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 
rcar_gen3_phy_pcie_modify_reg(struct phy * p,unsigned int reg,u32 clear,u32 set)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 
r8a77980_phy_pcie_power_on(struct phy * p)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 
r8a77980_phy_pcie_power_off(struct phy * p)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 
rcar_gen3_phy_pcie_probe(struct platform_device * pdev)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 
rcar_gen3_phy_pcie_remove(struct platform_device * pdev)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>");
150