xref: /openbmc/linux/drivers/net/phy/ncn26000.c (revision b53e7e8d)
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 
ncn26000_config_init(struct phy_device * phydev)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 
ncn26000_config_aneg(struct phy_device * phydev)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 
ncn26000_read_status(struct phy_device * phydev)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 
ncn26000_handle_interrupt(struct phy_device * phydev)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 
ncn26000_config_intr(struct phy_device * phydev)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");
172