// SPDX-License-Identifier: GPL-2.0-only
/*
 * i.MX IIM driver
 *
 * Copyright (c) 2017 Pengutronix, Michael Grzeschik <m.grzeschik@pengutronix.de>
 *
 * Based on the barebox iim driver,
 * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
 *      Orex Computed Radiography
 */

#include <linux/device.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/clk.h>

#define IIM_BANK_BASE(n)        (0x800 + 0x400 * (n))

struct imx_iim_drvdata {
        unsigned int nregs;
};

struct iim_priv {
        void __iomem *base;
        struct clk *clk;
};

static int imx_iim_read(void *context, unsigned int offset,
                          void *buf, size_t bytes)
{
        struct iim_priv *iim = context;
        int i, ret;
        u8 *buf8 = buf;

        ret = clk_prepare_enable(iim->clk);
        if (ret)
                return ret;

        for (i = offset; i < offset + bytes; i++) {
                int bank = i >> 5;
                int reg = i & 0x1f;

                *buf8++ = readl(iim->base + IIM_BANK_BASE(bank) + reg * 4);
        }

        clk_disable_unprepare(iim->clk);

        return 0;
}

static struct imx_iim_drvdata imx27_drvdata = {
        .nregs = 2 * 32,
};

static struct imx_iim_drvdata imx25_imx31_imx35_drvdata = {
        .nregs = 3 * 32,
};

static struct imx_iim_drvdata imx51_drvdata = {
        .nregs = 4 * 32,
};

static struct imx_iim_drvdata imx53_drvdata = {
        .nregs = 4 * 32 + 16,
};

static const struct of_device_id imx_iim_dt_ids[] = {
        {
                .compatible = "fsl,imx25-iim",
                .data = &imx25_imx31_imx35_drvdata,
        }, {
                .compatible = "fsl,imx27-iim",
                .data = &imx27_drvdata,
        }, {
                .compatible = "fsl,imx31-iim",
                .data = &imx25_imx31_imx35_drvdata,
        }, {
                .compatible = "fsl,imx35-iim",
                .data = &imx25_imx31_imx35_drvdata,
        }, {
                .compatible = "fsl,imx51-iim",
                .data = &imx51_drvdata,
        }, {
                .compatible = "fsl,imx53-iim",
                .data = &imx53_drvdata,
        }, {
                /* sentinel */
        },
};
MODULE_DEVICE_TABLE(of, imx_iim_dt_ids);

static int imx_iim_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct iim_priv *iim;
        struct nvmem_device *nvmem;
        struct nvmem_config cfg = {};
        const struct imx_iim_drvdata *drvdata = NULL;

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

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

        drvdata = of_device_get_match_data(&pdev->dev);

        iim->clk = devm_clk_get(dev, NULL);
        if (IS_ERR(iim->clk))
                return PTR_ERR(iim->clk);

        cfg.name = "imx-iim";
        cfg.read_only = true;
        cfg.word_size = 1;
        cfg.stride = 1;
        cfg.reg_read = imx_iim_read;
        cfg.dev = dev;
        cfg.size = drvdata->nregs;
        cfg.priv = iim;

        nvmem = devm_nvmem_register(dev, &cfg);

        return PTR_ERR_OR_ZERO(nvmem);
}

static struct platform_driver imx_iim_driver = {
        .probe  = imx_iim_probe,
        .driver = {
                .name   = "imx-iim",
                .of_match_table = imx_iim_dt_ids,
        },
};
module_platform_driver(imx_iim_driver);

MODULE_AUTHOR("Michael Grzeschik <m.grzeschik@pengutronix.de>");
MODULE_DESCRIPTION("i.MX IIM driver");
MODULE_LICENSE("GPL v2");