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
 29static int bcm_ns_usb2_phy_init(struct phy *phy)
 30{
 31	struct bcm_ns_usb2 *usb2 = phy_get_drvdata(phy);
 32	struct device *dev = usb2->dev;
 33	u32 ref_clk_rate, usb2ctl, usb_pll_ndiv, usb_pll_pdiv;
 34	int err = 0;
 35
 36	err = clk_prepare_enable(usb2->ref_clk);
 37	if (err < 0) {
 38		dev_err(dev, "Failed to prepare ref clock: %d\n", err);
 39		goto err_out;
 40	}
 41
 42	ref_clk_rate = clk_get_rate(usb2->ref_clk);
 43	if (!ref_clk_rate) {
 44		dev_err(dev, "Failed to get ref clock rate\n");
 45		err = -EINVAL;
 46		goto err_clk_off;
 47	}
 48
 49	usb2ctl = readl(usb2->base);
 50
 51	if (usb2ctl & BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK) {
 52		usb_pll_pdiv = usb2ctl;
 53		usb_pll_pdiv &= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK;
 54		usb_pll_pdiv >>= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_SHIFT;
 55	} else {
 56		usb_pll_pdiv = 1 << 3;
 57	}
 58
 59	/* Calculate ndiv based on a solid 1920 MHz that is for USB2 PHY */
 60	usb_pll_ndiv = (1920000000 * usb_pll_pdiv) / ref_clk_rate;
 61
 62	/* Unlock DMU PLL settings with some magic value */
 63	regmap_write(usb2->clkset, 0, 0x0000ea68);
 64
 65	/* Write USB 2.0 PLL control setting */
 66	usb2ctl &= ~BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK;
 67	usb2ctl |= usb_pll_ndiv << BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT;
 68
 69	writel(usb2ctl, usb2->base);
 70
 71	/* Lock DMU PLL settings */
 72	regmap_write(usb2->clkset, 0, 0x00000000);
 73
 74err_clk_off:
 75	clk_disable_unprepare(usb2->ref_clk);
 76err_out:
 77	return err;
 78}
 79
 80static const struct phy_ops ops = {
 81	.init		= bcm_ns_usb2_phy_init,
 82	.owner		= THIS_MODULE,
 83};
 84
 85static int bcm_ns_usb2_probe(struct platform_device *pdev)
 86{
 87	struct device *dev = &pdev->dev;
 88	struct bcm_ns_usb2 *usb2;
 89	struct phy_provider *phy_provider;
 90
 91	usb2 = devm_kzalloc(&pdev->dev, sizeof(*usb2), GFP_KERNEL);
 92	if (!usb2)
 93		return -ENOMEM;
 94	usb2->dev = dev;
 95
 96	usb2->base = devm_platform_ioremap_resource(pdev, 0);
 97	if (IS_ERR(usb2->base)) {
 98		dev_err(dev, "Failed to map control reg\n");
 99		return PTR_ERR(usb2->base);
100	}
101
102	usb2->clkset = syscon_regmap_lookup_by_phandle(dev->of_node,
103						       "brcm,syscon-clkset");
104	if (IS_ERR(usb2->clkset)) {
105		dev_err(dev, "Failed to lookup clkset regmap\n");
106		return PTR_ERR(usb2->clkset);
107	}
108
109	usb2->ref_clk = devm_clk_get(dev, "phy-ref-clk");
110	if (IS_ERR(usb2->ref_clk)) {
111		dev_err_probe(dev, PTR_ERR(usb2->ref_clk), "failed to get ref clk\n");
112		return PTR_ERR(usb2->ref_clk);
113	}
114
115	usb2->phy = devm_phy_create(dev, NULL, &ops);
116	if (IS_ERR(usb2->phy))
117		return PTR_ERR(usb2->phy);
118
119	phy_set_drvdata(usb2->phy, usb2);
120	platform_set_drvdata(pdev, usb2);
121
122	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
123	return PTR_ERR_OR_ZERO(phy_provider);
124}
125
126static const struct of_device_id bcm_ns_usb2_id_table[] = {
127	{ .compatible = "brcm,ns-usb2-phy", },
128	{},
129};
130MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);
131
132static struct platform_driver bcm_ns_usb2_driver = {
133	.probe		= bcm_ns_usb2_probe,
134	.driver = {
135		.name = "bcm_ns_usb2",
136		.of_match_table = bcm_ns_usb2_id_table,
137	},
138};
139module_platform_driver(bcm_ns_usb2_driver);
140
141MODULE_DESCRIPTION("Broadcom Northstar USB 2.0 PHY Driver");
142MODULE_LICENSE("GPL v2");