1/*
  2 * Copyright (C) 2015 Broadcom Corporation
  3 *
  4 * This program is free software; you can redistribute it and/or
  5 * modify it under the terms of the GNU General Public License as
  6 * published by the Free Software Foundation version 2.
  7 *
  8 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  9 * kind, whether express or implied; without even the implied warranty
 10 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 11 * GNU General Public License for more details.
 12 */
 13
 14#include <linux/delay.h>
 15#include <linux/io.h>
 16#include <linux/kernel.h>
 17#include <linux/module.h>
 18#include <linux/of.h>
 19#include <linux/of_platform.h>
 20#include <linux/of_mdio.h>
 21#include <linux/phy.h>
 22#include <linux/platform_device.h>
 23#include <linux/sched.h>
 24
 25#define IPROC_GPHY_MDCDIV    0x1a
 26
 27#define MII_CTRL_OFFSET      0x000
 28
 29#define MII_CTRL_DIV_SHIFT   0
 30#define MII_CTRL_PRE_SHIFT   7
 31#define MII_CTRL_BUSY_SHIFT  8
 32
 33#define MII_DATA_OFFSET      0x004
 34#define MII_DATA_MASK        0xffff
 35#define MII_DATA_TA_SHIFT    16
 36#define MII_DATA_TA_VAL      2
 37#define MII_DATA_RA_SHIFT    18
 38#define MII_DATA_PA_SHIFT    23
 39#define MII_DATA_OP_SHIFT    28
 40#define MII_DATA_OP_WRITE    1
 41#define MII_DATA_OP_READ     2
 42#define MII_DATA_SB_SHIFT    30
 43
 44struct iproc_mdio_priv {
 45	struct mii_bus *mii_bus;
 46	void __iomem *base;
 47};
 48
 49static inline int iproc_mdio_wait_for_idle(void __iomem *base)
 50{
 51	u32 val;
 52	unsigned int timeout = 1000; /* loop for 1s */
 53
 54	do {
 55		val = readl(base + MII_CTRL_OFFSET);
 56		if ((val & BIT(MII_CTRL_BUSY_SHIFT)) == 0)
 57			return 0;
 58
 59		usleep_range(1000, 2000);
 60	} while (timeout--);
 61
 62	return -ETIMEDOUT;
 63}
 64
 65static inline void iproc_mdio_config_clk(void __iomem *base)
 66{
 67	u32 val;
 68
 69	val = (IPROC_GPHY_MDCDIV << MII_CTRL_DIV_SHIFT) |
 70		  BIT(MII_CTRL_PRE_SHIFT);
 71	writel(val, base + MII_CTRL_OFFSET);
 72}
 73
 74static int iproc_mdio_read(struct mii_bus *bus, int phy_id, int reg)
 75{
 76	struct iproc_mdio_priv *priv = bus->priv;
 77	u32 cmd;
 78	int rc;
 79
 80	rc = iproc_mdio_wait_for_idle(priv->base);
 81	if (rc)
 82		return rc;
 83
 84	/* Prepare the read operation */
 85	cmd = (MII_DATA_TA_VAL << MII_DATA_TA_SHIFT) |
 86		(reg << MII_DATA_RA_SHIFT) |
 87		(phy_id << MII_DATA_PA_SHIFT) |
 88		BIT(MII_DATA_SB_SHIFT) |
 89		(MII_DATA_OP_READ << MII_DATA_OP_SHIFT);
 90
 91	writel(cmd, priv->base + MII_DATA_OFFSET);
 92
 93	rc = iproc_mdio_wait_for_idle(priv->base);
 94	if (rc)
 95		return rc;
 96
 97	cmd = readl(priv->base + MII_DATA_OFFSET) & MII_DATA_MASK;
 98
 99	return cmd;
100}
101
102static int iproc_mdio_write(struct mii_bus *bus, int phy_id,
103			    int reg, u16 val)
104{
105	struct iproc_mdio_priv *priv = bus->priv;
106	u32 cmd;
107	int rc;
108
109	rc = iproc_mdio_wait_for_idle(priv->base);
110	if (rc)
111		return rc;
112
113	/* Prepare the write operation */
114	cmd = (MII_DATA_TA_VAL << MII_DATA_TA_SHIFT) |
115		(reg << MII_DATA_RA_SHIFT) |
116		(phy_id << MII_DATA_PA_SHIFT) |
117		BIT(MII_DATA_SB_SHIFT) |
118		(MII_DATA_OP_WRITE << MII_DATA_OP_SHIFT) |
119		((u32)(val) & MII_DATA_MASK);
120
121	writel(cmd, priv->base + MII_DATA_OFFSET);
122
123	rc = iproc_mdio_wait_for_idle(priv->base);
124	if (rc)
125		return rc;
126
127	return 0;
128}
129
130static int iproc_mdio_probe(struct platform_device *pdev)
131{
132	struct iproc_mdio_priv *priv;
133	struct mii_bus *bus;
134	struct resource *res;
135	int rc;
136
137	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
138	if (!priv)
139		return -ENOMEM;
140
141	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
142	priv->base = devm_ioremap_resource(&pdev->dev, res);
143	if (IS_ERR(priv->base)) {
144		dev_err(&pdev->dev, "failed to ioremap register\n");
145		return PTR_ERR(priv->base);
146	}
147
148	priv->mii_bus = mdiobus_alloc();
149	if (!priv->mii_bus) {
150		dev_err(&pdev->dev, "MDIO bus alloc failed\n");
151		return -ENOMEM;
152	}
153
154	bus = priv->mii_bus;
155	bus->priv = priv;
156	bus->name = "iProc MDIO bus";
157	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id);
158	bus->parent = &pdev->dev;
159	bus->read = iproc_mdio_read;
160	bus->write = iproc_mdio_write;
161
162	iproc_mdio_config_clk(priv->base);
163
164	rc = of_mdiobus_register(bus, pdev->dev.of_node);
165	if (rc) {
166		dev_err(&pdev->dev, "MDIO bus registration failed\n");
167		goto err_iproc_mdio;
168	}
169
170	platform_set_drvdata(pdev, priv);
171
172	dev_info(&pdev->dev, "Broadcom iProc MDIO bus at 0x%p\n", priv->base);
173
174	return 0;
175
176err_iproc_mdio:
177	mdiobus_free(bus);
178	return rc;
179}
180
181static int iproc_mdio_remove(struct platform_device *pdev)
182{
183	struct iproc_mdio_priv *priv = platform_get_drvdata(pdev);
184
185	mdiobus_unregister(priv->mii_bus);
186	mdiobus_free(priv->mii_bus);
187
188	return 0;
189}
190
191static const struct of_device_id iproc_mdio_of_match[] = {
192	{ .compatible = "brcm,iproc-mdio", },
193	{ /* sentinel */ },
194};
195MODULE_DEVICE_TABLE(of, iproc_mdio_of_match);
196
197static struct platform_driver iproc_mdio_driver = {
198	.driver = {
199		.name = "iproc-mdio",
200		.of_match_table = iproc_mdio_of_match,
201	},
202	.probe = iproc_mdio_probe,
203	.remove = iproc_mdio_remove,
204};
205
206module_platform_driver(iproc_mdio_driver);
207
208MODULE_AUTHOR("Broadcom Corporation");
209MODULE_DESCRIPTION("Broadcom iProc MDIO bus controller");
210MODULE_LICENSE("GPL v2");
211MODULE_ALIAS("platform:iproc-mdio");