/*
   * Atmel PIO2 Port Multiplexer support
   *
   * Copyright (C) 2004-2006 Atmel Corporation
   *
   * 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.
   */
  
  #include <linux/clk.h>
  #include <linux/debugfs.h>
  #include <linux/export.h>
  #include <linux/fs.h>
  #include <linux/platform_device.h>
  #include <linux/irq.h>
  
  #include <asm/gpio.h>
  #include <asm/io.h>
  
  #include <mach/portmux.h>
  
  #include "pio.h"
  
  #define MAX_NR_PIO_DEVICES		8
  
  struct pio_device {
  	struct gpio_chip chip;
  	void __iomem *regs;
  	const struct platform_device *pdev;
  	struct clk *clk;
  	u32 pinmux_mask;
  	char name[8];
  };
  
  static struct pio_device pio_dev[MAX_NR_PIO_DEVICES];
  
  static struct pio_device *gpio_to_pio(unsigned int gpio)
  {
  	struct pio_device *pio;
  	unsigned int index;
  
  	index = gpio >> 5;
  	if (index >= MAX_NR_PIO_DEVICES)
  		return NULL;
  	pio = &pio_dev[index];
  	if (!pio->regs)
  		return NULL;
  
  	return pio;
  }
  
  /* Pin multiplexing API */
  static DEFINE_SPINLOCK(pio_lock);
  
  void __init at32_select_periph(unsigned int port, u32 pin_mask,
  			       unsigned int periph, unsigned long flags)
  {
  	struct pio_device *pio;
  
  	/* assign and verify pio */
  	pio = gpio_to_pio(port);
  	if (unlikely(!pio)) {
  		printk(KERN_WARNING "pio: invalid port %u
  ", port);
  		goto fail;
  	}
  
  	/* Test if any of the requested pins is already muxed */
  	spin_lock(&pio_lock);
  	if (unlikely(pio->pinmux_mask & pin_mask)) {
  		printk(KERN_WARNING "%s: pin(s) busy (requested 0x%x, busy 0x%x)
  ",
  		       pio->name, pin_mask, pio->pinmux_mask & pin_mask);
  		spin_unlock(&pio_lock);
  		goto fail;
  	}
  
  	pio->pinmux_mask |= pin_mask;
  
  	/* enable pull ups */
  	pio_writel(pio, PUER, pin_mask);
  
  	/* select either peripheral A or B */
  	if (periph)
  		pio_writel(pio, BSR, pin_mask);
  	else
  		pio_writel(pio, ASR, pin_mask);
  
  	/* enable peripheral control */
  	pio_writel(pio, PDR, pin_mask);
  
  	/* Disable pull ups if not requested. */
  	if (!(flags & AT32_GPIOF_PULLUP))
  		pio_writel(pio, PUDR, pin_mask);
  
  	spin_unlock(&pio_lock);
  
  	return;
  
  fail:
  	dump_stack();
  }
  
  void __init at32_select_gpio(unsigned int pin, unsigned long flags)
  {
  	struct pio_device *pio;
  	unsigned int pin_index = pin & 0x1f;
  	u32 mask = 1 << pin_index;
  
  	pio = gpio_to_pio(pin);
  	if (unlikely(!pio)) {
  		printk("pio: invalid pin %u
  ", pin);
  		goto fail;
  	}
  
  	if (unlikely(test_and_set_bit(pin_index, &pio->pinmux_mask))) {
  		printk("%s: pin %u is busy
  ", pio->name, pin_index);
  		goto fail;
  	}
  
  	if (flags & AT32_GPIOF_OUTPUT) {
  		if (flags & AT32_GPIOF_HIGH)
  			pio_writel(pio, SODR, mask);
  		else
  			pio_writel(pio, CODR, mask);
  		if (flags & AT32_GPIOF_MULTIDRV)
  			pio_writel(pio, MDER, mask);
  		else
  			pio_writel(pio, MDDR, mask);
  		pio_writel(pio, PUDR, mask);
  		pio_writel(pio, OER, mask);
  	} else {
  		if (flags & AT32_GPIOF_PULLUP)
  			pio_writel(pio, PUER, mask);
  		else
  			pio_writel(pio, PUDR, mask);
  		if (flags & AT32_GPIOF_DEGLITCH)
  			pio_writel(pio, IFER, mask);
  		else
  			pio_writel(pio, IFDR, mask);
  		pio_writel(pio, ODR, mask);
  	}
  
  	pio_writel(pio, PER, mask);
  
  	return;
  
  fail:
  	dump_stack();
  }
  
  /*
   * Undo a previous pin reservation. Will not affect the hardware
   * configuration.
   */
  void at32_deselect_pin(unsigned int pin)
  {
  	struct pio_device *pio;
  	unsigned int pin_index = pin & 0x1f;
  
  	pio = gpio_to_pio(pin);
  	if (unlikely(!pio)) {
  		printk("pio: invalid pin %u
  ", pin);
  		dump_stack();
  		return;
  	}
  
  	clear_bit(pin_index, &pio->pinmux_mask);
  }
  
  /* Reserve a pin, preventing anyone else from changing its configuration. */
  void __init at32_reserve_pin(unsigned int port, u32 pin_mask)
  {
  	struct pio_device *pio;
  
  	/* assign and verify pio */
  	pio = gpio_to_pio(port);
  	if (unlikely(!pio)) {
  		printk(KERN_WARNING "pio: invalid port %u
  ", port);
  		goto fail;
  	}
  
  	/* Test if any of the requested pins is already muxed */
  	spin_lock(&pio_lock);
  	if (unlikely(pio->pinmux_mask & pin_mask)) {
  		printk(KERN_WARNING "%s: pin(s) busy (req. 0x%x, busy 0x%x)
  ",
  		       pio->name, pin_mask, pio->pinmux_mask & pin_mask);
  		spin_unlock(&pio_lock);
  		goto fail;
  	}
  
  	/* Reserve pins */
  	pio->pinmux_mask |= pin_mask;
  	spin_unlock(&pio_lock);
  	return;
  
  fail:
  	dump_stack();
  }
  
  /*--------------------------------------------------------------------------*/
  
  /* GPIO API */
  
  static int direction_input(struct gpio_chip *chip, unsigned offset)
  {
  	struct pio_device *pio = container_of(chip, struct pio_device, chip);
  	u32 mask = 1 << offset;
  
  	if (!(pio_readl(pio, PSR) & mask))
  		return -EINVAL;
  
  	pio_writel(pio, ODR, mask);
  	return 0;
  }
  
  static int gpio_get(struct gpio_chip *chip, unsigned offset)
  {
  	struct pio_device *pio = container_of(chip, struct pio_device, chip);
  
  	return (pio_readl(pio, PDSR) >> offset) & 1;
  }
  
  static void gpio_set(struct gpio_chip *chip, unsigned offset, int value);
  
  static int direction_output(struct gpio_chip *chip, unsigned offset, int value)
  {
  	struct pio_device *pio = container_of(chip, struct pio_device, chip);
  	u32 mask = 1 << offset;
  
  	if (!(pio_readl(pio, PSR) & mask))
  		return -EINVAL;
  
  	gpio_set(chip, offset, value);
  	pio_writel(pio, OER, mask);
  	return 0;
  }
  
  static void gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  {
  	struct pio_device *pio = container_of(chip, struct pio_device, chip);
  	u32 mask = 1 << offset;
  
  	if (value)
  		pio_writel(pio, SODR, mask);
  	else
  		pio_writel(pio, CODR, mask);
  }
  
  /*--------------------------------------------------------------------------*/
  
  /* GPIO IRQ support */
  
  static void gpio_irq_mask(struct irq_data *d)
  {
  	unsigned		gpio = irq_to_gpio(d->irq);
  	struct pio_device	*pio = &pio_dev[gpio >> 5];
  
  	pio_writel(pio, IDR, 1 << (gpio & 0x1f));
  }
  
  static void gpio_irq_unmask(struct irq_data *d)
  {
  	unsigned		gpio = irq_to_gpio(d->irq);
  	struct pio_device	*pio = &pio_dev[gpio >> 5];
  
  	pio_writel(pio, IER, 1 << (gpio & 0x1f));
  }
  
  static int gpio_irq_type(struct irq_data *d, unsigned type)
  {
  	if (type != IRQ_TYPE_EDGE_BOTH && type != IRQ_TYPE_NONE)
  		return -EINVAL;
  
  	return 0;
  }
  
  static struct irq_chip gpio_irqchip = {
  	.name		= "gpio",
  	.irq_mask	= gpio_irq_mask,
  	.irq_unmask	= gpio_irq_unmask,
  	.irq_set_type	= gpio_irq_type,
  };
  
  static void gpio_irq_handler(unsigned irq, struct irq_desc *desc)
  {
  	struct pio_device	*pio = irq_desc_get_chip_data(desc);
  	unsigned		gpio_irq;
  
  	gpio_irq = (unsigned) irq_get_handler_data(irq);
  	for (;;) {
  		u32		isr;
  
  		/* ack pending GPIO interrupts */
  		isr = pio_readl(pio, ISR) & pio_readl(pio, IMR);
  		if (!isr)
  			break;
  		do {
  			int i;
  
  			i = ffs(isr) - 1;
  			isr &= ~(1 << i);
  
  			i += gpio_irq;
  			generic_handle_irq(i);
  		} while (isr);
  	}
  }
  
  static void __init
  gpio_irq_setup(struct pio_device *pio, int irq, int gpio_irq)
  {
  	unsigned	i;
  
  	irq_set_chip_data(irq, pio);
  	irq_set_handler_data(irq, (void *)gpio_irq);
  
  	for (i = 0; i < 32; i++, gpio_irq++) {
  		irq_set_chip_data(gpio_irq, pio);
  		irq_set_chip_and_handler(gpio_irq, &gpio_irqchip,
  					 handle_simple_irq);
  	}
  
  	irq_set_chained_handler(irq, gpio_irq_handler);
  }
  
  /*--------------------------------------------------------------------------*/
  
  #ifdef CONFIG_DEBUG_FS
  
  #include <linux/seq_file.h>
  
  /*
   * This shows more info than the generic gpio dump code:
   * pullups, deglitching, open drain drive.
   */
  static void pio_bank_show(struct seq_file *s, struct gpio_chip *chip)
  {
  	struct pio_device *pio = container_of(chip, struct pio_device, chip);
  	u32			psr, osr, imr, pdsr, pusr, ifsr, mdsr;
  	unsigned		i;
  	u32			mask;
  	char			bank;
  
  	psr = pio_readl(pio, PSR);
  	osr = pio_readl(pio, OSR);
  	imr = pio_readl(pio, IMR);
  	pdsr = pio_readl(pio, PDSR);
  	pusr = pio_readl(pio, PUSR);
  	ifsr = pio_readl(pio, IFSR);
  	mdsr = pio_readl(pio, MDSR);
  
  	bank = 'A' + pio->pdev->id;
  
  	for (i = 0, mask = 1; i < 32; i++, mask <<= 1) {
  		const char *label;
  
  		label = gpiochip_is_requested(chip, i);
  		if (!label && (imr & mask))
  			label = "[irq]";
  		if (!label)
  			continue;
  
  		seq_printf(s, " gpio-%-3d P%c%-2d (%-12s) %s %s %s",
  			chip->base + i, bank, i,
  			label,
  			(osr & mask) ? "out" : "in ",
  			(mask & pdsr) ? "hi" : "lo",
  			(mask & pusr) ? "  " : "up");
  		if (ifsr & mask)
  			seq_printf(s, " deglitch");
  		if ((osr & mdsr) & mask)
  			seq_printf(s, " open-drain");
  		if (imr & mask)
  			seq_printf(s, " irq-%d edge-both",
  				gpio_to_irq(chip->base + i));
  		seq_printf(s, "
  ");
  	}
  }
  
  #else
  #define pio_bank_show	NULL
  #endif
  
  
  /*--------------------------------------------------------------------------*/
  
  static int __init pio_probe(struct platform_device *pdev)
  {
  	struct pio_device *pio = NULL;
  	int irq = platform_get_irq(pdev, 0);
  	int gpio_irq_base = GPIO_IRQ_BASE + pdev->id * 32;
  
  	BUG_ON(pdev->id >= MAX_NR_PIO_DEVICES);
  	pio = &pio_dev[pdev->id];
  	BUG_ON(!pio->regs);
  
  	pio->chip.label = pio->name;
  	pio->chip.base = pdev->id * 32;
  	pio->chip.ngpio = 32;
  	pio->chip.dev = &pdev->dev;
  	pio->chip.owner = THIS_MODULE;
  
  	pio->chip.direction_input = direction_input;
  	pio->chip.get = gpio_get;
  	pio->chip.direction_output = direction_output;
  	pio->chip.set = gpio_set;
  	pio->chip.dbg_show = pio_bank_show;
  
  	gpiochip_add(&pio->chip);
  
  	gpio_irq_setup(pio, irq, gpio_irq_base);
  
  	platform_set_drvdata(pdev, pio);
  
  	printk(KERN_DEBUG "%s: base 0x%p, irq %d chains %d..%d
  ",
  	       pio->name, pio->regs, irq, gpio_irq_base, gpio_irq_base + 31);
  
  	return 0;
  }
  
  static struct platform_driver pio_driver = {
  	.driver		= {
  		.name		= "pio",
  	},
  };
  
  static int __init pio_init(void)
  {
  	return platform_driver_probe(&pio_driver, pio_probe);
  }
  postcore_initcall(pio_init);
  
  void __init at32_init_pio(struct platform_device *pdev)
  {
  	struct resource *regs;
  	struct pio_device *pio;
  
  	if (pdev->id > MAX_NR_PIO_DEVICES) {
  		dev_err(&pdev->dev, "only %d PIO devices supported
  ",
  			MAX_NR_PIO_DEVICES);
  		return;
  	}
  
  	pio = &pio_dev[pdev->id];
  	snprintf(pio->name, sizeof(pio->name), "pio%d", pdev->id);
  
  	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!regs) {
  		dev_err(&pdev->dev, "no mmio resource defined
  ");
  		return;
  	}
  
  	pio->clk = clk_get(&pdev->dev, "mck");
  	if (IS_ERR(pio->clk))
  		/*
  		 * This is a fatal error, but if we continue we might
  		 * be so lucky that we manage to initialize the
  		 * console and display this message...
  		 */
  		dev_err(&pdev->dev, "no mck clock defined
  ");
  	else
  		clk_enable(pio->clk);
  
  	pio->pdev = pdev;
  	pio->regs = ioremap(regs->start, resource_size(regs));
  
  	/* start with irqs disabled and acked */
  	pio_writel(pio, IDR, ~0UL);
  	(void) pio_readl(pio, ISR);
  }