1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Broadcom BCM6368 mdiomux bus controller driver
  4 *
  5 * Copyright (C) 2021 Álvaro Fernández Rojas <noltari@gmail.com>
  6 */
  7
  8#include <linux/delay.h>
  9#include <linux/io.h>
 10#include <linux/kernel.h>
 11#include <linux/mdio-mux.h>
 12#include <linux/module.h>
 13#include <linux/of.h>
 14#include <linux/of_platform.h>
 15#include <linux/of_mdio.h>
 16#include <linux/phy.h>
 17#include <linux/platform_device.h>
 18#include <linux/sched.h>
 19
 20#define MDIOC_REG		0x0
 21#define MDIOC_EXT_MASK		BIT(16)
 22#define MDIOC_REG_SHIFT		20
 23#define MDIOC_PHYID_SHIFT	25
 24#define MDIOC_RD_MASK		BIT(30)
 25#define MDIOC_WR_MASK		BIT(31)
 26
 27#define MDIOD_REG		0x4
 28
 29struct bcm6368_mdiomux_desc {
 30	void *mux_handle;
 31	void __iomem *base;
 32	struct device *dev;
 33	struct mii_bus *mii_bus;
 34	int ext_phy;
 35};
 36
 37static int bcm6368_mdiomux_read(struct mii_bus *bus, int phy_id, int loc)
 38{
 39	struct bcm6368_mdiomux_desc *md = bus->priv;
 40	uint32_t reg;
 41	int ret;
 42
 43	__raw_writel(0, md->base + MDIOC_REG);
 44
 45	reg = MDIOC_RD_MASK |
 46	      (phy_id << MDIOC_PHYID_SHIFT) |
 47	      (loc << MDIOC_REG_SHIFT);
 48	if (md->ext_phy)
 49		reg |= MDIOC_EXT_MASK;
 50
 51	__raw_writel(reg, md->base + MDIOC_REG);
 52	udelay(50);
 53	ret = __raw_readw(md->base + MDIOD_REG);
 54
 55	return ret;
 56}
 57
 58static int bcm6368_mdiomux_write(struct mii_bus *bus, int phy_id, int loc,
 59				 uint16_t val)
 60{
 61	struct bcm6368_mdiomux_desc *md = bus->priv;
 62	uint32_t reg;
 63
 64	__raw_writel(0, md->base + MDIOC_REG);
 65
 66	reg = MDIOC_WR_MASK |
 67	      (phy_id << MDIOC_PHYID_SHIFT) |
 68	      (loc << MDIOC_REG_SHIFT);
 69	if (md->ext_phy)
 70		reg |= MDIOC_EXT_MASK;
 71	reg |= val;
 72
 73	__raw_writel(reg, md->base + MDIOC_REG);
 74	udelay(50);
 75
 76	return 0;
 77}
 78
 79static int bcm6368_mdiomux_switch_fn(int current_child, int desired_child,
 80				     void *data)
 81{
 82	struct bcm6368_mdiomux_desc *md = data;
 83
 84	md->ext_phy = desired_child;
 85
 86	return 0;
 87}
 88
 89static int bcm6368_mdiomux_probe(struct platform_device *pdev)
 90{
 91	struct bcm6368_mdiomux_desc *md;
 92	struct mii_bus *bus;
 93	struct resource *res;
 94	int rc;
 95
 96	md = devm_kzalloc(&pdev->dev, sizeof(*md), GFP_KERNEL);
 97	if (!md)
 98		return -ENOMEM;
 99	md->dev = &pdev->dev;
100
101	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
102	if (!res)
103		return -EINVAL;
104
105	/*
106	 * Just ioremap, as this MDIO block is usually integrated into an
107	 * Ethernet MAC controller register range
108	 */
109	md->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
110	if (!md->base) {
111		dev_err(&pdev->dev, "failed to ioremap register\n");
112		return -ENOMEM;
113	}
114
115	md->mii_bus = devm_mdiobus_alloc(&pdev->dev);
116	if (!md->mii_bus) {
117		dev_err(&pdev->dev, "mdiomux bus alloc failed\n");
118		return -ENOMEM;
119	}
120
121	bus = md->mii_bus;
122	bus->priv = md;
123	bus->name = "BCM6368 MDIO mux bus";
124	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id);
125	bus->parent = &pdev->dev;
126	bus->read = bcm6368_mdiomux_read;
127	bus->write = bcm6368_mdiomux_write;
128	bus->phy_mask = 0x3f;
129	bus->dev.of_node = pdev->dev.of_node;
130
131	rc = mdiobus_register(bus);
132	if (rc) {
133		dev_err(&pdev->dev, "mdiomux registration failed\n");
134		return rc;
135	}
136
137	platform_set_drvdata(pdev, md);
138
139	rc = mdio_mux_init(md->dev, md->dev->of_node,
140			   bcm6368_mdiomux_switch_fn, &md->mux_handle, md,
141			   md->mii_bus);
142	if (rc) {
143		dev_info(md->dev, "mdiomux initialization failed\n");
144		goto out_register;
145	}
146
147	dev_info(&pdev->dev, "Broadcom BCM6368 MDIO mux bus\n");
148
149	return 0;
150
151out_register:
152	mdiobus_unregister(bus);
153	return rc;
154}
155
156static void bcm6368_mdiomux_remove(struct platform_device *pdev)
157{
158	struct bcm6368_mdiomux_desc *md = platform_get_drvdata(pdev);
159
160	mdio_mux_uninit(md->mux_handle);
161	mdiobus_unregister(md->mii_bus);
162}
163
164static const struct of_device_id bcm6368_mdiomux_ids[] = {
165	{ .compatible = "brcm,bcm6368-mdio-mux", },
166	{ /* sentinel */ }
167};
168MODULE_DEVICE_TABLE(of, bcm6368_mdiomux_ids);
169
170static struct platform_driver bcm6368_mdiomux_driver = {
171	.driver = {
172		.name = "bcm6368-mdio-mux",
173		.of_match_table = bcm6368_mdiomux_ids,
174	},
175	.probe	= bcm6368_mdiomux_probe,
176	.remove = bcm6368_mdiomux_remove,
177};
178module_platform_driver(bcm6368_mdiomux_driver);
179
180MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
181MODULE_DESCRIPTION("BCM6368 mdiomux bus controller driver");
182MODULE_LICENSE("GPL v2");