text: #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/err.h>
  #include <linux/of.h>
  #include <linux/io.h>
  #include <linux/delay.h>
  #include "am35x-phy-control.h"
  
  struct am335x_control_usb {
  	struct device *dev;
  	void __iomem *phy_reg;
  	void __iomem *wkup;
  	spinlock_t lock;
  	struct phy_control phy_ctrl;
  };
  
  #define AM335X_USB0_CTRL		0x0
  #define AM335X_USB1_CTRL		0x8
  #define AM335x_USB_WKUP			0x0
  
  #define USBPHY_CM_PWRDN		(1 << 0)
  #define USBPHY_OTG_PWRDN	(1 << 1)
  #define USBPHY_OTGVDET_EN	(1 << 19)
  #define USBPHY_OTGSESSEND_EN	(1 << 20)
  
  #define AM335X_PHY0_WK_EN	(1 << 0)
  #define AM335X_PHY1_WK_EN	(1 << 8)
  
  static void am335x_phy_wkup(struct  phy_control *phy_ctrl, u32 id, bool on)
  {
  	struct am335x_control_usb *usb_ctrl;
  	u32 val;
  	u32 reg;
  
  	usb_ctrl = container_of(phy_ctrl, struct am335x_control_usb, phy_ctrl);
  
  	switch (id) {
  	case 0:
  		reg = AM335X_PHY0_WK_EN;
  		break;
  	case 1:
  		reg = AM335X_PHY1_WK_EN;
  		break;
  	default:
  		WARN_ON(1);
  		return;
  	}
  
  	spin_lock(&usb_ctrl->lock);
  	val = readl(usb_ctrl->wkup);
  
  	if (on)
  		val |= reg;
  	else
  		val &= ~reg;
  
  	writel(val, usb_ctrl->wkup);
  	spin_unlock(&usb_ctrl->lock);
  }
  
  static void am335x_phy_power(struct phy_control *phy_ctrl, u32 id, bool on)
  {
  	struct am335x_control_usb *usb_ctrl;
  	u32 val;
  	u32 reg;
  
  	usb_ctrl = container_of(phy_ctrl, struct am335x_control_usb, phy_ctrl);
  
  	switch (id) {
  	case 0:
  		reg = AM335X_USB0_CTRL;
  		break;
  	case 1:
  		reg = AM335X_USB1_CTRL;
  		break;
  	default:
  		WARN_ON(1);
  		return;
  	}
  
  	val = readl(usb_ctrl->phy_reg + reg);
  	if (on) {
  		val &= ~(USBPHY_CM_PWRDN | USBPHY_OTG_PWRDN);
  		val |= USBPHY_OTGVDET_EN | USBPHY_OTGSESSEND_EN;
  	} else {
  		val |= USBPHY_CM_PWRDN | USBPHY_OTG_PWRDN;
  	}
  
  	writel(val, usb_ctrl->phy_reg + reg);
  
  	/*
  	 * Give the PHY ~1ms to complete the power up operation.
  	 * Tests have shown unstable behaviour if other USB PHY related
  	 * registers are written too shortly after such a transition.
  	 */
  	if (on)
  		mdelay(1);
  }
  
  static const struct phy_control ctrl_am335x = {
  	.phy_power = am335x_phy_power,
  	.phy_wkup = am335x_phy_wkup,
  };
  
  static const struct of_device_id omap_control_usb_id_table[] = {
  	{ .compatible = "ti,am335x-usb-ctrl-module", .data = &ctrl_am335x },
  	{}
  };
  MODULE_DEVICE_TABLE(of, omap_control_usb_id_table);
  
  static struct platform_driver am335x_control_driver;
  static int match(struct device *dev, void *data)
  {
  	struct device_node *node = (struct device_node *)data;
  	return dev->of_node == node &&
  		dev->driver == &am335x_control_driver.driver;
  }
  
  struct phy_control *am335x_get_phy_control(struct device *dev)
  {
  	struct device_node *node;
  	struct am335x_control_usb *ctrl_usb;
  
  	node = of_parse_phandle(dev->of_node, "ti,ctrl_mod", 0);
  	if (!node)
  		return NULL;
  
  	dev = bus_find_device(&platform_bus_type, NULL, node, match);
  	ctrl_usb = dev_get_drvdata(dev);
  	if (!ctrl_usb)
  		return NULL;
  	return &ctrl_usb->phy_ctrl;
  }
  EXPORT_SYMBOL_GPL(am335x_get_phy_control);
  
  static int am335x_control_usb_probe(struct platform_device *pdev)
  {
  	struct resource	*res;
  	struct am335x_control_usb *ctrl_usb;
  	const struct of_device_id *of_id;
  	const struct phy_control *phy_ctrl;
  
  	of_id = of_match_node(omap_control_usb_id_table, pdev->dev.of_node);
  	if (!of_id)
  		return -EINVAL;
  
  	phy_ctrl = of_id->data;
  
  	ctrl_usb = devm_kzalloc(&pdev->dev, sizeof(*ctrl_usb), GFP_KERNEL);
  	if (!ctrl_usb) {
  		dev_err(&pdev->dev, "unable to alloc memory for control usb\n");
  		return -ENOMEM;
  	}
  
  	ctrl_usb->dev = &pdev->dev;
  
  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "phy_ctrl");
  	ctrl_usb->phy_reg = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(ctrl_usb->phy_reg))
  		return PTR_ERR(ctrl_usb->phy_reg);
  
  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "wakeup");
  	ctrl_usb->wkup = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(ctrl_usb->wkup))
  		return PTR_ERR(ctrl_usb->wkup);
  
  	spin_lock_init(&ctrl_usb->lock);
  	ctrl_usb->phy_ctrl = *phy_ctrl;
  
  	dev_set_drvdata(ctrl_usb->dev, ctrl_usb);
  	return 0;
  }
  
  static struct platform_driver am335x_control_driver = {
  	.probe		= am335x_control_usb_probe,
  	.driver		= {
  		.name	= "am335x-control-usb",
  		.owner	= THIS_MODULE,
  		.of_match_table = omap_control_usb_id_table,
  	},
  };
  
  module_platform_driver(am335x_control_driver);
  MODULE_LICENSE("GPL v2");
  