net/mdio/mdio-mux-bcm6368.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * Broadcom BCM6368 mdiomux bus controller driver
0004  *
0005  * Copyright (C) 2021 Álvaro Fernández Rojas <noltari@gmail.com>
0006  */
0007
0008 #include <linux/delay.h>
0009 #include <linux/io.h>
0010 #include <linux/kernel.h>
0011 #include <linux/mdio-mux.h>
0012 #include <linux/module.h>
0013 #include <linux/of.h>
0014 #include <linux/of_platform.h>
0015 #include <linux/of_mdio.h>
0016 #include <linux/phy.h>
0017 #include <linux/platform_device.h>
0018 #include <linux/sched.h>
0019
0020 #define MDIOC_REG       0x0
0021 #define MDIOC_EXT_MASK      BIT(16)
0022 #define MDIOC_REG_SHIFT     20
0023 #define MDIOC_PHYID_SHIFT   25
0024 #define MDIOC_RD_MASK       BIT(30)
0025 #define MDIOC_WR_MASK       BIT(31)
0026
0027 #define MDIOD_REG       0x4
0028
0029 struct bcm6368_mdiomux_desc {
0030     void *mux_handle;
0031     void __iomem *base;
0032     struct device *dev;
0033     struct mii_bus *mii_bus;
0034     int ext_phy;
0035 };
0036
0037 static int bcm6368_mdiomux_read(struct mii_bus *bus, int phy_id, int loc)
0038 {
0039     struct bcm6368_mdiomux_desc *md = bus->priv;
0040     uint32_t reg;
0041     int ret;
0042
0043     __raw_writel(0, md->base + MDIOC_REG);
0044
0045     reg = MDIOC_RD_MASK |
0046           (phy_id << MDIOC_PHYID_SHIFT) |
0047           (loc << MDIOC_REG_SHIFT);
0048     if (md->ext_phy)
0049         reg |= MDIOC_EXT_MASK;
0050
0051     __raw_writel(reg, md->base + MDIOC_REG);
0052     udelay(50);
0053     ret = __raw_readw(md->base + MDIOD_REG);
0054
0055     return ret;
0056 }
0057
0058 static int bcm6368_mdiomux_write(struct mii_bus *bus, int phy_id, int loc,
0059                  uint16_t val)
0060 {
0061     struct bcm6368_mdiomux_desc *md = bus->priv;
0062     uint32_t reg;
0063
0064     __raw_writel(0, md->base + MDIOC_REG);
0065
0066     reg = MDIOC_WR_MASK |
0067           (phy_id << MDIOC_PHYID_SHIFT) |
0068           (loc << MDIOC_REG_SHIFT);
0069     if (md->ext_phy)
0070         reg |= MDIOC_EXT_MASK;
0071     reg |= val;
0072
0073     __raw_writel(reg, md->base + MDIOC_REG);
0074     udelay(50);
0075
0076     return 0;
0077 }
0078
0079 static int bcm6368_mdiomux_switch_fn(int current_child, int desired_child,
0080                      void *data)
0081 {
0082     struct bcm6368_mdiomux_desc *md = data;
0083
0084     md->ext_phy = desired_child;
0085
0086     return 0;
0087 }
0088
0089 static int bcm6368_mdiomux_probe(struct platform_device *pdev)
0090 {
0091     struct bcm6368_mdiomux_desc *md;
0092     struct mii_bus *bus;
0093     struct resource *res;
0094     int rc;
0095
0096     md = devm_kzalloc(&pdev->dev, sizeof(*md), GFP_KERNEL);
0097     if (!md)
0098         return -ENOMEM;
0099     md->dev = &pdev->dev;
0100
0101     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
0102     if (!res)
0103         return -EINVAL;
0104
0105     /*
0106      * Just ioremap, as this MDIO block is usually integrated into an
0107      * Ethernet MAC controller register range
0108      */
0109     md->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
0110     if (!md->base) {
0111         dev_err(&pdev->dev, "failed to ioremap register\n");
0112         return -ENOMEM;
0113     }
0114
0115     md->mii_bus = devm_mdiobus_alloc(&pdev->dev);
0116     if (!md->mii_bus) {
0117         dev_err(&pdev->dev, "mdiomux bus alloc failed\n");
0118         return -ENOMEM;
0119     }
0120
0121     bus = md->mii_bus;
0122     bus->priv = md;
0123     bus->name = "BCM6368 MDIO mux bus";
0124     snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id);
0125     bus->parent = &pdev->dev;
0126     bus->read = bcm6368_mdiomux_read;
0127     bus->write = bcm6368_mdiomux_write;
0128     bus->phy_mask = 0x3f;
0129     bus->dev.of_node = pdev->dev.of_node;
0130
0131     rc = mdiobus_register(bus);
0132     if (rc) {
0133         dev_err(&pdev->dev, "mdiomux registration failed\n");
0134         return rc;
0135     }
0136
0137     platform_set_drvdata(pdev, md);
0138
0139     rc = mdio_mux_init(md->dev, md->dev->of_node,
0140                bcm6368_mdiomux_switch_fn, &md->mux_handle, md,
0141                md->mii_bus);
0142     if (rc) {
0143         dev_info(md->dev, "mdiomux initialization failed\n");
0144         goto out_register;
0145     }
0146
0147     dev_info(&pdev->dev, "Broadcom BCM6368 MDIO mux bus\n");
0148
0149     return 0;
0150
0151 out_register:
0152     mdiobus_unregister(bus);
0153     return rc;
0154 }
0155
0156 static int bcm6368_mdiomux_remove(struct platform_device *pdev)
0157 {
0158     struct bcm6368_mdiomux_desc *md = platform_get_drvdata(pdev);
0159
0160     mdio_mux_uninit(md->mux_handle);
0161     mdiobus_unregister(md->mii_bus);
0162
0163     return 0;
0164 }
0165
0166 static const struct of_device_id bcm6368_mdiomux_ids[] = {
0167     { .compatible = "brcm,bcm6368-mdio-mux", },
0168     { /* sentinel */ }
0169 };
0170 MODULE_DEVICE_TABLE(of, bcm6368_mdiomux_ids);
0171
0172 static struct platform_driver bcm6368_mdiomux_driver = {
0173     .driver = {
0174         .name = "bcm6368-mdio-mux",
0175         .of_match_table = bcm6368_mdiomux_ids,
0176     },
0177     .probe  = bcm6368_mdiomux_probe,
0178     .remove = bcm6368_mdiomux_remove,
0179 };
0180 module_platform_driver(bcm6368_mdiomux_driver);
0181
0182 MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
0183 MODULE_DESCRIPTION("BCM6368 mdiomux bus controller driver");
0184 MODULE_LICENSE("GPL v2");