/*
   * Renesas R-Car USB phy driver
   *
   * Copyright (C) 2012-2013 Renesas Solutions Corp.
   * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
   * Copyright (C) 2013 Cogent Embedded, Inc.
   *
   * 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/delay.h>
  #include <linux/io.h>
  #include <linux/usb/otg.h>
  #include <linux/platform_device.h>
  #include <linux/spinlock.h>
  #include <linux/module.h>
  #include <linux/platform_data/usb-rcar-phy.h>
  
  /* REGS block */
  #define USBPCTRL0	0x00
  #define USBPCTRL1	0x04
  #define USBST		0x08
  #define USBEH0		0x0C
  #define USBOH0		0x1C
  #define USBCTL0		0x58
  
  /* High-speed signal quality characteristic control registers (R8A7778 only) */
  #define HSQCTL1		0x24
  #define HSQCTL2		0x28
  
  /* USBPCTRL0 */
  #define OVC2		(1 << 10) /* (R8A7779 only)			*/
  				/* Switches the OVC input pin for port 2: */
  				/* 1: USB_OVC2, 0: OVC2			*/
  #define OVC1_VBUS1	(1 << 9) /* Switches the OVC input pin for port 1: */
  				/* 1: USB_OVC1, 0: OVC1/VBUS1		*/
  				/* Function mode: set to 0		*/
  #define OVC0		(1 << 8) /* Switches the OVC input pin for port 0: */
  				/* 1: USB_OVC0 pin, 0: OVC0		*/
  #define OVC2_ACT 	(1 << 6) /* (R8A7779 only)			*/
  				/* Host mode: OVC2 polarity:		*/
  				/* 1: active-high, 0: active-low	*/
  #define PENC		(1 << 4) /* Function mode: output level of PENC1 pin: */
  				/* 1: high, 0: low			*/
  #define OVC0_ACT 	(1 << 3) /* Host mode: OVC0 polarity:		*/
  				/* 1: active-high, 0: active-low	*/
  #define OVC1_ACT	(1 << 1) /* Host mode: OVC1 polarity:		*/
  				/* 1: active-high, 0: active-low	*/
  				/* Function mode: be sure to set to 1	*/
  #define PORT1		(1 << 0) /* Selects port 1 mode:		*/
  				/* 1: function, 0: host			*/
  /* USBPCTRL1 */
  #define PHY_RST		(1 << 2)
  #define PLL_ENB		(1 << 1)
  #define PHY_ENB		(1 << 0)
  
  /* USBST */
  #define ST_ACT		(1 << 31)
  #define ST_PLL		(1 << 30)
  
  struct rcar_usb_phy_priv {
  	struct usb_phy phy;
  	spinlock_t lock;
  
  	void __iomem *reg0;
  	void __iomem *reg1;
  	int counter;
  };
  
  #define usb_phy_to_priv(p) container_of(p, struct rcar_usb_phy_priv, phy)
  
  
  /*
   * USB initial/install operation.
   *
   * This function setup USB phy.
   * The used value and setting order came from
   * [USB :: Initial setting] on datasheet.
   */
  static int rcar_usb_phy_init(struct usb_phy *phy)
  {
  	struct rcar_usb_phy_priv *priv = usb_phy_to_priv(phy);
  	struct device *dev = phy->dev;
  	struct rcar_phy_platform_data *pdata = dev_get_platdata(dev);
  	void __iomem *reg0 = priv->reg0;
  	void __iomem *reg1 = priv->reg1;
  	static const u8 ovcn_act[] = { OVC0_ACT, OVC1_ACT, OVC2_ACT };
  	int i;
  	u32 val;
  	unsigned long flags;
  
  	spin_lock_irqsave(&priv->lock, flags);
  	if (priv->counter++ == 0) {
  
  		/*
  		 * USB phy start-up
  		 */
  
  		/* (1) USB-PHY standby release */
  		iowrite32(PHY_ENB, (reg0 + USBPCTRL1));
  
  		/* (2) start USB-PHY internal PLL */
  		iowrite32(PHY_ENB | PLL_ENB, (reg0 + USBPCTRL1));
  
  		/* (3) set USB-PHY in accord with the conditions of usage */
  		if (reg1) {
  			u32 hsqctl1 = pdata->ferrite_bead ? 0x41 : 0;
  			u32 hsqctl2 = pdata->ferrite_bead ? 0x0d : 7;
  
  			iowrite32(hsqctl1, reg1 + HSQCTL1);
  			iowrite32(hsqctl2, reg1 + HSQCTL2);
  		}
  
  		/* (4) USB module status check */
  		for (i = 0; i < 1024; i++) {
  			udelay(10);
  			val = ioread32(reg0 + USBST);
  			if (val == (ST_ACT | ST_PLL))
  				break;
  		}
  
  		if (val != (ST_ACT | ST_PLL)) {
  			dev_err(dev, "USB phy not ready
  ");
  			goto phy_init_end;
  		}
  
  		/* (5) USB-PHY reset clear */
  		iowrite32(PHY_ENB | PLL_ENB | PHY_RST, (reg0 + USBPCTRL1));
  
  		/* Board specific port settings */
  		val = 0;
  		if (pdata->port1_func)
  			val |= PORT1;
  		if (pdata->penc1)
  			val |= PENC;
  		for (i = 0; i < 3; i++) {
  			/* OVCn bits follow each other in the right order */
  			if (pdata->ovc_pin[i].select_3_3v)
  				val |= OVC0 << i;
  			/* OVCn_ACT bits are spaced by irregular intervals */
  			if (pdata->ovc_pin[i].active_high)
  				val |= ovcn_act[i];
  		}
  		iowrite32(val, (reg0 + USBPCTRL0));
  
  		/*
  		 * Bus alignment settings
  		 */
  
  		/* (1) EHCI bus alignment (little endian) */
  		iowrite32(0x00000000, (reg0 + USBEH0));
  
  		/* (1) OHCI bus alignment (little endian) */
  		iowrite32(0x00000000, (reg0 + USBOH0));
  	}
  
  phy_init_end:
  	spin_unlock_irqrestore(&priv->lock, flags);
  
  	return 0;
  }
  
  static void rcar_usb_phy_shutdown(struct usb_phy *phy)
  {
  	struct rcar_usb_phy_priv *priv = usb_phy_to_priv(phy);
  	void __iomem *reg0 = priv->reg0;
  	unsigned long flags;
  
  	spin_lock_irqsave(&priv->lock, flags);
  
  	if (priv->counter-- == 1)	/* last user */
  		iowrite32(0x00000000, (reg0 + USBPCTRL1));
  
  	spin_unlock_irqrestore(&priv->lock, flags);
  }
  
  static int rcar_usb_phy_probe(struct platform_device *pdev)
  {
  	struct rcar_usb_phy_priv *priv;
  	struct resource *res0, *res1;
  	struct device *dev = &pdev->dev;
  	void __iomem *reg0, *reg1 = NULL;
  	int ret;
  
  	if (!dev_get_platdata(&pdev->dev)) {
  		dev_err(dev, "No platform data
  ");
  		return -EINVAL;
  	}
  
  	res0 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	reg0 = devm_ioremap_resource(dev, res0);
  	if (IS_ERR(reg0))
  		return PTR_ERR(reg0);
  
  	res1 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
  	if (res1) {
  		reg1 = devm_ioremap_resource(dev, res1);
  		if (IS_ERR(reg1))
  			return PTR_ERR(reg1);
  	}
  
  	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  	if (!priv) {
  		dev_err(dev, "priv data allocation error
  ");
  		return -ENOMEM;
  	}
  
  	priv->reg0		= reg0;
  	priv->reg1		= reg1;
  	priv->counter		= 0;
  	priv->phy.dev		= dev;
  	priv->phy.label		= dev_name(dev);
  	priv->phy.init		= rcar_usb_phy_init;
  	priv->phy.shutdown	= rcar_usb_phy_shutdown;
  	spin_lock_init(&priv->lock);
  
  	ret = usb_add_phy(&priv->phy, USB_PHY_TYPE_USB2);
  	if (ret < 0) {
  		dev_err(dev, "usb phy addition error
  ");
  		return ret;
  	}
  
  	platform_set_drvdata(pdev, priv);
  
  	return ret;
  }
  
  static int rcar_usb_phy_remove(struct platform_device *pdev)
  {
  	struct rcar_usb_phy_priv *priv = platform_get_drvdata(pdev);
  
  	usb_remove_phy(&priv->phy);
  
  	return 0;
  }
  
  static struct platform_driver rcar_usb_phy_driver = {
  	.driver		= {
  		.name	= "rcar_usb_phy",
  	},
  	.probe		= rcar_usb_phy_probe,
  	.remove		= rcar_usb_phy_remove,
  };
  
  module_platform_driver(rcar_usb_phy_driver);
  
  MODULE_LICENSE("GPL v2");
  MODULE_DESCRIPTION("Renesas R-Car USB phy");
  MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");