/*
 * Copyright (c) 2011 The Chromium OS Authors.
 * SPDX-License-Identifier:     GPL-2.0+
 */

#include <common.h>
#include <dm.h>
#include <fdtdec.h>
#include <malloc.h>
#include <asm/gpio.h>
#include <dt-bindings/gpio/gpio.h>

DECLARE_GLOBAL_DATA_PTR;

/* Flags for each GPIO */
#define GPIOF_OUTPUT    (1 << 0)        /* Currently set as an output */
#define GPIOF_HIGH      (1 << 1)        /* Currently set high */

struct gpio_state {
        const char *label;      /* label given by requester */
        u8 flags;               /* flags (GPIOF_...) */
};

/* Access routines for GPIO state */
static u8 *get_gpio_flags(struct udevice *dev, unsigned offset)
{
        struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
        struct gpio_state *state = dev_get_priv(dev);

        if (offset >= uc_priv->gpio_count) {
                static u8 invalid_flags;
                printf("sandbox_gpio: error: invalid gpio %u\n", offset);
                return &invalid_flags;
        }

        return &state[offset].flags;
}

static int get_gpio_flag(struct udevice *dev, unsigned offset, int flag)
{
        return (*get_gpio_flags(dev, offset) & flag) != 0;
}

static int set_gpio_flag(struct udevice *dev, unsigned offset, int flag,
                         int value)
{
        u8 *gpio = get_gpio_flags(dev, offset);

        if (value)
                *gpio |= flag;
        else
                *gpio &= ~flag;

        return 0;
}

/*
 * Back-channel sandbox-internal-only access to GPIO state
 */

int sandbox_gpio_get_value(struct udevice *dev, unsigned offset)
{
        if (get_gpio_flag(dev, offset, GPIOF_OUTPUT))
                debug("sandbox_gpio: get_value on output gpio %u\n", offset);
        return get_gpio_flag(dev, offset, GPIOF_HIGH);
}

int sandbox_gpio_set_value(struct udevice *dev, unsigned offset, int value)
{
        return set_gpio_flag(dev, offset, GPIOF_HIGH, value);
}

int sandbox_gpio_get_direction(struct udevice *dev, unsigned offset)
{
        return get_gpio_flag(dev, offset, GPIOF_OUTPUT);
}

int sandbox_gpio_set_direction(struct udevice *dev, unsigned offset, int output)
{
        return set_gpio_flag(dev, offset, GPIOF_OUTPUT, output);
}

/*
 * These functions implement the public interface within U-Boot
 */

/* set GPIO port 'offset' as an input */
static int sb_gpio_direction_input(struct udevice *dev, unsigned offset)
{
        debug("%s: offset:%u\n", __func__, offset);

        return sandbox_gpio_set_direction(dev, offset, 0);
}

/* set GPIO port 'offset' as an output, with polarity 'value' */
static int sb_gpio_direction_output(struct udevice *dev, unsigned offset,
                                    int value)
{
        debug("%s: offset:%u, value = %d\n", __func__, offset, value);

        return sandbox_gpio_set_direction(dev, offset, 1) |
                sandbox_gpio_set_value(dev, offset, value);
}

/* read GPIO IN value of port 'offset' */
static int sb_gpio_get_value(struct udevice *dev, unsigned offset)
{
        debug("%s: offset:%u\n", __func__, offset);

        return sandbox_gpio_get_value(dev, offset);
}

/* write GPIO OUT value to port 'offset' */
static int sb_gpio_set_value(struct udevice *dev, unsigned offset, int value)
{
        debug("%s: offset:%u, value = %d\n", __func__, offset, value);

        if (!sandbox_gpio_get_direction(dev, offset)) {
                printf("sandbox_gpio: error: set_value on input gpio %u\n",
                       offset);
                return -1;
        }

        return sandbox_gpio_set_value(dev, offset, value);
}

static int sb_gpio_get_function(struct udevice *dev, unsigned offset)
{
        if (get_gpio_flag(dev, offset, GPIOF_OUTPUT))
                return GPIOF_OUTPUT;
        return GPIOF_INPUT;
}

static int sb_gpio_xlate(struct udevice *dev, struct gpio_desc *desc,
                         struct fdtdec_phandle_args *args)
{
        desc->offset = args->args[0];
        if (args->args_count < 2)
                return 0;
        if (args->args[1] & GPIO_ACTIVE_LOW)
                desc->flags |= GPIOD_ACTIVE_LOW;
        if (args->args[1] & 2)
                desc->flags |= GPIOD_IS_IN;
        if (args->args[1] & 4)
                desc->flags |= GPIOD_IS_OUT;
        if (args->args[1] & 8)
                desc->flags |= GPIOD_IS_OUT_ACTIVE;

        return 0;
}

static const struct dm_gpio_ops gpio_sandbox_ops = {
        .direction_input        = sb_gpio_direction_input,
        .direction_output       = sb_gpio_direction_output,
        .get_value              = sb_gpio_get_value,
        .set_value              = sb_gpio_set_value,
        .get_function           = sb_gpio_get_function,
        .xlate                  = sb_gpio_xlate,
};

static int sandbox_gpio_ofdata_to_platdata(struct udevice *dev)
{
        struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);

        uc_priv->gpio_count = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
                                             "num-gpios", 0);
        uc_priv->bank_name = fdt_getprop(gd->fdt_blob, dev->of_offset,
                                         "gpio-bank-name", NULL);

        return 0;
}

static int gpio_sandbox_probe(struct udevice *dev)
{
        struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);

        if (dev->of_offset == -1) {
                /* Tell the uclass how many GPIOs we have */
                uc_priv->gpio_count = CONFIG_SANDBOX_GPIO_COUNT;
        }

        dev->priv = calloc(sizeof(struct gpio_state), uc_priv->gpio_count);

        return 0;
}

static int gpio_sandbox_remove(struct udevice *dev)
{
        free(dev->priv);

        return 0;
}

static const struct udevice_id sandbox_gpio_ids[] = {
        { .compatible = "sandbox,gpio" },
        { }
};

U_BOOT_DRIVER(gpio_sandbox) = {
        .name   = "gpio_sandbox",
        .id     = UCLASS_GPIO,
        .of_match = sandbox_gpio_ids,
        .ofdata_to_platdata = sandbox_gpio_ofdata_to_platdata,
        .probe  = gpio_sandbox_probe,
        .remove = gpio_sandbox_remove,
        .ops    = &gpio_sandbox_ops,
};