1// SPDX-License-Identifier: GPL-2.0-or-later
  2/* Copyright (C) 2019 IBM Corp. */
  3
  4#include <linux/bitfield.h>
  5#include <linux/delay.h>
  6#include <linux/iopoll.h>
  7#include <linux/mdio.h>
  8#include <linux/module.h>
  9#include <linux/of.h>
 10#include <linux/of_mdio.h>
 11#include <linux/phy.h>
 12#include <linux/platform_device.h>
 13
 14#define DRV_NAME "mdio-aspeed"
 15
 16#define ASPEED_MDIO_CTRL		0x0
 17#define   ASPEED_MDIO_CTRL_FIRE		BIT(31)
 18#define   ASPEED_MDIO_CTRL_ST		BIT(28)
 19#define     ASPEED_MDIO_CTRL_ST_C45	0
 20#define     ASPEED_MDIO_CTRL_ST_C22	1
 21#define   ASPEED_MDIO_CTRL_OP		GENMASK(27, 26)
 22#define     MDIO_C22_OP_WRITE		0b01
 23#define     MDIO_C22_OP_READ		0b10
 24#define   ASPEED_MDIO_CTRL_PHYAD	GENMASK(25, 21)
 25#define   ASPEED_MDIO_CTRL_REGAD	GENMASK(20, 16)
 26#define   ASPEED_MDIO_CTRL_MIIWDATA	GENMASK(15, 0)
 27
 28#define ASPEED_MDIO_DATA		0x4
 29#define   ASPEED_MDIO_DATA_MDC_THRES	GENMASK(31, 24)
 30#define   ASPEED_MDIO_DATA_MDIO_EDGE	BIT(23)
 31#define   ASPEED_MDIO_DATA_MDIO_LATCH	GENMASK(22, 20)
 32#define   ASPEED_MDIO_DATA_IDLE		BIT(16)
 33#define   ASPEED_MDIO_DATA_MIIRDATA	GENMASK(15, 0)
 34
 35#define ASPEED_MDIO_INTERVAL_US		100
 36#define ASPEED_MDIO_TIMEOUT_US		(ASPEED_MDIO_INTERVAL_US * 10)
 37
 38struct aspeed_mdio {
 39	void __iomem *base;
 40};
 41
 42static int aspeed_mdio_read(struct mii_bus *bus, int addr, int regnum)
 43{
 44	struct aspeed_mdio *ctx = bus->priv;
 45	u32 ctrl;
 46	u32 data;
 47	int rc;
 48
 49	dev_dbg(&bus->dev, "%s: addr: %d, regnum: %d\n", __func__, addr,
 50		regnum);
 51
 52	/* Just clause 22 for the moment */
 53	if (regnum & MII_ADDR_C45)
 54		return -EOPNOTSUPP;
 55
 56	ctrl = ASPEED_MDIO_CTRL_FIRE
 57		| FIELD_PREP(ASPEED_MDIO_CTRL_ST, ASPEED_MDIO_CTRL_ST_C22)
 58		| FIELD_PREP(ASPEED_MDIO_CTRL_OP, MDIO_C22_OP_READ)
 59		| FIELD_PREP(ASPEED_MDIO_CTRL_PHYAD, addr)
 60		| FIELD_PREP(ASPEED_MDIO_CTRL_REGAD, regnum);
 61
 62	iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL);
 63
 64	rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_DATA, data,
 65				data & ASPEED_MDIO_DATA_IDLE,
 66				ASPEED_MDIO_INTERVAL_US,
 67				ASPEED_MDIO_TIMEOUT_US);
 68	if (rc < 0)
 69		return rc;
 70
 71	return FIELD_GET(ASPEED_MDIO_DATA_MIIRDATA, data);
 72}
 73
 74static int aspeed_mdio_write(struct mii_bus *bus, int addr, int regnum, u16 val)
 75{
 76	struct aspeed_mdio *ctx = bus->priv;
 77	u32 ctrl;
 78
 79	dev_dbg(&bus->dev, "%s: addr: %d, regnum: %d, val: 0x%x\n",
 80		__func__, addr, regnum, val);
 81
 82	/* Just clause 22 for the moment */
 83	if (regnum & MII_ADDR_C45)
 84		return -EOPNOTSUPP;
 85
 86	ctrl = ASPEED_MDIO_CTRL_FIRE
 87		| FIELD_PREP(ASPEED_MDIO_CTRL_ST, ASPEED_MDIO_CTRL_ST_C22)
 88		| FIELD_PREP(ASPEED_MDIO_CTRL_OP, MDIO_C22_OP_WRITE)
 89		| FIELD_PREP(ASPEED_MDIO_CTRL_PHYAD, addr)
 90		| FIELD_PREP(ASPEED_MDIO_CTRL_REGAD, regnum)
 91		| FIELD_PREP(ASPEED_MDIO_CTRL_MIIWDATA, val);
 92
 93	iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL);
 94
 95	return readl_poll_timeout(ctx->base + ASPEED_MDIO_CTRL, ctrl,
 96				  !(ctrl & ASPEED_MDIO_CTRL_FIRE),
 97				  ASPEED_MDIO_INTERVAL_US,
 98				  ASPEED_MDIO_TIMEOUT_US);
 99}
100
101static int aspeed_mdio_probe(struct platform_device *pdev)
102{
103	struct aspeed_mdio *ctx;
104	struct mii_bus *bus;
105	int rc;
106
107	bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*ctx));
108	if (!bus)
109		return -ENOMEM;
110
111	ctx = bus->priv;
112	ctx->base = devm_platform_ioremap_resource(pdev, 0);
113	if (IS_ERR(ctx->base))
114		return PTR_ERR(ctx->base);
115
116	bus->name = DRV_NAME;
117	snprintf(bus->id, MII_BUS_ID_SIZE, "%s%d", pdev->name, pdev->id);
118	bus->parent = &pdev->dev;
119	bus->read = aspeed_mdio_read;
120	bus->write = aspeed_mdio_write;
121
122	rc = of_mdiobus_register(bus, pdev->dev.of_node);
123	if (rc) {
124		dev_err(&pdev->dev, "Cannot register MDIO bus!\n");
125		return rc;
126	}
127
128	platform_set_drvdata(pdev, bus);
129
130	return 0;
131}
132
133static int aspeed_mdio_remove(struct platform_device *pdev)
134{
135	mdiobus_unregister(platform_get_drvdata(pdev));
136
137	return 0;
138}
139
140static const struct of_device_id aspeed_mdio_of_match[] = {
141	{ .compatible = "aspeed,ast2600-mdio", },
142	{ },
143};
144
145static struct platform_driver aspeed_mdio_driver = {
146	.driver = {
147		.name = DRV_NAME,
148		.of_match_table = aspeed_mdio_of_match,
149	},
150	.probe = aspeed_mdio_probe,
151	.remove = aspeed_mdio_remove,
152};
153
154module_platform_driver(aspeed_mdio_driver);
155
156MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
157MODULE_LICENSE("GPL");