// SPDX-License-Identifier: GPL-2.0-only
// Copyright (C) 2015 Broadcom Corporation

#include <linux/delay.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>

#define PCIE_CFG_OFFSET         0x00
#define PCIE1_PHY_IDDQ_SHIFT    10
#define PCIE0_PHY_IDDQ_SHIFT    2

enum cygnus_pcie_phy_id {
        CYGNUS_PHY_PCIE0 = 0,
        CYGNUS_PHY_PCIE1,
        MAX_NUM_PHYS,
};

struct cygnus_pcie_phy_core;

/**
 * struct cygnus_pcie_phy - Cygnus PCIe PHY device
 * @core: pointer to the Cygnus PCIe PHY core control
 * @id: internal ID to identify the Cygnus PCIe PHY
 * @phy: pointer to the kernel PHY device
 */
struct cygnus_pcie_phy {
        struct cygnus_pcie_phy_core *core;
        enum cygnus_pcie_phy_id id;
        struct phy *phy;
};

/**
 * struct cygnus_pcie_phy_core - Cygnus PCIe PHY core control
 * @dev: pointer to device
 * @base: base register
 * @lock: mutex to protect access to individual PHYs
 * @phys: pointer to Cygnus PHY device
 */
struct cygnus_pcie_phy_core {
        struct device *dev;
        void __iomem *base;
        struct mutex lock;
        struct cygnus_pcie_phy phys[MAX_NUM_PHYS];
};

static int cygnus_pcie_power_config(struct cygnus_pcie_phy *phy, bool enable)
{
        struct cygnus_pcie_phy_core *core = phy->core;
        unsigned shift;
        u32 val;

        mutex_lock(&core->lock);

        switch (phy->id) {
        case CYGNUS_PHY_PCIE0:
                shift = PCIE0_PHY_IDDQ_SHIFT;
                break;

        case CYGNUS_PHY_PCIE1:
                shift = PCIE1_PHY_IDDQ_SHIFT;
                break;

        default:
                mutex_unlock(&core->lock);
                dev_err(core->dev, "PCIe PHY %d invalid\n", phy->id);
                return -EINVAL;
        }

        if (enable) {
                val = readl(core->base + PCIE_CFG_OFFSET);
                val &= ~BIT(shift);
                writel(val, core->base + PCIE_CFG_OFFSET);
                /*
                 * Wait 50 ms for the PCIe Serdes to stabilize after the analog
                 * front end is brought up
                 */
                msleep(50);
        } else {
                val = readl(core->base + PCIE_CFG_OFFSET);
                val |= BIT(shift);
                writel(val, core->base + PCIE_CFG_OFFSET);
        }

        mutex_unlock(&core->lock);
        dev_dbg(core->dev, "PCIe PHY %d %s\n", phy->id,
                enable ? "enabled" : "disabled");
        return 0;
}

static int cygnus_pcie_phy_power_on(struct phy *p)
{
        struct cygnus_pcie_phy *phy = phy_get_drvdata(p);

        return cygnus_pcie_power_config(phy, true);
}

static int cygnus_pcie_phy_power_off(struct phy *p)
{
        struct cygnus_pcie_phy *phy = phy_get_drvdata(p);

        return cygnus_pcie_power_config(phy, false);
}

static const struct phy_ops cygnus_pcie_phy_ops = {
        .power_on = cygnus_pcie_phy_power_on,
        .power_off = cygnus_pcie_phy_power_off,
        .owner = THIS_MODULE,
};

static int cygnus_pcie_phy_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *node = dev->of_node;
        struct cygnus_pcie_phy_core *core;
        struct phy_provider *provider;
        unsigned cnt = 0;

        if (of_get_child_count(node) == 0) {
                dev_err(dev, "PHY no child node\n");
                return -ENODEV;
        }

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

        core->dev = dev;

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

        mutex_init(&core->lock);

        for_each_available_child_of_node_scoped(node, child) {
                unsigned int id;
                struct cygnus_pcie_phy *p;

                if (of_property_read_u32(child, "reg", &id)) {
                        dev_err(dev, "missing reg property for %pOFn\n",
                                child);
                        return -EINVAL;
                }

                if (id >= MAX_NUM_PHYS) {
                        dev_err(dev, "invalid PHY id: %u\n", id);
                        return -EINVAL;
                }

                if (core->phys[id].phy) {
                        dev_err(dev, "duplicated PHY id: %u\n", id);
                        return -EINVAL;
                }

                p = &core->phys[id];
                p->phy = devm_phy_create(dev, child, &cygnus_pcie_phy_ops);
                if (IS_ERR(p->phy)) {
                        dev_err(dev, "failed to create PHY\n");
                        return PTR_ERR(p->phy);
                }

                p->core = core;
                p->id = id;
                phy_set_drvdata(p->phy, p);
                cnt++;
        }

        dev_set_drvdata(dev, core);

        provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
        if (IS_ERR(provider)) {
                dev_err(dev, "failed to register PHY provider\n");
                return PTR_ERR(provider);
        }

        dev_dbg(dev, "registered %u PCIe PHY(s)\n", cnt);

        return 0;
}

static const struct of_device_id cygnus_pcie_phy_match_table[] = {
        { .compatible = "brcm,cygnus-pcie-phy" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, cygnus_pcie_phy_match_table);

static struct platform_driver cygnus_pcie_phy_driver = {
        .driver = {
                .name = "cygnus-pcie-phy",
                .of_match_table = cygnus_pcie_phy_match_table,
        },
        .probe = cygnus_pcie_phy_probe,
};
module_platform_driver(cygnus_pcie_phy_driver);

MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>");
MODULE_DESCRIPTION("Broadcom Cygnus PCIe PHY driver");
MODULE_LICENSE("GPL v2");