patch.  The other is the GPIO module, which will
be supported through a later patch.

There are also minor changes to the header file, mostly related
to GPIO support; nothing yet in mainline cares about those.  A
few references to OMAP-specific symbols are disabled; when they
can all be removed, the TWL4030 support ceases being OMAP-specific.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>

1 files changed, 17 insertions, 404 deletions

diff --git a/drivers/mfd/twl4030-core.c b/drivers/mfd/twl4030-core.c
index fd9a016..dd843c4 100644
--- a/drivers/mfd/twl4030-core.c
+++ b/drivers/mfd/twl4030-core.c
@@ -27,15 +27,11 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  */
 
-#include <linux/kernel_stat.h>
 #include <linux/init.h>
 #include <linux/mutex.h>
-#include <linux/interrupt.h>
-#include <linux/irq.h>
-#include <linux/random.h>
-#include <linux/kthread.h>
 #include <linux/platform_device.h>
 #include <linux/clk.h>
+#include <linux/err.h>
 
 #include <linux/i2c.h>
 #include <linux/i2c/twl4030.h>
@@ -93,26 +89,6 @@
 #define twl_has_usb()	false
 #endif
 
-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
-}
-
-/* Primary Interrupt Handler on TWL4030 Registers */
-
-/* Register Definitions */
-
-#define REG_PIH_ISR_P1			(0x1)
-#define REG_PIH_ISR_P2			(0x2)
-#define REG_PIH_SIR			(0x3)
 
 /* Triton Core internal information (BEGIN) */
 
@@ -175,138 +151,6 @@ static inline void activate_irq(int irq)
 
 /*----------------------------------------------------------------------*/
 
-/**
- * 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;
-};
-
-/* TWL4030 INT module interrupt mask registers */
-static const u8 __initconst twl4030_int_imr_regs[] = {
-	TWL4030_INT_PWR_IMR1,
-	TWL4030_INT_PWR_IMR2,
-};
-
-/* TWL4030 INT module interrupt status registers */
-static const u8 __initconst twl4030_int_isr_regs[] = {
-	TWL4030_INT_PWR_ISR1,
-	TWL4030_INT_PWR_ISR2,
-};
-
-/* 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,
-};
-
-/* 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,
-};
-
-/* 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,
-	},
-	{
-		.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,
-	},
-	{
-		.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,
-	},
-	{
-		.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,
-	},
-	{
-		.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,
-	},
-};
-
-/*----------------------------------------------------------------*/
-
 /* is driver active, bound to a chip? */
 static bool inuse;
 
@@ -367,33 +211,6 @@ static struct twl4030mapping twl4030_map[TWL4030_MODULE_LAST + 1] = {
 
 /*----------------------------------------------------------------------*/
 
-/*
- * TWL4030 doesn't have PIH mask, hence dummy function for mask
- * and unmask of the (eight) interrupts reported at that level ...
- * masking is only available from SIH (secondary) modules.
- */
-
-static void twl4030_i2c_ackirq(unsigned int irq)
-{
-}
-
-static void twl4030_i2c_disableint(unsigned int irq)
-{
-}
-
-static void twl4030_i2c_enableint(unsigned int irq)
-{
-}
-
-static struct irq_chip twl4030_irq_chip = {
-	.name	= "twl4030",
-	.ack	= twl4030_i2c_ackirq,
-	.mask	= twl4030_i2c_disableint,
-	.unmask	= twl4030_i2c_enableint,
-};
-
-/*----------------------------------------------------------------------*/
-
 /* Exported Functions */
 
 /**
@@ -535,108 +352,11 @@ EXPORT_SYMBOL(twl4030_i2c_read_u8);
 
 /*----------------------------------------------------------------------*/
 
-static unsigned twl4030_irq_base;
-
-static struct completion irq_event;
-
-/*
- * This thread processes interrupts reported by the Primary Interrupt Handler.
- */
-static int twl4030_irq_thread(void *data)
-{
-	long irq = (long)data;
-	irq_desc_t *desc = irq_desc + irq;
-	static unsigned i2c_errors;
-	const static unsigned max_i2c_errors = 100;
-
-	current->flags |= PF_NOFREEZE;
-
-	while (!kthread_should_stop()) {
-		int ret;
-		int module_irq;
-		u8 pih_isr;
-
-		/* Wait for IRQ, then read PIH irq status (also blocking) */
-		wait_for_completion_interruptible(&irq_event);
-
-		ret = twl4030_i2c_read_u8(TWL4030_MODULE_PIH, &pih_isr,
-					  REG_PIH_ISR_P1);
-		if (ret) {
-			pr_warning("%s: I2C error %d reading PIH ISR\n",
-					DRIVER_NAME, ret);
-			if (++i2c_errors >= max_i2c_errors) {
-				printk(KERN_ERR "Maximum I2C error count"
-						" exceeded.  Terminating %s.\n",
-						__func__);
-				break;
-			}
-			complete(&irq_event);
-			continue;
-		}
-
-		/* these handlers deal with the relevant SIH irq status */
-		local_irq_disable();
-		for (module_irq = twl4030_irq_base;
-				pih_isr;
-				pih_isr >>= 1, module_irq++) {
-			if (pih_isr & 0x1) {
-				irq_desc_t *d = irq_desc + module_irq;
-
-				d->handle_irq(module_irq, d);
-			}
-		}
-		local_irq_enable();
-
-		desc->chip->unmask(irq);
-	}
-
-	return 0;
-}
-
 /*
- * do_twl4030_irq() 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.
+ * NOTE:  We know the first 8 IRQs after pdata->base_irq are
+ * for the PIH, and the next are for the PWR_INT SIH, since
+ * that's how twl_init_irq() sets things up.
  */
-static void do_twl4030_irq(unsigned int irq, irq_desc_t *desc)
-{
-	const unsigned int cpu = smp_processor_id();
-
-	/*
-	 * Earlier this was desc->triggered = 1;
-	 */
-	desc->status |= IRQ_LEVEL;
-
-	/*
-	 * Acknowledge, clear _AND_ disable the interrupt.
-	 */
-	desc->chip->ack(irq);
-
-	if (!desc->depth) {
-		kstat_cpu(cpu).irqs[irq]++;
-
-		complete(&irq_event);
-	}
-}
-
-static struct task_struct * __init start_twl4030_irq_thread(long irq)
-{
-	struct task_struct *thread;
-
-	init_completion(&irq_event);
-	thread = kthread_run(twl4030_irq_thread, (void *)irq, "twl4030-irq");
-	if (!thread)
-		pr_err("%s: could not create twl4030 irq %ld thread!\n",
-		       DRIVER_NAME, irq);
-
-	return thread;
-}
-
-/*----------------------------------------------------------------------*/
 
 static int add_children(struct twl4030_platform_data *pdata)
 {
@@ -668,7 +388,7 @@ static int add_children(struct twl4030_platform_data *pdata)
 
 		if (status == 0) {
 			struct resource r = {
-				.start = TWL4030_PWRIRQ_CHG_PRES,
+				.start = pdata->irq_base + 8 + 1,
 				.flags = IORESOURCE_IRQ,
 			};
 
@@ -817,8 +537,7 @@ static int add_children(struct twl4030_platform_data *pdata)
 		/* RTC module IRQ */
 		if (status == 0) {
 			struct resource	r = {
-				/* REVISIT don't hard-wire this stuff */
-				.start = TWL4030_PWRIRQ_RTC,
+				.start = pdata->irq_base + 8 + 3,
 				.flags = IORESOURCE_IRQ,
 			};
 
@@ -863,7 +582,7 @@ static int add_children(struct twl4030_platform_data *pdata)
 
 		if (status == 0) {
 			struct resource r = {
-				.start = TWL4030_PWRIRQ_USB_PRES,
+				.start = pdata->irq_base + 8 + 2,
 				.flags = IORESOURCE_IRQ,
 			};
 
@@ -965,123 +684,17 @@ static void __init clocks_init(void)
 
 /*----------------------------------------------------------------------*/
 
-/**
- * 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)
- *
- * 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.
- */
-static int __init twl4030_i2c_clear_isr(u8 mod_no, u8 reg, u8 cor)
-{
-	u8 tmp;
-
-	return (cor) ? twl4030_i2c_read_u8(mod_no, &tmp, reg) :
-		twl4030_i2c_write_u8(mod_no, 0xff, reg);
-}
-
-/**
- * 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)
-{
-	u8 tmp = 0;
-
-	WARN_ON(twl4030_i2c_read_u8(mod_no, &tmp, reg) < 0);
-
-	tmp &= TWL4030_SIH_CTRL_COR_MASK;
-	tmp >>= __ffs(TWL4030_SIH_CTRL_COR_MASK);
-
-	return tmp;
-}
-
-/**
- * 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 __init twl4030_mask_clear_intrs(const struct twl4030_mod_iregs *t,
-					    const u8 t_sz)
-{
-	int i, j;
-
-	/*
-	 * 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;
-
-		/* Are ISRs cleared by reads or writes? */
-		cor = twl4030_read_cor_bit(tmr.mod_no, tmr.sih_ctrl);
-
-		for (j = 0; j < tmr.reg_cnt; j++) {
-
-			/* Mask interrupts at the TWL4030 */
-			WARN_ON(twl4030_i2c_write_u8(tmr.mod_no, 0xff,
-						     tmr.imrs[j]) < 0);
-
-			/* Clear TWL4030 ISRs */
-			WARN_ON(twl4030_i2c_clear_isr(tmr.mod_no,
-						      tmr.isrs[j], cor) < 0);
-		}
-	}
-}
-
-
-static void twl_init_irq(int irq_num, unsigned irq_base, unsigned irq_end)
-{
-	int	i;
-
-	/*
-	 * 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));
-
-	twl4030_irq_base = irq_base;
-
-	/* install an irq handler for each of the PIH modules */
-	for (i = irq_base; i < irq_end; i++) {
-		set_irq_chip_and_handler(i, &twl4030_irq_chip,
-				handle_simple_irq);
-		activate_irq(i);
-	}
-
-	/* install an irq handler to demultiplex the TWL4030 interrupt */
-	set_irq_data(irq_num, start_twl4030_irq_thread(irq_num));
-	set_irq_chained_handler(irq_num, do_twl4030_irq);
-}
-
-/*----------------------------------------------------------------------*/
+int twl_init_irq(int irq_num, unsigned irq_base, unsigned irq_end);
+int twl_exit_irq(void);
 
 static int twl4030_remove(struct i2c_client *client)
 {
 	unsigned i;
+	int status;
 
-	/* FIXME undo twl_init_irq() */
-	if (twl4030_irq_base) {
-		dev_err(&client->dev, "can't yet clean up IRQs?\n");
-		return -ENOSYS;
-	}
+	status = twl_exit_irq();
+	if (status < 0)
+		return status;
 
 	for (i = 0; i < TWL4030_NUM_SLAVES; i++) {
 		struct twl4030_client	*twl = &twl4030_modules[i];
@@ -1112,7 +725,7 @@ twl4030_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		return -EIO;
 	}
 
-	if (inuse || twl4030_irq_base) {
+	if (inuse) {
 		dev_dbg(&client->dev, "driver is already in use\n");
 		return -EBUSY;
 	}
@@ -1146,9 +759,9 @@ twl4030_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	if (client->irq
 			&& pdata->irq_base
 			&& pdata->irq_end > pdata->irq_base) {
-		twl_init_irq(client->irq, pdata->irq_base, pdata->irq_end);
-		dev_info(&client->dev, "IRQ %d chains IRQs %d..%d\n",
-				client->irq, pdata->irq_base, pdata->irq_end - 1);
+		status = twl_init_irq(client->irq, pdata->irq_base, pdata->irq_end);
+		if (status < 0)
+			goto fail;
 	}
 
 	status = add_children(pdata);