// SPDX-License-Identifier: GPL-2.0+

  /*
   * drivers/net/phy/national.c
   *
   * Driver for National Semiconductor PHYs
   *
   * Author: Stuart Menefy <stuart.menefy@st.com>
   * Maintainer: Giuseppe Cavallaro <peppe.cavallaro@st.com>
   *
   * Copyright (c) 2008 STMicroelectronics Limited

   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

  #define DEBUG

  /* DP83865 phy identifier values */
  #define DP83865_PHY_ID	0x20005c7a

  #define DP83865_INT_STATUS	0x14
  #define DP83865_INT_MASK	0x15
  #define DP83865_INT_CLEAR	0x17

  
  #define DP83865_INT_REMOTE_FAULT 0x0008
  #define DP83865_INT_ANE_COMPLETED 0x0010
  #define DP83865_INT_LINK_CHANGE	0xe000
  #define DP83865_INT_MASK_DEFAULT (DP83865_INT_REMOTE_FAULT | \
  				DP83865_INT_ANE_COMPLETED | \
  				DP83865_INT_LINK_CHANGE)
  
  /* Advanced proprietary configuration */
  #define NS_EXP_MEM_CTL	0x16
  #define NS_EXP_MEM_DATA	0x1d
  #define NS_EXP_MEM_ADD	0x1e
  
  #define LED_CTRL_REG 0x13
  #define AN_FALLBACK_AN 0x0001
  #define AN_FALLBACK_CRC 0x0002
  #define AN_FALLBACK_IE 0x0004
  #define ALL_FALLBACK_ON (AN_FALLBACK_AN |  AN_FALLBACK_CRC | AN_FALLBACK_IE)
  
  enum hdx_loopback {
  	hdx_loopback_on = 0,
  	hdx_loopback_off = 1,
  };
  
  static u8 ns_exp_read(struct phy_device *phydev, u16 reg)
  {
  	phy_write(phydev, NS_EXP_MEM_ADD, reg);
  	return phy_read(phydev, NS_EXP_MEM_DATA);
  }
  
  static void ns_exp_write(struct phy_device *phydev, u16 reg, u8 data)
  {
  	phy_write(phydev, NS_EXP_MEM_ADD, reg);
  	phy_write(phydev, NS_EXP_MEM_DATA, data);
  }
  
  static int ns_config_intr(struct phy_device *phydev)
  {
  	int err;
  
  	if (phydev->interrupts == PHY_INTERRUPT_ENABLED)

  		err = phy_write(phydev, DP83865_INT_MASK,

  				DP83865_INT_MASK_DEFAULT);
  	else

  		err = phy_write(phydev, DP83865_INT_MASK, 0);

  
  	return err;
  }
  
  static int ns_ack_interrupt(struct phy_device *phydev)
  {

  	int ret = phy_read(phydev, DP83865_INT_STATUS);

  	if (ret < 0)
  		return ret;

  	/* Clear the interrupt status bit by writing a “1”
  	 * to the corresponding bit in INT_CLEAR (2:0 are reserved) */
  	ret = phy_write(phydev, DP83865_INT_CLEAR, ret & ~0x7);
  
  	return ret;

  }
  
  static void ns_giga_speed_fallback(struct phy_device *phydev, int mode)
  {
  	int bmcr = phy_read(phydev, MII_BMCR);
  
  	phy_write(phydev, MII_BMCR, (bmcr | BMCR_PDOWN));
  
  	/* Enable 8 bit expended memory read/write (no auto increment) */
  	phy_write(phydev, NS_EXP_MEM_CTL, 0);
  	phy_write(phydev, NS_EXP_MEM_ADD, 0x1C0);
  	phy_write(phydev, NS_EXP_MEM_DATA, 0x0008);
  	phy_write(phydev, MII_BMCR, (bmcr & ~BMCR_PDOWN));
  	phy_write(phydev, LED_CTRL_REG, mode);

  }
  
  static void ns_10_base_t_hdx_loopack(struct phy_device *phydev, int disable)
  {

  	u16 lb_dis = BIT(1);

  	if (disable)

  		ns_exp_write(phydev, 0x1c0,
  			     ns_exp_read(phydev, 0x1c0) | lb_dis);

  	else
  		ns_exp_write(phydev, 0x1c0,

  			     ns_exp_read(phydev, 0x1c0) & ~lb_dis);

  	pr_debug("10BASE-T HDX loopback %s
  ",

  		 (ns_exp_read(phydev, 0x1c0) & lb_dis) ? "off" : "on");

  }
  
  static int ns_config_init(struct phy_device *phydev)
  {
  	ns_giga_speed_fallback(phydev, ALL_FALLBACK_ON);
  	/* In the latest MAC or switches design, the 10 Mbps loopback
  	   is desired to be turned off. */
  	ns_10_base_t_hdx_loopack(phydev, hdx_loopback_off);
  	return ns_ack_interrupt(phydev);
  }

  static struct phy_driver dp83865_driver[] = { {

  	.phy_id = DP83865_PHY_ID,
  	.phy_id_mask = 0xfffffff0,
  	.name = "NatSemi DP83865",

  	/* PHY_GBIT_FEATURES */

  	.config_init = ns_config_init,

  	.ack_interrupt = ns_ack_interrupt,
  	.config_intr = ns_config_intr,

  } };

  module_phy_driver(dp83865_driver);

  
  MODULE_DESCRIPTION("NatSemi PHY driver");
  MODULE_AUTHOR("Stuart Menefy");
  MODULE_LICENSE("GPL");

  static struct mdio_device_id __maybe_unused ns_tbl[] = {

  	{ DP83865_PHY_ID, 0xfffffff0 },
  	{ }
  };
  
  MODULE_DEVICE_TABLE(mdio, ns_tbl);