/*
 * 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 "ssb_private.h"

#include <linux/gpio/driver.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/export.h>
#include <linux/ssb/ssb.h>


/**************************************************
 * Shared
 **************************************************/

#if IS_ENABLED(CONFIG_SSB_EMBEDDED)
static int ssb_gpio_to_irq(struct gpio_chip *chip, unsigned int gpio)
{
        struct ssb_bus *bus = gpiochip_get_data(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 int gpio)
{
        struct ssb_bus *bus = gpiochip_get_data(chip);

        return !!ssb_chipco_gpio_in(&bus->chipco, 1 << gpio);
}

static int ssb_gpio_chipco_set_value(struct gpio_chip *chip, unsigned int gpio,
                                     int value)
{
        struct ssb_bus *bus = gpiochip_get_data(chip);

        ssb_chipco_gpio_out(&bus->chipco, 1 << gpio, value ? 1 << gpio : 0);

        return 0;
}

static int ssb_gpio_chipco_direction_input(struct gpio_chip *chip,
                                           unsigned int gpio)
{
        struct ssb_bus *bus = gpiochip_get_data(chip);

        ssb_chipco_gpio_outen(&bus->chipco, 1 << gpio, 0);
        return 0;
}

static int ssb_gpio_chipco_direction_output(struct gpio_chip *chip,
                                            unsigned int gpio, int value)
{
        struct ssb_bus *bus = gpiochip_get_data(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 int gpio)
{
        struct ssb_bus *bus = gpiochip_get_data(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 int gpio)
{
        struct ssb_bus *bus = gpiochip_get_data(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_domain_irq_safe(bus->irq_domain, 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_create_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_data(chip, bus);
        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 int gpio)
{
        struct ssb_bus *bus = gpiochip_get_data(chip);

        return !!ssb_extif_gpio_in(&bus->extif, 1 << gpio);
}

static int ssb_gpio_extif_set_value(struct gpio_chip *chip, unsigned int gpio,
                                    int value)
{
        struct ssb_bus *bus = gpiochip_get_data(chip);

        ssb_extif_gpio_out(&bus->extif, 1 << gpio, value ? 1 << gpio : 0);

        return 0;
}

static int ssb_gpio_extif_direction_input(struct gpio_chip *chip,
                                          unsigned int gpio)
{
        struct ssb_bus *bus = gpiochip_get_data(chip);

        ssb_extif_gpio_outen(&bus->extif, 1 << gpio, 0);
        return 0;
}

static int ssb_gpio_extif_direction_output(struct gpio_chip *chip,
                                           unsigned int gpio, int value)
{
        struct ssb_bus *bus = gpiochip_get_data(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_domain_irq_safe(bus->irq_domain, 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_create_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_data(chip, bus);
        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);
        return -1;
}

int ssb_gpio_unregister(struct ssb_bus *bus)
{
        if (ssb_chipco_available(&bus->chipco) ||
            ssb_extif_available(&bus->extif)) {
                gpiochip_remove(&bus->gpio);
                return 0;
        }
        return -1;
}