// SPDX-License-Identifier: GPL-2.0+

  /*
   *  Driver for NEC VR4100 series General-purpose I/O Unit.
   *
   *  Copyright (C) 2002 MontaVista Software Inc.

   *	Author: Yoichi Yuasa <source@mvista.com>
   *  Copyright (C) 2003-2009  Yoichi Yuasa <yuasa@linux-mips.org>

   */
  #include <linux/errno.h>
  #include <linux/fs.h>

  #include <linux/gpio/driver.h>

  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/io.h>
  #include <linux/irq.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>

  #include <linux/spinlock.h>
  #include <linux/types.h>
  
  #include <asm/vr41xx/giu.h>
  #include <asm/vr41xx/irq.h>
  #include <asm/vr41xx/vr41xx.h>

  MODULE_AUTHOR("Yoichi Yuasa <yuasa@linux-mips.org>");

  MODULE_DESCRIPTION("NEC VR4100 series General-purpose I/O Unit driver");
  MODULE_LICENSE("GPL");
  
  #define GIUIOSELL	0x00
  #define GIUIOSELH	0x02
  #define GIUPIODL	0x04
  #define GIUPIODH	0x06
  #define GIUINTSTATL	0x08
  #define GIUINTSTATH	0x0a
  #define GIUINTENL	0x0c
  #define GIUINTENH	0x0e
  #define GIUINTTYPL	0x10
  #define GIUINTTYPH	0x12
  #define GIUINTALSELL	0x14
  #define GIUINTALSELH	0x16
  #define GIUINTHTSELL	0x18
  #define GIUINTHTSELH	0x1a
  #define GIUPODATL	0x1c
  #define GIUPODATEN	0x1c
  #define GIUPODATH	0x1e
   #define PIOEN0		0x0100
   #define PIOEN1		0x0200
  #define GIUPODAT	0x1e
  #define GIUFEDGEINHL	0x20
  #define GIUFEDGEINHH	0x22
  #define GIUREDGEINHL	0x24
  #define GIUREDGEINHH	0x26
  
  #define GIUUSEUPDN	0x1e0
  #define GIUTERMUPDN	0x1e2
  
  #define GPIO_HAS_PULLUPDOWN_IO		0x0001
  #define GPIO_HAS_OUTPUT_ENABLE		0x0002
  #define GPIO_HAS_INTERRUPT_EDGE_SELECT	0x0100
  
  enum {
  	GPIO_INPUT,
  	GPIO_OUTPUT,
  };
  
  static DEFINE_SPINLOCK(giu_lock);
  static unsigned long giu_flags;
  
  static void __iomem *giu_base;

  static struct gpio_chip vr41xx_gpio_chip;

  
  #define giu_read(offset)		readw(giu_base + (offset))
  #define giu_write(offset, value)	writew((value), giu_base + (offset))
  
  #define GPIO_PIN_OF_IRQ(irq)	((irq) - GIU_IRQ_BASE)
  #define GIUINT_HIGH_OFFSET	16
  #define GIUINT_HIGH_MAX		32
  
  static inline u16 giu_set(u16 offset, u16 set)
  {
  	u16 data;
  
  	data = giu_read(offset);
  	data |= set;
  	giu_write(offset, data);
  
  	return data;
  }
  
  static inline u16 giu_clear(u16 offset, u16 clear)
  {
  	u16 data;
  
  	data = giu_read(offset);
  	data &= ~clear;
  	giu_write(offset, data);
  
  	return data;
  }

  static void ack_giuint_low(struct irq_data *d)

  {

  	giu_write(GIUINTSTATL, 1 << GPIO_PIN_OF_IRQ(d->irq));

  }

  static void mask_giuint_low(struct irq_data *d)

  {

  	giu_clear(GIUINTENL, 1 << GPIO_PIN_OF_IRQ(d->irq));

  }

  static void mask_ack_giuint_low(struct irq_data *d)

  {
  	unsigned int pin;

  	pin = GPIO_PIN_OF_IRQ(d->irq);

  	giu_clear(GIUINTENL, 1 << pin);
  	giu_write(GIUINTSTATL, 1 << pin);
  }

  static void unmask_giuint_low(struct irq_data *d)

  {

  	giu_set(GIUINTENL, 1 << GPIO_PIN_OF_IRQ(d->irq));

  }

  static unsigned int startup_giuint(struct irq_data *data)
  {

  	int ret;
  
  	ret = gpiochip_lock_as_irq(&vr41xx_gpio_chip, irqd_to_hwirq(data));
  	if (ret) {

  		dev_err(vr41xx_gpio_chip.parent,

  			"unable to lock HW IRQ %lu for IRQ
  ",
  			data->hwirq);

  		return ret;
  	}

  	/* Satisfy the .enable semantics by unmasking the line */
  	unmask_giuint_low(data);
  	return 0;
  }
  
  static void shutdown_giuint(struct irq_data *data)
  {
  	mask_giuint_low(data);

  	gpiochip_unlock_as_irq(&vr41xx_gpio_chip, data->hwirq);

  }

  static struct irq_chip giuint_low_irq_chip = {
  	.name		= "GIUINTL",

  	.irq_ack	= ack_giuint_low,
  	.irq_mask	= mask_giuint_low,
  	.irq_mask_ack	= mask_ack_giuint_low,
  	.irq_unmask	= unmask_giuint_low,

  	.irq_startup	= startup_giuint,
  	.irq_shutdown	= shutdown_giuint,

  };

  static void ack_giuint_high(struct irq_data *d)

  {
  	giu_write(GIUINTSTATH,

  		  1 << (GPIO_PIN_OF_IRQ(d->irq) - GIUINT_HIGH_OFFSET));

  }

  static void mask_giuint_high(struct irq_data *d)

  {

  	giu_clear(GIUINTENH, 1 << (GPIO_PIN_OF_IRQ(d->irq) - GIUINT_HIGH_OFFSET));

  }

  static void mask_ack_giuint_high(struct irq_data *d)

  {
  	unsigned int pin;

  	pin = GPIO_PIN_OF_IRQ(d->irq) - GIUINT_HIGH_OFFSET;

  	giu_clear(GIUINTENH, 1 << pin);
  	giu_write(GIUINTSTATH, 1 << pin);
  }

  static void unmask_giuint_high(struct irq_data *d)

  {

  	giu_set(GIUINTENH, 1 << (GPIO_PIN_OF_IRQ(d->irq) - GIUINT_HIGH_OFFSET));

  }
  
  static struct irq_chip giuint_high_irq_chip = {
  	.name		= "GIUINTH",

  	.irq_ack	= ack_giuint_high,
  	.irq_mask	= mask_giuint_high,
  	.irq_mask_ack	= mask_ack_giuint_high,
  	.irq_unmask	= unmask_giuint_high,

  };
  
  static int giu_get_irq(unsigned int irq)
  {
  	u16 pendl, pendh, maskl, maskh;
  	int i;
  
  	pendl = giu_read(GIUINTSTATL);
  	pendh = giu_read(GIUINTSTATH);
  	maskl = giu_read(GIUINTENL);
  	maskh = giu_read(GIUINTENH);
  
  	maskl &= pendl;
  	maskh &= pendh;
  
  	if (maskl) {
  		for (i = 0; i < 16; i++) {
  			if (maskl & (1 << i))
  				return GIU_IRQ(i);
  		}
  	} else if (maskh) {
  		for (i = 0; i < 16; i++) {
  			if (maskh & (1 << i))
  				return GIU_IRQ(i + GIUINT_HIGH_OFFSET);
  		}
  	}
  
  	printk(KERN_ERR "spurious GIU interrupt: %04x(%04x),%04x(%04x)
  ",
  	       maskl, pendl, maskh, pendh);
  
  	atomic_inc(&irq_err_count);
  
  	return -EINVAL;
  }
  
  void vr41xx_set_irq_trigger(unsigned int pin, irq_trigger_t trigger,
  			    irq_signal_t signal)
  {
  	u16 mask;
  
  	if (pin < GIUINT_HIGH_OFFSET) {
  		mask = 1 << pin;
  		if (trigger != IRQ_TRIGGER_LEVEL) {
  			giu_set(GIUINTTYPL, mask);
  			if (signal == IRQ_SIGNAL_HOLD)
  				giu_set(GIUINTHTSELL, mask);
  			else
  				giu_clear(GIUINTHTSELL, mask);
  			if (giu_flags & GPIO_HAS_INTERRUPT_EDGE_SELECT) {
  				switch (trigger) {
  				case IRQ_TRIGGER_EDGE_FALLING:
  					giu_set(GIUFEDGEINHL, mask);
  					giu_clear(GIUREDGEINHL, mask);
  					break;
  				case IRQ_TRIGGER_EDGE_RISING:
  					giu_clear(GIUFEDGEINHL, mask);
  					giu_set(GIUREDGEINHL, mask);
  					break;
  				default:
  					giu_set(GIUFEDGEINHL, mask);
  					giu_set(GIUREDGEINHL, mask);
  					break;
  				}
  			}

  			irq_set_chip_and_handler(GIU_IRQ(pin),

  						 &giuint_low_irq_chip,
  						 handle_edge_irq);
  		} else {
  			giu_clear(GIUINTTYPL, mask);
  			giu_clear(GIUINTHTSELL, mask);

  			irq_set_chip_and_handler(GIU_IRQ(pin),

  						 &giuint_low_irq_chip,
  						 handle_level_irq);
  		}
  		giu_write(GIUINTSTATL, mask);
  	} else if (pin < GIUINT_HIGH_MAX) {
  		mask = 1 << (pin - GIUINT_HIGH_OFFSET);
  		if (trigger != IRQ_TRIGGER_LEVEL) {
  			giu_set(GIUINTTYPH, mask);
  			if (signal == IRQ_SIGNAL_HOLD)
  				giu_set(GIUINTHTSELH, mask);
  			else
  				giu_clear(GIUINTHTSELH, mask);
  			if (giu_flags & GPIO_HAS_INTERRUPT_EDGE_SELECT) {
  				switch (trigger) {
  				case IRQ_TRIGGER_EDGE_FALLING:
  					giu_set(GIUFEDGEINHH, mask);
  					giu_clear(GIUREDGEINHH, mask);
  					break;
  				case IRQ_TRIGGER_EDGE_RISING:
  					giu_clear(GIUFEDGEINHH, mask);
  					giu_set(GIUREDGEINHH, mask);
  					break;
  				default:
  					giu_set(GIUFEDGEINHH, mask);
  					giu_set(GIUREDGEINHH, mask);
  					break;
  				}
  			}

  			irq_set_chip_and_handler(GIU_IRQ(pin),

  						 &giuint_high_irq_chip,
  						 handle_edge_irq);
  		} else {
  			giu_clear(GIUINTTYPH, mask);
  			giu_clear(GIUINTHTSELH, mask);

  			irq_set_chip_and_handler(GIU_IRQ(pin),

  						 &giuint_high_irq_chip,
  						 handle_level_irq);
  		}
  		giu_write(GIUINTSTATH, mask);
  	}
  }
  EXPORT_SYMBOL_GPL(vr41xx_set_irq_trigger);
  
  void vr41xx_set_irq_level(unsigned int pin, irq_level_t level)
  {
  	u16 mask;
  
  	if (pin < GIUINT_HIGH_OFFSET) {
  		mask = 1 << pin;
  		if (level == IRQ_LEVEL_HIGH)
  			giu_set(GIUINTALSELL, mask);
  		else
  			giu_clear(GIUINTALSELL, mask);
  		giu_write(GIUINTSTATL, mask);
  	} else if (pin < GIUINT_HIGH_MAX) {
  		mask = 1 << (pin - GIUINT_HIGH_OFFSET);
  		if (level == IRQ_LEVEL_HIGH)
  			giu_set(GIUINTALSELH, mask);
  		else
  			giu_clear(GIUINTALSELH, mask);
  		giu_write(GIUINTSTATH, mask);
  	}
  }
  EXPORT_SYMBOL_GPL(vr41xx_set_irq_level);
  
  static int giu_set_direction(struct gpio_chip *chip, unsigned pin, int dir)
  {
  	u16 offset, mask, reg;
  	unsigned long flags;
  
  	if (pin >= chip->ngpio)
  		return -EINVAL;
  
  	if (pin < 16) {
  		offset = GIUIOSELL;
  		mask = 1 << pin;
  	} else if (pin < 32) {
  		offset = GIUIOSELH;
  		mask = 1 << (pin - 16);
  	} else {
  		if (giu_flags & GPIO_HAS_OUTPUT_ENABLE) {
  			offset = GIUPODATEN;
  			mask = 1 << (pin - 32);
  		} else {
  			switch (pin) {
  			case 48:
  				offset = GIUPODATH;
  				mask = PIOEN0;
  				break;
  			case 49:
  				offset = GIUPODATH;
  				mask = PIOEN1;
  				break;
  			default:
  				return -EINVAL;
  			}
  		}
  	}
  
  	spin_lock_irqsave(&giu_lock, flags);
  
  	reg = giu_read(offset);
  	if (dir == GPIO_OUTPUT)
  		reg |= mask;
  	else
  		reg &= ~mask;
  	giu_write(offset, reg);
  
  	spin_unlock_irqrestore(&giu_lock, flags);
  
  	return 0;
  }

  static int vr41xx_gpio_get(struct gpio_chip *chip, unsigned pin)
  {
  	u16 reg, mask;
  
  	if (pin >= chip->ngpio)
  		return -EINVAL;
  
  	if (pin < 16) {
  		reg = giu_read(GIUPIODL);
  		mask = 1 << pin;
  	} else if (pin < 32) {
  		reg = giu_read(GIUPIODH);
  		mask = 1 << (pin - 16);
  	} else if (pin < 48) {
  		reg = giu_read(GIUPODATL);
  		mask = 1 << (pin - 32);
  	} else {
  		reg = giu_read(GIUPODATH);
  		mask = 1 << (pin - 48);
  	}
  
  	if (reg & mask)
  		return 1;
  
  	return 0;
  }
  
  static void vr41xx_gpio_set(struct gpio_chip *chip, unsigned pin,
  			    int value)
  {
  	u16 offset, mask, reg;
  	unsigned long flags;
  
  	if (pin >= chip->ngpio)
  		return;
  
  	if (pin < 16) {
  		offset = GIUPIODL;
  		mask = 1 << pin;
  	} else if (pin < 32) {
  		offset = GIUPIODH;
  		mask = 1 << (pin - 16);
  	} else if (pin < 48) {
  		offset = GIUPODATL;
  		mask = 1 << (pin - 32);
  	} else {
  		offset = GIUPODATH;
  		mask = 1 << (pin - 48);
  	}
  
  	spin_lock_irqsave(&giu_lock, flags);
  
  	reg = giu_read(offset);
  	if (value)
  		reg |= mask;
  	else
  		reg &= ~mask;
  	giu_write(offset, reg);
  
  	spin_unlock_irqrestore(&giu_lock, flags);
  }
  
  
  static int vr41xx_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
  {
  	return giu_set_direction(chip, offset, GPIO_INPUT);
  }
  
  static int vr41xx_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
  				int value)
  {
  	vr41xx_gpio_set(chip, offset, value);
  
  	return giu_set_direction(chip, offset, GPIO_OUTPUT);
  }
  
  static int vr41xx_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
  {
  	if (offset >= chip->ngpio)
  		return -EINVAL;
  
  	return GIU_IRQ_BASE + offset;
  }
  
  static struct gpio_chip vr41xx_gpio_chip = {
  	.label			= "vr41xx",
  	.owner			= THIS_MODULE,
  	.direction_input	= vr41xx_gpio_direction_input,
  	.get			= vr41xx_gpio_get,
  	.direction_output	= vr41xx_gpio_direction_output,
  	.set			= vr41xx_gpio_set,
  	.to_irq			= vr41xx_gpio_to_irq,
  };

  static int giu_probe(struct platform_device *pdev)

  {

  	unsigned int trigger, i, pin;
  	struct irq_chip *chip;

  	int irq;

  
  	switch (pdev->id) {
  	case GPIO_50PINS_PULLUPDOWN:
  		giu_flags = GPIO_HAS_PULLUPDOWN_IO;
  		vr41xx_gpio_chip.ngpio = 50;
  		break;
  	case GPIO_36PINS:
  		vr41xx_gpio_chip.ngpio = 36;
  		break;
  	case GPIO_48PINS_EDGE_SELECT:
  		giu_flags = GPIO_HAS_INTERRUPT_EDGE_SELECT;
  		vr41xx_gpio_chip.ngpio = 48;
  		break;
  	default:
  		dev_err(&pdev->dev, "GIU: unknown ID %d
  ", pdev->id);
  		return -ENODEV;
  	}

  	giu_base = devm_platform_ioremap_resource(pdev, 0);
  	if (IS_ERR(giu_base))
  		return PTR_ERR(giu_base);

  	vr41xx_gpio_chip.parent = &pdev->dev;

  	if (gpiochip_add_data(&vr41xx_gpio_chip, NULL))

  		return -ENODEV;

  
  	giu_write(GIUINTENL, 0);
  	giu_write(GIUINTENH, 0);
  
  	trigger = giu_read(GIUINTTYPH) << 16;
  	trigger |= giu_read(GIUINTTYPL);
  	for (i = GIU_IRQ_BASE; i <= GIU_IRQ_LAST; i++) {
  		pin = GPIO_PIN_OF_IRQ(i);
  		if (pin < GIUINT_HIGH_OFFSET)
  			chip = &giuint_low_irq_chip;
  		else
  			chip = &giuint_high_irq_chip;
  
  		if (trigger & (1 << pin))

  			irq_set_chip_and_handler(i, chip, handle_edge_irq);

  		else

  			irq_set_chip_and_handler(i, chip, handle_level_irq);

  
  	}
  
  	irq = platform_get_irq(pdev, 0);
  	if (irq < 0 || irq >= nr_irqs)
  		return -EBUSY;
  
  	return cascade_irq(irq, giu_get_irq);
  }

  static int giu_remove(struct platform_device *pdev)

  {
  	if (giu_base) {

  		giu_base = NULL;
  	}
  
  	return 0;
  }
  
  static struct platform_driver giu_device_driver = {
  	.probe		= giu_probe,

  	.remove		= giu_remove,

  	.driver		= {
  		.name	= "GIU",

  	},
  };

  module_platform_driver(giu_device_driver);