kernel/drivers/usb/dwc3/ulpi.c

   1 /**
   2  * ulpi.c - DesignWare USB3 Controller's ULPI PHY interface
   3  *
   4  * Copyright (C) 2015 Intel Corporation
   5  *
   6  * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/ulpi/regs.h>
  14
  15 #include "core.h"
  16 #include "io.h"
  17
  18 #define DWC3_ULPI_ADDR(a) \
  19                 ((a >= ULPI_EXT_VENDOR_SPECIFIC) ? \
  20                 DWC3_GUSB2PHYACC_ADDR(ULPI_ACCESS_EXTENDED) | \
  21                 DWC3_GUSB2PHYACC_EXTEND_ADDR(a) : DWC3_GUSB2PHYACC_ADDR(a))
  22
  23 static int dwc3_ulpi_busyloop(struct dwc3 *dwc)
  24 {
  25         unsigned count = 1000;
  26         u32 reg;
  27
  28         while (count--) {
  29                 reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
  30                 if (!(reg & DWC3_GUSB2PHYACC_BUSY))
  31                         return 0;
  32                 cpu_relax();
  33         }
  34
  35         return -ETIMEDOUT;
  36 }
  37
  38 static int dwc3_ulpi_read(struct ulpi_ops *ops, u8 addr)
  39 {
  40         struct dwc3 *dwc = dev_get_drvdata(ops->dev);
  41         u32 reg;
  42         int ret;
  43
  44         reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
  45         dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg);
  46
  47         ret = dwc3_ulpi_busyloop(dwc);
  48         if (ret)
  49                 return ret;
  50
  51         reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
  52
  53         return DWC3_GUSB2PHYACC_DATA(reg);
  54 }
  55
  56 static int dwc3_ulpi_write(struct ulpi_ops *ops, u8 addr, u8 val)
  57 {
  58         struct dwc3 *dwc = dev_get_drvdata(ops->dev);
  59         u32 reg;
  60
  61         reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
  62         reg |= DWC3_GUSB2PHYACC_WRITE | val;
  63         dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg);
  64
  65         return dwc3_ulpi_busyloop(dwc);
  66 }
  67
  68 static struct ulpi_ops dwc3_ulpi_ops = {
  69         .read = dwc3_ulpi_read,
  70         .write = dwc3_ulpi_write,
  71 };
  72
  73 int dwc3_ulpi_init(struct dwc3 *dwc)
  74 {
  75         /* Register the interface */
  76         dwc->ulpi = ulpi_register_interface(dwc->dev, &dwc3_ulpi_ops);
  77         if (IS_ERR(dwc->ulpi)) {
  78                 dev_err(dwc->dev, "failed to register ULPI interface");
  79                 return PTR_ERR(dwc->ulpi);
  80         }
  81
  82         return 0;
  83 }
  84
  85 void dwc3_ulpi_exit(struct dwc3 *dwc)
  86 {
  87         if (dwc->ulpi) {
  88                 ulpi_unregister_interface(dwc->ulpi);
  89                 dwc->ulpi = NULL;
  90         }
  91 }