/*
 * Intel Reference Systems cplds
 *
 * Copyright (C) 2014 Robert Jarzmik
 *
 * 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.
 *
 * Cplds motherboard driver, supporting lubbock and mainstone SoC board.
 */

#include <linux/bitops.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/of_platform.h>

#define FPGA_IRQ_MASK_EN 0x0
#define FPGA_IRQ_SET_CLR 0x10

#define CPLDS_NB_IRQ	32

struct cplds {
	void __iomem *base;
	int irq;
	unsigned int irq_mask;
	struct gpio_desc *gpio0;
	struct irq_domain *irqdomain;
};

static irqreturn_t cplds_irq_handler(int in_irq, void *d)
{
	struct cplds *fpga = d;
	unsigned long pending;
	unsigned int bit;

	do {
		pending = readl(fpga->base + FPGA_IRQ_SET_CLR) & fpga->irq_mask;
		for_each_set_bit(bit, &pending, CPLDS_NB_IRQ) {
			generic_handle_irq(irq_find_mapping(fpga->irqdomain,
							    bit));
		}
	} while (pending);

	return IRQ_HANDLED;
}

static void cplds_irq_mask(struct irq_data *d)
{
	struct cplds *fpga = irq_data_get_irq_chip_data(d);
	unsigned int cplds_irq = irqd_to_hwirq(d);
	unsigned int bit = BIT(cplds_irq);

	fpga->irq_mask &= ~bit;
	writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);
}

static void cplds_irq_unmask(struct irq_data *d)
{
	struct cplds *fpga = irq_data_get_irq_chip_data(d);
	unsigned int cplds_irq = irqd_to_hwirq(d);
	unsigned int set, bit = BIT(cplds_irq);

	set = readl(fpga->base + FPGA_IRQ_SET_CLR);
	writel(set & ~bit, fpga->base + FPGA_IRQ_SET_CLR);

	fpga->irq_mask |= bit;
	writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);
}

static struct irq_chip cplds_irq_chip = {
	.name		= "pxa_cplds",
	.irq_ack	= cplds_irq_mask,
	.irq_mask	= cplds_irq_mask,
	.irq_unmask	= cplds_irq_unmask,
	.flags		= IRQCHIP_MASK_ON_SUSPEND | IRQCHIP_SKIP_SET_WAKE,
};

static int cplds_irq_domain_map(struct irq_domain *d, unsigned int irq,
				   irq_hw_number_t hwirq)
{
	struct cplds *fpga = d->host_data;

	irq_set_chip_and_handler(irq, &cplds_irq_chip, handle_level_irq);
	irq_set_chip_data(irq, fpga);

	return 0;
}

static const struct irq_domain_ops cplds_irq_domain_ops = {
	.xlate = irq_domain_xlate_twocell,
	.map = cplds_irq_domain_map,
};

static int cplds_resume(struct platform_device *pdev)
{
	struct cplds *fpga = platform_get_drvdata(pdev);

	writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);

	return 0;
}

static int cplds_probe(struct platform_device *pdev)
{
	struct resource *res;
	struct cplds *fpga;
	int ret;
	int base_irq;
	unsigned long irqflags = 0;

	fpga = devm_kzalloc(&pdev->dev, sizeof(*fpga), GFP_KERNEL);
	if (!fpga)
		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (res) {
		fpga->irq = (unsigned int)res->start;
		irqflags = res->flags;
	}
	if (!fpga->irq)
		return -ENODEV;

	base_irq = platform_get_irq(pdev, 1);
	if (base_irq < 0)
		base_irq = 0;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	fpga->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(fpga->base))
		return PTR_ERR(fpga->base);

	platform_set_drvdata(pdev, fpga);

	writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);
	writel(0, fpga->base + FPGA_IRQ_SET_CLR);

	ret = devm_request_irq(&pdev->dev, fpga->irq, cplds_irq_handler,
			       irqflags, dev_name(&pdev->dev), fpga);
	if (ret == -ENOSYS)
		return -EPROBE_DEFER;

	if (ret) {
		dev_err(&pdev->dev, "couldn't request main irq%d: %d\n",
			fpga->irq, ret);
		return ret;
	}

	irq_set_irq_wake(fpga->irq, 1);
	fpga->irqdomain = irq_domain_add_linear(pdev->dev.of_node,
					       CPLDS_NB_IRQ,
					       &cplds_irq_domain_ops, fpga);
	if (!fpga->irqdomain)
		return -ENODEV;

	if (base_irq) {
		ret = irq_create_strict_mappings(fpga->irqdomain, base_irq, 0,
						 CPLDS_NB_IRQ);
		if (ret) {
			dev_err(&pdev->dev, "couldn't create the irq mapping %d..%d\n",
				base_irq, base_irq + CPLDS_NB_IRQ);
			return ret;
		}
	}

	return 0;
}

static int cplds_remove(struct platform_device *pdev)
{
	struct cplds *fpga = platform_get_drvdata(pdev);

	irq_set_chip_and_handler(fpga->irq, NULL, NULL);

	return 0;
}

static const struct of_device_id cplds_id_table[] = {
	{ .compatible = "intel,lubbock-cplds-irqs", },
	{ .compatible = "intel,mainstone-cplds-irqs", },
	{ }
};
MODULE_DEVICE_TABLE(of, cplds_id_table);

static struct platform_driver cplds_driver = {
	.driver		= {
		.name	= "pxa_cplds_irqs",
		.of_match_table = of_match_ptr(cplds_id_table),
	},
	.probe		= cplds_probe,
	.remove		= cplds_remove,
	.resume		= cplds_resume,
};

module_platform_driver(cplds_driver);

MODULE_DESCRIPTION("PXA Cplds interrupts driver");
MODULE_AUTHOR("Robert Jarzmik <robert.jarzmik@free.fr>");
MODULE_LICENSE("GPL");