// SPDX-License-Identifier: GPL-2.0-only
/*
 * Renesas R-Car E-FUSE/OTP Driver
 *
 * Copyright (C) 2024 Glider bv
 */

#include <linux/device.h>
#include <linux/export.h>
#include <linux/io.h>
#include <linux/mod_devicetable.h>
#include <linux/nvmem-provider.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>

struct rcar_fuse {
        struct nvmem_keepout keepouts[2];
        struct nvmem_device *nvmem;
        struct device *dev;
        void __iomem *base;
};

struct rcar_fuse_data {
        unsigned int bank;      /* 0: PFC + E-FUSE, 1: OPT_MEM + E-FUSE */
        unsigned int start;     /* inclusive */
        unsigned int end;       /* exclusive */
};

static int rcar_fuse_reg_read(void *priv, unsigned int offset, void *val,
                              size_t bytes)
{
        struct rcar_fuse *fuse = priv;
        int ret;

        ret = pm_runtime_resume_and_get(fuse->dev);
        if (ret < 0)
                return ret;

        __ioread32_copy(val, fuse->base + offset, bytes / 4);

        pm_runtime_put(fuse->dev);

        return 0;
}

static int rcar_fuse_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        const struct rcar_fuse_data *data = device_get_match_data(dev);
        struct nvmem_config config = {
                .dev = dev,
                .name = "rcar-fuse",
                .id = NVMEM_DEVID_NONE,
                .owner = THIS_MODULE,
                .type = NVMEM_TYPE_OTP,
                .read_only = true,
                .root_only = true,
                .reg_read = rcar_fuse_reg_read,
                .word_size = 4,
                .stride = 4,
        };
        struct rcar_fuse *fuse;
        struct resource *res;
        int ret;

        ret = devm_pm_runtime_enable(dev);
        if (ret < 0)
                return ret;

        fuse = devm_kzalloc(dev, sizeof(*fuse), GFP_KERNEL);
        if (!fuse)
                return -ENOMEM;

        fuse->base = devm_platform_get_and_ioremap_resource(pdev, data->bank,
                                                            &res);
        if (IS_ERR(fuse->base))
                return PTR_ERR(fuse->base);

        fuse->dev = dev;
        fuse->keepouts[0].start = 0;
        fuse->keepouts[0].end = data->start;
        fuse->keepouts[1].start = data->end;
        fuse->keepouts[1].end = resource_size(res);

        config.keepout = fuse->keepouts;
        config.nkeepout = ARRAY_SIZE(fuse->keepouts);
        config.size = resource_size(res);
        config.priv = fuse;

        fuse->nvmem = devm_nvmem_register(dev, &config);
        if (IS_ERR(fuse->nvmem))
                return dev_err_probe(dev, PTR_ERR(fuse->nvmem),
                                     "Failed to register NVMEM device\n");

        return 0;
}

static const struct rcar_fuse_data rcar_fuse_v3u = {
        .bank = 0,
        .start = 0x0c0,
        .end = 0x0e8,
};

static const struct rcar_fuse_data rcar_fuse_s4 = {
        .bank = 0,
        .start = 0x0c0,
        .end = 0x14c,
};

static const struct rcar_fuse_data rcar_fuse_v4h = {
        .bank = 1,
        .start = 0x100,
        .end = 0x1a0,
};

static const struct rcar_fuse_data rcar_fuse_v4m = {
        .bank = 1,
        .start = 0x100,
        .end = 0x110,
};

static const struct of_device_id rcar_fuse_match[] = {
        { .compatible = "renesas,r8a779a0-efuse", .data = &rcar_fuse_v3u },
        { .compatible = "renesas,r8a779f0-efuse", .data = &rcar_fuse_s4 },
        { .compatible = "renesas,r8a779g0-otp", .data = &rcar_fuse_v4h },
        { .compatible = "renesas,r8a779h0-otp", .data = &rcar_fuse_v4m },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, rcar_fuse_match);

static struct platform_driver rcar_fuse_driver = {
        .probe = rcar_fuse_probe,
        .driver = {
                .name = "rcar_fuse",
                .of_match_table = rcar_fuse_match,
        },
};
module_platform_driver(rcar_fuse_driver);

MODULE_DESCRIPTION("Renesas R-Car E-FUSE/OTP driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Geert Uytterhoeven");