drivers/net/mdio/mdio-ipq8064.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Qualcomm IPQ8064 MDIO interface driver
   3  *
   4  * Copyright (C) 2019 Christian Lamparter <chunkeey@gmail.com>
   5  * Copyright (C) 2020 Ansuel Smith <ansuelsmth@gmail.com>
   6  */
   7
   8 #include <linux/delay.h>
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/of_mdio.h>
  12 #include <linux/of_address.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/regmap.h>
  15
  16 /* MII address register definitions */
  17 #define MII_ADDR_REG_ADDR                       0x10
  18 #define MII_BUSY                                BIT(0)
  19 #define MII_WRITE                               BIT(1)
  20 #define MII_CLKRANGE(x)                         ((x) << 2)
  21 #define MII_CLKRANGE_60_100M                    MII_CLKRANGE(0)
  22 #define MII_CLKRANGE_100_150M                   MII_CLKRANGE(1)
  23 #define MII_CLKRANGE_20_35M                     MII_CLKRANGE(2)
  24 #define MII_CLKRANGE_35_60M                     MII_CLKRANGE(3)
  25 #define MII_CLKRANGE_150_250M                   MII_CLKRANGE(4)
  26 #define MII_CLKRANGE_250_300M                   MII_CLKRANGE(5)
  27 #define MII_CLKRANGE_MASK                       GENMASK(4, 2)
  28 #define MII_REG_SHIFT                           6
  29 #define MII_REG_MASK                            GENMASK(10, 6)
  30 #define MII_ADDR_SHIFT                          11
  31 #define MII_ADDR_MASK                           GENMASK(15, 11)
  32
  33 #define MII_DATA_REG_ADDR                       0x14
  34
  35 #define MII_MDIO_DELAY_USEC                     (1000)
  36 #define MII_MDIO_RETRY_MSEC                     (10)
  37
  38 struct ipq8064_mdio {
  39         struct regmap *base; /* NSS_GMAC0_BASE */
  40 };
  41
  42 static int
  43 ipq8064_mdio_wait_busy(struct ipq8064_mdio *priv)
  44 {
  45         u32 busy;
  46
  47         return regmap_read_poll_timeout(priv->base, MII_ADDR_REG_ADDR, busy,
  48                                         !(busy & MII_BUSY), MII_MDIO_DELAY_USEC,
  49                                         MII_MDIO_RETRY_MSEC * USEC_PER_MSEC);
  50 }
  51
  52 static int
  53 ipq8064_mdio_read(struct mii_bus *bus, int phy_addr, int reg_offset)
  54 {
  55         u32 miiaddr = MII_BUSY | MII_CLKRANGE_250_300M;
  56         struct ipq8064_mdio *priv = bus->priv;
  57         u32 ret_val;
  58         int err;
  59
  60         miiaddr |= ((phy_addr << MII_ADDR_SHIFT) & MII_ADDR_MASK) |
  61                    ((reg_offset << MII_REG_SHIFT) & MII_REG_MASK);
  62
  63         regmap_write(priv->base, MII_ADDR_REG_ADDR, miiaddr);
  64         usleep_range(10, 13);
  65
  66         err = ipq8064_mdio_wait_busy(priv);
  67         if (err)
  68                 return err;
  69
  70         regmap_read(priv->base, MII_DATA_REG_ADDR, &ret_val);
  71         return (int)ret_val;
  72 }
  73
  74 static int
  75 ipq8064_mdio_write(struct mii_bus *bus, int phy_addr, int reg_offset, u16 data)
  76 {
  77         u32 miiaddr = MII_WRITE | MII_BUSY | MII_CLKRANGE_250_300M;
  78         struct ipq8064_mdio *priv = bus->priv;
  79
  80         regmap_write(priv->base, MII_DATA_REG_ADDR, data);
  81
  82         miiaddr |= ((phy_addr << MII_ADDR_SHIFT) & MII_ADDR_MASK) |
  83                    ((reg_offset << MII_REG_SHIFT) & MII_REG_MASK);
  84
  85         regmap_write(priv->base, MII_ADDR_REG_ADDR, miiaddr);
  86
  87         /* For the specific reg 31 extra time is needed or the next
  88          * read will produce garbage data.
  89          */
  90         if (reg_offset == 31)
  91                 usleep_range(30, 43);
  92         else
  93                 usleep_range(10, 13);
  94
  95         return ipq8064_mdio_wait_busy(priv);
  96 }
  97
  98 static const struct regmap_config ipq8064_mdio_regmap_config = {
  99         .reg_bits = 32,
 100         .reg_stride = 4,
 101         .val_bits = 32,
 102         .can_multi_write = false,
 103         /* the mdio lock is used by any user of this mdio driver */
 104         .disable_locking = true,
 105
 106         .cache_type = REGCACHE_NONE,
 107 };
 108
 109 static int
 110 ipq8064_mdio_probe(struct platform_device *pdev)
 111 {
 112         struct device_node *np = pdev->dev.of_node;
 113         struct ipq8064_mdio *priv;
 114         struct resource res;
 115         struct mii_bus *bus;
 116         void __iomem *base;
 117         int ret;
 118
 119         if (of_address_to_resource(np, 0, &res))
 120                 return -ENOMEM;
 121
 122         base = devm_ioremap(&pdev->dev, res.start, resource_size(&res));
 123         if (!base)
 124                 return -ENOMEM;
 125
 126         bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*priv));
 127         if (!bus)
 128                 return -ENOMEM;
 129
 130         bus->name = "ipq8064_mdio_bus";
 131         bus->read = ipq8064_mdio_read;
 132         bus->write = ipq8064_mdio_write;
 133         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev));
 134         bus->parent = &pdev->dev;
 135
 136         priv = bus->priv;
 137         priv->base = devm_regmap_init_mmio(&pdev->dev, base,
 138                                            &ipq8064_mdio_regmap_config);
 139         if (IS_ERR(priv->base))
 140                 return PTR_ERR(priv->base);
 141
 142         ret = of_mdiobus_register(bus, np);
 143         if (ret)
 144                 return ret;
 145
 146         platform_set_drvdata(pdev, bus);
 147         return 0;
 148 }
 149
 150 static void ipq8064_mdio_remove(struct platform_device *pdev)
 151 {
 152         struct mii_bus *bus = platform_get_drvdata(pdev);
 153
 154         mdiobus_unregister(bus);
 155 }
 156
 157 static const struct of_device_id ipq8064_mdio_dt_ids[] = {
 158         { .compatible = "qcom,ipq8064-mdio" },
 159         { }
 160 };
 161 MODULE_DEVICE_TABLE(of, ipq8064_mdio_dt_ids);
 162
 163 static struct platform_driver ipq8064_mdio_driver = {
 164         .probe = ipq8064_mdio_probe,
 165         .remove = ipq8064_mdio_remove,
 166         .driver = {
 167                 .name = "ipq8064-mdio",
 168                 .of_match_table = ipq8064_mdio_dt_ids,
 169         },
 170 };
 171
 172 module_platform_driver(ipq8064_mdio_driver);
 173
 174 MODULE_DESCRIPTION("Qualcomm IPQ8064 MDIO interface driver");
 175 MODULE_AUTHOR("Christian Lamparter <chunkeey@gmail.com>");
 176 MODULE_AUTHOR("Ansuel Smith <ansuelsmth@gmail.com>");
 177 MODULE_LICENSE("GPL");