// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * omap-ocp2scp.c - transform ocp interface protocol to scp protocol
 *
 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
 * Author: Kishon Vijay Abraham I <kishon@ti.com>
 */

#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/of_platform.h>

#define OCP2SCP_TIMING 0x18
#define SYNC2_MASK 0xf

static int omap_ocp2scp_probe(struct platform_device *pdev)
{
        int ret;
        u32 reg;
        void __iomem *regs;
        struct resource *res;
        struct device_node *np = pdev->dev.of_node;

        if (np) {
                ret = of_platform_populate(np, NULL, NULL, &pdev->dev);
                if (ret) {
                        dev_err(&pdev->dev,
                            "failed to add resources for ocp2scp child\n");
                        goto err0;
                }
        }

        pm_runtime_enable(&pdev->dev);
        /*
         * As per AM572x TRM: http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf
         * under section 26.3.2.2, table 26-26 OCP2SCP TIMING Caution;
         * As per OMAP4430 TRM: http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf
         * under section 23.12.6.2.2 , Table 23-1213 OCP2SCP TIMING Caution;
         * As per OMAP4460 TRM: http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf
         * under section 23.12.6.2.2, Table 23-1213 OCP2SCP TIMING Caution;
         * As per OMAP543x TRM http://www.ti.com/lit/pdf/swpu249
         * under section 27.3.2.2, Table 27-27 OCP2SCP TIMING Caution;
         *
         * Read path of OCP2SCP is not working properly due to low reset value
         * of SYNC2 parameter in OCP2SCP. Suggested reset value is 0x6 or more.
         */
        if (!of_device_is_compatible(np, "ti,am437x-ocp2scp")) {
                res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
                regs = devm_ioremap_resource(&pdev->dev, res);
                if (IS_ERR(regs)) {
                        ret = PTR_ERR(regs);
                        goto err1;
                }

                pm_runtime_get_sync(&pdev->dev);
                reg = readl_relaxed(regs + OCP2SCP_TIMING);
                reg &= ~(SYNC2_MASK);
                reg |= 0x6;
                writel_relaxed(reg, regs + OCP2SCP_TIMING);
                pm_runtime_put_sync(&pdev->dev);
        }

        return 0;

err1:
        pm_runtime_disable(&pdev->dev);

err0:
        of_platform_depopulate(&pdev->dev);

        return ret;
}

static void omap_ocp2scp_remove(struct platform_device *pdev)
{
        pm_runtime_disable(&pdev->dev);
        of_platform_depopulate(&pdev->dev);
}

#ifdef CONFIG_OF
static const struct of_device_id omap_ocp2scp_id_table[] = {
        { .compatible = "ti,omap-ocp2scp" },
        { .compatible = "ti,am437x-ocp2scp" },
        {}
};
MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table);
#endif

static struct platform_driver omap_ocp2scp_driver = {
        .probe          = omap_ocp2scp_probe,
        .remove         = omap_ocp2scp_remove,
        .driver         = {
                .name   = "omap-ocp2scp",
                .of_match_table = of_match_ptr(omap_ocp2scp_id_table),
        },
};

module_platform_driver(omap_ocp2scp_driver);

MODULE_ALIAS("platform:omap-ocp2scp");
MODULE_AUTHOR("Texas Instruments Inc.");
MODULE_DESCRIPTION("OMAP OCP2SCP driver");
MODULE_LICENSE("GPL v2");