/*
 * wm831x-irq.c  --  Interrupt controller support for Wolfson WM831x PMICs
 *
 * Copyright 2009 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <broonie@opensource.wolfsonmicro.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.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/irq.h>
#include <linux/mfd/core.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>

#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/gpio.h>
#include <linux/mfd/wm831x/irq.h>

#include <linux/delay.h>

struct wm831x_irq_data {
	int primary;
	int reg;
	int mask;
};

static struct wm831x_irq_data wm831x_irqs[] = {
	[WM831X_IRQ_TEMP_THW] = {
		.primary = WM831X_TEMP_INT,
		.reg = 1,
		.mask = WM831X_TEMP_THW_EINT,
	},
	[WM831X_IRQ_GPIO_1] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP1_EINT,
	},
	[WM831X_IRQ_GPIO_2] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP2_EINT,
	},
	[WM831X_IRQ_GPIO_3] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP3_EINT,
	},
	[WM831X_IRQ_GPIO_4] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP4_EINT,
	},
	[WM831X_IRQ_GPIO_5] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP5_EINT,
	},
	[WM831X_IRQ_GPIO_6] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP6_EINT,
	},
	[WM831X_IRQ_GPIO_7] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP7_EINT,
	},
	[WM831X_IRQ_GPIO_8] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP8_EINT,
	},
	[WM831X_IRQ_GPIO_9] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP9_EINT,
	},
	[WM831X_IRQ_GPIO_10] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP10_EINT,
	},
	[WM831X_IRQ_GPIO_11] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP11_EINT,
	},
	[WM831X_IRQ_GPIO_12] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP12_EINT,
	},
	[WM831X_IRQ_GPIO_13] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP13_EINT,
	},
	[WM831X_IRQ_GPIO_14] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP14_EINT,
	},
	[WM831X_IRQ_GPIO_15] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP15_EINT,
	},
	[WM831X_IRQ_GPIO_16] = {
		.primary = WM831X_GP_INT,
		.reg = 5,
		.mask = WM831X_GP16_EINT,
	},
	[WM831X_IRQ_ON] = {
		.primary = WM831X_ON_PIN_INT,
		.reg = 1,
		.mask = WM831X_ON_PIN_EINT,
	},
	[WM831X_IRQ_PPM_SYSLO] = {
		.primary = WM831X_PPM_INT,
		.reg = 1,
		.mask = WM831X_PPM_SYSLO_EINT,
	},
	[WM831X_IRQ_PPM_PWR_SRC] = {
		.primary = WM831X_PPM_INT,
		.reg = 1,
		.mask = WM831X_PPM_PWR_SRC_EINT,
	},
	[WM831X_IRQ_PPM_USB_CURR] = {
		.primary = WM831X_PPM_INT,
		.reg = 1,
		.mask = WM831X_PPM_USB_CURR_EINT,
	},
	[WM831X_IRQ_WDOG_TO] = {
		.primary = WM831X_WDOG_INT,
		.reg = 1,
		.mask = WM831X_WDOG_TO_EINT,
	},
	[WM831X_IRQ_RTC_PER] = {
		.primary = WM831X_RTC_INT,
		.reg = 1,
		.mask = WM831X_RTC_PER_EINT,
	},
	[WM831X_IRQ_RTC_ALM] = {
		.primary = WM831X_RTC_INT,
		.reg = 1,
		.mask = WM831X_RTC_ALM_EINT,
	},
	[WM831X_IRQ_CHG_BATT_HOT] = {
		.primary = WM831X_CHG_INT,
		.reg = 2,
		.mask = WM831X_CHG_BATT_HOT_EINT,
	},
	[WM831X_IRQ_CHG_BATT_COLD] = {
		.primary = WM831X_CHG_INT,
		.reg = 2,
		.mask = WM831X_CHG_BATT_COLD_EINT,
	},
	[WM831X_IRQ_CHG_BATT_FAIL] = {
		.primary = WM831X_CHG_INT,
		.reg = 2,
		.mask = WM831X_CHG_BATT_FAIL_EINT,
	},
	[WM831X_IRQ_CHG_OV] = {
		.primary = WM831X_CHG_INT,
		.reg = 2,
		.mask = WM831X_CHG_OV_EINT,
	},
	[WM831X_IRQ_CHG_END] = {
		.primary = WM831X_CHG_INT,
		.reg = 2,
		.mask = WM831X_CHG_END_EINT,
	},
	[WM831X_IRQ_CHG_TO] = {
		.primary = WM831X_CHG_INT,
		.reg = 2,
		.mask = WM831X_CHG_TO_EINT,
	},
	[WM831X_IRQ_CHG_MODE] = {
		.primary = WM831X_CHG_INT,
		.reg = 2,
		.mask = WM831X_CHG_MODE_EINT,
	},
	[WM831X_IRQ_CHG_START] = {
		.primary = WM831X_CHG_INT,
		.reg = 2,
		.mask = WM831X_CHG_START_EINT,
	},
	[WM831X_IRQ_TCHDATA] = {
		.primary = WM831X_TCHDATA_INT,
		.reg = 1,
		.mask = WM831X_TCHDATA_EINT,
	},
	[WM831X_IRQ_TCHPD] = {
		.primary = WM831X_TCHPD_INT,
		.reg = 1,
		.mask = WM831X_TCHPD_EINT,
	},
	[WM831X_IRQ_AUXADC_DATA] = {
		.primary = WM831X_AUXADC_INT,
		.reg = 1,
		.mask = WM831X_AUXADC_DATA_EINT,
	},
	[WM831X_IRQ_AUXADC_DCOMP1] = {
		.primary = WM831X_AUXADC_INT,
		.reg = 1,
		.mask = WM831X_AUXADC_DCOMP1_EINT,
	},
	[WM831X_IRQ_AUXADC_DCOMP2] = {
		.primary = WM831X_AUXADC_INT,
		.reg = 1,
		.mask = WM831X_AUXADC_DCOMP2_EINT,
	},
	[WM831X_IRQ_AUXADC_DCOMP3] = {
		.primary = WM831X_AUXADC_INT,
		.reg = 1,
		.mask = WM831X_AUXADC_DCOMP3_EINT,
	},
	[WM831X_IRQ_AUXADC_DCOMP4] = {
		.primary = WM831X_AUXADC_INT,
		.reg = 1,
		.mask = WM831X_AUXADC_DCOMP4_EINT,
	},
	[WM831X_IRQ_CS1] = {
		.primary = WM831X_CS_INT,
		.reg = 2,
		.mask = WM831X_CS1_EINT,
	},
	[WM831X_IRQ_CS2] = {
		.primary = WM831X_CS_INT,
		.reg = 2,
		.mask = WM831X_CS2_EINT,
	},
	[WM831X_IRQ_HC_DC1] = {
		.primary = WM831X_HC_INT,
		.reg = 4,
		.mask = WM831X_HC_DC1_EINT,
	},
	[WM831X_IRQ_HC_DC2] = {
		.primary = WM831X_HC_INT,
		.reg = 4,
		.mask = WM831X_HC_DC2_EINT,
	},
	[WM831X_IRQ_UV_LDO1] = {
		.primary = WM831X_UV_INT,
		.reg = 3,
		.mask = WM831X_UV_LDO1_EINT,
	},
	[WM831X_IRQ_UV_LDO2] = {
		.primary = WM831X_UV_INT,
		.reg = 3,
		.mask = WM831X_UV_LDO2_EINT,
	},
	[WM831X_IRQ_UV_LDO3] = {
		.primary = WM831X_UV_INT,
		.reg = 3,
		.mask = WM831X_UV_LDO3_EINT,
	},
	[WM831X_IRQ_UV_LDO4] = {
		.primary = WM831X_UV_INT,
		.reg = 3,
		.mask = WM831X_UV_LDO4_EINT,
	},
	[WM831X_IRQ_UV_LDO5] = {
		.primary = WM831X_UV_INT,
		.reg = 3,
		.mask = WM831X_UV_LDO5_EINT,
	},
	[WM831X_IRQ_UV_LDO6] = {
		.primary = WM831X_UV_INT,
		.reg = 3,
		.mask = WM831X_UV_LDO6_EINT,
	},
	[WM831X_IRQ_UV_LDO7] = {
		.primary = WM831X_UV_INT,
		.reg = 3,
		.mask = WM831X_UV_LDO7_EINT,
	},
	[WM831X_IRQ_UV_LDO8] = {
		.primary = WM831X_UV_INT,
		.reg = 3,
		.mask = WM831X_UV_LDO8_EINT,
	},
	[WM831X_IRQ_UV_LDO9] = {
		.primary = WM831X_UV_INT,
		.reg = 3,
		.mask = WM831X_UV_LDO9_EINT,
	},
	[WM831X_IRQ_UV_LDO10] = {
		.primary = WM831X_UV_INT,
		.reg = 3,
		.mask = WM831X_UV_LDO10_EINT,
	},
	[WM831X_IRQ_UV_DC1] = {
		.primary = WM831X_UV_INT,
		.reg = 4,
		.mask = WM831X_UV_DC1_EINT,
	},
	[WM831X_IRQ_UV_DC2] = {
		.primary = WM831X_UV_INT,
		.reg = 4,
		.mask = WM831X_UV_DC2_EINT,
	},
	[WM831X_IRQ_UV_DC3] = {
		.primary = WM831X_UV_INT,
		.reg = 4,
		.mask = WM831X_UV_DC3_EINT,
	},
	[WM831X_IRQ_UV_DC4] = {
		.primary = WM831X_UV_INT,
		.reg = 4,
		.mask = WM831X_UV_DC4_EINT,
	},
};

static inline int irq_data_to_status_reg(struct wm831x_irq_data *irq_data)
{
	return WM831X_INTERRUPT_STATUS_1 - 1 + irq_data->reg;
}

static inline struct wm831x_irq_data *irq_to_wm831x_irq(struct wm831x *wm831x,
							int irq)
{
	return &wm831x_irqs[irq];
}

static void wm831x_irq_lock(struct irq_data *data)
{
	struct wm831x *wm831x = irq_data_get_irq_chip_data(data);

	mutex_lock(&wm831x->irq_lock);
}

static void wm831x_irq_sync_unlock(struct irq_data *data)
{
	struct wm831x *wm831x = irq_data_get_irq_chip_data(data);
	int i;

	for (i = 0; i < ARRAY_SIZE(wm831x->gpio_update); i++) {
		if (wm831x->gpio_update[i]) {
			wm831x_set_bits(wm831x, WM831X_GPIO1_CONTROL + i,
					WM831X_GPN_INT_MODE | WM831X_GPN_POL,
					wm831x->gpio_update[i]);
			wm831x->gpio_update[i] = 0;
		}
	}

	for (i = 0; i < ARRAY_SIZE(wm831x->irq_masks_cur); i++) {
		/* If there's been a change in the mask write it back
		 * to the hardware. */
		if (wm831x->irq_masks_cur[i] != wm831x->irq_masks_cache[i]) {
			dev_dbg(wm831x->dev, "IRQ mask sync: %x = %x\n",
				WM831X_INTERRUPT_STATUS_1_MASK + i,
				wm831x->irq_masks_cur[i]);

			wm831x->irq_masks_cache[i] = wm831x->irq_masks_cur[i];
			wm831x_reg_write(wm831x,
					 WM831X_INTERRUPT_STATUS_1_MASK + i,
					 wm831x->irq_masks_cur[i]);
		}
	}

	mutex_unlock(&wm831x->irq_lock);
}

static void wm831x_irq_enable(struct irq_data *data)
{
	struct wm831x *wm831x = irq_data_get_irq_chip_data(data);
	struct wm831x_irq_data *irq_data = irq_to_wm831x_irq(wm831x,
							     data->hwirq);

	wm831x->irq_masks_cur[irq_data->reg - 1] &= ~irq_data->mask;
}

static void wm831x_irq_disable(struct irq_data *data)
{
	struct wm831x *wm831x = irq_data_get_irq_chip_data(data);
	struct wm831x_irq_data *irq_data = irq_to_wm831x_irq(wm831x,
							     data->hwirq);

	wm831x->irq_masks_cur[irq_data->reg - 1] |= irq_data->mask;
}

static int wm831x_irq_set_type(struct irq_data *data, unsigned int type)
{
	struct wm831x *wm831x = irq_data_get_irq_chip_data(data);
	int irq;

	irq = data->hwirq;

	if (irq < WM831X_IRQ_GPIO_1 || irq > WM831X_IRQ_GPIO_11) {
		/* Ignore internal-only IRQs */
		if (irq >= 0 && irq < WM831X_NUM_IRQS)
			return 0;
		else
			return -EINVAL;
	}

	/* Rebase the IRQ into the GPIO range so we've got a sensible array
	 * index.
	 */
	irq -= WM831X_IRQ_GPIO_1;

	/* We set the high bit to flag that we need an update; don't
	 * do the update here as we can be called with the bus lock
	 * held.
	 */
	wm831x->gpio_level_low[irq] = false;
	wm831x->gpio_level_high[irq] = false;
	switch (type) {
	case IRQ_TYPE_EDGE_BOTH:
		wm831x->gpio_update[irq] = 0x10000 | WM831X_GPN_INT_MODE;
		break;
	case IRQ_TYPE_EDGE_RISING:
		wm831x->gpio_update[irq] = 0x10000 | WM831X_GPN_POL;
		break;
	case IRQ_TYPE_EDGE_FALLING:
		wm831x->gpio_update[irq] = 0x10000;
		break;
	case IRQ_TYPE_LEVEL_HIGH:
		wm831x->gpio_update[irq] = 0x10000 | WM831X_GPN_POL;
		wm831x->gpio_level_high[irq] = true;
		break;
	case IRQ_TYPE_LEVEL_LOW:
		wm831x->gpio_update[irq] = 0x10000;
		wm831x->gpio_level_low[irq] = true;
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static struct irq_chip wm831x_irq_chip = {
	.name			= "wm831x",
	.irq_bus_lock		= wm831x_irq_lock,
	.irq_bus_sync_unlock	= wm831x_irq_sync_unlock,
	.irq_disable		= wm831x_irq_disable,
	.irq_enable		= wm831x_irq_enable,
	.irq_set_type		= wm831x_irq_set_type,
};

/* The processing of the primary interrupt occurs in a thread so that
 * we can interact with the device over I2C or SPI. */
static irqreturn_t wm831x_irq_thread(int irq, void *data)
{
	struct wm831x *wm831x = data;
	unsigned int i;
	int primary, status_addr, ret;
	int status_regs[WM831X_NUM_IRQ_REGS] = { 0 };
	int read[WM831X_NUM_IRQ_REGS] = { 0 };
	int *status;

	primary = wm831x_reg_read(wm831x, WM831X_SYSTEM_INTERRUPTS);
	if (primary < 0) {
		dev_err(wm831x->dev, "Failed to read system interrupt: %d\n",
			primary);
		goto out;
	}

	/* The touch interrupts are visible in the primary register as
	 * an optimisation; open code this to avoid complicating the
	 * main handling loop and so we can also skip iterating the
	 * descriptors.
	 */
	if (primary & WM831X_TCHPD_INT)
		handle_nested_irq(irq_find_mapping(wm831x->irq_domain,
						   WM831X_IRQ_TCHPD));
	if (primary & WM831X_TCHDATA_INT)
		handle_nested_irq(irq_find_mapping(wm831x->irq_domain,
						   WM831X_IRQ_TCHDATA));
	primary &= ~(WM831X_TCHDATA_EINT | WM831X_TCHPD_EINT);

	for (i = 0; i < ARRAY_SIZE(wm831x_irqs); i++) {
		int offset = wm831x_irqs[i].reg - 1;

		if (!(primary & wm831x_irqs[i].primary))
			continue;

		status = &status_regs[offset];

		/* Hopefully there should only be one register to read
		 * each time otherwise we ought to do a block read. */
		if (!read[offset]) {
			status_addr = irq_data_to_status_reg(&wm831x_irqs[i]);

			*status = wm831x_reg_read(wm831x, status_addr);
			if (*status < 0) {
				dev_err(wm831x->dev,
					"Failed to read IRQ status: %d\n",
					*status);
				goto out;
			}

			read[offset] = 1;

			/* Ignore any bits that we don't think are masked */
			*status &= ~wm831x->irq_masks_cur[offset];

			/* Acknowledge now so we don't miss
			 * notifications while we handle.
			 */
			wm831x_reg_write(wm831x, status_addr, *status);
		}

		if (*status & wm831x_irqs[i].mask)
			handle_nested_irq(irq_find_mapping(wm831x->irq_domain,
							   i));

		/* Simulate an edge triggered IRQ by polling the input
		 * status.  This is sucky but improves interoperability.
		 */
		if (primary == WM831X_GP_INT &&
		    wm831x->gpio_level_high[i - WM831X_IRQ_GPIO_1]) {
			ret = wm831x_reg_read(wm831x, WM831X_GPIO_LEVEL);
			while (ret & 1 << (i - WM831X_IRQ_GPIO_1)) {
				handle_nested_irq(irq_find_mapping(wm831x->irq_domain,
								   i));
				ret = wm831x_reg_read(wm831x,
						      WM831X_GPIO_LEVEL);
			}
		}

		if (primary == WM831X_GP_INT &&
		    wm831x->gpio_level_low[i - WM831X_IRQ_GPIO_1]) {
			ret = wm831x_reg_read(wm831x, WM831X_GPIO_LEVEL);
			while (!(ret & 1 << (i - WM831X_IRQ_GPIO_1))) {
				handle_nested_irq(irq_find_mapping(wm831x->irq_domain,
								   i));
				ret = wm831x_reg_read(wm831x,
						      WM831X_GPIO_LEVEL);
			}
		}
	}

out:
	return IRQ_HANDLED;
}

static int wm831x_irq_map(struct irq_domain *h, unsigned int virq,
			  irq_hw_number_t hw)
{
	irq_set_chip_data(virq, h->host_data);
	irq_set_chip_and_handler(virq, &wm831x_irq_chip, handle_edge_irq);
	irq_set_nested_thread(virq, 1);

	/* ARM needs us to explicitly flag the IRQ as valid
	 * and will set them noprobe when we do so. */
#ifdef CONFIG_ARM
	set_irq_flags(virq, IRQF_VALID);
#else
	irq_set_noprobe(virq);
#endif

	return 0;
}

static struct irq_domain_ops wm831x_irq_domain_ops = {
	.map	= wm831x_irq_map,
	.xlate	= irq_domain_xlate_twocell,
};

int wm831x_irq_init(struct wm831x *wm831x, int irq)
{
	struct wm831x_pdata *pdata = dev_get_platdata(wm831x->dev);
	struct irq_domain *domain;
	int i, ret, irq_base;

	mutex_init(&wm831x->irq_lock);

	/* Mask the individual interrupt sources */
	for (i = 0; i < ARRAY_SIZE(wm831x->irq_masks_cur); i++) {
		wm831x->irq_masks_cur[i] = 0xffff;
		wm831x->irq_masks_cache[i] = 0xffff;
		wm831x_reg_write(wm831x, WM831X_INTERRUPT_STATUS_1_MASK + i,
				 0xffff);
	}

	/* Try to dynamically allocate IRQs if no base is specified */
	if (pdata && pdata->irq_base) {
		irq_base = irq_alloc_descs(pdata->irq_base, 0,
					   WM831X_NUM_IRQS, 0);
		if (irq_base < 0) {
			dev_warn(wm831x->dev, "Failed to allocate IRQs: %d\n",
				 irq_base);
			irq_base = 0;
		}
	} else {
		irq_base = 0;
	}

	if (irq_base)
		domain = irq_domain_add_legacy(wm831x->dev->of_node,
					       ARRAY_SIZE(wm831x_irqs),
					       irq_base, 0,
					       &wm831x_irq_domain_ops,
					       wm831x);
	else
		domain = irq_domain_add_linear(wm831x->dev->of_node,
					       ARRAY_SIZE(wm831x_irqs),
					       &wm831x_irq_domain_ops,
					       wm831x);

	if (!domain) {
		dev_warn(wm831x->dev, "Failed to allocate IRQ domain\n");
		return -EINVAL;
	}

	if (pdata && pdata->irq_cmos)
		i = 0;
	else
		i = WM831X_IRQ_OD;

	wm831x_set_bits(wm831x, WM831X_IRQ_CONFIG,
			WM831X_IRQ_OD, i);

	wm831x->irq = irq;
	wm831x->irq_domain = domain;

	if (irq) {
		/* Try to flag /IRQ as a wake source; there are a number of
		 * unconditional wake sources in the PMIC so this isn't
		 * conditional but we don't actually care *too* much if it
		 * fails.
		 */
		ret = enable_irq_wake(irq);
		if (ret != 0) {
			dev_warn(wm831x->dev,
				 "Can't enable IRQ as wake source: %d\n",
				 ret);
		}

		ret = request_threaded_irq(irq, NULL, wm831x_irq_thread,
					   IRQF_TRIGGER_LOW | IRQF_ONESHOT,
					   "wm831x", wm831x);
		if (ret != 0) {
			dev_err(wm831x->dev, "Failed to request IRQ %d: %d\n",
				irq, ret);
			return ret;
		}
	} else {
		dev_warn(wm831x->dev,
			 "No interrupt specified - functionality limited\n");
	}

	/* Enable top level interrupts, we mask at secondary level */
	wm831x_reg_write(wm831x, WM831X_SYSTEM_INTERRUPTS_MASK, 0);

	return 0;
}

void wm831x_irq_exit(struct wm831x *wm831x)
{
	if (wm831x->irq)
		free_irq(wm831x->irq, wm831x);
}