/*
   * GPIOs on MPC512x/8349/8572/8610 and compatible
   *
   * Copyright (C) 2008 Peter Korsgaard <jacmet@sunsite.dk>
   *
   * This file is licensed under the terms of the GNU General Public License
   * version 2.  This program is licensed "as is" without any warranty of any
   * kind, whether express or implied.
   */
  
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/spinlock.h>
  #include <linux/io.h>
  #include <linux/of.h>
  #include <linux/of_gpio.h>
  #include <linux/of_irq.h>
  #include <linux/gpio.h>
  #include <linux/slab.h>
  #include <linux/irq.h>
  
  #define MPC8XXX_GPIO_PINS	32
  
  #define GPIO_DIR		0x00
  #define GPIO_ODR		0x04
  #define GPIO_DAT		0x08
  #define GPIO_IER		0x0c
  #define GPIO_IMR		0x10
  #define GPIO_ICR		0x14
  #define GPIO_ICR2		0x18
  
  struct mpc8xxx_gpio_chip {
  	struct of_mm_gpio_chip mm_gc;
  	spinlock_t lock;
  
  	/*
  	 * shadowed data register to be able to clear/set output pins in
  	 * open drain mode safely
  	 */
  	u32 data;
  	struct irq_domain *irq;
  	const void *of_dev_id_data;
  };
  
  static inline u32 mpc8xxx_gpio2mask(unsigned int gpio)
  {
  	return 1u << (MPC8XXX_GPIO_PINS - 1 - gpio);
  }
  
  static inline struct mpc8xxx_gpio_chip *
  to_mpc8xxx_gpio_chip(struct of_mm_gpio_chip *mm)
  {
  	return container_of(mm, struct mpc8xxx_gpio_chip, mm_gc);
  }
  
  static void mpc8xxx_gpio_save_regs(struct of_mm_gpio_chip *mm)
  {
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm);
  
  	mpc8xxx_gc->data = in_be32(mm->regs + GPIO_DAT);
  }
  
  /* Workaround GPIO 1 errata on MPC8572/MPC8536. The status of GPIOs
   * defined as output cannot be determined by reading GPDAT register,
   * so we use shadow data register instead. The status of input pins
   * is determined by reading GPDAT register.
   */
  static int mpc8572_gpio_get(struct gpio_chip *gc, unsigned int gpio)
  {
  	u32 val;
  	struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm);
  	u32 out_mask, out_shadow;
  
  	out_mask = in_be32(mm->regs + GPIO_DIR);
  
  	val = in_be32(mm->regs + GPIO_DAT) & ~out_mask;
  	out_shadow = mpc8xxx_gc->data & out_mask;
  
  	return (val | out_shadow) & mpc8xxx_gpio2mask(gpio);
  }
  
  static int mpc8xxx_gpio_get(struct gpio_chip *gc, unsigned int gpio)
  {
  	struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
  
  	return in_be32(mm->regs + GPIO_DAT) & mpc8xxx_gpio2mask(gpio);
  }
  
  static void mpc8xxx_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
  {
  	struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm);
  	unsigned long flags;
  
  	spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
  
  	if (val)
  		mpc8xxx_gc->data |= mpc8xxx_gpio2mask(gpio);
  	else
  		mpc8xxx_gc->data &= ~mpc8xxx_gpio2mask(gpio);
  
  	out_be32(mm->regs + GPIO_DAT, mpc8xxx_gc->data);
  
  	spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
  }
  
  static int mpc8xxx_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
  {
  	struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm);
  	unsigned long flags;
  
  	spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
  
  	clrbits32(mm->regs + GPIO_DIR, mpc8xxx_gpio2mask(gpio));
  
  	spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
  
  	return 0;
  }
  
  static int mpc8xxx_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
  {
  	struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm);
  	unsigned long flags;
  
  	mpc8xxx_gpio_set(gc, gpio, val);
  
  	spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
  
  	setbits32(mm->regs + GPIO_DIR, mpc8xxx_gpio2mask(gpio));
  
  	spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
  
  	return 0;
  }
  
  static int mpc5121_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
  {
  	/* GPIO 28..31 are input only on MPC5121 */
  	if (gpio >= 28)
  		return -EINVAL;
  
  	return mpc8xxx_gpio_dir_out(gc, gpio, val);
  }
  
  static int mpc8xxx_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
  {
  	struct of_mm_gpio_chip *mm = to_of_mm_gpio_chip(gc);
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = to_mpc8xxx_gpio_chip(mm);
  
  	if (mpc8xxx_gc->irq && offset < MPC8XXX_GPIO_PINS)
  		return irq_create_mapping(mpc8xxx_gc->irq, offset);
  	else
  		return -ENXIO;
  }
  
  static void mpc8xxx_gpio_irq_cascade(unsigned int irq, struct irq_desc *desc)
  {
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = irq_desc_get_handler_data(desc);
  	struct irq_chip *chip = irq_desc_get_chip(desc);
  	struct of_mm_gpio_chip *mm = &mpc8xxx_gc->mm_gc;
  	unsigned int mask;
  
  	mask = in_be32(mm->regs + GPIO_IER) & in_be32(mm->regs + GPIO_IMR);
  	if (mask)
  		generic_handle_irq(irq_linear_revmap(mpc8xxx_gc->irq,
  						     32 - ffs(mask)));
  	if (chip->irq_eoi)
  		chip->irq_eoi(&desc->irq_data);
  }
  
  static void mpc8xxx_irq_unmask(struct irq_data *d)
  {
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = irq_data_get_irq_chip_data(d);
  	struct of_mm_gpio_chip *mm = &mpc8xxx_gc->mm_gc;
  	unsigned long flags;
  
  	spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
  
  	setbits32(mm->regs + GPIO_IMR, mpc8xxx_gpio2mask(irqd_to_hwirq(d)));
  
  	spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
  }
  
  static void mpc8xxx_irq_mask(struct irq_data *d)
  {
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = irq_data_get_irq_chip_data(d);
  	struct of_mm_gpio_chip *mm = &mpc8xxx_gc->mm_gc;
  	unsigned long flags;
  
  	spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
  
  	clrbits32(mm->regs + GPIO_IMR, mpc8xxx_gpio2mask(irqd_to_hwirq(d)));
  
  	spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
  }
  
  static void mpc8xxx_irq_ack(struct irq_data *d)
  {
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = irq_data_get_irq_chip_data(d);
  	struct of_mm_gpio_chip *mm = &mpc8xxx_gc->mm_gc;
  
  	out_be32(mm->regs + GPIO_IER, mpc8xxx_gpio2mask(irqd_to_hwirq(d)));
  }
  
  static int mpc8xxx_irq_set_type(struct irq_data *d, unsigned int flow_type)
  {
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = irq_data_get_irq_chip_data(d);
  	struct of_mm_gpio_chip *mm = &mpc8xxx_gc->mm_gc;
  	unsigned long flags;
  
  	switch (flow_type) {
  	case IRQ_TYPE_EDGE_FALLING:
  		spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
  		setbits32(mm->regs + GPIO_ICR,
  			  mpc8xxx_gpio2mask(irqd_to_hwirq(d)));
  		spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
  		break;
  
  	case IRQ_TYPE_EDGE_BOTH:
  		spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
  		clrbits32(mm->regs + GPIO_ICR,
  			  mpc8xxx_gpio2mask(irqd_to_hwirq(d)));
  		spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
  		break;
  
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static int mpc512x_irq_set_type(struct irq_data *d, unsigned int flow_type)
  {
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = irq_data_get_irq_chip_data(d);
  	struct of_mm_gpio_chip *mm = &mpc8xxx_gc->mm_gc;
  	unsigned long gpio = irqd_to_hwirq(d);
  	void __iomem *reg;
  	unsigned int shift;
  	unsigned long flags;
  
  	if (gpio < 16) {
  		reg = mm->regs + GPIO_ICR;
  		shift = (15 - gpio) * 2;
  	} else {
  		reg = mm->regs + GPIO_ICR2;
  		shift = (15 - (gpio % 16)) * 2;
  	}
  
  	switch (flow_type) {
  	case IRQ_TYPE_EDGE_FALLING:
  	case IRQ_TYPE_LEVEL_LOW:
  		spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
  		clrsetbits_be32(reg, 3 << shift, 2 << shift);
  		spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
  		break;
  
  	case IRQ_TYPE_EDGE_RISING:
  	case IRQ_TYPE_LEVEL_HIGH:
  		spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
  		clrsetbits_be32(reg, 3 << shift, 1 << shift);
  		spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
  		break;
  
  	case IRQ_TYPE_EDGE_BOTH:
  		spin_lock_irqsave(&mpc8xxx_gc->lock, flags);
  		clrbits32(reg, 3 << shift);
  		spin_unlock_irqrestore(&mpc8xxx_gc->lock, flags);
  		break;
  
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static struct irq_chip mpc8xxx_irq_chip = {
  	.name		= "mpc8xxx-gpio",
  	.irq_unmask	= mpc8xxx_irq_unmask,
  	.irq_mask	= mpc8xxx_irq_mask,
  	.irq_ack	= mpc8xxx_irq_ack,
  	.irq_set_type	= mpc8xxx_irq_set_type,
  };
  
  static int mpc8xxx_gpio_irq_map(struct irq_domain *h, unsigned int irq,
  				irq_hw_number_t hwirq)
  {
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc = h->host_data;
  
  	if (mpc8xxx_gc->of_dev_id_data)
  		mpc8xxx_irq_chip.irq_set_type = mpc8xxx_gc->of_dev_id_data;
  
  	irq_set_chip_data(irq, h->host_data);
  	irq_set_chip_and_handler(irq, &mpc8xxx_irq_chip, handle_level_irq);
  
  	return 0;
  }
  
  static struct irq_domain_ops mpc8xxx_gpio_irq_ops = {
  	.map	= mpc8xxx_gpio_irq_map,
  	.xlate	= irq_domain_xlate_twocell,
  };
  
  static struct of_device_id mpc8xxx_gpio_ids[] __initdata = {
  	{ .compatible = "fsl,mpc8349-gpio", },
  	{ .compatible = "fsl,mpc8572-gpio", },
  	{ .compatible = "fsl,mpc8610-gpio", },
  	{ .compatible = "fsl,mpc5121-gpio", .data = mpc512x_irq_set_type, },
  	{ .compatible = "fsl,pq3-gpio",     },
  	{ .compatible = "fsl,qoriq-gpio",   },
  	{}
  };
  
  static void __init mpc8xxx_add_controller(struct device_node *np)
  {
  	struct mpc8xxx_gpio_chip *mpc8xxx_gc;
  	struct of_mm_gpio_chip *mm_gc;
  	struct gpio_chip *gc;
  	const struct of_device_id *id;
  	unsigned hwirq;
  	int ret;
  
  	mpc8xxx_gc = kzalloc(sizeof(*mpc8xxx_gc), GFP_KERNEL);
  	if (!mpc8xxx_gc) {
  		ret = -ENOMEM;
  		goto err;
  	}
  
  	spin_lock_init(&mpc8xxx_gc->lock);
  
  	mm_gc = &mpc8xxx_gc->mm_gc;
  	gc = &mm_gc->gc;
  
  	mm_gc->save_regs = mpc8xxx_gpio_save_regs;
  	gc->ngpio = MPC8XXX_GPIO_PINS;
  	gc->direction_input = mpc8xxx_gpio_dir_in;
  	gc->direction_output = of_device_is_compatible(np, "fsl,mpc5121-gpio") ?
  		mpc5121_gpio_dir_out : mpc8xxx_gpio_dir_out;
  	gc->get = of_device_is_compatible(np, "fsl,mpc8572-gpio") ?
  		mpc8572_gpio_get : mpc8xxx_gpio_get;
  	gc->set = mpc8xxx_gpio_set;
  	gc->to_irq = mpc8xxx_gpio_to_irq;
  
  	ret = of_mm_gpiochip_add(np, mm_gc);
  	if (ret)
  		goto err;
  
  	hwirq = irq_of_parse_and_map(np, 0);
  	if (hwirq == NO_IRQ)
  		goto skip_irq;
  
  	mpc8xxx_gc->irq = irq_domain_add_linear(np, MPC8XXX_GPIO_PINS,
  					&mpc8xxx_gpio_irq_ops, mpc8xxx_gc);
  	if (!mpc8xxx_gc->irq)
  		goto skip_irq;
  
  	id = of_match_node(mpc8xxx_gpio_ids, np);
  	if (id)
  		mpc8xxx_gc->of_dev_id_data = id->data;
  
  	/* ack and mask all irqs */
  	out_be32(mm_gc->regs + GPIO_IER, 0xffffffff);
  	out_be32(mm_gc->regs + GPIO_IMR, 0);
  
  	irq_set_handler_data(hwirq, mpc8xxx_gc);
  	irq_set_chained_handler(hwirq, mpc8xxx_gpio_irq_cascade);
  
  skip_irq:
  	return;
  
  err:
  	pr_err("%s: registration failed with status %d
  ",
  	       np->full_name, ret);
  	kfree(mpc8xxx_gc);
  
  	return;
  }
  
  static int __init mpc8xxx_add_gpiochips(void)
  {
  	struct device_node *np;
  
  	for_each_matching_node(np, mpc8xxx_gpio_ids)
  		mpc8xxx_add_controller(np);
  
  	return 0;
  }
  arch_initcall(mpc8xxx_add_gpiochips);