renesas/phy-rcar-gen3-pcie.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Renesas R-Car Gen3 PCIe PHY driver
   4  *
   5  * Copyright (C) 2018 Cogent Embedded, Inc.
   6  */
   7
   8 #include <linux/clk.h>
   9 #include <linux/io.h>
  10 #include <linux/module.h>
  11 #include <linux/of.h>
  12 #include <linux/phy/phy.h>
  13 #include <linux/of_device.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/spinlock.h>
  16
  17 #define PHY_CTRL                0x4000          /* R8A77980 only */
  18
  19 /* PHY control register (PHY_CTRL) */
  20 #define PHY_CTRL_PHY_PWDN       BIT(2)
  21
  22 struct rcar_gen3_phy {
  23         struct phy *phy;
  24         spinlock_t lock;
  25         void __iomem *base;
  26 };
  27
  28 static void rcar_gen3_phy_pcie_modify_reg(struct phy *p, unsigned int reg,
  29                                           u32 clear, u32 set)
  30 {
  31         struct rcar_gen3_phy *phy = phy_get_drvdata(p);
  32         void __iomem *base = phy->base;
  33         unsigned long flags;
  34         u32 value;
  35
  36         spin_lock_irqsave(&phy->lock, flags);
  37
  38         value = readl(base + reg);
  39         value &= ~clear;
  40         value |= set;
  41         writel(value, base + reg);
  42
  43         spin_unlock_irqrestore(&phy->lock, flags);
  44 }
  45
  46 static int r8a77980_phy_pcie_power_on(struct phy *p)
  47 {
  48         /* Power on the PCIe PHY */
  49         rcar_gen3_phy_pcie_modify_reg(p, PHY_CTRL, PHY_CTRL_PHY_PWDN, 0);
  50
  51         return 0;
  52 }
  53
  54 static int r8a77980_phy_pcie_power_off(struct phy *p)
  55 {
  56         /* Power off the PCIe PHY */
  57         rcar_gen3_phy_pcie_modify_reg(p, PHY_CTRL, 0, PHY_CTRL_PHY_PWDN);
  58
  59         return 0;
  60 }
  61
  62 static const struct phy_ops r8a77980_phy_pcie_ops = {
  63         .power_on       = r8a77980_phy_pcie_power_on,
  64         .power_off      = r8a77980_phy_pcie_power_off,
  65         .owner          = THIS_MODULE,
  66 };
  67
  68 static const struct of_device_id rcar_gen3_phy_pcie_match_table[] = {
  69         { .compatible = "renesas,r8a77980-pcie-phy" },
  70         { }
  71 };
  72 MODULE_DEVICE_TABLE(of, rcar_gen3_phy_pcie_match_table);
  73
  74 static int rcar_gen3_phy_pcie_probe(struct platform_device *pdev)
  75 {
  76         struct device *dev = &pdev->dev;
  77         struct phy_provider *provider;
  78         struct rcar_gen3_phy *phy;
  79         void __iomem *base;
  80         int error;
  81
  82         if (!dev->of_node) {
  83                 dev_err(dev,
  84                         "This driver must only be instantiated from the device tree\n");
  85                 return -EINVAL;
  86         }
  87
  88         base = devm_platform_ioremap_resource(pdev, 0);
  89         if (IS_ERR(base))
  90                 return PTR_ERR(base);
  91
  92         phy = devm_kzalloc(dev, sizeof(*phy), GFP_KERNEL);
  93         if (!phy)
  94                 return -ENOMEM;
  95
  96         spin_lock_init(&phy->lock);
  97
  98         phy->base = base;
  99
 100         /*
 101          * devm_phy_create() will call pm_runtime_enable(&phy->dev);
 102          * And then, phy-core will manage runtime PM for this device.
 103          */
 104         pm_runtime_enable(dev);
 105
 106         phy->phy = devm_phy_create(dev, NULL, &r8a77980_phy_pcie_ops);
 107         if (IS_ERR(phy->phy)) {
 108                 dev_err(dev, "Failed to create PCIe PHY\n");
 109                 error = PTR_ERR(phy->phy);
 110                 goto error;
 111         }
 112         phy_set_drvdata(phy->phy, phy);
 113
 114         provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
 115         if (IS_ERR(provider)) {
 116                 dev_err(dev, "Failed to register PHY provider\n");
 117                 error = PTR_ERR(provider);
 118                 goto error;
 119         }
 120
 121         return 0;
 122
 123 error:
 124         pm_runtime_disable(dev);
 125
 126         return error;
 127 }
 128
 129 static int rcar_gen3_phy_pcie_remove(struct platform_device *pdev)
 130 {
 131         pm_runtime_disable(&pdev->dev);
 132
 133         return 0;
 134 };
 135
 136 static struct platform_driver rcar_gen3_phy_driver = {
 137         .driver = {
 138                 .name           = "phy_rcar_gen3_pcie",
 139                 .of_match_table = rcar_gen3_phy_pcie_match_table,
 140         },
 141         .probe  = rcar_gen3_phy_pcie_probe,
 142         .remove = rcar_gen3_phy_pcie_remove,
 143 };
 144
 145 module_platform_driver(rcar_gen3_phy_driver);
 146
 147 MODULE_LICENSE("GPL v2");
 148 MODULE_DESCRIPTION("Renesas R-Car Gen3 PCIe PHY");
 149 MODULE_AUTHOR("Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>");