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phy: bcm-ns-usb2: new driver for USB 2.0 PHY on Northstar
Northstar is a family of SoCs used in home routers. They have USB 2.0 and 3.0 controllers with PHYs that need to be properly initialized. This driver provides PHY init support in a generic way and can be bound with an EHCI controller driver. There are (just a few) registers being defined in bcma header. It's because DMU/CRU registers will be also needed in other drivers. We will need them e.g. in PCIe controller/PHY driver and at some point probably in clock driver for BCM53573 chipset. By using include/linux/bcma/ we avoid code duplication. Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
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‎Documentation/devicetree/bindings/phy/bcm-ns-usb2-phy.txt

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Driver for Broadcom Northstar USB 2.0 PHY
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Required properties:
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- compatible: brcm,ns-usb2-phy
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- reg: iomem address range of DMU (Device Management Unit)
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- reg-names: "dmu", the only needed & supported reg right now
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- clocks: USB PHY reference clock
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- clock-names: "phy-ref-clk", the only needed & supported clock right now
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To initialize USB 2.0 PHY driver needs to setup PLL correctly. To do this it
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requires passing phandle to the USB PHY reference clock.
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Example:
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usb2-phy {
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compatible = "brcm,ns-usb2-phy";
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reg = <0x1800c000 0x1000>;
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reg-names = "dmu";
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#phy-cells = <0>;
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clocks = <&genpll BCM_NSP_GENPLL_USB_PHY_REF_CLK>;
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clock-names = "phy-ref-clk";
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};

‎drivers/phy/Kconfig

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@@ -15,6 +15,15 @@ config GENERIC_PHY
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phy users can obtain reference to the PHY. All the users of this
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framework should select this config.
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config PHY_BCM_NS_USB2
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tristate "Broadcom Northstar USB 2.0 PHY Driver"
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depends on ARCH_BCM_IPROC || COMPILE_TEST
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depends on HAS_IOMEM && OF
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select GENERIC_PHY
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help
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Enable this to support Broadcom USB 2.0 PHY connected to the USB
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controller on Northstar family.
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config PHY_BERLIN_USB
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tristate "Marvell Berlin USB PHY Driver"
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depends on ARCH_BERLIN && RESET_CONTROLLER && HAS_IOMEM && OF

‎drivers/phy/Makefile

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#
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obj-$(CONFIG_GENERIC_PHY) += phy-core.o
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obj-$(CONFIG_PHY_BCM_NS_USB2) += phy-bcm-ns-usb2.o
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obj-$(CONFIG_PHY_BERLIN_USB) += phy-berlin-usb.o
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obj-$(CONFIG_PHY_BERLIN_SATA) += phy-berlin-sata.o
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obj-$(CONFIG_PHY_DM816X_USB) += phy-dm816x-usb.o

‎drivers/phy/phy-bcm-ns-usb2.c

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/*
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* Broadcom Northstar USB 2.0 PHY Driver
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*
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* Copyright (C) 2016 Rafał Miłecki <zajec5@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/bcma/bcma.h>
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/of_address.h>
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#include <linux/of_platform.h>
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#include <linux/phy/phy.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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struct bcm_ns_usb2 {
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struct device *dev;
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struct clk *ref_clk;
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struct phy *phy;
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void __iomem *dmu;
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};
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static int bcm_ns_usb2_phy_init(struct phy *phy)
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{
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struct bcm_ns_usb2 *usb2 = phy_get_drvdata(phy);
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struct device *dev = usb2->dev;
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void __iomem *dmu = usb2->dmu;
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u32 ref_clk_rate, usb2ctl, usb_pll_ndiv, usb_pll_pdiv;
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int err = 0;
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err = clk_prepare_enable(usb2->ref_clk);
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if (err < 0) {
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dev_err(dev, "Failed to prepare ref clock: %d\n", err);
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goto err_out;
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}
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ref_clk_rate = clk_get_rate(usb2->ref_clk);
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if (!ref_clk_rate) {
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dev_err(dev, "Failed to get ref clock rate\n");
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err = -EINVAL;
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goto err_clk_off;
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}
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usb2ctl = readl(dmu + BCMA_DMU_CRU_USB2_CONTROL);
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if (usb2ctl & BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK) {
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usb_pll_pdiv = usb2ctl;
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usb_pll_pdiv &= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK;
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usb_pll_pdiv >>= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_SHIFT;
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} else {
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usb_pll_pdiv = 1 << 3;
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}
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/* Calculate ndiv based on a solid 1920 MHz that is for USB2 PHY */
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usb_pll_ndiv = (1920000000 * usb_pll_pdiv) / ref_clk_rate;
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/* Unlock DMU PLL settings with some magic value */
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writel(0x0000ea68, dmu + BCMA_DMU_CRU_CLKSET_KEY);
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/* Write USB 2.0 PLL control setting */
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usb2ctl &= ~BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK;
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usb2ctl |= usb_pll_ndiv << BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT;
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writel(usb2ctl, dmu + BCMA_DMU_CRU_USB2_CONTROL);
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/* Lock DMU PLL settings */
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writel(0x00000000, dmu + BCMA_DMU_CRU_CLKSET_KEY);
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err_clk_off:
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clk_disable_unprepare(usb2->ref_clk);
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err_out:
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return err;
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}
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static const struct phy_ops ops = {
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.init = bcm_ns_usb2_phy_init,
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.owner = THIS_MODULE,
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};
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static int bcm_ns_usb2_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct bcm_ns_usb2 *usb2;
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struct resource *res;
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struct phy_provider *phy_provider;
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usb2 = devm_kzalloc(&pdev->dev, sizeof(*usb2), GFP_KERNEL);
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if (!usb2)
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return -ENOMEM;
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usb2->dev = dev;
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res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dmu");
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usb2->dmu = devm_ioremap_resource(dev, res);
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if (IS_ERR(usb2->dmu)) {
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dev_err(dev, "Failed to map DMU regs\n");
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return PTR_ERR(usb2->dmu);
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}
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usb2->ref_clk = devm_clk_get(dev, "phy-ref-clk");
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if (IS_ERR(usb2->ref_clk)) {
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dev_err(dev, "Clock not defined\n");
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return PTR_ERR(usb2->ref_clk);
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}
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usb2->phy = devm_phy_create(dev, NULL, &ops);
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if (IS_ERR(dev))
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return PTR_ERR(dev);
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phy_set_drvdata(usb2->phy, usb2);
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platform_set_drvdata(pdev, usb2);
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phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
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return PTR_ERR_OR_ZERO(phy_provider);
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}
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static const struct of_device_id bcm_ns_usb2_id_table[] = {
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{ .compatible = "brcm,ns-usb2-phy", },
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{},
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};
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MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);
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static struct platform_driver bcm_ns_usb2_driver = {
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.probe = bcm_ns_usb2_probe,
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.driver = {
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.name = "bcm_ns_usb2",
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.of_match_table = bcm_ns_usb2_id_table,
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},
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};
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module_platform_driver(bcm_ns_usb2_driver);
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MODULE_LICENSE("GPL v2");

‎include/linux/bcma/bcma.h

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#include <linux/pci.h>
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#include <linux/mod_devicetable.h>
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#include <linux/bcma/bcma_driver_arm_c9.h>
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#include <linux/bcma/bcma_driver_chipcommon.h>
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#include <linux/bcma/bcma_driver_pci.h>
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#include <linux/bcma/bcma_driver_pcie2.h>

‎include/linux/bcma/bcma_driver_arm_c9.h

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#ifndef LINUX_BCMA_DRIVER_ARM_C9_H_
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#define LINUX_BCMA_DRIVER_ARM_C9_H_
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/* DMU (Device Management Unit) */
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#define BCMA_DMU_CRU_USB2_CONTROL 0x0164
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#define BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK 0x00000FFC
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#define BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT 2
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#define BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK 0x00007000
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#define BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_SHIFT 12
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#define BCMA_DMU_CRU_CLKSET_KEY 0x0180
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#define BCMA_DMU_CRU_STRAPS_CTRL 0x02A0
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#define BCMA_DMU_CRU_STRAPS_CTRL_USB3 0x00000010
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#define BCMA_DMU_CRU_STRAPS_CTRL_4BYTE 0x00008000
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#endif /* LINUX_BCMA_DRIVER_ARM_C9_H_ */

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