// SPDX-License-Identifier: GPL-2.0+
/*
 * LPC32xxGPIO driver
 *
 * (C) Copyright 2014  DENX Software Engineering GmbH
 * Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
 */

#include <common.h>
#include <asm/io.h>
#include <asm/arch-lpc32xx/cpu.h>
#include <asm/arch-lpc32xx/gpio.h>
#include <asm-generic/gpio.h>
#include <dm.h>

/**
 * LPC32xx GPIOs work in banks but are non-homogeneous:
 * - each bank holds a different number of GPIOs
 * - some GPIOs are input/ouput, some input only, some output only;
 * - some GPIOs have different meanings as an input and as an output;
 * - some GPIOs are controlled on a given port and bit index, but
 *   read on another one.
*
 * In order to keep this code simple, GPIOS are considered here as
 * homogeneous and linear, from 0 to 159.
 *
 *      ** WARNING #1 **
 *
 * Client code is responsible for properly using valid GPIO numbers,
 * including cases where a single physical GPIO has differing numbers
 * for setting its direction, reading it and/or writing to it.
 *
 *      ** WARNING #2 **
 *
 * Please read NOTE in description of lpc32xx_gpio_get_function().
 */

#define LPC32XX_GPIOS 160

struct lpc32xx_gpio_priv {
        struct gpio_regs *regs;
        /* GPIO FUNCTION: SEE WARNING #2 */
        signed char function[LPC32XX_GPIOS];
};

/**
 * We have 4 GPIO ports of 32 bits each
 *
 * Port mapping offset (32 bits each):
 * - Port 0: 0
 * - Port 1: 32
 * - Port 2: 64
 * - Port 3: GPO / GPIO (output): 96
 * - Port 3: GPI: 128
 */

#define MAX_GPIO 160

#define GPIO_TO_PORT(gpio) ((gpio / 32) & 7)
#define GPIO_TO_RANK(gpio) (gpio % 32)
#define GPIO_TO_MASK(gpio) (1 << (gpio % 32))

/**
 * Configure a GPIO number 'offset' as input
 */

static int lpc32xx_gpio_direction_input(struct udevice *dev, unsigned offset)
{
        int port, mask;
        struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
        struct gpio_regs *regs = gpio_priv->regs;

        port = GPIO_TO_PORT(offset);
        mask = GPIO_TO_MASK(offset);

        switch (port) {
        case 0:
                writel(mask, &regs->p0_dir_clr);
                break;
        case 1:
                writel(mask, &regs->p1_dir_clr);
                break;
        case 2:
                /* ports 2 and 3 share a common direction */
                writel(mask, &regs->p2_p3_dir_clr);
                break;
        case 3:
                /* Setup direction only for GPIO_xx. */
                if ((mask >= 25) && (mask <= 30))
                        writel(mask, &regs->p2_p3_dir_clr);
                break;
        case 4:
                /* GPI_xx; nothing to do. */
                break;
        default:
                return -1;
        }

        /* GPIO FUNCTION: SEE WARNING #2 */
        gpio_priv->function[offset] = GPIOF_INPUT;

        return 0;
}

/**
 * Get the value of a GPIO
 */

static int lpc32xx_gpio_get_value(struct udevice *dev, unsigned offset)
{
        int port, rank, mask, value;
        struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
        struct gpio_regs *regs = gpio_priv->regs;

        port = GPIO_TO_PORT(offset);

        switch (port) {
        case 0:
                value = readl(&regs->p0_inp_state);
                break;
        case 1:
                value = readl(&regs->p1_inp_state);
                break;
        case 2:
                value = readl(&regs->p2_inp_state);
                break;
        case 3:
                /* Read GPO_xx and GPIO_xx (as output) using p3_outp_state. */
                value = readl(&regs->p3_outp_state);
                break;
        case 4:
                /* Read GPI_xx and GPIO_xx (as input) using p3_inp_state. */
                value = readl(&regs->p3_inp_state);
                break;
        default:
                return -1;
        }

        rank = GPIO_TO_RANK(offset);
        mask = GPIO_TO_MASK(offset);

        return (value & mask) >> rank;
}

/**
 * Set a GPIO
 */

static int gpio_set(struct udevice *dev, unsigned gpio)
{
        int port, mask;
        struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
        struct gpio_regs *regs = gpio_priv->regs;

        port = GPIO_TO_PORT(gpio);
        mask = GPIO_TO_MASK(gpio);

        switch (port) {
        case 0:
                writel(mask, &regs->p0_outp_set);
                break;
        case 1:
                writel(mask, &regs->p1_outp_set);
                break;
        case 2:
                writel(mask, &regs->p2_outp_set);
                break;
        case 3:
                writel(mask, &regs->p3_outp_set);
                break;
        case 4:
                /* GPI_xx; invalid. */
        default:
                return -1;
        }
        return 0;
}

/**
 * Clear a GPIO
 */

static int gpio_clr(struct udevice *dev, unsigned gpio)
{
        int port, mask;
        struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
        struct gpio_regs *regs = gpio_priv->regs;

        port = GPIO_TO_PORT(gpio);
        mask = GPIO_TO_MASK(gpio);

        switch (port) {
        case 0:
                writel(mask, &regs->p0_outp_clr);
                break;
        case 1:
                writel(mask, &regs->p1_outp_clr);
                break;
        case 2:
                writel(mask, &regs->p2_outp_clr);
                break;
        case 3:
                writel(mask, &regs->p3_outp_clr);
                break;
        case 4:
                /* GPI_xx; invalid. */
        default:
                return -1;
        }
        return 0;
}

/**
 * Set the value of a GPIO
 */

static int lpc32xx_gpio_set_value(struct udevice *dev, unsigned offset,
                                 int value)
{
        if (value)
                return gpio_set(dev, offset);
        else
                return gpio_clr(dev, offset);
}

/**
 * Configure a GPIO number 'offset' as output with given initial value.
 */

static int lpc32xx_gpio_direction_output(struct udevice *dev, unsigned offset,
                                       int value)
{
        int port, mask;
        struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
        struct gpio_regs *regs = gpio_priv->regs;

        port = GPIO_TO_PORT(offset);
        mask = GPIO_TO_MASK(offset);

        switch (port) {
        case 0:
                writel(mask, &regs->p0_dir_set);
                break;
        case 1:
                writel(mask, &regs->p1_dir_set);
                break;
        case 2:
                /* ports 2 and 3 share a common direction */
                writel(mask, &regs->p2_p3_dir_set);
                break;
        case 3:
                /* Setup direction only for GPIO_xx. */
                if ((mask >= 25) && (mask <= 30))
                        writel(mask, &regs->p2_p3_dir_set);
                break;
        case 4:
                /* GPI_xx; invalid. */
        default:
                return -1;
        }

        /* GPIO FUNCTION: SEE WARNING #2 */
        gpio_priv->function[offset] = GPIOF_OUTPUT;

        return lpc32xx_gpio_set_value(dev, offset, value);
}

/**
 * GPIO functions are supposed to be computed from their current
 * configuration, but that's way too complicated in LPC32XX. A simpler
 * approach is used, where the GPIO functions are cached in an array.
 * When the GPIO is in use, its function is either "input" or "output"
 * depending on its direction, otherwise its function is "unknown".
 *
 *      ** NOTE **
 *
 * THIS APPROACH WAS CHOSEN DU TO THE COMPLEX NATURE OF THE LPC32XX
 * GPIOS; DO NOT TAKE THIS AS AN EXAMPLE FOR NEW CODE.
 */

static int lpc32xx_gpio_get_function(struct udevice *dev, unsigned offset)
{
        struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
        return gpio_priv->function[offset];
}

static const struct dm_gpio_ops gpio_lpc32xx_ops = {
        .direction_input        = lpc32xx_gpio_direction_input,
        .direction_output       = lpc32xx_gpio_direction_output,
        .get_value              = lpc32xx_gpio_get_value,
        .set_value              = lpc32xx_gpio_set_value,
        .get_function           = lpc32xx_gpio_get_function,
};

static int lpc32xx_gpio_probe(struct udevice *dev)
{
        struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
        struct gpio_dev_priv *uc_priv = dev->uclass_priv;

        if (dev_of_offset(dev) == -1) {
                /* Tell the uclass how many GPIOs we have */
                uc_priv->gpio_count = LPC32XX_GPIOS;
        }

        /* set base address for GPIO registers */
        gpio_priv->regs = (struct gpio_regs *)GPIO_BASE;

        /* all GPIO functions are unknown until requested */
        /* GPIO FUNCTION: SEE WARNING #2 */
        memset(gpio_priv->function, GPIOF_UNKNOWN, sizeof(gpio_priv->function));

        return 0;
}

U_BOOT_DRIVER(gpio_lpc32xx) = {
        .name   = "gpio_lpc32xx",
        .id     = UCLASS_GPIO,
        .ops    = &gpio_lpc32xx_ops,
        .probe  = lpc32xx_gpio_probe,
        .priv_auto_alloc_size = sizeof(struct lpc32xx_gpio_priv),
};