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
 21struct 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
 32static 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
 88err_clk_off:
 89	clk_disable_unprepare(usb2->ref_clk);
 90err_out:
 91	return err;
 92}
 93
 94static const struct phy_ops ops = {
 95	.init		= bcm_ns_usb2_phy_init,
 96	.owner		= THIS_MODULE,
 97};
 98
 99static 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_find_property(dev->of_node, "brcm,syscon-clkset", NULL)) {
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
150static const struct of_device_id bcm_ns_usb2_id_table[] = {
151	{ .compatible = "brcm,ns-usb2-phy", },
152	{},
153};
154MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);
155
156static 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};
163module_platform_driver(bcm_ns_usb2_driver);
164
165MODULE_LICENSE("GPL v2");