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