/*
   * Copyright (C) ST-Ericsson SA 2010
   *
   * License Terms: GNU General Public License, version 2
   * Author: Hanumath Prasad <hanumath.prasad@stericsson.com> for ST-Ericsson
   * Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/platform_device.h>
  #include <linux/slab.h>
  #include <linux/gpio.h>
  #include <linux/irq.h>
  #include <linux/interrupt.h>

  #include <linux/mfd/tc3589x.h>

  
  /*
   * These registers are modified under the irq bus lock and cached to avoid
   * unnecessary writes in bus_sync_unlock.
   */
  enum { REG_IBE, REG_IEV, REG_IS, REG_IE };
  
  #define CACHE_NR_REGS	4
  #define CACHE_NR_BANKS	3

  struct tc3589x_gpio {

  	struct gpio_chip chip;

  	struct tc3589x *tc3589x;

  	struct device *dev;
  	struct mutex irq_lock;
  
  	int irq_base;
  
  	/* Caches of interrupt control registers for bus_lock */
  	u8 regs[CACHE_NR_REGS][CACHE_NR_BANKS];
  	u8 oldregs[CACHE_NR_REGS][CACHE_NR_BANKS];
  };

  static inline struct tc3589x_gpio *to_tc3589x_gpio(struct gpio_chip *chip)

  {

  	return container_of(chip, struct tc3589x_gpio, chip);

  }

  static int tc3589x_gpio_get(struct gpio_chip *chip, unsigned offset)

  {

  	struct tc3589x_gpio *tc3589x_gpio = to_tc3589x_gpio(chip);
  	struct tc3589x *tc3589x = tc3589x_gpio->tc3589x;
  	u8 reg = TC3589x_GPIODATA0 + (offset / 8) * 2;

  	u8 mask = 1 << (offset % 8);
  	int ret;

  	ret = tc3589x_reg_read(tc3589x, reg);

  	if (ret < 0)
  		return ret;
  
  	return ret & mask;
  }

  static void tc3589x_gpio_set(struct gpio_chip *chip, unsigned offset, int val)

  {

  	struct tc3589x_gpio *tc3589x_gpio = to_tc3589x_gpio(chip);
  	struct tc3589x *tc3589x = tc3589x_gpio->tc3589x;
  	u8 reg = TC3589x_GPIODATA0 + (offset / 8) * 2;

  	unsigned pos = offset % 8;
  	u8 data[] = {!!val << pos, 1 << pos};

  	tc3589x_block_write(tc3589x, reg, ARRAY_SIZE(data), data);

  }

  static int tc3589x_gpio_direction_output(struct gpio_chip *chip,

  					 unsigned offset, int val)
  {

  	struct tc3589x_gpio *tc3589x_gpio = to_tc3589x_gpio(chip);
  	struct tc3589x *tc3589x = tc3589x_gpio->tc3589x;
  	u8 reg = TC3589x_GPIODIR0 + offset / 8;

  	unsigned pos = offset % 8;

  	tc3589x_gpio_set(chip, offset, val);

  	return tc3589x_set_bits(tc3589x, reg, 1 << pos, 1 << pos);

  }

  static int tc3589x_gpio_direction_input(struct gpio_chip *chip,

  					unsigned offset)
  {

  	struct tc3589x_gpio *tc3589x_gpio = to_tc3589x_gpio(chip);
  	struct tc3589x *tc3589x = tc3589x_gpio->tc3589x;
  	u8 reg = TC3589x_GPIODIR0 + offset / 8;

  	unsigned pos = offset % 8;

  	return tc3589x_set_bits(tc3589x, reg, 1 << pos, 0);

  }

  static int tc3589x_gpio_to_irq(struct gpio_chip *chip, unsigned offset)

  {

  	struct tc3589x_gpio *tc3589x_gpio = to_tc3589x_gpio(chip);

  	return tc3589x_gpio->irq_base + offset;

  }
  
  static struct gpio_chip template_chip = {

  	.label			= "tc3589x",

  	.owner			= THIS_MODULE,

  	.direction_input	= tc3589x_gpio_direction_input,
  	.get			= tc3589x_gpio_get,
  	.direction_output	= tc3589x_gpio_direction_output,
  	.set			= tc3589x_gpio_set,
  	.to_irq			= tc3589x_gpio_to_irq,

  	.can_sleep		= 1,
  };

  static int tc3589x_gpio_irq_set_type(struct irq_data *d, unsigned int type)

  {

  	struct tc3589x_gpio *tc3589x_gpio = irq_data_get_irq_chip_data(d);
  	int offset = d->irq - tc3589x_gpio->irq_base;

  	int regoffset = offset / 8;
  	int mask = 1 << (offset % 8);
  
  	if (type == IRQ_TYPE_EDGE_BOTH) {

  		tc3589x_gpio->regs[REG_IBE][regoffset] |= mask;

  		return 0;
  	}

  	tc3589x_gpio->regs[REG_IBE][regoffset] &= ~mask;

  
  	if (type == IRQ_TYPE_LEVEL_LOW || type == IRQ_TYPE_LEVEL_HIGH)

  		tc3589x_gpio->regs[REG_IS][regoffset] |= mask;

  	else

  		tc3589x_gpio->regs[REG_IS][regoffset] &= ~mask;

  
  	if (type == IRQ_TYPE_EDGE_RISING || type == IRQ_TYPE_LEVEL_HIGH)

  		tc3589x_gpio->regs[REG_IEV][regoffset] |= mask;

  	else

  		tc3589x_gpio->regs[REG_IEV][regoffset] &= ~mask;

  
  	return 0;
  }

  static void tc3589x_gpio_irq_lock(struct irq_data *d)

  {

  	struct tc3589x_gpio *tc3589x_gpio = irq_data_get_irq_chip_data(d);

  	mutex_lock(&tc3589x_gpio->irq_lock);

  }

  static void tc3589x_gpio_irq_sync_unlock(struct irq_data *d)

  {

  	struct tc3589x_gpio *tc3589x_gpio = irq_data_get_irq_chip_data(d);

  	struct tc3589x *tc3589x = tc3589x_gpio->tc3589x;

  	static const u8 regmap[] = {

  		[REG_IBE]	= TC3589x_GPIOIBE0,
  		[REG_IEV]	= TC3589x_GPIOIEV0,
  		[REG_IS]	= TC3589x_GPIOIS0,
  		[REG_IE]	= TC3589x_GPIOIE0,

  	};
  	int i, j;
  
  	for (i = 0; i < CACHE_NR_REGS; i++) {
  		for (j = 0; j < CACHE_NR_BANKS; j++) {

  			u8 old = tc3589x_gpio->oldregs[i][j];
  			u8 new = tc3589x_gpio->regs[i][j];

  
  			if (new == old)
  				continue;

  			tc3589x_gpio->oldregs[i][j] = new;
  			tc3589x_reg_write(tc3589x, regmap[i] + j * 8, new);

  		}
  	}

  	mutex_unlock(&tc3589x_gpio->irq_lock);

  }

  static void tc3589x_gpio_irq_mask(struct irq_data *d)

  {

  	struct tc3589x_gpio *tc3589x_gpio = irq_data_get_irq_chip_data(d);
  	int offset = d->irq - tc3589x_gpio->irq_base;

  	int regoffset = offset / 8;
  	int mask = 1 << (offset % 8);

  	tc3589x_gpio->regs[REG_IE][regoffset] &= ~mask;

  }

  static void tc3589x_gpio_irq_unmask(struct irq_data *d)

  {

  	struct tc3589x_gpio *tc3589x_gpio = irq_data_get_irq_chip_data(d);
  	int offset = d->irq - tc3589x_gpio->irq_base;

  	int regoffset = offset / 8;
  	int mask = 1 << (offset % 8);

  	tc3589x_gpio->regs[REG_IE][regoffset] |= mask;

  }

  static struct irq_chip tc3589x_gpio_irq_chip = {
  	.name			= "tc3589x-gpio",

  	.irq_bus_lock		= tc3589x_gpio_irq_lock,
  	.irq_bus_sync_unlock	= tc3589x_gpio_irq_sync_unlock,
  	.irq_mask		= tc3589x_gpio_irq_mask,
  	.irq_unmask		= tc3589x_gpio_irq_unmask,
  	.irq_set_type		= tc3589x_gpio_irq_set_type,

  };

  static irqreturn_t tc3589x_gpio_irq(int irq, void *dev)

  {

  	struct tc3589x_gpio *tc3589x_gpio = dev;
  	struct tc3589x *tc3589x = tc3589x_gpio->tc3589x;

  	u8 status[CACHE_NR_BANKS];
  	int ret;
  	int i;

  	ret = tc3589x_block_read(tc3589x, TC3589x_GPIOMIS0,

  				 ARRAY_SIZE(status), status);
  	if (ret < 0)
  		return IRQ_NONE;
  
  	for (i = 0; i < ARRAY_SIZE(status); i++) {
  		unsigned int stat = status[i];
  		if (!stat)
  			continue;
  
  		while (stat) {
  			int bit = __ffs(stat);
  			int line = i * 8 + bit;

  			handle_nested_irq(tc3589x_gpio->irq_base + line);

  			stat &= ~(1 << bit);
  		}

  		tc3589x_reg_write(tc3589x, TC3589x_GPIOIC0 + i, status[i]);

  	}
  
  	return IRQ_HANDLED;
  }

  static int tc3589x_gpio_irq_init(struct tc3589x_gpio *tc3589x_gpio)

  {

  	int base = tc3589x_gpio->irq_base;

  	int irq;

  	for (irq = base; irq < base + tc3589x_gpio->chip.ngpio; irq++) {

  		irq_set_chip_data(irq, tc3589x_gpio);
  		irq_set_chip_and_handler(irq, &tc3589x_gpio_irq_chip,

  					 handle_simple_irq);

  		irq_set_nested_thread(irq, 1);

  #ifdef CONFIG_ARM
  		set_irq_flags(irq, IRQF_VALID);
  #else

  		irq_set_noprobe(irq);

  #endif
  	}
  
  	return 0;
  }

  static void tc3589x_gpio_irq_remove(struct tc3589x_gpio *tc3589x_gpio)

  {

  	int base = tc3589x_gpio->irq_base;

  	int irq;

  	for (irq = base; irq < base + tc3589x_gpio->chip.ngpio; irq++) {

  #ifdef CONFIG_ARM
  		set_irq_flags(irq, 0);
  #endif

  		irq_set_chip_and_handler(irq, NULL, NULL);
  		irq_set_chip_data(irq, NULL);

  	}
  }

  static int __devinit tc3589x_gpio_probe(struct platform_device *pdev)

  {

  	struct tc3589x *tc3589x = dev_get_drvdata(pdev->dev.parent);
  	struct tc3589x_gpio_platform_data *pdata;
  	struct tc3589x_gpio *tc3589x_gpio;

  	int ret;
  	int irq;

  	pdata = tc3589x->pdata->gpio;

  	if (!pdata)
  		return -ENODEV;
  
  	irq = platform_get_irq(pdev, 0);
  	if (irq < 0)
  		return irq;

  	tc3589x_gpio = kzalloc(sizeof(struct tc3589x_gpio), GFP_KERNEL);
  	if (!tc3589x_gpio)

  		return -ENOMEM;

  	mutex_init(&tc3589x_gpio->irq_lock);

  	tc3589x_gpio->dev = &pdev->dev;
  	tc3589x_gpio->tc3589x = tc3589x;

  	tc3589x_gpio->chip = template_chip;
  	tc3589x_gpio->chip.ngpio = tc3589x->num_gpio;
  	tc3589x_gpio->chip.dev = &pdev->dev;
  	tc3589x_gpio->chip.base = pdata->gpio_base;

  	tc3589x_gpio->irq_base = tc3589x->irq_base + TC3589x_INT_GPIO(0);

  
  	/* Bring the GPIO module out of reset */

  	ret = tc3589x_set_bits(tc3589x, TC3589x_RSTCTRL,
  			       TC3589x_RSTCTRL_GPIRST, 0);

  	if (ret < 0)
  		goto out_free;

  	ret = tc3589x_gpio_irq_init(tc3589x_gpio);

  	if (ret)
  		goto out_free;

  	ret = request_threaded_irq(irq, NULL, tc3589x_gpio_irq, IRQF_ONESHOT,
  				   "tc3589x-gpio", tc3589x_gpio);

  	if (ret) {
  		dev_err(&pdev->dev, "unable to get irq: %d
  ", ret);
  		goto out_removeirq;
  	}

  	ret = gpiochip_add(&tc3589x_gpio->chip);

  	if (ret) {
  		dev_err(&pdev->dev, "unable to add gpiochip: %d
  ", ret);
  		goto out_freeirq;
  	}

  	if (pdata->setup)

  		pdata->setup(tc3589x, tc3589x_gpio->chip.base);

  	platform_set_drvdata(pdev, tc3589x_gpio);

  
  	return 0;
  
  out_freeirq:

  	free_irq(irq, tc3589x_gpio);

  out_removeirq:

  	tc3589x_gpio_irq_remove(tc3589x_gpio);

  out_free:

  	kfree(tc3589x_gpio);

  	return ret;
  }

  static int __devexit tc3589x_gpio_remove(struct platform_device *pdev)

  {

  	struct tc3589x_gpio *tc3589x_gpio = platform_get_drvdata(pdev);
  	struct tc3589x *tc3589x = tc3589x_gpio->tc3589x;
  	struct tc3589x_gpio_platform_data *pdata = tc3589x->pdata->gpio;

  	int irq = platform_get_irq(pdev, 0);
  	int ret;

  	if (pdata->remove)

  		pdata->remove(tc3589x, tc3589x_gpio->chip.base);

  	ret = gpiochip_remove(&tc3589x_gpio->chip);

  	if (ret < 0) {

  		dev_err(tc3589x_gpio->dev,

  			"unable to remove gpiochip: %d
  ", ret);
  		return ret;
  	}

  	free_irq(irq, tc3589x_gpio);
  	tc3589x_gpio_irq_remove(tc3589x_gpio);

  
  	platform_set_drvdata(pdev, NULL);

  	kfree(tc3589x_gpio);

  
  	return 0;
  }

  static struct platform_driver tc3589x_gpio_driver = {
  	.driver.name	= "tc3589x-gpio",

  	.driver.owner	= THIS_MODULE,

  	.probe		= tc3589x_gpio_probe,
  	.remove		= __devexit_p(tc3589x_gpio_remove),

  };

  static int __init tc3589x_gpio_init(void)

  {

  	return platform_driver_register(&tc3589x_gpio_driver);

  }

  subsys_initcall(tc3589x_gpio_init);

  static void __exit tc3589x_gpio_exit(void)

  {

  	platform_driver_unregister(&tc3589x_gpio_driver);

  }

  module_exit(tc3589x_gpio_exit);

  
  MODULE_LICENSE("GPL v2");

  MODULE_DESCRIPTION("TC3589x GPIO driver");

  MODULE_AUTHOR("Hanumath Prasad, Rabin Vincent");