// SPDX-License-Identifier: GPL-2.0

#include <linux/acpi.h>
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/gpio/driver.h>
#include <linux/gpio/generic.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/resource.h>
#include <linux/types.h>

/* Number of pins on BlueField */
#define MLXBF_GPIO_NR 54

/* Pad Electrical Controls. */
#define MLXBF_GPIO_PAD_CONTROL_FIRST_WORD 0x0700
#define MLXBF_GPIO_PAD_CONTROL_1_FIRST_WORD 0x0708
#define MLXBF_GPIO_PAD_CONTROL_2_FIRST_WORD 0x0710
#define MLXBF_GPIO_PAD_CONTROL_3_FIRST_WORD 0x0718

#define MLXBF_GPIO_PIN_DIR_I 0x1040
#define MLXBF_GPIO_PIN_DIR_O 0x1048
#define MLXBF_GPIO_PIN_STATE 0x1000
#define MLXBF_GPIO_SCRATCHPAD 0x20

#ifdef CONFIG_PM
struct mlxbf_gpio_context_save_regs {
        u64 scratchpad;
        u64 pad_control[MLXBF_GPIO_NR];
        u64 pin_dir_i;
        u64 pin_dir_o;
};
#endif

/* Device state structure. */
struct mlxbf_gpio_state {
        struct gpio_generic_chip chip;

        /* Memory Address */
        void __iomem *base;

#ifdef CONFIG_PM
        struct mlxbf_gpio_context_save_regs csave_regs;
#endif
};

static int mlxbf_gpio_probe(struct platform_device *pdev)
{
        struct gpio_generic_chip_config config;
        struct mlxbf_gpio_state *gs;
        struct device *dev = &pdev->dev;
        struct gpio_chip *gc;
        int ret;

        gs = devm_kzalloc(&pdev->dev, sizeof(*gs), GFP_KERNEL);
        if (!gs)
                return -ENOMEM;

        gs->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(gs->base))
                return PTR_ERR(gs->base);

        gc = &gs->chip.gc;

        config = (struct gpio_generic_chip_config) {
                .dev = dev,
                .sz = 8,
                .dat = gs->base + MLXBF_GPIO_PIN_STATE,
                .dirout = gs->base + MLXBF_GPIO_PIN_DIR_O,
                .dirin =  gs->base + MLXBF_GPIO_PIN_DIR_I,
        };

        ret = gpio_generic_chip_init(&gs->chip, &config);
        if (ret)
                return -ENODEV;

        gc->owner = THIS_MODULE;
        gc->ngpio = MLXBF_GPIO_NR;

        ret = devm_gpiochip_add_data(dev, &gs->chip.gc, gs);
        if (ret) {
                dev_err(&pdev->dev, "Failed adding memory mapped gpiochip\n");
                return ret;
        }

        platform_set_drvdata(pdev, gs);
        dev_info(&pdev->dev, "registered Mellanox BlueField GPIO");
        return 0;
}

#ifdef CONFIG_PM
static int mlxbf_gpio_suspend(struct platform_device *pdev, pm_message_t state)
{
        struct mlxbf_gpio_state *gs = platform_get_drvdata(pdev);

        gs->csave_regs.scratchpad = readq(gs->base + MLXBF_GPIO_SCRATCHPAD);
        gs->csave_regs.pad_control[0] =
                readq(gs->base + MLXBF_GPIO_PAD_CONTROL_FIRST_WORD);
        gs->csave_regs.pad_control[1] =
                readq(gs->base + MLXBF_GPIO_PAD_CONTROL_1_FIRST_WORD);
        gs->csave_regs.pad_control[2] =
                readq(gs->base + MLXBF_GPIO_PAD_CONTROL_2_FIRST_WORD);
        gs->csave_regs.pad_control[3] =
                readq(gs->base + MLXBF_GPIO_PAD_CONTROL_3_FIRST_WORD);
        gs->csave_regs.pin_dir_i = readq(gs->base + MLXBF_GPIO_PIN_DIR_I);
        gs->csave_regs.pin_dir_o = readq(gs->base + MLXBF_GPIO_PIN_DIR_O);

        return 0;
}

static int mlxbf_gpio_resume(struct platform_device *pdev)
{
        struct mlxbf_gpio_state *gs = platform_get_drvdata(pdev);

        writeq(gs->csave_regs.scratchpad, gs->base + MLXBF_GPIO_SCRATCHPAD);
        writeq(gs->csave_regs.pad_control[0],
               gs->base + MLXBF_GPIO_PAD_CONTROL_FIRST_WORD);
        writeq(gs->csave_regs.pad_control[1],
               gs->base + MLXBF_GPIO_PAD_CONTROL_1_FIRST_WORD);
        writeq(gs->csave_regs.pad_control[2],
               gs->base + MLXBF_GPIO_PAD_CONTROL_2_FIRST_WORD);
        writeq(gs->csave_regs.pad_control[3],
               gs->base + MLXBF_GPIO_PAD_CONTROL_3_FIRST_WORD);
        writeq(gs->csave_regs.pin_dir_i, gs->base + MLXBF_GPIO_PIN_DIR_I);
        writeq(gs->csave_regs.pin_dir_o, gs->base + MLXBF_GPIO_PIN_DIR_O);

        return 0;
}
#endif

static const struct acpi_device_id __maybe_unused mlxbf_gpio_acpi_match[] = {
        { "MLNXBF02", 0 },
        {}
};
MODULE_DEVICE_TABLE(acpi, mlxbf_gpio_acpi_match);

static struct platform_driver mlxbf_gpio_driver = {
        .driver = {
                .name = "mlxbf_gpio",
                .acpi_match_table = ACPI_PTR(mlxbf_gpio_acpi_match),
        },
        .probe    = mlxbf_gpio_probe,
#ifdef CONFIG_PM
        .suspend  = mlxbf_gpio_suspend,
        .resume   = mlxbf_gpio_resume,
#endif
};

module_platform_driver(mlxbf_gpio_driver);

MODULE_DESCRIPTION("Mellanox BlueField GPIO Driver");
MODULE_AUTHOR("Mellanox Technologies");
MODULE_LICENSE("GPL");