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Commit d3feb406 authored by Rafał Miłecki's avatar Rafał Miłecki Committed by Kishon Vijay Abraham I
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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: default avatarRafał Miłecki <zajec5@gmail.com>
Signed-off-by: default avatarKishon Vijay Abraham I <kishon@ti.com>
parent 444525d4

Documentation/devicetree/bindings/phy/bcm-ns-usb2-phy.txt

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Driver for Broadcom Northstar USB 2.0 PHY



Required properties:

- compatible: brcm,ns-usb2-phy

- reg: iomem address range of DMU (Device Management Unit)

- reg-names: "dmu", the only needed & supported reg right now

- clocks: USB PHY reference clock

- clock-names: "phy-ref-clk", the only needed & supported clock right now



To initialize USB 2.0 PHY driver needs to setup PLL correctly. To do this it

requires passing phandle to the USB PHY reference clock.



Example:

	usb2-phy {

		compatible = "brcm,ns-usb2-phy";

		reg = <0x1800c000 0x1000>;

		reg-names = "dmu";

		#phy-cells = <0>;

		clocks = <&genpll BCM_NSP_GENPLL_USB_PHY_REF_CLK>;

		clock-names = "phy-ref-clk";

	};

drivers/phy/Kconfig

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@@ -15,6 +15,15 @@ config GENERIC_PHY 
	  phy users can obtain reference to the PHY. All the users of this

	  framework should select this config.



config PHY_BCM_NS_USB2

	tristate "Broadcom Northstar USB 2.0 PHY Driver"

	depends on ARCH_BCM_IPROC || COMPILE_TEST

	depends on HAS_IOMEM && OF

	select GENERIC_PHY

	help

	  Enable this to support Broadcom USB 2.0 PHY connected to the USB

	  controller on Northstar family.



config PHY_BERLIN_USB

	tristate "Marvell Berlin USB PHY Driver"

	depends on ARCH_BERLIN && RESET_CONTROLLER && HAS_IOMEM && OF

drivers/phy/Makefile

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@@ -3,6 +3,7 @@ 
#



obj-$(CONFIG_GENERIC_PHY)		+= phy-core.o

obj-$(CONFIG_PHY_BCM_NS_USB2)		+= phy-bcm-ns-usb2.o

obj-$(CONFIG_PHY_BERLIN_USB)		+= phy-berlin-usb.o

obj-$(CONFIG_PHY_BERLIN_SATA)		+= phy-berlin-sata.o

obj-$(CONFIG_PHY_DM816X_USB)		+= phy-dm816x-usb.o

drivers/phy/phy-bcm-ns-usb2.c

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/*

 * Broadcom Northstar USB 2.0 PHY Driver

 *

 * Copyright (C) 2016 Rafał Miłecki <zajec5@gmail.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 */



#include <linux/bcma/bcma.h>

#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/err.h>

#include <linux/module.h>

#include <linux/of_address.h>

#include <linux/of_platform.h>

#include <linux/phy/phy.h>

#include <linux/platform_device.h>

#include <linux/slab.h>



struct bcm_ns_usb2 {

	struct device *dev;

	struct clk *ref_clk;

	struct phy *phy;

	void __iomem *dmu;

};



static int bcm_ns_usb2_phy_init(struct phy *phy)

{

	struct bcm_ns_usb2 *usb2 = phy_get_drvdata(phy);

	struct device *dev = usb2->dev;

	void __iomem *dmu = usb2->dmu;

	u32 ref_clk_rate, usb2ctl, usb_pll_ndiv, usb_pll_pdiv;

	int err = 0;



	err = clk_prepare_enable(usb2->ref_clk);

	if (err < 0) {

		dev_err(dev, "Failed to prepare ref clock: %d\n", err);

		goto err_out;

	}



	ref_clk_rate = clk_get_rate(usb2->ref_clk);

	if (!ref_clk_rate) {

		dev_err(dev, "Failed to get ref clock rate\n");

		err = -EINVAL;

		goto err_clk_off;

	}



	usb2ctl = readl(dmu + BCMA_DMU_CRU_USB2_CONTROL);



	if (usb2ctl & BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK) {

		usb_pll_pdiv = usb2ctl;

		usb_pll_pdiv &= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK;

		usb_pll_pdiv >>= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_SHIFT;

	} else {

		usb_pll_pdiv = 1 << 3;

	}



	/* Calculate ndiv based on a solid 1920 MHz that is for USB2 PHY */

	usb_pll_ndiv = (1920000000 * usb_pll_pdiv) / ref_clk_rate;



	/* Unlock DMU PLL settings with some magic value */

	writel(0x0000ea68, dmu + BCMA_DMU_CRU_CLKSET_KEY);



	/* Write USB 2.0 PLL control setting */

	usb2ctl &= ~BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK;

	usb2ctl |= usb_pll_ndiv << BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT;

	writel(usb2ctl, dmu + BCMA_DMU_CRU_USB2_CONTROL);



	/* Lock DMU PLL settings */

	writel(0x00000000, dmu + BCMA_DMU_CRU_CLKSET_KEY);



err_clk_off:

	clk_disable_unprepare(usb2->ref_clk);

err_out:

	return err;

}



static const struct phy_ops ops = {

	.init		= bcm_ns_usb2_phy_init,

	.owner		= THIS_MODULE,

};



static int bcm_ns_usb2_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct bcm_ns_usb2 *usb2;

	struct resource *res;

	struct phy_provider *phy_provider;



	usb2 = devm_kzalloc(&pdev->dev, sizeof(*usb2), GFP_KERNEL);

	if (!usb2)

		return -ENOMEM;

	usb2->dev = dev;



	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dmu");

	usb2->dmu = devm_ioremap_resource(dev, res);

	if (IS_ERR(usb2->dmu)) {

		dev_err(dev, "Failed to map DMU regs\n");

		return PTR_ERR(usb2->dmu);

	}



	usb2->ref_clk = devm_clk_get(dev, "phy-ref-clk");

	if (IS_ERR(usb2->ref_clk)) {

		dev_err(dev, "Clock not defined\n");

		return PTR_ERR(usb2->ref_clk);

	}



	usb2->phy = devm_phy_create(dev, NULL, &ops);

	if (IS_ERR(dev))

		return PTR_ERR(dev);



	phy_set_drvdata(usb2->phy, usb2);

	platform_set_drvdata(pdev, usb2);



	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);

	return PTR_ERR_OR_ZERO(phy_provider);

}



static const struct of_device_id bcm_ns_usb2_id_table[] = {

	{ .compatible = "brcm,ns-usb2-phy", },

	{},

};

MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);



static struct platform_driver bcm_ns_usb2_driver = {

	.probe		= bcm_ns_usb2_probe,

	.driver = {

		.name = "bcm_ns_usb2",

		.of_match_table = bcm_ns_usb2_id_table,

	},

};

module_platform_driver(bcm_ns_usb2_driver);



MODULE_LICENSE("GPL v2");

include/linux/bcma/bcma.h

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@@ -4,6 +4,7 @@ 
#include <linux/pci.h>

#include <linux/mod_devicetable.h>



#include <linux/bcma/bcma_driver_arm_c9.h>

#include <linux/bcma/bcma_driver_chipcommon.h>

#include <linux/bcma/bcma_driver_pci.h>

#include <linux/bcma/bcma_driver_pcie2.h>