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/module.h>
13 #include <linux/of_address.h>
14 #include <linux/of_platform.h>
15 #include <linux/phy/phy.h>
16 #include <linux/platform_device.h>
17 #include <linux/slab.h>
18
19 struct bcm_ns_usb2 {
20 struct device *dev;
21 struct clk *ref_clk;
22 struct phy *phy;
23 void __iomem *dmu;
24 };
25
bcm_ns_usb2_phy_init(struct phy * phy)26 static int bcm_ns_usb2_phy_init(struct phy *phy)
27 {
28 struct bcm_ns_usb2 *usb2 = phy_get_drvdata(phy);
29 struct device *dev = usb2->dev;
30 void __iomem *dmu = usb2->dmu;
31 u32 ref_clk_rate, usb2ctl, usb_pll_ndiv, usb_pll_pdiv;
32 int err = 0;
33
34 err = clk_prepare_enable(usb2->ref_clk);
35 if (err < 0) {
36 dev_err(dev, "Failed to prepare ref clock: %d\n", err);
37 goto err_out;
38 }
39
40 ref_clk_rate = clk_get_rate(usb2->ref_clk);
41 if (!ref_clk_rate) {
42 dev_err(dev, "Failed to get ref clock rate\n");
43 err = -EINVAL;
44 goto err_clk_off;
45 }
46
47 usb2ctl = readl(dmu + BCMA_DMU_CRU_USB2_CONTROL);
48
49 if (usb2ctl & BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK) {
50 usb_pll_pdiv = usb2ctl;
51 usb_pll_pdiv &= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK;
52 usb_pll_pdiv >>= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_SHIFT;
53 } else {
54 usb_pll_pdiv = 1 << 3;
55 }
56
57 /* Calculate ndiv based on a solid 1920 MHz that is for USB2 PHY */
58 usb_pll_ndiv = (1920000000 * usb_pll_pdiv) / ref_clk_rate;
59
60 /* Unlock DMU PLL settings with some magic value */
61 writel(0x0000ea68, dmu + BCMA_DMU_CRU_CLKSET_KEY);
62
63 /* Write USB 2.0 PLL control setting */
64 usb2ctl &= ~BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK;
65 usb2ctl |= usb_pll_ndiv << BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT;
66 writel(usb2ctl, dmu + BCMA_DMU_CRU_USB2_CONTROL);
67
68 /* Lock DMU PLL settings */
69 writel(0x00000000, dmu + BCMA_DMU_CRU_CLKSET_KEY);
70
71 err_clk_off:
72 clk_disable_unprepare(usb2->ref_clk);
73 err_out:
74 return err;
75 }
76
77 static const struct phy_ops ops = {
78 .init = bcm_ns_usb2_phy_init,
79 .owner = THIS_MODULE,
80 };
81
bcm_ns_usb2_probe(struct platform_device * pdev)82 static int bcm_ns_usb2_probe(struct platform_device *pdev)
83 {
84 struct device *dev = &pdev->dev;
85 struct bcm_ns_usb2 *usb2;
86 struct resource *res;
87 struct phy_provider *phy_provider;
88
89 usb2 = devm_kzalloc(&pdev->dev, sizeof(*usb2), GFP_KERNEL);
90 if (!usb2)
91 return -ENOMEM;
92 usb2->dev = dev;
93
94 res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dmu");
95 usb2->dmu = devm_ioremap_resource(dev, res);
96 if (IS_ERR(usb2->dmu)) {
97 dev_err(dev, "Failed to map DMU regs\n");
98 return PTR_ERR(usb2->dmu);
99 }
100
101 usb2->ref_clk = devm_clk_get(dev, "phy-ref-clk");
102 if (IS_ERR(usb2->ref_clk)) {
103 dev_err(dev, "Clock not defined\n");
104 return PTR_ERR(usb2->ref_clk);
105 }
106
107 usb2->phy = devm_phy_create(dev, NULL, &ops);
108 if (IS_ERR(usb2->phy))
109 return PTR_ERR(usb2->phy);
110
111 phy_set_drvdata(usb2->phy, usb2);
112 platform_set_drvdata(pdev, usb2);
113
114 phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
115 return PTR_ERR_OR_ZERO(phy_provider);
116 }
117
118 static const struct of_device_id bcm_ns_usb2_id_table[] = {
119 { .compatible = "brcm,ns-usb2-phy", },
120 {},
121 };
122 MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);
123
124 static struct platform_driver bcm_ns_usb2_driver = {
125 .probe = bcm_ns_usb2_probe,
126 .driver = {
127 .name = "bcm_ns_usb2",
128 .of_match_table = bcm_ns_usb2_id_table,
129 },
130 };
131 module_platform_driver(bcm_ns_usb2_driver);
132
133 MODULE_LICENSE("GPL v2");
134