linux/drivers/net/mdio/mdio-mux-bcm6368.c
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   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 int 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        return 0;
 164}
 165
 166static const struct of_device_id bcm6368_mdiomux_ids[] = {
 167        { .compatible = "brcm,bcm6368-mdio-mux", },
 168        { /* sentinel */ }
 169};
 170MODULE_DEVICE_TABLE(of, bcm6368_mdiomux_ids);
 171
 172static struct platform_driver bcm6368_mdiomux_driver = {
 173        .driver = {
 174                .name = "bcm6368-mdio-mux",
 175                .of_match_table = bcm6368_mdiomux_ids,
 176        },
 177        .probe  = bcm6368_mdiomux_probe,
 178        .remove = bcm6368_mdiomux_remove,
 179};
 180module_platform_driver(bcm6368_mdiomux_driver);
 181
 182MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
 183MODULE_DESCRIPTION("BCM6368 mdiomux bus controller driver");
 184MODULE_LICENSE("GPL v2");
 185
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