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