/*
 * SuperH Pin Function Controller GPIO driver.
 *
 * Copyright (C) 2008 Magnus Damm
 * Copyright (C) 2009 - 2012 Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */

#include <linux/device.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/pinctrl/consumer.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include "core.h"

struct sh_pfc_gpio_data_reg {
	const struct pinmux_data_reg *info;
	unsigned long shadow;
};

struct sh_pfc_gpio_pin {
	u8 dbit;
	u8 dreg;
};

struct sh_pfc_chip {
	struct sh_pfc			*pfc;
	struct gpio_chip		gpio_chip;

	struct sh_pfc_window		*mem;
	struct sh_pfc_gpio_data_reg	*regs;
	struct sh_pfc_gpio_pin		*pins;
};

static struct sh_pfc_chip *gpio_to_pfc_chip(struct gpio_chip *gc)
{
	return container_of(gc, struct sh_pfc_chip, gpio_chip);
}

static struct sh_pfc *gpio_to_pfc(struct gpio_chip *gc)
{
	return gpio_to_pfc_chip(gc)->pfc;
}

static void gpio_get_data_reg(struct sh_pfc_chip *chip, unsigned int offset,
			      struct sh_pfc_gpio_data_reg **reg,
			      unsigned int *bit)
{
	int idx = sh_pfc_get_pin_index(chip->pfc, offset);
	struct sh_pfc_gpio_pin *gpio_pin = &chip->pins[idx];

	*reg = &chip->regs[gpio_pin->dreg];
	*bit = gpio_pin->dbit;
}

static unsigned long gpio_read_data_reg(struct sh_pfc_chip *chip,
					const struct pinmux_data_reg *dreg)
{
	void __iomem *mem = dreg->reg - chip->mem->phys + chip->mem->virt;

	return sh_pfc_read_raw_reg(mem, dreg->reg_width);
}

static void gpio_write_data_reg(struct sh_pfc_chip *chip,
				const struct pinmux_data_reg *dreg,
				unsigned long value)
{
	void __iomem *mem = dreg->reg - chip->mem->phys + chip->mem->virt;

	sh_pfc_write_raw_reg(mem, dreg->reg_width, value);
}

static void gpio_setup_data_reg(struct sh_pfc_chip *chip, unsigned idx)
{
	struct sh_pfc *pfc = chip->pfc;
	struct sh_pfc_gpio_pin *gpio_pin = &chip->pins[idx];
	const struct sh_pfc_pin *pin = &pfc->info->pins[idx];
	const struct pinmux_data_reg *dreg;
	unsigned int bit;
	unsigned int i;

	for (i = 0, dreg = pfc->info->data_regs; dreg->reg; ++i, ++dreg) {
		for (bit = 0; bit < dreg->reg_width; bit++) {
			if (dreg->enum_ids[bit] == pin->enum_id) {
				gpio_pin->dreg = i;
				gpio_pin->dbit = bit;
				return;
			}
		}
	}

	BUG();
}

static int gpio_setup_data_regs(struct sh_pfc_chip *chip)
{
	struct sh_pfc *pfc = chip->pfc;
	const struct pinmux_data_reg *dreg;
	unsigned int i;

	/* Count the number of data registers, allocate memory and initialize
	 * them.
	 */
	for (i = 0; pfc->info->data_regs[i].reg_width; ++i)
		;

	chip->regs = devm_kzalloc(pfc->dev, i * sizeof(*chip->regs),
				  GFP_KERNEL);
	if (chip->regs == NULL)
		return -ENOMEM;

	for (i = 0, dreg = pfc->info->data_regs; dreg->reg_width; ++i, ++dreg) {
		chip->regs[i].info = dreg;
		chip->regs[i].shadow = gpio_read_data_reg(chip, dreg);
	}

	for (i = 0; i < pfc->info->nr_pins; i++) {
		if (pfc->info->pins[i].enum_id == 0)
			continue;

		gpio_setup_data_reg(chip, i);
	}

	return 0;
}

/* -----------------------------------------------------------------------------
 * Pin GPIOs
 */

static int gpio_pin_request(struct gpio_chip *gc, unsigned offset)
{
	struct sh_pfc *pfc = gpio_to_pfc(gc);
	int idx = sh_pfc_get_pin_index(pfc, offset);

	if (idx < 0 || pfc->info->pins[idx].enum_id == 0)
		return -EINVAL;

	return pinctrl_request_gpio(offset);
}

static void gpio_pin_free(struct gpio_chip *gc, unsigned offset)
{
	return pinctrl_free_gpio(offset);
}

static void gpio_pin_set_value(struct sh_pfc_chip *chip, unsigned offset,
			       int value)
{
	struct sh_pfc_gpio_data_reg *reg;
	unsigned long pos;
	unsigned int bit;

	gpio_get_data_reg(chip, offset, &reg, &bit);

	pos = reg->info->reg_width - (bit + 1);

	if (value)
		set_bit(pos, &reg->shadow);
	else
		clear_bit(pos, &reg->shadow);

	gpio_write_data_reg(chip, reg->info, reg->shadow);
}

static int gpio_pin_direction_input(struct gpio_chip *gc, unsigned offset)
{
	return pinctrl_gpio_direction_input(offset);
}

static int gpio_pin_direction_output(struct gpio_chip *gc, unsigned offset,
				    int value)
{
	gpio_pin_set_value(gpio_to_pfc_chip(gc), offset, value);

	return pinctrl_gpio_direction_output(offset);
}

static int gpio_pin_get(struct gpio_chip *gc, unsigned offset)
{
	struct sh_pfc_chip *chip = gpio_to_pfc_chip(gc);
	struct sh_pfc_gpio_data_reg *reg;
	unsigned long pos;
	unsigned int bit;

	gpio_get_data_reg(chip, offset, &reg, &bit);

	pos = reg->info->reg_width - (bit + 1);

	return (gpio_read_data_reg(chip, reg->info) >> pos) & 1;
}

static void gpio_pin_set(struct gpio_chip *gc, unsigned offset, int value)
{
	gpio_pin_set_value(gpio_to_pfc_chip(gc), offset, value);
}

static int gpio_pin_to_irq(struct gpio_chip *gc, unsigned offset)
{
	struct sh_pfc *pfc = gpio_to_pfc(gc);
	unsigned int i, k;

	for (i = 0; i < pfc->info->gpio_irq_size; i++) {
		const short *gpios = pfc->info->gpio_irq[i].gpios;

		for (k = 0; gpios[k] >= 0; k++) {
			if (gpios[k] == offset)
				goto found;
		}
	}

	return -ENOSYS;

found:
	if (pfc->num_irqs)
		return pfc->irqs[i];
	else
		return pfc->info->gpio_irq[i].irq;
}

static int gpio_pin_setup(struct sh_pfc_chip *chip)
{
	struct sh_pfc *pfc = chip->pfc;
	struct gpio_chip *gc = &chip->gpio_chip;
	int ret;

	chip->pins = devm_kzalloc(pfc->dev, pfc->info->nr_pins *
				  sizeof(*chip->pins), GFP_KERNEL);
	if (chip->pins == NULL)
		return -ENOMEM;

	ret = gpio_setup_data_regs(chip);
	if (ret < 0)
		return ret;

	gc->request = gpio_pin_request;
	gc->free = gpio_pin_free;
	gc->direction_input = gpio_pin_direction_input;
	gc->get = gpio_pin_get;
	gc->direction_output = gpio_pin_direction_output;
	gc->set = gpio_pin_set;
	gc->to_irq = gpio_pin_to_irq;

	gc->label = pfc->info->name;
	gc->dev = pfc->dev;
	gc->owner = THIS_MODULE;
	gc->base = 0;
	gc->ngpio = pfc->nr_gpio_pins;

	return 0;
}

/* -----------------------------------------------------------------------------
 * Function GPIOs
 */

static int gpio_function_request(struct gpio_chip *gc, unsigned offset)
{
	static bool __print_once;
	struct sh_pfc *pfc = gpio_to_pfc(gc);
	unsigned int mark = pfc->info->func_gpios[offset].enum_id;
	unsigned long flags;
	int ret;

	if (!__print_once) {
		dev_notice(pfc->dev,
			   "Use of GPIO API for function requests is deprecated."
			   " Convert to pinctrl\n");
		__print_once = true;
	}

	if (mark == 0)
		return -EINVAL;

	spin_lock_irqsave(&pfc->lock, flags);
	ret = sh_pfc_config_mux(pfc, mark, PINMUX_TYPE_FUNCTION);
	spin_unlock_irqrestore(&pfc->lock, flags);

	return ret;
}

static void gpio_function_free(struct gpio_chip *gc, unsigned offset)
{
}

static int gpio_function_setup(struct sh_pfc_chip *chip)
{
	struct sh_pfc *pfc = chip->pfc;
	struct gpio_chip *gc = &chip->gpio_chip;

	gc->request = gpio_function_request;
	gc->free = gpio_function_free;

	gc->label = pfc->info->name;
	gc->owner = THIS_MODULE;
	gc->base = pfc->nr_gpio_pins;
	gc->ngpio = pfc->info->nr_func_gpios;

	return 0;
}

/* -----------------------------------------------------------------------------
 * Register/unregister
 */

static struct sh_pfc_chip *
sh_pfc_add_gpiochip(struct sh_pfc *pfc, int(*setup)(struct sh_pfc_chip *),
		    struct sh_pfc_window *mem)
{
	struct sh_pfc_chip *chip;
	int ret;

	chip = devm_kzalloc(pfc->dev, sizeof(*chip), GFP_KERNEL);
	if (unlikely(!chip))
		return ERR_PTR(-ENOMEM);

	chip->mem = mem;
	chip->pfc = pfc;

	ret = setup(chip);
	if (ret < 0)
		return ERR_PTR(ret);

	ret = gpiochip_add(&chip->gpio_chip);
	if (unlikely(ret < 0))
		return ERR_PTR(ret);

	dev_info(pfc->dev, "%s handling gpio %u -> %u\n",
		 chip->gpio_chip.label, chip->gpio_chip.base,
		 chip->gpio_chip.base + chip->gpio_chip.ngpio - 1);

	return chip;
}

int sh_pfc_register_gpiochip(struct sh_pfc *pfc)
{
	struct sh_pfc_chip *chip;
	unsigned int i;
	int ret;

	if (pfc->info->data_regs == NULL)
		return 0;

	/* Find the memory window that contain the GPIO registers. Boards that
	 * register a separate GPIO device will not supply a memory resource
	 * that covers the data registers. In that case don't try to handle
	 * GPIOs.
	 */
	for (i = 0; i < pfc->num_windows; ++i) {
		struct sh_pfc_window *window = &pfc->windows[i];

		if (pfc->info->data_regs[0].reg >= window->phys &&
		    pfc->info->data_regs[0].reg < window->phys + window->size)
			break;
	}

	if (i == pfc->num_windows)
		return 0;

	/* If we have IRQ resources make sure their number is correct. */
	if (pfc->num_irqs && pfc->num_irqs != pfc->info->gpio_irq_size) {
		dev_err(pfc->dev, "invalid number of IRQ resources\n");
		return -EINVAL;
	}

	/* Register the real GPIOs chip. */
	chip = sh_pfc_add_gpiochip(pfc, gpio_pin_setup, &pfc->windows[i]);
	if (IS_ERR(chip))
		return PTR_ERR(chip);

	pfc->gpio = chip;

	/* Register the GPIO to pin mappings. As pins with GPIO ports must come
	 * first in the ranges, skip the pins without GPIO ports by stopping at
	 * the first range that contains such a pin.
	 */
	for (i = 0; i < pfc->nr_ranges; ++i) {
		const struct sh_pfc_pin_range *range = &pfc->ranges[i];

		if (range->start >= pfc->nr_gpio_pins)
			break;

		ret = gpiochip_add_pin_range(&chip->gpio_chip,
					     dev_name(pfc->dev),
					     range->start, range->start,
					     range->end - range->start + 1);
		if (ret < 0)
			return ret;
	}

	/* Register the function GPIOs chip. */
	if (pfc->info->nr_func_gpios == 0)
		return 0;

	chip = sh_pfc_add_gpiochip(pfc, gpio_function_setup, NULL);
	if (IS_ERR(chip))
		return PTR_ERR(chip);

	pfc->func = chip;

	return 0;
}

int sh_pfc_unregister_gpiochip(struct sh_pfc *pfc)
{
	int err;
	int ret;

	ret = gpiochip_remove(&pfc->gpio->gpio_chip);
	err = gpiochip_remove(&pfc->func->gpio_chip);

	return ret < 0 ? ret : err;
}