/* linux/drivers/usb/phy/phy-samsung-usb3.c
 *
 * Copyright (c) 2013 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 *
 * Author: Vivek Gautam <gautam.vivek@samsung.com>
 *
 * Samsung USB 3.0 PHY transceiver; talks to DWC3 controller.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/usb/samsung_usb_phy.h>
#include <linux/platform_data/samsung-usbphy.h>

#include "phy-samsung-usb.h"

/*
 * Sets the phy clk as EXTREFCLK (XXTI) which is internal clock from clock core.
 */
static u32 samsung_usb3phy_set_refclk(struct samsung_usbphy *sphy)
{
	u32 reg;
	u32 refclk;

	refclk = sphy->ref_clk_freq;

	reg = PHYCLKRST_REFCLKSEL_EXT_REFCLK |
		PHYCLKRST_FSEL(refclk);

	switch (refclk) {
	case FSEL_CLKSEL_50M:
		reg |= (PHYCLKRST_MPLL_MULTIPLIER_50M_REF |
			PHYCLKRST_SSC_REFCLKSEL(0x00));
		break;
	case FSEL_CLKSEL_20M:
		reg |= (PHYCLKRST_MPLL_MULTIPLIER_20MHZ_REF |
			PHYCLKRST_SSC_REFCLKSEL(0x00));
		break;
	case FSEL_CLKSEL_19200K:
		reg |= (PHYCLKRST_MPLL_MULTIPLIER_19200KHZ_REF |
			PHYCLKRST_SSC_REFCLKSEL(0x88));
		break;
	case FSEL_CLKSEL_24M:
	default:
		reg |= (PHYCLKRST_MPLL_MULTIPLIER_24MHZ_REF |
			PHYCLKRST_SSC_REFCLKSEL(0x88));
		break;
	}

	return reg;
}

static int samsung_exynos5_usb3phy_enable(struct samsung_usbphy *sphy)
{
	void __iomem *regs = sphy->regs;
	u32 phyparam0;
	u32 phyparam1;
	u32 linksystem;
	u32 phybatchg;
	u32 phytest;
	u32 phyclkrst;

	/* Reset USB 3.0 PHY */
	writel(0x0, regs + EXYNOS5_DRD_PHYREG0);

	phyparam0 = readl(regs + EXYNOS5_DRD_PHYPARAM0);
	/* Select PHY CLK source */
	phyparam0 &= ~PHYPARAM0_REF_USE_PAD;
	/* Set Loss-of-Signal Detector sensitivity */
	phyparam0 &= ~PHYPARAM0_REF_LOSLEVEL_MASK;
	phyparam0 |= PHYPARAM0_REF_LOSLEVEL;
	writel(phyparam0, regs + EXYNOS5_DRD_PHYPARAM0);

	writel(0x0, regs + EXYNOS5_DRD_PHYRESUME);

	/*
	 * Setting the Frame length Adj value[6:1] to default 0x20
	 * See xHCI 1.0 spec, 5.2.4
	 */
	linksystem = LINKSYSTEM_XHCI_VERSION_CONTROL |
			LINKSYSTEM_FLADJ(0x20);
	writel(linksystem, regs + EXYNOS5_DRD_LINKSYSTEM);

	phyparam1 = readl(regs + EXYNOS5_DRD_PHYPARAM1);
	/* Set Tx De-Emphasis level */
	phyparam1 &= ~PHYPARAM1_PCS_TXDEEMPH_MASK;
	phyparam1 |= PHYPARAM1_PCS_TXDEEMPH;
	writel(phyparam1, regs + EXYNOS5_DRD_PHYPARAM1);

	phybatchg = readl(regs + EXYNOS5_DRD_PHYBATCHG);
	phybatchg |= PHYBATCHG_UTMI_CLKSEL;
	writel(phybatchg, regs + EXYNOS5_DRD_PHYBATCHG);

	/* PHYTEST POWERDOWN Control */
	phytest = readl(regs + EXYNOS5_DRD_PHYTEST);
	phytest &= ~(PHYTEST_POWERDOWN_SSP |
			PHYTEST_POWERDOWN_HSP);
	writel(phytest, regs + EXYNOS5_DRD_PHYTEST);

	/* UTMI Power Control */
	writel(PHYUTMI_OTGDISABLE, regs + EXYNOS5_DRD_PHYUTMI);

	phyclkrst = samsung_usb3phy_set_refclk(sphy);

	phyclkrst |= PHYCLKRST_PORTRESET |
			/* Digital power supply in normal operating mode */
			PHYCLKRST_RETENABLEN |
			/* Enable ref clock for SS function */
			PHYCLKRST_REF_SSP_EN |
			/* Enable spread spectrum */
			PHYCLKRST_SSC_EN |
			/* Power down HS Bias and PLL blocks in suspend mode */
			PHYCLKRST_COMMONONN;

	writel(phyclkrst, regs + EXYNOS5_DRD_PHYCLKRST);

	udelay(10);

	phyclkrst &= ~(PHYCLKRST_PORTRESET);
	writel(phyclkrst, regs + EXYNOS5_DRD_PHYCLKRST);

	return 0;
}

static void samsung_exynos5_usb3phy_disable(struct samsung_usbphy *sphy)
{
	u32 phyutmi;
	u32 phyclkrst;
	u32 phytest;
	void __iomem *regs = sphy->regs;

	phyutmi = PHYUTMI_OTGDISABLE |
			PHYUTMI_FORCESUSPEND |
			PHYUTMI_FORCESLEEP;
	writel(phyutmi, regs + EXYNOS5_DRD_PHYUTMI);

	/* Resetting the PHYCLKRST enable bits to reduce leakage current */
	phyclkrst = readl(regs + EXYNOS5_DRD_PHYCLKRST);
	phyclkrst &= ~(PHYCLKRST_REF_SSP_EN |
			PHYCLKRST_SSC_EN |
			PHYCLKRST_COMMONONN);
	writel(phyclkrst, regs + EXYNOS5_DRD_PHYCLKRST);

	/* Control PHYTEST to remove leakage current */
	phytest = readl(regs + EXYNOS5_DRD_PHYTEST);
	phytest |= (PHYTEST_POWERDOWN_SSP |
			PHYTEST_POWERDOWN_HSP);
	writel(phytest, regs + EXYNOS5_DRD_PHYTEST);
}

static int samsung_usb3phy_init(struct usb_phy *phy)
{
	struct samsung_usbphy *sphy;
	unsigned long flags;
	int ret = 0;

	sphy = phy_to_sphy(phy);

	/* Enable the phy clock */
	ret = clk_prepare_enable(sphy->clk);
	if (ret) {
		dev_err(sphy->dev, "%s: clk_prepare_enable failed\n", __func__);
		return ret;
	}

	spin_lock_irqsave(&sphy->lock, flags);

	/* setting default phy-type for USB 3.0 */
	samsung_usbphy_set_type(&sphy->phy, USB_PHY_TYPE_DEVICE);

	/* Disable phy isolation */
	samsung_usbphy_set_isolation(sphy, false);

	/* Initialize usb phy registers */
	samsung_exynos5_usb3phy_enable(sphy);

	spin_unlock_irqrestore(&sphy->lock, flags);

	/* Disable the phy clock */
	clk_disable_unprepare(sphy->clk);

	return ret;
}

/*
 * The function passed to the usb driver for phy shutdown
 */
static void samsung_usb3phy_shutdown(struct usb_phy *phy)
{
	struct samsung_usbphy *sphy;
	unsigned long flags;

	sphy = phy_to_sphy(phy);

	if (clk_prepare_enable(sphy->clk)) {
		dev_err(sphy->dev, "%s: clk_prepare_enable failed\n", __func__);
		return;
	}

	spin_lock_irqsave(&sphy->lock, flags);

	/* setting default phy-type for USB 3.0 */
	samsung_usbphy_set_type(&sphy->phy, USB_PHY_TYPE_DEVICE);

	/* De-initialize usb phy registers */
	samsung_exynos5_usb3phy_disable(sphy);

	/* Enable phy isolation */
	samsung_usbphy_set_isolation(sphy, true);

	spin_unlock_irqrestore(&sphy->lock, flags);

	clk_disable_unprepare(sphy->clk);
}

static int samsung_usb3phy_probe(struct platform_device *pdev)
{
	struct samsung_usbphy *sphy;
	struct samsung_usbphy_data *pdata = pdev->dev.platform_data;
	struct device *dev = &pdev->dev;
	struct resource *phy_mem;
	void __iomem	*phy_base;
	struct clk *clk;
	int ret;

	phy_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!phy_mem) {
		dev_err(dev, "%s: missing mem resource\n", __func__);
		return -ENODEV;
	}

	phy_base = devm_ioremap_resource(dev, phy_mem);
	if (IS_ERR(phy_base))
		return PTR_ERR(phy_base);

	sphy = devm_kzalloc(dev, sizeof(*sphy), GFP_KERNEL);
	if (!sphy)
		return -ENOMEM;

	clk = devm_clk_get(dev, "usbdrd30");
	if (IS_ERR(clk)) {
		dev_err(dev, "Failed to get device clock\n");
		return PTR_ERR(clk);
	}

	sphy->dev = dev;

	if (dev->of_node) {
		ret = samsung_usbphy_parse_dt(sphy);
		if (ret < 0)
			return ret;
	} else {
		if (!pdata) {
			dev_err(dev, "no platform data specified\n");
			return -EINVAL;
		}
	}

	sphy->plat		= pdata;
	sphy->regs		= phy_base;
	sphy->clk		= clk;
	sphy->phy.dev		= sphy->dev;
	sphy->phy.label		= "samsung-usb3phy";
	sphy->phy.init		= samsung_usb3phy_init;
	sphy->phy.shutdown	= samsung_usb3phy_shutdown;
	sphy->drv_data		= samsung_usbphy_get_driver_data(pdev);
	sphy->ref_clk_freq	= samsung_usbphy_get_refclk_freq(sphy);

	spin_lock_init(&sphy->lock);

	platform_set_drvdata(pdev, sphy);

	return usb_add_phy(&sphy->phy, USB_PHY_TYPE_USB3);
}

static int samsung_usb3phy_remove(struct platform_device *pdev)
{
	struct samsung_usbphy *sphy = platform_get_drvdata(pdev);

	usb_remove_phy(&sphy->phy);

	if (sphy->pmuregs)
		iounmap(sphy->pmuregs);
	if (sphy->sysreg)
		iounmap(sphy->sysreg);

	return 0;
}

static struct samsung_usbphy_drvdata usb3phy_exynos5 = {
	.cpu_type		= TYPE_EXYNOS5250,
	.devphy_en_mask		= EXYNOS_USBPHY_ENABLE,
};

#ifdef CONFIG_OF
static const struct of_device_id samsung_usbphy_dt_match[] = {
	{
		.compatible = "samsung,exynos5250-usb3phy",
		.data = &usb3phy_exynos5
	},
	{},
};
MODULE_DEVICE_TABLE(of, samsung_usbphy_dt_match);
#endif

static struct platform_device_id samsung_usbphy_driver_ids[] = {
	{
		.name		= "exynos5250-usb3phy",
		.driver_data	= (unsigned long)&usb3phy_exynos5,
	},
	{},
};

MODULE_DEVICE_TABLE(platform, samsung_usbphy_driver_ids);

static struct platform_driver samsung_usb3phy_driver = {
	.probe		= samsung_usb3phy_probe,
	.remove		= samsung_usb3phy_remove,
	.id_table	= samsung_usbphy_driver_ids,
	.driver		= {
		.name	= "samsung-usb3phy",
		.owner	= THIS_MODULE,
		.of_match_table = of_match_ptr(samsung_usbphy_dt_match),
	},
};

module_platform_driver(samsung_usb3phy_driver);

MODULE_DESCRIPTION("Samsung USB 3.0 phy controller");
MODULE_AUTHOR("Vivek Gautam <gautam.vivek@samsung.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:samsung-usb3phy");