/*
 * Broadcom specific AMBA
 * 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/driver.h>
#include <linux/interrupt.h>
#include <linux/export.h>
#include <linux/bcma/bcma.h>

#include "bcma_private.h"

#define BCMA_GPIO_MAX_PINS      32

static inline struct bcma_drv_cc *bcma_gpio_get_cc(struct gpio_chip *chip)
{
        return container_of(chip, struct bcma_drv_cc, gpio);
}

static int bcma_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
{
        struct bcma_drv_cc *cc = bcma_gpio_get_cc(chip);

        return !!bcma_chipco_gpio_in(cc, 1 << gpio);
}

static void bcma_gpio_set_value(struct gpio_chip *chip, unsigned gpio,
                                int value)
{
        struct bcma_drv_cc *cc = bcma_gpio_get_cc(chip);

        bcma_chipco_gpio_out(cc, 1 << gpio, value ? 1 << gpio : 0);
}

static int bcma_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
{
        struct bcma_drv_cc *cc = bcma_gpio_get_cc(chip);

        bcma_chipco_gpio_outen(cc, 1 << gpio, 0);
        return 0;
}

static int bcma_gpio_direction_output(struct gpio_chip *chip, unsigned gpio,
                                      int value)
{
        struct bcma_drv_cc *cc = bcma_gpio_get_cc(chip);

        bcma_chipco_gpio_outen(cc, 1 << gpio, 1 << gpio);
        bcma_chipco_gpio_out(cc, 1 << gpio, value ? 1 << gpio : 0);
        return 0;
}

static int bcma_gpio_request(struct gpio_chip *chip, unsigned gpio)
{
        struct bcma_drv_cc *cc = bcma_gpio_get_cc(chip);

        bcma_chipco_gpio_control(cc, 1 << gpio, 0);
        /* clear pulldown */
        bcma_chipco_gpio_pulldown(cc, 1 << gpio, 0);
        /* Set pullup */
        bcma_chipco_gpio_pullup(cc, 1 << gpio, 1 << gpio);

        return 0;
}

static void bcma_gpio_free(struct gpio_chip *chip, unsigned gpio)
{
        struct bcma_drv_cc *cc = bcma_gpio_get_cc(chip);

        /* clear pullup */
        bcma_chipco_gpio_pullup(cc, 1 << gpio, 0);
}

#if IS_BUILTIN(CONFIG_BCM47XX) || IS_BUILTIN(CONFIG_ARCH_BCM_5301X)

static void bcma_gpio_irq_unmask(struct irq_data *d)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct bcma_drv_cc *cc = bcma_gpio_get_cc(gc);
        int gpio = irqd_to_hwirq(d);
        u32 val = bcma_chipco_gpio_in(cc, BIT(gpio));

        bcma_chipco_gpio_polarity(cc, BIT(gpio), val);
        bcma_chipco_gpio_intmask(cc, BIT(gpio), BIT(gpio));
}

static void bcma_gpio_irq_mask(struct irq_data *d)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct bcma_drv_cc *cc = bcma_gpio_get_cc(gc);
        int gpio = irqd_to_hwirq(d);

        bcma_chipco_gpio_intmask(cc, BIT(gpio), 0);
}

static struct irq_chip bcma_gpio_irq_chip = {
        .name           = "BCMA-GPIO",
        .irq_mask       = bcma_gpio_irq_mask,
        .irq_unmask     = bcma_gpio_irq_unmask,
};

static irqreturn_t bcma_gpio_irq_handler(int irq, void *dev_id)
{
        struct bcma_drv_cc *cc = dev_id;
        struct gpio_chip *gc = &cc->gpio;
        u32 val = bcma_cc_read32(cc, BCMA_CC_GPIOIN);
        u32 mask = bcma_cc_read32(cc, BCMA_CC_GPIOIRQ);
        u32 pol = bcma_cc_read32(cc, BCMA_CC_GPIOPOL);
        unsigned long irqs = (val ^ pol) & mask;
        int gpio;

        if (!irqs)
                return IRQ_NONE;

        for_each_set_bit(gpio, &irqs, gc->ngpio)
                generic_handle_irq(irq_find_mapping(gc->irqdomain, gpio));
        bcma_chipco_gpio_polarity(cc, irqs, val & irqs);

        return IRQ_HANDLED;
}

static int bcma_gpio_irq_init(struct bcma_drv_cc *cc)
{
        struct gpio_chip *chip = &cc->gpio;
        int hwirq, err;

        if (cc->core->bus->hosttype != BCMA_HOSTTYPE_SOC)
                return 0;

        hwirq = bcma_core_irq(cc->core, 0);
        err = request_irq(hwirq, bcma_gpio_irq_handler, IRQF_SHARED, "gpio",
                          cc);
        if (err)
                return err;

        bcma_chipco_gpio_intmask(cc, ~0, 0);
        bcma_cc_set32(cc, BCMA_CC_IRQMASK, BCMA_CC_IRQ_GPIO);

        err =  gpiochip_irqchip_add(chip,
                                    &bcma_gpio_irq_chip,
                                    0,
                                    handle_simple_irq,
                                    IRQ_TYPE_NONE);
        if (err) {
                free_irq(hwirq, cc);
                return err;
        }

        return 0;
}

static void bcma_gpio_irq_exit(struct bcma_drv_cc *cc)
{
        if (cc->core->bus->hosttype != BCMA_HOSTTYPE_SOC)
                return;

        bcma_cc_mask32(cc, BCMA_CC_IRQMASK, ~BCMA_CC_IRQ_GPIO);
        free_irq(bcma_core_irq(cc->core, 0), cc);
}
#else
static int bcma_gpio_irq_init(struct bcma_drv_cc *cc)
{
        return 0;
}

static void bcma_gpio_irq_exit(struct bcma_drv_cc *cc)
{
}
#endif

int bcma_gpio_init(struct bcma_drv_cc *cc)
{
        struct bcma_bus *bus = cc->core->bus;
        struct gpio_chip *chip = &cc->gpio;
        int err;

        chip->label             = "bcma_gpio";
        chip->owner             = THIS_MODULE;
        chip->request           = bcma_gpio_request;
        chip->free              = bcma_gpio_free;
        chip->get               = bcma_gpio_get_value;
        chip->set               = bcma_gpio_set_value;
        chip->direction_input   = bcma_gpio_direction_input;
        chip->direction_output  = bcma_gpio_direction_output;
        chip->owner             = THIS_MODULE;
#if 0 /* Not in RHEL */
        chip->parent            = bcma_bus_get_host_dev(bus);
#endif
#if IS_BUILTIN(CONFIG_OF)
        if (cc->core->bus->hosttype == BCMA_HOSTTYPE_SOC)
                chip->of_node   = cc->core->dev.of_node;
#endif
        switch (bus->chipinfo.id) {
        case BCMA_CHIP_ID_BCM4707:
        case BCMA_CHIP_ID_BCM5357:
        case BCMA_CHIP_ID_BCM53572:
        case BCMA_CHIP_ID_BCM47094:
                chip->ngpio     = 32;
                break;
        default:
                chip->ngpio     = 16;
        }

        /*
         * Register SoC GPIO devices with absolute GPIO pin base.
         * On MIPS, we don't have Device Tree and we can't use relative (per chip)
         * GPIO numbers.
         * On some ARM devices, user space may want to access some system GPIO
         * pins directly, which is easier to do with a predictable GPIO base.
         */
        if (IS_BUILTIN(CONFIG_BCM47XX) ||
            cc->core->bus->hosttype == BCMA_HOSTTYPE_SOC)
                chip->base              = bus->num * BCMA_GPIO_MAX_PINS;
        else
                chip->base              = -1;

        err = gpiochip_add(chip);
        if (err)
                return err;

        err = bcma_gpio_irq_init(cc);
        if (err) {
                gpiochip_remove(chip);
                return err;
        }

        return 0;
}

int bcma_gpio_unregister(struct bcma_drv_cc *cc)
{
        bcma_gpio_irq_exit(cc);
        gpiochip_remove(&cc->gpio);
        return 0;
}