/*
 * Driver for Microsemi VSC85xx PHYs
 *
 * Author: Nagaraju Lakkaraju
 * License: Dual MIT/GPL
 * Copyright (c) 2016 Microsemi Corporation
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mdio.h>
#include <linux/mii.h>
#include <linux/phy.h>

enum rgmii_rx_clock_delay {
	RGMII_RX_CLK_DELAY_0_2_NS = 0,
	RGMII_RX_CLK_DELAY_0_8_NS = 1,
	RGMII_RX_CLK_DELAY_1_1_NS = 2,
	RGMII_RX_CLK_DELAY_1_7_NS = 3,
	RGMII_RX_CLK_DELAY_2_0_NS = 4,
	RGMII_RX_CLK_DELAY_2_3_NS = 5,
	RGMII_RX_CLK_DELAY_2_6_NS = 6,
	RGMII_RX_CLK_DELAY_3_4_NS = 7
};

#define MII_VSC85XX_INT_MASK		  25
#define MII_VSC85XX_INT_MASK_MASK	  0xa000
#define MII_VSC85XX_INT_STATUS		  26

#define MSCC_EXT_PAGE_ACCESS		  31
#define MSCC_PHY_PAGE_STANDARD		  0x0000 /* Standard registers */
#define MSCC_PHY_PAGE_EXTENDED_2	  0x0002 /* Extended reg - page 2 */

/* Extended Page 2 Registers */
#define MSCC_PHY_RGMII_CNTL		  20
#define RGMII_RX_CLK_DELAY_MASK		  0x0070
#define RGMII_RX_CLK_DELAY_POS		  4

/* Microsemi PHY ID's */
#define PHY_ID_VSC8531			  0x00070570
#define PHY_ID_VSC8541			  0x00070770

static int vsc85xx_phy_page_set(struct phy_device *phydev, u8 page)
{
	int rc;

	rc = phy_write(phydev, MSCC_EXT_PAGE_ACCESS, page);
	return rc;
}

static int vsc85xx_default_config(struct phy_device *phydev)
{
	int rc;
	u16 reg_val;

	mutex_lock(&phydev->lock);
	rc = vsc85xx_phy_page_set(phydev, MSCC_PHY_PAGE_EXTENDED_2);
	if (rc != 0)
		goto out_unlock;

	reg_val = phy_read(phydev, MSCC_PHY_RGMII_CNTL);
	reg_val &= ~(RGMII_RX_CLK_DELAY_MASK);
	reg_val |= (RGMII_RX_CLK_DELAY_1_1_NS << RGMII_RX_CLK_DELAY_POS);
	phy_write(phydev, MSCC_PHY_RGMII_CNTL, reg_val);
	rc = vsc85xx_phy_page_set(phydev, MSCC_PHY_PAGE_STANDARD);

out_unlock:
	mutex_unlock(&phydev->lock);

	return rc;
}

static int vsc85xx_config_init(struct phy_device *phydev)
{
	int rc;

	rc = vsc85xx_default_config(phydev);
	if (rc)
		return rc;
	rc = genphy_config_init(phydev);

	return rc;
}

static int vsc85xx_ack_interrupt(struct phy_device *phydev)
{
	int rc = 0;

	if (phydev->interrupts == PHY_INTERRUPT_ENABLED)
		rc = phy_read(phydev, MII_VSC85XX_INT_STATUS);

	return (rc < 0) ? rc : 0;
}

static int vsc85xx_config_intr(struct phy_device *phydev)
{
	int rc;

	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
		rc = phy_write(phydev, MII_VSC85XX_INT_MASK,
			       MII_VSC85XX_INT_MASK_MASK);
	} else {
		rc = phy_write(phydev, MII_VSC85XX_INT_MASK, 0);
		if (rc < 0)
			return rc;
		rc = phy_read(phydev, MII_VSC85XX_INT_STATUS);
	}

	return rc;
}

/* Microsemi VSC85xx PHYs */
static struct phy_driver vsc85xx_driver[] = {
{
	.phy_id		= PHY_ID_VSC8531,
	.name		= "Microsemi VSC8531",
	.phy_id_mask    = 0xfffffff0,
	.features	= PHY_GBIT_FEATURES,
	.flags		= PHY_HAS_INTERRUPT,
	.soft_reset	= &genphy_soft_reset,
	.config_init    = &vsc85xx_config_init,
	.config_aneg    = &genphy_config_aneg,
	.aneg_done	= &genphy_aneg_done,
	.read_status    = &genphy_read_status,
	.ack_interrupt  = &vsc85xx_ack_interrupt,
	.config_intr    = &vsc85xx_config_intr,
	.suspend	= &genphy_suspend,
	.resume		= &genphy_resume,
},
{
	.phy_id		= PHY_ID_VSC8541,
	.name		= "Microsemi VSC8541 SyncE",
	.phy_id_mask    = 0xfffffff0,
	.features	= PHY_GBIT_FEATURES,
	.flags		= PHY_HAS_INTERRUPT,
	.soft_reset	= &genphy_soft_reset,
	.config_init    = &vsc85xx_config_init,
	.config_aneg    = &genphy_config_aneg,
	.aneg_done	= &genphy_aneg_done,
	.read_status    = &genphy_read_status,
	.ack_interrupt  = &vsc85xx_ack_interrupt,
	.config_intr    = &vsc85xx_config_intr,
	.suspend	= &genphy_suspend,
	.resume		= &genphy_resume,
}

};

module_phy_driver(vsc85xx_driver);

static struct mdio_device_id __maybe_unused vsc85xx_tbl[] = {
	{ PHY_ID_VSC8531, 0xfffffff0, },
	{ PHY_ID_VSC8541, 0xfffffff0, },
	{ }
};

MODULE_DEVICE_TABLE(mdio, vsc85xx_tbl);

MODULE_DESCRIPTION("Microsemi VSC85xx PHY driver");
MODULE_AUTHOR("Nagaraju Lakkaraju");
MODULE_LICENSE("Dual MIT/GPL");