/*
   * Sonics Silicon Backplane
   * GPIO driver
   *
   * Copyright 2011, Broadcom Corporation
   * Copyright 2012, Hauke Mehrtens <hauke@hauke-m.de>
   *
   * Licensed under the GNU/GPL. See COPYING for details.
   */
  
  #include <linux/gpio.h>
  #include <linux/irq.h>
  #include <linux/interrupt.h>
  #include <linux/irqdomain.h>
  #include <linux/export.h>
  #include <linux/ssb/ssb.h>
  
  #include "ssb_private.h"
  
  
  /**************************************************
   * Shared
   **************************************************/
  
  static struct ssb_bus *ssb_gpio_get_bus(struct gpio_chip *chip)
  {
  	return container_of(chip, struct ssb_bus, gpio);
  }
  
  #if IS_ENABLED(CONFIG_SSB_EMBEDDED)
  static int ssb_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
  {
  	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
  
  	if (bus->bustype == SSB_BUSTYPE_SSB)
  		return irq_find_mapping(bus->irq_domain, gpio);
  	else
  		return -EINVAL;
  }
  #endif
  
  /**************************************************
   * ChipCommon
   **************************************************/
  
  static int ssb_gpio_chipco_get_value(struct gpio_chip *chip, unsigned gpio)
  {
  	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
  
  	return !!ssb_chipco_gpio_in(&bus->chipco, 1 << gpio);
  }
  
  static void ssb_gpio_chipco_set_value(struct gpio_chip *chip, unsigned gpio,
  				      int value)
  {
  	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
  
  	ssb_chipco_gpio_out(&bus->chipco, 1 << gpio, value ? 1 << gpio : 0);
  }
  
  static int ssb_gpio_chipco_direction_input(struct gpio_chip *chip,
  					   unsigned gpio)
  {
  	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
  
  	ssb_chipco_gpio_outen(&bus->chipco, 1 << gpio, 0);
  	return 0;
  }
  
  static int ssb_gpio_chipco_direction_output(struct gpio_chip *chip,
  					    unsigned gpio, int value)
  {
  	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
  
  	ssb_chipco_gpio_outen(&bus->chipco, 1 << gpio, 1 << gpio);
  	ssb_chipco_gpio_out(&bus->chipco, 1 << gpio, value ? 1 << gpio : 0);
  	return 0;
  }
  
  static int ssb_gpio_chipco_request(struct gpio_chip *chip, unsigned gpio)
  {
  	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
  
  	ssb_chipco_gpio_control(&bus->chipco, 1 << gpio, 0);
  	/* clear pulldown */
  	ssb_chipco_gpio_pulldown(&bus->chipco, 1 << gpio, 0);
  	/* Set pullup */
  	ssb_chipco_gpio_pullup(&bus->chipco, 1 << gpio, 1 << gpio);
  
  	return 0;
  }
  
  static void ssb_gpio_chipco_free(struct gpio_chip *chip, unsigned gpio)
  {
  	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
  
  	/* clear pullup */
  	ssb_chipco_gpio_pullup(&bus->chipco, 1 << gpio, 0);
  }
  
  #if IS_ENABLED(CONFIG_SSB_EMBEDDED)
  static void ssb_gpio_irq_chipco_mask(struct irq_data *d)
  {
  	struct ssb_bus *bus = irq_data_get_irq_chip_data(d);
  	int gpio = irqd_to_hwirq(d);
  
  	ssb_chipco_gpio_intmask(&bus->chipco, BIT(gpio), 0);
  }
  
  static void ssb_gpio_irq_chipco_unmask(struct irq_data *d)
  {
  	struct ssb_bus *bus = irq_data_get_irq_chip_data(d);
  	int gpio = irqd_to_hwirq(d);
  	u32 val = ssb_chipco_gpio_in(&bus->chipco, BIT(gpio));
  
  	ssb_chipco_gpio_polarity(&bus->chipco, BIT(gpio), val);
  	ssb_chipco_gpio_intmask(&bus->chipco, BIT(gpio), BIT(gpio));
  }
  
  static struct irq_chip ssb_gpio_irq_chipco_chip = {
  	.name		= "SSB-GPIO-CC",
  	.irq_mask	= ssb_gpio_irq_chipco_mask,
  	.irq_unmask	= ssb_gpio_irq_chipco_unmask,
  };
  
  static irqreturn_t ssb_gpio_irq_chipco_handler(int irq, void *dev_id)
  {
  	struct ssb_bus *bus = dev_id;
  	struct ssb_chipcommon *chipco = &bus->chipco;
  	u32 val = chipco_read32(chipco, SSB_CHIPCO_GPIOIN);
  	u32 mask = chipco_read32(chipco, SSB_CHIPCO_GPIOIRQ);
  	u32 pol = chipco_read32(chipco, SSB_CHIPCO_GPIOPOL);
  	unsigned long irqs = (val ^ pol) & mask;
  	int gpio;
  
  	if (!irqs)
  		return IRQ_NONE;
  
  	for_each_set_bit(gpio, &irqs, bus->gpio.ngpio)
  		generic_handle_irq(ssb_gpio_to_irq(&bus->gpio, gpio));
  	ssb_chipco_gpio_polarity(chipco, irqs, val & irqs);
  
  	return IRQ_HANDLED;
  }
  
  static int ssb_gpio_irq_chipco_domain_init(struct ssb_bus *bus)
  {
  	struct ssb_chipcommon *chipco = &bus->chipco;
  	struct gpio_chip *chip = &bus->gpio;
  	int gpio, hwirq, err;
  
  	if (bus->bustype != SSB_BUSTYPE_SSB)
  		return 0;
  
  	bus->irq_domain = irq_domain_add_linear(NULL, chip->ngpio,
  						&irq_domain_simple_ops, chipco);
  	if (!bus->irq_domain) {
  		err = -ENODEV;
  		goto err_irq_domain;
  	}
  	for (gpio = 0; gpio < chip->ngpio; gpio++) {
  		int irq = irq_create_mapping(bus->irq_domain, gpio);
  
  		irq_set_chip_data(irq, bus);
  		irq_set_chip_and_handler(irq, &ssb_gpio_irq_chipco_chip,
  					 handle_simple_irq);
  	}
  
  	hwirq = ssb_mips_irq(bus->chipco.dev) + 2;
  	err = request_irq(hwirq, ssb_gpio_irq_chipco_handler, IRQF_SHARED,
  			  "gpio", bus);
  	if (err)
  		goto err_req_irq;
  
  	ssb_chipco_gpio_intmask(&bus->chipco, ~0, 0);
  	chipco_set32(chipco, SSB_CHIPCO_IRQMASK, SSB_CHIPCO_IRQ_GPIO);
  
  	return 0;
  
  err_req_irq:
  	for (gpio = 0; gpio < chip->ngpio; gpio++) {
  		int irq = irq_find_mapping(bus->irq_domain, gpio);
  
  		irq_dispose_mapping(irq);
  	}
  	irq_domain_remove(bus->irq_domain);
  err_irq_domain:
  	return err;
  }
  
  static void ssb_gpio_irq_chipco_domain_exit(struct ssb_bus *bus)
  {
  	struct ssb_chipcommon *chipco = &bus->chipco;
  	struct gpio_chip *chip = &bus->gpio;
  	int gpio;
  
  	if (bus->bustype != SSB_BUSTYPE_SSB)
  		return;
  
  	chipco_mask32(chipco, SSB_CHIPCO_IRQMASK, ~SSB_CHIPCO_IRQ_GPIO);
  	free_irq(ssb_mips_irq(bus->chipco.dev) + 2, chipco);
  	for (gpio = 0; gpio < chip->ngpio; gpio++) {
  		int irq = irq_find_mapping(bus->irq_domain, gpio);
  
  		irq_dispose_mapping(irq);
  	}
  	irq_domain_remove(bus->irq_domain);
  }
  #else
  static int ssb_gpio_irq_chipco_domain_init(struct ssb_bus *bus)
  {
  	return 0;
  }
  
  static void ssb_gpio_irq_chipco_domain_exit(struct ssb_bus *bus)
  {
  }
  #endif
  
  static int ssb_gpio_chipco_init(struct ssb_bus *bus)
  {
  	struct gpio_chip *chip = &bus->gpio;
  	int err;
  
  	chip->label		= "ssb_chipco_gpio";
  	chip->owner		= THIS_MODULE;
  	chip->request		= ssb_gpio_chipco_request;
  	chip->free		= ssb_gpio_chipco_free;
  	chip->get		= ssb_gpio_chipco_get_value;
  	chip->set		= ssb_gpio_chipco_set_value;
  	chip->direction_input	= ssb_gpio_chipco_direction_input;
  	chip->direction_output	= ssb_gpio_chipco_direction_output;
  #if IS_ENABLED(CONFIG_SSB_EMBEDDED)
  	chip->to_irq		= ssb_gpio_to_irq;
  #endif
  	chip->ngpio		= 16;
  	/* There is just one SoC in one device and its GPIO addresses should be
  	 * deterministic to address them more easily. The other buses could get
  	 * a random base number. */
  	if (bus->bustype == SSB_BUSTYPE_SSB)
  		chip->base		= 0;
  	else
  		chip->base		= -1;
  
  	err = ssb_gpio_irq_chipco_domain_init(bus);
  	if (err)
  		return err;
  
  	err = gpiochip_add(chip);
  	if (err) {
  		ssb_gpio_irq_chipco_domain_exit(bus);
  		return err;
  	}
  
  	return 0;
  }
  
  /**************************************************
   * EXTIF
   **************************************************/
  
  #ifdef CONFIG_SSB_DRIVER_EXTIF
  
  static int ssb_gpio_extif_get_value(struct gpio_chip *chip, unsigned gpio)
  {
  	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
  
  	return !!ssb_extif_gpio_in(&bus->extif, 1 << gpio);
  }
  
  static void ssb_gpio_extif_set_value(struct gpio_chip *chip, unsigned gpio,
  				     int value)
  {
  	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
  
  	ssb_extif_gpio_out(&bus->extif, 1 << gpio, value ? 1 << gpio : 0);
  }
  
  static int ssb_gpio_extif_direction_input(struct gpio_chip *chip,
  					  unsigned gpio)
  {
  	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
  
  	ssb_extif_gpio_outen(&bus->extif, 1 << gpio, 0);
  	return 0;
  }
  
  static int ssb_gpio_extif_direction_output(struct gpio_chip *chip,
  					   unsigned gpio, int value)
  {
  	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
  
  	ssb_extif_gpio_outen(&bus->extif, 1 << gpio, 1 << gpio);
  	ssb_extif_gpio_out(&bus->extif, 1 << gpio, value ? 1 << gpio : 0);
  	return 0;
  }
  
  #if IS_ENABLED(CONFIG_SSB_EMBEDDED)
  static void ssb_gpio_irq_extif_mask(struct irq_data *d)
  {
  	struct ssb_bus *bus = irq_data_get_irq_chip_data(d);
  	int gpio = irqd_to_hwirq(d);
  
  	ssb_extif_gpio_intmask(&bus->extif, BIT(gpio), 0);
  }
  
  static void ssb_gpio_irq_extif_unmask(struct irq_data *d)
  {
  	struct ssb_bus *bus = irq_data_get_irq_chip_data(d);
  	int gpio = irqd_to_hwirq(d);
  	u32 val = ssb_extif_gpio_in(&bus->extif, BIT(gpio));
  
  	ssb_extif_gpio_polarity(&bus->extif, BIT(gpio), val);
  	ssb_extif_gpio_intmask(&bus->extif, BIT(gpio), BIT(gpio));
  }
  
  static struct irq_chip ssb_gpio_irq_extif_chip = {
  	.name		= "SSB-GPIO-EXTIF",
  	.irq_mask	= ssb_gpio_irq_extif_mask,
  	.irq_unmask	= ssb_gpio_irq_extif_unmask,
  };
  
  static irqreturn_t ssb_gpio_irq_extif_handler(int irq, void *dev_id)
  {
  	struct ssb_bus *bus = dev_id;
  	struct ssb_extif *extif = &bus->extif;
  	u32 val = ssb_read32(extif->dev, SSB_EXTIF_GPIO_IN);
  	u32 mask = ssb_read32(extif->dev, SSB_EXTIF_GPIO_INTMASK);
  	u32 pol = ssb_read32(extif->dev, SSB_EXTIF_GPIO_INTPOL);
  	unsigned long irqs = (val ^ pol) & mask;
  	int gpio;
  
  	if (!irqs)
  		return IRQ_NONE;
  
  	for_each_set_bit(gpio, &irqs, bus->gpio.ngpio)
  		generic_handle_irq(ssb_gpio_to_irq(&bus->gpio, gpio));
  	ssb_extif_gpio_polarity(extif, irqs, val & irqs);
  
  	return IRQ_HANDLED;
  }
  
  static int ssb_gpio_irq_extif_domain_init(struct ssb_bus *bus)
  {
  	struct ssb_extif *extif = &bus->extif;
  	struct gpio_chip *chip = &bus->gpio;
  	int gpio, hwirq, err;
  
  	if (bus->bustype != SSB_BUSTYPE_SSB)
  		return 0;
  
  	bus->irq_domain = irq_domain_add_linear(NULL, chip->ngpio,
  						&irq_domain_simple_ops, extif);
  	if (!bus->irq_domain) {
  		err = -ENODEV;
  		goto err_irq_domain;
  	}
  	for (gpio = 0; gpio < chip->ngpio; gpio++) {
  		int irq = irq_create_mapping(bus->irq_domain, gpio);
  
  		irq_set_chip_data(irq, bus);
  		irq_set_chip_and_handler(irq, &ssb_gpio_irq_extif_chip,
  					 handle_simple_irq);
  	}
  
  	hwirq = ssb_mips_irq(bus->extif.dev) + 2;
  	err = request_irq(hwirq, ssb_gpio_irq_extif_handler, IRQF_SHARED,
  			  "gpio", bus);
  	if (err)
  		goto err_req_irq;
  
  	ssb_extif_gpio_intmask(&bus->extif, ~0, 0);
  
  	return 0;
  
  err_req_irq:
  	for (gpio = 0; gpio < chip->ngpio; gpio++) {
  		int irq = irq_find_mapping(bus->irq_domain, gpio);
  
  		irq_dispose_mapping(irq);
  	}
  	irq_domain_remove(bus->irq_domain);
  err_irq_domain:
  	return err;
  }
  
  static void ssb_gpio_irq_extif_domain_exit(struct ssb_bus *bus)
  {
  	struct ssb_extif *extif = &bus->extif;
  	struct gpio_chip *chip = &bus->gpio;
  	int gpio;
  
  	if (bus->bustype != SSB_BUSTYPE_SSB)
  		return;
  
  	free_irq(ssb_mips_irq(bus->extif.dev) + 2, extif);
  	for (gpio = 0; gpio < chip->ngpio; gpio++) {
  		int irq = irq_find_mapping(bus->irq_domain, gpio);
  
  		irq_dispose_mapping(irq);
  	}
  	irq_domain_remove(bus->irq_domain);
  }
  #else
  static int ssb_gpio_irq_extif_domain_init(struct ssb_bus *bus)
  {
  	return 0;
  }
  
  static void ssb_gpio_irq_extif_domain_exit(struct ssb_bus *bus)
  {
  }
  #endif
  
  static int ssb_gpio_extif_init(struct ssb_bus *bus)
  {
  	struct gpio_chip *chip = &bus->gpio;
  	int err;
  
  	chip->label		= "ssb_extif_gpio";
  	chip->owner		= THIS_MODULE;
  	chip->get		= ssb_gpio_extif_get_value;
  	chip->set		= ssb_gpio_extif_set_value;
  	chip->direction_input	= ssb_gpio_extif_direction_input;
  	chip->direction_output	= ssb_gpio_extif_direction_output;
  #if IS_ENABLED(CONFIG_SSB_EMBEDDED)
  	chip->to_irq		= ssb_gpio_to_irq;
  #endif
  	chip->ngpio		= 5;
  	/* There is just one SoC in one device and its GPIO addresses should be
  	 * deterministic to address them more easily. The other buses could get
  	 * a random base number. */
  	if (bus->bustype == SSB_BUSTYPE_SSB)
  		chip->base		= 0;
  	else
  		chip->base		= -1;
  
  	err = ssb_gpio_irq_extif_domain_init(bus);
  	if (err)
  		return err;
  
  	err = gpiochip_add(chip);
  	if (err) {
  		ssb_gpio_irq_extif_domain_exit(bus);
  		return err;
  	}
  
  	return 0;
  }
  
  #else
  static int ssb_gpio_extif_init(struct ssb_bus *bus)
  {
  	return -ENOTSUPP;
  }
  #endif
  
  /**************************************************
   * Init
   **************************************************/
  
  int ssb_gpio_init(struct ssb_bus *bus)
  {
  	if (ssb_chipco_available(&bus->chipco))
  		return ssb_gpio_chipco_init(bus);
  	else if (ssb_extif_available(&bus->extif))
  		return ssb_gpio_extif_init(bus);
  	else
  		SSB_WARN_ON(1);
  
  	return -1;
  }
  
  int ssb_gpio_unregister(struct ssb_bus *bus)
  {
  	if (ssb_chipco_available(&bus->chipco) ||
  	    ssb_extif_available(&bus->extif)) {
  		return gpiochip_remove(&bus->gpio);
  	} else {
  		SSB_WARN_ON(1);
  	}
  
  	return -1;
  }