1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Broadcom Northstar USB 2.0 PHY Driver
4  *
5  * Copyright (C) 2016 Rafał Miłecki <zajec5@gmail.com>
6  */
7 
8 #include <linux/bcma/bcma.h>
9 #include <linux/clk.h>
10 #include <linux/delay.h>
11 #include <linux/err.h>
12 #include <linux/mfd/syscon.h>
13 #include <linux/module.h>
14 #include <linux/of_address.h>
15 #include <linux/of_platform.h>
16 #include <linux/phy/phy.h>
17 #include <linux/platform_device.h>
18 #include <linux/regmap.h>
19 #include <linux/slab.h>
20 
21 struct bcm_ns_usb2 {
22 	struct device *dev;
23 	struct clk *ref_clk;
24 	struct phy *phy;
25 	struct regmap *clkset;
26 	void __iomem *base;
27 
28 	/* Deprecated binding */
29 	void __iomem *dmu;
30 };
31 
bcm_ns_usb2_phy_init(struct phy * phy)32 static int bcm_ns_usb2_phy_init(struct phy *phy)
33 {
34 	struct bcm_ns_usb2 *usb2 = phy_get_drvdata(phy);
35 	struct device *dev = usb2->dev;
36 	u32 ref_clk_rate, usb2ctl, usb_pll_ndiv, usb_pll_pdiv;
37 	int err = 0;
38 
39 	err = clk_prepare_enable(usb2->ref_clk);
40 	if (err < 0) {
41 		dev_err(dev, "Failed to prepare ref clock: %d\n", err);
42 		goto err_out;
43 	}
44 
45 	ref_clk_rate = clk_get_rate(usb2->ref_clk);
46 	if (!ref_clk_rate) {
47 		dev_err(dev, "Failed to get ref clock rate\n");
48 		err = -EINVAL;
49 		goto err_clk_off;
50 	}
51 
52 	if (usb2->base)
53 		usb2ctl = readl(usb2->base);
54 	else
55 		usb2ctl = readl(usb2->dmu + BCMA_DMU_CRU_USB2_CONTROL);
56 
57 	if (usb2ctl & BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK) {
58 		usb_pll_pdiv = usb2ctl;
59 		usb_pll_pdiv &= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK;
60 		usb_pll_pdiv >>= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_SHIFT;
61 	} else {
62 		usb_pll_pdiv = 1 << 3;
63 	}
64 
65 	/* Calculate ndiv based on a solid 1920 MHz that is for USB2 PHY */
66 	usb_pll_ndiv = (1920000000 * usb_pll_pdiv) / ref_clk_rate;
67 
68 	/* Unlock DMU PLL settings with some magic value */
69 	if (usb2->clkset)
70 		regmap_write(usb2->clkset, 0, 0x0000ea68);
71 	else
72 		writel(0x0000ea68, usb2->dmu + BCMA_DMU_CRU_CLKSET_KEY);
73 
74 	/* Write USB 2.0 PLL control setting */
75 	usb2ctl &= ~BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK;
76 	usb2ctl |= usb_pll_ndiv << BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT;
77 	if (usb2->base)
78 		writel(usb2ctl, usb2->base);
79 	else
80 		writel(usb2ctl, usb2->dmu + BCMA_DMU_CRU_USB2_CONTROL);
81 
82 	/* Lock DMU PLL settings */
83 	if (usb2->clkset)
84 		regmap_write(usb2->clkset, 0, 0x00000000);
85 	else
86 		writel(0x00000000, usb2->dmu + BCMA_DMU_CRU_CLKSET_KEY);
87 
88 err_clk_off:
89 	clk_disable_unprepare(usb2->ref_clk);
90 err_out:
91 	return err;
92 }
93 
94 static const struct phy_ops ops = {
95 	.init		= bcm_ns_usb2_phy_init,
96 	.owner		= THIS_MODULE,
97 };
98 
bcm_ns_usb2_probe(struct platform_device * pdev)99 static int bcm_ns_usb2_probe(struct platform_device *pdev)
100 {
101 	struct device *dev = &pdev->dev;
102 	struct bcm_ns_usb2 *usb2;
103 	struct phy_provider *phy_provider;
104 
105 	usb2 = devm_kzalloc(&pdev->dev, sizeof(*usb2), GFP_KERNEL);
106 	if (!usb2)
107 		return -ENOMEM;
108 	usb2->dev = dev;
109 
110 	if (of_property_present(dev->of_node, "brcm,syscon-clkset")) {
111 		usb2->base = devm_platform_ioremap_resource(pdev, 0);
112 		if (IS_ERR(usb2->base)) {
113 			dev_err(dev, "Failed to map control reg\n");
114 			return PTR_ERR(usb2->base);
115 		}
116 
117 		usb2->clkset = syscon_regmap_lookup_by_phandle(dev->of_node,
118 							       "brcm,syscon-clkset");
119 		if (IS_ERR(usb2->clkset)) {
120 			dev_err(dev, "Failed to lookup clkset regmap\n");
121 			return PTR_ERR(usb2->clkset);
122 		}
123 	} else {
124 		usb2->dmu = devm_platform_ioremap_resource_byname(pdev, "dmu");
125 		if (IS_ERR(usb2->dmu)) {
126 			dev_err(dev, "Failed to map DMU regs\n");
127 			return PTR_ERR(usb2->dmu);
128 		}
129 
130 		dev_warn(dev, "using deprecated DT binding\n");
131 	}
132 
133 	usb2->ref_clk = devm_clk_get(dev, "phy-ref-clk");
134 	if (IS_ERR(usb2->ref_clk)) {
135 		dev_err_probe(dev, PTR_ERR(usb2->ref_clk), "failed to get ref clk\n");
136 		return PTR_ERR(usb2->ref_clk);
137 	}
138 
139 	usb2->phy = devm_phy_create(dev, NULL, &ops);
140 	if (IS_ERR(usb2->phy))
141 		return PTR_ERR(usb2->phy);
142 
143 	phy_set_drvdata(usb2->phy, usb2);
144 	platform_set_drvdata(pdev, usb2);
145 
146 	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
147 	return PTR_ERR_OR_ZERO(phy_provider);
148 }
149 
150 static const struct of_device_id bcm_ns_usb2_id_table[] = {
151 	{ .compatible = "brcm,ns-usb2-phy", },
152 	{},
153 };
154 MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);
155 
156 static struct platform_driver bcm_ns_usb2_driver = {
157 	.probe		= bcm_ns_usb2_probe,
158 	.driver = {
159 		.name = "bcm_ns_usb2",
160 		.of_match_table = bcm_ns_usb2_id_table,
161 	},
162 };
163 module_platform_driver(bcm_ns_usb2_driver);
164 
165 MODULE_LICENSE("GPL v2");
166