text: // SPDX-License-Identifier: GPL-2.0+
  /*
   * phy-keystone - USB PHY, talking to dwc3 controller in Keystone.
   *
   * Copyright (C) 2013 Texas Instruments Incorporated - https://www.ti.com
   *
   * Author: WingMan Kwok <w-kwok2@ti.com>
   */
  
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/usb/usb_phy_generic.h>
  #include <linux/io.h>
  #include <linux/of.h>
  
  #include "phy-generic.h"
  
  /* USB PHY control register offsets */
  #define USB_PHY_CTL_UTMI		0x0000
  #define USB_PHY_CTL_PIPE		0x0004
  #define USB_PHY_CTL_PARAM_1		0x0008
  #define USB_PHY_CTL_PARAM_2		0x000c
  #define USB_PHY_CTL_CLOCK		0x0010
  #define USB_PHY_CTL_PLL			0x0014
  
  #define PHY_REF_SSP_EN			BIT(29)
  
  struct keystone_usbphy {
  	struct usb_phy_generic	usb_phy_gen;
  	void __iomem			*phy_ctrl;
  };
  
  static inline u32 keystone_usbphy_readl(void __iomem *base, u32 offset)
  {
  	return readl(base + offset);
  }
  
  static inline void keystone_usbphy_writel(void __iomem *base,
  					  u32 offset, u32 value)
  {
  	writel(value, base + offset);
  }
  
  static int keystone_usbphy_init(struct usb_phy *phy)
  {
  	struct keystone_usbphy *k_phy = dev_get_drvdata(phy->dev);
  	u32 val;
  
  	val  = keystone_usbphy_readl(k_phy->phy_ctrl, USB_PHY_CTL_CLOCK);
  	keystone_usbphy_writel(k_phy->phy_ctrl, USB_PHY_CTL_CLOCK,
  				val | PHY_REF_SSP_EN);
  	return 0;
  }
  
  static void keystone_usbphy_shutdown(struct usb_phy *phy)
  {
  	struct keystone_usbphy *k_phy = dev_get_drvdata(phy->dev);
  	u32 val;
  
  	val  = keystone_usbphy_readl(k_phy->phy_ctrl, USB_PHY_CTL_CLOCK);
  	keystone_usbphy_writel(k_phy->phy_ctrl, USB_PHY_CTL_CLOCK,
  				val &= ~PHY_REF_SSP_EN);
  }
  
  static int keystone_usbphy_probe(struct platform_device *pdev)
  {
  	struct device		*dev = &pdev->dev;
  	struct keystone_usbphy	*k_phy;
  	int ret;
  
  	k_phy = devm_kzalloc(dev, sizeof(*k_phy), GFP_KERNEL);
  	if (!k_phy)
  		return -ENOMEM;
  
  	k_phy->phy_ctrl = devm_platform_ioremap_resource(pdev, 0);
  	if (IS_ERR(k_phy->phy_ctrl))
  		return PTR_ERR(k_phy->phy_ctrl);
  
  	ret = usb_phy_gen_create_phy(dev, &k_phy->usb_phy_gen);
  	if (ret)
  		return ret;
  
  	k_phy->usb_phy_gen.phy.init = keystone_usbphy_init;
  	k_phy->usb_phy_gen.phy.shutdown = keystone_usbphy_shutdown;
  
  	platform_set_drvdata(pdev, k_phy);
  
  	return usb_add_phy_dev(&k_phy->usb_phy_gen.phy);
  }
  
  static int keystone_usbphy_remove(struct platform_device *pdev)
  {
  	struct keystone_usbphy *k_phy = platform_get_drvdata(pdev);
  
  	usb_remove_phy(&k_phy->usb_phy_gen.phy);
  
  	return 0;
  }
  
  static const struct of_device_id keystone_usbphy_ids[] = {
  	{ .compatible = "ti,keystone-usbphy" },
  	{ }
  };
  MODULE_DEVICE_TABLE(of, keystone_usbphy_ids);
  
  static struct platform_driver keystone_usbphy_driver = {
  	.probe          = keystone_usbphy_probe,
  	.remove         = keystone_usbphy_remove,
  	.driver         = {
  		.name   = "keystone-usbphy",
  		.of_match_table = keystone_usbphy_ids,
  	},
  };
  
  module_platform_driver(keystone_usbphy_driver);
  
  MODULE_ALIAS("platform:keystone-usbphy");
  MODULE_AUTHOR("Texas Instruments Inc.");
  MODULE_DESCRIPTION("Keystone USB phy driver");
  MODULE_LICENSE("GPL v2");
  