/*
 * twl6030-irq.c - TWL6030 irq support
 *
 * Copyright (C) 2005-2009 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>
 *
 * TWL6030 specific code and IRQ handling changes by
 * Jagadeesh Bhaskar Pakaravoor <j-pakaravoor@ti.com>
 * Balaji T K <balajitk@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/kthread.h>
#include <linux/i2c/twl.h>

/*
 * TWL6030 (unlike its predecessors, which had two level interrupt handling)
 * three interrupt registers INT_STS_A, INT_STS_B and INT_STS_C.
 * It exposes status bits saying who has raised an interrupt. There are
 * three mask registers that corresponds to these status registers, that
 * enables/disables these interrupts.
 *
 * We set up IRQs starting at a platform-specified base. An interrupt map table,
 * specifies mapping between interrupt number and the associated module.
 *
 */

static int twl6030_interrupt_mapping[24] = {
	PWR_INTR_OFFSET,	/* Bit 0	PWRON			*/
	PWR_INTR_OFFSET,	/* Bit 1	RPWRON			*/
	PWR_INTR_OFFSET,	/* Bit 2	BAT_VLOW		*/
	RTC_INTR_OFFSET,	/* Bit 3	RTC_ALARM		*/
	RTC_INTR_OFFSET,	/* Bit 4	RTC_PERIOD		*/
	HOTDIE_INTR_OFFSET,	/* Bit 5	HOT_DIE			*/
	SMPSLDO_INTR_OFFSET,	/* Bit 6	VXXX_SHORT		*/
	SMPSLDO_INTR_OFFSET,	/* Bit 7	VMMC_SHORT		*/

	SMPSLDO_INTR_OFFSET,	/* Bit 8	VUSIM_SHORT		*/
	BATDETECT_INTR_OFFSET,	/* Bit 9	BAT			*/
	SIMDETECT_INTR_OFFSET,	/* Bit 10	SIM			*/
	MMCDETECT_INTR_OFFSET,	/* Bit 11	MMC			*/
	RSV_INTR_OFFSET,  	/* Bit 12	Reserved		*/
	MADC_INTR_OFFSET,	/* Bit 13	GPADC_RT_EOC		*/
	MADC_INTR_OFFSET,	/* Bit 14	GPADC_SW_EOC		*/
	GASGAUGE_INTR_OFFSET,	/* Bit 15	CC_AUTOCAL		*/

	USBOTG_INTR_OFFSET,	/* Bit 16	ID_WKUP			*/
	USBOTG_INTR_OFFSET,	/* Bit 17	VBUS_WKUP		*/
	USBOTG_INTR_OFFSET,	/* Bit 18	ID			*/
	USBOTG_INTR_OFFSET,	/* Bit 19	VBUS			*/
	CHARGER_INTR_OFFSET,	/* Bit 20	CHRG_CTRL		*/
	CHARGER_INTR_OFFSET,	/* Bit 21	EXT_CHRG		*/
	CHARGER_INTR_OFFSET,	/* Bit 22	INT_CHRG		*/
	RSV_INTR_OFFSET,	/* Bit 23	Reserved		*/
};
/*----------------------------------------------------------------------*/

static unsigned twl6030_irq_base;

static struct completion irq_event;

/*
 * This thread processes interrupts reported by the Primary Interrupt Handler.
 */
static int twl6030_irq_thread(void *data)
{
	long irq = (long)data;
	static unsigned i2c_errors;
	static const unsigned max_i2c_errors = 100;
	int ret;

	current->flags |= PF_NOFREEZE;

	while (!kthread_should_stop()) {
		int i;
		union {
		u8 bytes[4];
		u32 int_sts;
		} sts;

		/* Wait for IRQ, then read PIH irq status (also blocking) */
		wait_for_completion_interruptible(&irq_event);

		/* read INT_STS_A, B and C in one shot using a burst read */
		ret = twl_i2c_read(TWL_MODULE_PIH, sts.bytes,
				REG_INT_STS_A, 3);
		if (ret) {
			pr_warning("twl6030: I2C error %d reading PIH ISR\n",
					ret);
			if (++i2c_errors >= max_i2c_errors) {
				printk(KERN_ERR "Maximum I2C error count"
						" exceeded.  Terminating %s.\n",
						__func__);
				break;
			}
			complete(&irq_event);
			continue;
		}


		sts.bytes[3] = 0; /* Only 24 bits are valid*/

		for (i = 0; sts.int_sts; sts.int_sts >>= 1, i++) {
			local_irq_disable();
			if (sts.int_sts & 0x1) {
				int module_irq = twl6030_irq_base +
					twl6030_interrupt_mapping[i];
				struct irq_desc *d = irq_to_desc(module_irq);

				if (!d) {
					pr_err("twl6030: Invalid SIH IRQ: %d\n",
					       module_irq);
					return -EINVAL;
				}

				/* These can't be masked ... always warn
				 * if we get any surprises.
				 */
				if (d->status & IRQ_DISABLED)
					note_interrupt(module_irq, d,
							IRQ_NONE);
				else
					d->handle_irq(module_irq, d);

			}
		local_irq_enable();
		}
		ret = twl_i2c_write(TWL_MODULE_PIH, sts.bytes,
				REG_INT_STS_A, 3); /* clear INT_STS_A */
		if (ret)
			pr_warning("twl6030: I2C error in clearing PIH ISR\n");

		enable_irq(irq);
	}

	return 0;
}

/*
 * handle_twl6030_int() is the desc->handle method for the twl6030 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 twl6030 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_twl6030_pih(int irq, void *devid)
{
	disable_irq_nosync(irq);
	complete(devid);
	return IRQ_HANDLED;
}

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

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
}

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

static unsigned twl6030_irq_next;

/*----------------------------------------------------------------------*/
int twl6030_interrupt_unmask(u8 bit_mask, u8 offset)
{
	int ret;
	u8 unmask_value;
	ret = twl_i2c_read_u8(TWL_MODULE_PIH, &unmask_value,
			REG_INT_STS_A + offset);
	unmask_value &= (~(bit_mask));
	ret |= twl_i2c_write_u8(TWL_MODULE_PIH, unmask_value,
			REG_INT_STS_A + offset); /* unmask INT_MSK_A/B/C */
	return ret;
}
EXPORT_SYMBOL(twl6030_interrupt_unmask);

int twl6030_interrupt_mask(u8 bit_mask, u8 offset)
{
	int ret;
	u8 mask_value;
	ret = twl_i2c_read_u8(TWL_MODULE_PIH, &mask_value,
			REG_INT_STS_A + offset);
	mask_value |= (bit_mask);
	ret |= twl_i2c_write_u8(TWL_MODULE_PIH, mask_value,
			REG_INT_STS_A + offset); /* mask INT_MSK_A/B/C */
	return ret;
}
EXPORT_SYMBOL(twl6030_interrupt_mask);

int twl6030_init_irq(int irq_num, unsigned irq_base, unsigned irq_end)
{

	int	status = 0;
	int	i;
	struct task_struct	*task;
	int ret;
	u8 mask[4];

	static struct irq_chip	twl6030_irq_chip;
	mask[1] = 0xFF;
	mask[2] = 0xFF;
	mask[3] = 0xFF;
	ret = twl_i2c_write(TWL_MODULE_PIH, &mask[0],
			REG_INT_MSK_LINE_A, 3); /* MASK ALL INT LINES */
	ret = twl_i2c_write(TWL_MODULE_PIH, &mask[0],
			REG_INT_MSK_STS_A, 3); /* MASK ALL INT STS */
	ret = twl_i2c_write(TWL_MODULE_PIH, &mask[0],
			REG_INT_STS_A, 3); /* clear INT_STS_A,B,C */

	twl6030_irq_base = irq_base;

	/* install an irq handler for each of the modules;
	 * clone dummy irq_chip since PIH can't *do* anything
	 */
	twl6030_irq_chip = dummy_irq_chip;
	twl6030_irq_chip.name = "twl6030";
	twl6030_irq_chip.set_type = NULL;

	for (i = irq_base; i < irq_end; i++) {
		set_irq_chip_and_handler(i, &twl6030_irq_chip,
				handle_simple_irq);
		activate_irq(i);
	}

	twl6030_irq_next = i;
	pr_info("twl6030: %s (irq %d) chaining IRQs %d..%d\n", "PIH",
			irq_num, irq_base, twl6030_irq_next - 1);

	/* install an irq handler to demultiplex the TWL6030 interrupt */
	init_completion(&irq_event);
	task = kthread_run(twl6030_irq_thread, (void *)irq_num, "twl6030-irq");
	if (IS_ERR(task)) {
		pr_err("twl6030: could not create irq %d thread!\n", irq_num);
		status = PTR_ERR(task);
		goto fail_kthread;
	}

	status = request_irq(irq_num, handle_twl6030_pih, IRQF_DISABLED,
				"TWL6030-PIH", &irq_event);
	if (status < 0) {
		pr_err("twl6030: could not claim irq%d: %d\n", irq_num, status);
		goto fail_irq;
	}
	return status;
fail_irq:
	free_irq(irq_num, &irq_event);

fail_kthread:
	for (i = irq_base; i < irq_end; i++)
		set_irq_chip_and_handler(i, NULL, NULL);
	return status;
}

int twl6030_exit_irq(void)
{

	if (twl6030_irq_base) {
		pr_err("twl6030: can't yet clean up IRQs?\n");
		return -ENOSYS;
	}
	return 0;
}