drivers/net/phy/ncn26000.c

   1 // SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
   2 /*
   3  *  Driver for the onsemi 10BASE-T1S NCN26000 PHYs family.
   4  *
   5  * Copyright 2022 onsemi
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/bitfield.h>
   9 #include <linux/errno.h>
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/mii.h>
  13 #include <linux/phy.h>
  14
  15 #include "mdio-open-alliance.h"
  16
  17 #define PHY_ID_NCN26000                 0x180FF5A1
  18
  19 #define NCN26000_REG_IRQ_CTL            16
  20 #define NCN26000_REG_IRQ_STATUS         17
  21
  22 // the NCN26000 maps link_ctrl to BMCR_ANENABLE
  23 #define NCN26000_BCMR_LINK_CTRL_BIT     BMCR_ANENABLE
  24
  25 // the NCN26000 maps link_status to BMSR_ANEGCOMPLETE
  26 #define NCN26000_BMSR_LINK_STATUS_BIT   BMSR_ANEGCOMPLETE
  27
  28 #define NCN26000_IRQ_LINKST_BIT         BIT(0)
  29 #define NCN26000_IRQ_PLCAST_BIT         BIT(1)
  30 #define NCN26000_IRQ_LJABBER_BIT        BIT(2)
  31 #define NCN26000_IRQ_RJABBER_BIT        BIT(3)
  32 #define NCN26000_IRQ_PLCAREC_BIT        BIT(4)
  33 #define NCN26000_IRQ_PHYSCOL_BIT        BIT(5)
  34 #define NCN26000_IRQ_RESET_BIT          BIT(15)
  35
  36 #define TO_TMR_DEFAULT                  32
  37
  38 static int ncn26000_config_init(struct phy_device *phydev)
  39 {
  40         /* HW bug workaround: the default value of the PLCA TO_TIMER should be
  41          * 32, where the current version of NCN26000 reports 24. This will be
  42          * fixed in future PHY versions. For the time being, we force the
  43          * correct default here.
  44          */
  45         return phy_write_mmd(phydev, MDIO_MMD_VEND2, MDIO_OATC14_PLCA_TOTMR,
  46                              TO_TMR_DEFAULT);
  47 }
  48
  49 static int ncn26000_config_aneg(struct phy_device *phydev)
  50 {
  51         /* Note: the NCN26000 supports only P2MP link mode. Therefore, AN is not
  52          * supported. However, this function is invoked by phylib to enable the
  53          * PHY, regardless of the AN support.
  54          */
  55         phydev->mdix_ctrl = ETH_TP_MDI_AUTO;
  56         phydev->mdix = ETH_TP_MDI;
  57
  58         // bring up the link
  59         return phy_write(phydev, MII_BMCR, NCN26000_BCMR_LINK_CTRL_BIT);
  60 }
  61
  62 static int ncn26000_read_status(struct phy_device *phydev)
  63 {
  64         /* The NCN26000 reports NCN26000_LINK_STATUS_BIT if the link status of
  65          * the PHY is up. It further reports the logical AND of the link status
  66          * and the PLCA status in the BMSR_LSTATUS bit.
  67          */
  68         int ret;
  69
  70         /* The link state is latched low so that momentary link
  71          * drops can be detected. Do not double-read the status
  72          * in polling mode to detect such short link drops except
  73          * the link was already down.
  74          */
  75         if (!phy_polling_mode(phydev) || !phydev->link) {
  76                 ret = phy_read(phydev, MII_BMSR);
  77                 if (ret < 0)
  78                         return ret;
  79                 else if (ret & NCN26000_BMSR_LINK_STATUS_BIT)
  80                         goto upd_link;
  81         }
  82
  83         ret = phy_read(phydev, MII_BMSR);
  84         if (ret < 0)
  85                 return ret;
  86
  87 upd_link:
  88         // update link status
  89         if (ret & NCN26000_BMSR_LINK_STATUS_BIT) {
  90                 phydev->link = 1;
  91                 phydev->pause = 0;
  92                 phydev->duplex = DUPLEX_HALF;
  93                 phydev->speed = SPEED_10;
  94         } else {
  95                 phydev->link = 0;
  96                 phydev->duplex = DUPLEX_UNKNOWN;
  97                 phydev->speed = SPEED_UNKNOWN;
  98         }
  99
 100         return 0;
 101 }
 102
 103 static irqreturn_t ncn26000_handle_interrupt(struct phy_device *phydev)
 104 {
 105         int ret;
 106
 107         // read and aknowledge the IRQ status register
 108         ret = phy_read(phydev, NCN26000_REG_IRQ_STATUS);
 109
 110         // check only link status changes
 111         if (ret < 0 || (ret & NCN26000_REG_IRQ_STATUS) == 0)
 112                 return IRQ_NONE;
 113
 114         phy_trigger_machine(phydev);
 115         return IRQ_HANDLED;
 116 }
 117
 118 static int ncn26000_config_intr(struct phy_device *phydev)
 119 {
 120         int ret;
 121         u16 irqe;
 122
 123         if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
 124                 // acknowledge IRQs
 125                 ret = phy_read(phydev, NCN26000_REG_IRQ_STATUS);
 126                 if (ret < 0)
 127                         return ret;
 128
 129                 // get link status notifications
 130                 irqe = NCN26000_IRQ_LINKST_BIT;
 131         } else {
 132                 // disable all IRQs
 133                 irqe = 0;
 134         }
 135
 136         ret = phy_write(phydev, NCN26000_REG_IRQ_CTL, irqe);
 137         if (ret != 0)
 138                 return ret;
 139
 140         return 0;
 141 }
 142
 143 static struct phy_driver ncn26000_driver[] = {
 144         {
 145                 PHY_ID_MATCH_MODEL(PHY_ID_NCN26000),
 146                 .name                   = "NCN26000",
 147                 .features               = PHY_BASIC_T1S_P2MP_FEATURES,
 148                 .config_init            = ncn26000_config_init,
 149                 .config_intr            = ncn26000_config_intr,
 150                 .config_aneg            = ncn26000_config_aneg,
 151                 .read_status            = ncn26000_read_status,
 152                 .handle_interrupt       = ncn26000_handle_interrupt,
 153                 .get_plca_cfg           = genphy_c45_plca_get_cfg,
 154                 .set_plca_cfg           = genphy_c45_plca_set_cfg,
 155                 .get_plca_status        = genphy_c45_plca_get_status,
 156                 .soft_reset             = genphy_soft_reset,
 157         },
 158 };
 159
 160 module_phy_driver(ncn26000_driver);
 161
 162 static struct mdio_device_id __maybe_unused ncn26000_tbl[] = {
 163         { PHY_ID_MATCH_MODEL(PHY_ID_NCN26000) },
 164         { }
 165 };
 166
 167 MODULE_DEVICE_TABLE(mdio, ncn26000_tbl);
 168
 169 MODULE_AUTHOR("Piergiorgio Beruto");
 170 MODULE_DESCRIPTION("onsemi 10BASE-T1S PHY driver");
 171 MODULE_LICENSE("Dual BSD/GPL");