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/delay.h>
  14 #include <linux/time64.h>
  15 #include <linux/ulpi/regs.h>
  16
  17 #include "core.h"
  18 #include "io.h"
  19
  20 #define DWC3_ULPI_ADDR(a) \
  21                 ((a >= ULPI_EXT_VENDOR_SPECIFIC) ? \
  22                 DWC3_GUSB2PHYACC_ADDR(ULPI_ACCESS_EXTENDED) | \
  23                 DWC3_GUSB2PHYACC_EXTEND_ADDR(a) : DWC3_GUSB2PHYACC_ADDR(a))
  24
  25 #define DWC3_ULPI_BASE_DELAY    DIV_ROUND_UP(NSEC_PER_SEC, 60000000L)
  26
  27 static int dwc3_ulpi_busyloop(struct dwc3 *dwc, u8 addr, bool read)
  28 {
  29         unsigned long ns = 5L * DWC3_ULPI_BASE_DELAY;
  30         unsigned int count = 1000;
  31         u32 reg;
  32
  33         if (addr >= ULPI_EXT_VENDOR_SPECIFIC)
  34                 ns += DWC3_ULPI_BASE_DELAY;
  35
  36         if (read)
  37                 ns += DWC3_ULPI_BASE_DELAY;
  38
  39         while (count--) {
  40                 ndelay(ns);
  41                 reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
  42                 if (!(reg & DWC3_GUSB2PHYACC_BUSY))
  43                         return 0;
  44                 cpu_relax();
  45         }
  46
  47         return -ETIMEDOUT;
  48 }
  49
  50 static int dwc3_ulpi_read(struct device *dev, u8 addr)
  51 {
  52         struct dwc3 *dwc = dev_get_drvdata(dev);
  53         u32 reg;
  54         int ret;
  55
  56         reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
  57         dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg);
  58
  59         ret = dwc3_ulpi_busyloop(dwc, addr, true);
  60         if (ret)
  61                 return ret;
  62
  63         reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
  64
  65         return DWC3_GUSB2PHYACC_DATA(reg);
  66 }
  67
  68 static int dwc3_ulpi_write(struct device *dev, u8 addr, u8 val)
  69 {
  70         struct dwc3 *dwc = dev_get_drvdata(dev);
  71         u32 reg;
  72
  73         reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
  74         reg |= DWC3_GUSB2PHYACC_WRITE | val;
  75         dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg);
  76
  77         return dwc3_ulpi_busyloop(dwc, addr, false);
  78 }
  79
  80 static const struct ulpi_ops dwc3_ulpi_ops = {
  81         .read = dwc3_ulpi_read,
  82         .write = dwc3_ulpi_write,
  83 };
  84
  85 int dwc3_ulpi_init(struct dwc3 *dwc)
  86 {
  87         /* Register the interface */
  88         dwc->ulpi = ulpi_register_interface(dwc->dev, &dwc3_ulpi_ops);
  89         if (IS_ERR(dwc->ulpi)) {
  90                 dev_err(dwc->dev, "failed to register ULPI interface");
  91                 return PTR_ERR(dwc->ulpi);
  92         }
  93
  94         return 0;
  95 }
  96
  97 void dwc3_ulpi_exit(struct dwc3 *dwc)
  98 {
  99         if (dwc->ulpi) {
 100                 ulpi_unregister_interface(dwc->ulpi);
 101                 dwc->ulpi = NULL;
 102         }
 103 }