/*
 * Copyright (C) 2003-2015 Broadcom Corporation
 * All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 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.
 */

#include <linux/gpio.h>
#include <linux/platform_device.h>
#include <linux/of_device.h>
#include <linux/module.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/irqchip/chained_irq.h>

/*
 * XLP GPIO has multiple 32 bit registers for each feature where each register
 * controls 32 pins. So, pins up to 64 require 2 32-bit registers and up to 96
 * require 3 32-bit registers for each feature.
 * Here we only define offset of the first register for each feature. Offset of
 * the registers for pins greater than 32 can be calculated as following(Use
 * GPIO_INT_STAT as example):
 *
 * offset = (gpio / XLP_GPIO_REGSZ) * 4;
 * reg_addr = addr + offset;
 *
 * where addr is base address of the that feature register and gpio is the pin.
 */
#define GPIO_OUTPUT_EN		0x00
#define GPIO_PADDRV		0x08
#define GPIO_INT_EN00		0x18
#define GPIO_INT_EN10		0x20
#define GPIO_INT_EN20		0x28
#define GPIO_INT_EN30		0x30
#define GPIO_INT_POL		0x38
#define GPIO_INT_TYPE		0x40
#define GPIO_INT_STAT		0x48

#define GPIO_9XX_BYTESWAP	0X00
#define GPIO_9XX_CTRL		0X04
#define GPIO_9XX_OUTPUT_EN	0x14
#define GPIO_9XX_PADDRV		0x24
/*
 * Only for 4 interrupt enable reg are defined for now,
 * total reg available are 12.
 */
#define GPIO_9XX_INT_EN00	0x44
#define GPIO_9XX_INT_EN10	0x54
#define GPIO_9XX_INT_EN20	0x64
#define GPIO_9XX_INT_EN30	0x74
#define GPIO_9XX_INT_POL	0x104
#define GPIO_9XX_INT_TYPE	0x114
#define GPIO_9XX_INT_STAT	0x124

#define GPIO_3XX_INT_EN00	0x18
#define GPIO_3XX_INT_EN10	0x20
#define GPIO_3XX_INT_EN20	0x28
#define GPIO_3XX_INT_EN30	0x30
#define GPIO_3XX_INT_POL	0x78
#define GPIO_3XX_INT_TYPE	0x80
#define GPIO_3XX_INT_STAT	0x88

/* Interrupt type register mask */
#define XLP_GPIO_IRQ_TYPE_LVL	0x0
#define XLP_GPIO_IRQ_TYPE_EDGE	0x1

/* Interrupt polarity register mask */
#define XLP_GPIO_IRQ_POL_HIGH	0x0
#define XLP_GPIO_IRQ_POL_LOW	0x1

#define XLP_GPIO_REGSZ		32
#define XLP_GPIO_IRQ_BASE	768
#define XLP_MAX_NR_GPIO		96

/* XLP variants supported by this driver */
enum {
	XLP_GPIO_VARIANT_XLP832 = 1,
	XLP_GPIO_VARIANT_XLP316,
	XLP_GPIO_VARIANT_XLP208,
	XLP_GPIO_VARIANT_XLP980,
	XLP_GPIO_VARIANT_XLP532
};

struct xlp_gpio_priv {
	struct gpio_chip chip;
	DECLARE_BITMAP(gpio_enabled_mask, XLP_MAX_NR_GPIO);
	void __iomem *gpio_intr_en;	/* pointer to first intr enable reg */
	void __iomem *gpio_intr_stat;	/* pointer to first intr status reg */
	void __iomem *gpio_intr_type;	/* pointer to first intr type reg */
	void __iomem *gpio_intr_pol;	/* pointer to first intr polarity reg */
	void __iomem *gpio_out_en;	/* pointer to first output enable reg */
	void __iomem *gpio_paddrv;	/* pointer to first pad drive reg */
	spinlock_t lock;
};

static int xlp_gpio_get_reg(void __iomem *addr, unsigned gpio)
{
	u32 pos, regset;

	pos = gpio % XLP_GPIO_REGSZ;
	regset = (gpio / XLP_GPIO_REGSZ) * 4;
	return !!(readl(addr + regset) & BIT(pos));
}

static void xlp_gpio_set_reg(void __iomem *addr, unsigned gpio, int state)
{
	u32 value, pos, regset;

	pos = gpio % XLP_GPIO_REGSZ;
	regset = (gpio / XLP_GPIO_REGSZ) * 4;
	value = readl(addr + regset);

	if (state)
		value |= BIT(pos);
	else
		value &= ~BIT(pos);

	writel(value, addr + regset);
}

static void xlp_gpio_irq_disable(struct irq_data *d)
{
	struct gpio_chip *gc  = irq_data_get_irq_chip_data(d);
	struct xlp_gpio_priv *priv = gpiochip_get_data(gc);
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	xlp_gpio_set_reg(priv->gpio_intr_en, d->hwirq, 0x0);
	__clear_bit(d->hwirq, priv->gpio_enabled_mask);
	spin_unlock_irqrestore(&priv->lock, flags);
}

static void xlp_gpio_irq_mask_ack(struct irq_data *d)
{
	struct gpio_chip *gc  = irq_data_get_irq_chip_data(d);
	struct xlp_gpio_priv *priv = gpiochip_get_data(gc);
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	xlp_gpio_set_reg(priv->gpio_intr_en, d->hwirq, 0x0);
	xlp_gpio_set_reg(priv->gpio_intr_stat, d->hwirq, 0x1);
	__clear_bit(d->hwirq, priv->gpio_enabled_mask);
	spin_unlock_irqrestore(&priv->lock, flags);
}

static void xlp_gpio_irq_unmask(struct irq_data *d)
{
	struct gpio_chip *gc  = irq_data_get_irq_chip_data(d);
	struct xlp_gpio_priv *priv = gpiochip_get_data(gc);
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	xlp_gpio_set_reg(priv->gpio_intr_en, d->hwirq, 0x1);
	__set_bit(d->hwirq, priv->gpio_enabled_mask);
	spin_unlock_irqrestore(&priv->lock, flags);
}

static int xlp_gpio_set_irq_type(struct irq_data *d, unsigned int type)
{
	struct gpio_chip *gc  = irq_data_get_irq_chip_data(d);
	struct xlp_gpio_priv *priv = gpiochip_get_data(gc);
	int pol, irq_type;

	switch (type) {
	case IRQ_TYPE_EDGE_RISING:
		irq_type = XLP_GPIO_IRQ_TYPE_EDGE;
		pol = XLP_GPIO_IRQ_POL_HIGH;
		break;
	case IRQ_TYPE_EDGE_FALLING:
		irq_type = XLP_GPIO_IRQ_TYPE_EDGE;
		pol = XLP_GPIO_IRQ_POL_LOW;
		break;
	case IRQ_TYPE_LEVEL_HIGH:
		irq_type = XLP_GPIO_IRQ_TYPE_LVL;
		pol = XLP_GPIO_IRQ_POL_HIGH;
		break;
	case IRQ_TYPE_LEVEL_LOW:
		irq_type = XLP_GPIO_IRQ_TYPE_LVL;
		pol = XLP_GPIO_IRQ_POL_LOW;
		break;
	default:
		return -EINVAL;
	}

	xlp_gpio_set_reg(priv->gpio_intr_type, d->hwirq, irq_type);
	xlp_gpio_set_reg(priv->gpio_intr_pol, d->hwirq, pol);

	return 0;
}

static struct irq_chip xlp_gpio_irq_chip = {
	.name		= "XLP-GPIO",
	.irq_mask_ack	= xlp_gpio_irq_mask_ack,
	.irq_disable	= xlp_gpio_irq_disable,
	.irq_set_type	= xlp_gpio_set_irq_type,
	.irq_unmask	= xlp_gpio_irq_unmask,
	.flags		= IRQCHIP_ONESHOT_SAFE,
};

static void xlp_gpio_generic_handler(struct irq_desc *desc)
{
	struct xlp_gpio_priv *priv = irq_desc_get_handler_data(desc);
	struct irq_chip *irqchip = irq_desc_get_chip(desc);
	int gpio, regoff;
	u32 gpio_stat;

	regoff = -1;
	gpio_stat = 0;

	chained_irq_enter(irqchip, desc);
	for_each_set_bit(gpio, priv->gpio_enabled_mask, XLP_MAX_NR_GPIO) {
		if (regoff != gpio / XLP_GPIO_REGSZ) {
			regoff = gpio / XLP_GPIO_REGSZ;
			gpio_stat = readl(priv->gpio_intr_stat + regoff * 4);
		}

		if (gpio_stat & BIT(gpio % XLP_GPIO_REGSZ))
			generic_handle_irq(irq_find_mapping(
						priv->chip.irqdomain, gpio));
	}
	chained_irq_exit(irqchip, desc);
}

static int xlp_gpio_dir_output(struct gpio_chip *gc, unsigned gpio, int state)
{
	struct xlp_gpio_priv *priv = gpiochip_get_data(gc);

	BUG_ON(gpio >= gc->ngpio);
	xlp_gpio_set_reg(priv->gpio_out_en, gpio, 0x1);

	return 0;
}

static int xlp_gpio_dir_input(struct gpio_chip *gc, unsigned gpio)
{
	struct xlp_gpio_priv *priv = gpiochip_get_data(gc);

	BUG_ON(gpio >= gc->ngpio);
	xlp_gpio_set_reg(priv->gpio_out_en, gpio, 0x0);

	return 0;
}

static int xlp_gpio_get(struct gpio_chip *gc, unsigned gpio)
{
	struct xlp_gpio_priv *priv = gpiochip_get_data(gc);

	BUG_ON(gpio >= gc->ngpio);
	return xlp_gpio_get_reg(priv->gpio_paddrv, gpio);
}

static void xlp_gpio_set(struct gpio_chip *gc, unsigned gpio, int state)
{
	struct xlp_gpio_priv *priv = gpiochip_get_data(gc);

	BUG_ON(gpio >= gc->ngpio);
	xlp_gpio_set_reg(priv->gpio_paddrv, gpio, state);
}

static const struct of_device_id xlp_gpio_of_ids[] = {
	{
		.compatible = "netlogic,xlp832-gpio",
		.data	    = (void *)XLP_GPIO_VARIANT_XLP832,
	},
	{
		.compatible = "netlogic,xlp316-gpio",
		.data	    = (void *)XLP_GPIO_VARIANT_XLP316,
	},
	{
		.compatible = "netlogic,xlp208-gpio",
		.data	    = (void *)XLP_GPIO_VARIANT_XLP208,
	},
	{
		.compatible = "netlogic,xlp980-gpio",
		.data	    = (void *)XLP_GPIO_VARIANT_XLP980,
	},
	{
		.compatible = "netlogic,xlp532-gpio",
		.data	    = (void *)XLP_GPIO_VARIANT_XLP532,
	},
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, xlp_gpio_of_ids);

static int xlp_gpio_probe(struct platform_device *pdev)
{
	struct gpio_chip *gc;
	struct resource *iores;
	struct xlp_gpio_priv *priv;
	const struct of_device_id *of_id;
	void __iomem *gpio_base;
	int irq_base, irq, err;
	int ngpio;
	u32 soc_type;

	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!iores)
		return -ENODEV;

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

	gpio_base = devm_ioremap_resource(&pdev->dev, iores);
	if (IS_ERR(gpio_base))
		return PTR_ERR(gpio_base);

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	of_id = of_match_device(xlp_gpio_of_ids, &pdev->dev);
	if (!of_id) {
		dev_err(&pdev->dev, "Failed to get soc type!\n");
		return -ENODEV;
	}

	soc_type = (uintptr_t) of_id->data;

	switch (soc_type) {
	case XLP_GPIO_VARIANT_XLP832:
		priv->gpio_out_en = gpio_base + GPIO_OUTPUT_EN;
		priv->gpio_paddrv = gpio_base + GPIO_PADDRV;
		priv->gpio_intr_stat = gpio_base + GPIO_INT_STAT;
		priv->gpio_intr_type = gpio_base + GPIO_INT_TYPE;
		priv->gpio_intr_pol = gpio_base + GPIO_INT_POL;
		priv->gpio_intr_en = gpio_base + GPIO_INT_EN00;
		ngpio = 41;
		break;
	case XLP_GPIO_VARIANT_XLP208:
	case XLP_GPIO_VARIANT_XLP316:
		priv->gpio_out_en = gpio_base + GPIO_OUTPUT_EN;
		priv->gpio_paddrv = gpio_base + GPIO_PADDRV;
		priv->gpio_intr_stat = gpio_base + GPIO_3XX_INT_STAT;
		priv->gpio_intr_type = gpio_base + GPIO_3XX_INT_TYPE;
		priv->gpio_intr_pol = gpio_base + GPIO_3XX_INT_POL;
		priv->gpio_intr_en = gpio_base + GPIO_3XX_INT_EN00;

		ngpio = (soc_type == XLP_GPIO_VARIANT_XLP208) ? 42 : 57;
		break;
	case XLP_GPIO_VARIANT_XLP980:
	case XLP_GPIO_VARIANT_XLP532:
		priv->gpio_out_en = gpio_base + GPIO_9XX_OUTPUT_EN;
		priv->gpio_paddrv = gpio_base + GPIO_9XX_PADDRV;
		priv->gpio_intr_stat = gpio_base + GPIO_9XX_INT_STAT;
		priv->gpio_intr_type = gpio_base + GPIO_9XX_INT_TYPE;
		priv->gpio_intr_pol = gpio_base + GPIO_9XX_INT_POL;
		priv->gpio_intr_en = gpio_base + GPIO_9XX_INT_EN00;

		ngpio = (soc_type == XLP_GPIO_VARIANT_XLP980) ? 66 : 67;
		break;
	default:
		dev_err(&pdev->dev, "Unknown Processor type!\n");
		return -ENODEV;
	}

	bitmap_zero(priv->gpio_enabled_mask, XLP_MAX_NR_GPIO);

	gc = &priv->chip;

	gc->owner = THIS_MODULE;
	gc->label = dev_name(&pdev->dev);
	gc->base = 0;
	gc->parent = &pdev->dev;
	gc->ngpio = ngpio;
	gc->of_node = pdev->dev.of_node;
	gc->direction_output = xlp_gpio_dir_output;
	gc->direction_input = xlp_gpio_dir_input;
	gc->set = xlp_gpio_set;
	gc->get = xlp_gpio_get;

	spin_lock_init(&priv->lock);
	irq_base = irq_alloc_descs(-1, XLP_GPIO_IRQ_BASE, gc->ngpio, 0);
	if (irq_base < 0) {
		dev_err(&pdev->dev, "Failed to allocate IRQ numbers\n");
		return -ENODEV;
	}

	err = gpiochip_add_data(gc, priv);
	if (err < 0)
		goto out_free_desc;

	err = gpiochip_irqchip_add(gc, &xlp_gpio_irq_chip, irq_base,
				handle_level_irq, IRQ_TYPE_NONE);
	if (err) {
		dev_err(&pdev->dev, "Could not connect irqchip to gpiochip!\n");
		goto out_gpio_remove;
	}

	gpiochip_set_chained_irqchip(gc, &xlp_gpio_irq_chip, irq,
			xlp_gpio_generic_handler);

	dev_info(&pdev->dev, "registered %d GPIOs\n", gc->ngpio);

	return 0;

out_gpio_remove:
	gpiochip_remove(gc);
out_free_desc:
	irq_free_descs(irq_base, gc->ngpio);
	return err;
}

static struct platform_driver xlp_gpio_driver = {
	.driver		= {
		.name	= "xlp-gpio",
		.of_match_table = xlp_gpio_of_ids,
	},
	.probe		= xlp_gpio_probe,
};
module_platform_driver(xlp_gpio_driver);

MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
MODULE_AUTHOR("Ganesan Ramalingam <ganesanr@broadcom.com>");
MODULE_DESCRIPTION("Netlogic XLP GPIO Driver");
MODULE_LICENSE("GPL v2");