// SPDX-License-Identifier: GPL-2.0+
/*
 * Driver for AMD am79c PHYs
 *
 * Author: Heiko Schocher <hs@denx.de>
 *
 * Copyright (c) 2011 DENX Software Engineering GmbH
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mii.h>
#include <linux/phy.h>

#define PHY_ID_AC101L           0x00225520
#define PHY_ID_AM79C874         0x0022561b

#define MII_AM79C_IR            17      /* Interrupt Status/Control Register */
#define MII_AM79C_IR_EN_LINK    0x0400  /* IR enable Linkstate */
#define MII_AM79C_IR_EN_ANEG    0x0100  /* IR enable Aneg Complete */
#define MII_AM79C_IR_IMASK_INIT (MII_AM79C_IR_EN_LINK | MII_AM79C_IR_EN_ANEG)

#define MII_AM79C_IR_LINK_DOWN  BIT(2)
#define MII_AM79C_IR_ANEG_DONE  BIT(0)
#define MII_AM79C_IR_IMASK_STAT (MII_AM79C_IR_LINK_DOWN | MII_AM79C_IR_ANEG_DONE)

MODULE_DESCRIPTION("AMD PHY driver");
MODULE_AUTHOR("Heiko Schocher <hs@denx.de>");
MODULE_LICENSE("GPL");

static int am79c_ack_interrupt(struct phy_device *phydev)
{
        int err;

        err = phy_read(phydev, MII_BMSR);
        if (err < 0)
                return err;

        err = phy_read(phydev, MII_AM79C_IR);
        if (err < 0)
                return err;

        return 0;
}

static int am79c_config_init(struct phy_device *phydev)
{
        return 0;
}

static int am79c_config_intr(struct phy_device *phydev)
{
        int err;

        if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
                err = am79c_ack_interrupt(phydev);
                if (err)
                        return err;

                err = phy_write(phydev, MII_AM79C_IR, MII_AM79C_IR_IMASK_INIT);
        } else {
                err = phy_write(phydev, MII_AM79C_IR, 0);
                if (err)
                        return err;

                err = am79c_ack_interrupt(phydev);
        }

        return err;
}

static irqreturn_t am79c_handle_interrupt(struct phy_device *phydev)
{
        int irq_status;

        irq_status = phy_read(phydev, MII_AM79C_IR);
        if (irq_status < 0) {
                phy_error(phydev);
                return IRQ_NONE;
        }

        if (!(irq_status & MII_AM79C_IR_IMASK_STAT))
                return IRQ_NONE;

        phy_trigger_machine(phydev);

        return IRQ_HANDLED;
}

static struct phy_driver am79c_drivers[] = {
        {
                .phy_id         = PHY_ID_AM79C874,
                .name           = "AM79C874",
                .phy_id_mask    = 0xfffffff0,
                /* PHY_BASIC_FEATURES */
                .config_init    = am79c_config_init,
                .config_intr    = am79c_config_intr,
                .handle_interrupt = am79c_handle_interrupt,
        },
        {
                .phy_id         = PHY_ID_AC101L,
                .name           = "AC101L",
                .phy_id_mask    = 0xfffffff0,
                /* PHY_BASIC_FEATURES */
                .config_init    = am79c_config_init,
                .config_intr    = am79c_config_intr,
                .handle_interrupt = am79c_handle_interrupt,
        },
};

module_phy_driver(am79c_drivers);

static const struct mdio_device_id __maybe_unused amd_tbl[] = {
        { PHY_ID_AC101L, 0xfffffff0 },
        { PHY_ID_AM79C874, 0xfffffff0 },
        { }
};

MODULE_DEVICE_TABLE(mdio, amd_tbl);