drivers/usb/phy/phy-ulpi-viewport.c

   1 /*
   2  * Copyright (C) 2011 Google, Inc.
   3  *
   4  * This software is licensed under the terms of the GNU General Public
   5  * License version 2, as published by the Free Software Foundation, and
   6  * may be copied, distributed, and modified under those terms.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include <linux/export.h>
  16 #include <linux/kernel.h>
  17 #include <linux/usb.h>
  18 #include <linux/io.h>
  19 #include <linux/usb/otg.h>
  20 #include <linux/usb/ulpi.h>
  21
  22 #define ULPI_VIEW_WAKEUP        (1 << 31)
  23 #define ULPI_VIEW_RUN           (1 << 30)
  24 #define ULPI_VIEW_WRITE         (1 << 29)
  25 #define ULPI_VIEW_READ          (0 << 29)
  26 #define ULPI_VIEW_ADDR(x)       (((x) & 0xff) << 16)
  27 #define ULPI_VIEW_DATA_READ(x)  (((x) >> 8) & 0xff)
  28 #define ULPI_VIEW_DATA_WRITE(x) ((x) & 0xff)
  29
  30 static int ulpi_viewport_wait(void __iomem *view, u32 mask)
  31 {
  32         unsigned long usec = 2000;
  33
  34         while (usec--) {
  35                 if (!(readl(view) & mask))
  36                         return 0;
  37
  38                 udelay(1);
  39         }
  40
  41         return -ETIMEDOUT;
  42 }
  43
  44 static int ulpi_viewport_read(struct usb_phy *otg, u32 reg)
  45 {
  46         int ret;
  47         void __iomem *view = otg->io_priv;
  48
  49         writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
  50         ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
  51         if (ret)
  52                 return ret;
  53
  54         writel(ULPI_VIEW_RUN | ULPI_VIEW_READ | ULPI_VIEW_ADDR(reg), view);
  55         ret = ulpi_viewport_wait(view, ULPI_VIEW_RUN);
  56         if (ret)
  57                 return ret;
  58
  59         return ULPI_VIEW_DATA_READ(readl(view));
  60 }
  61
  62 static int ulpi_viewport_write(struct usb_phy *otg, u32 val, u32 reg)
  63 {
  64         int ret;
  65         void __iomem *view = otg->io_priv;
  66
  67         writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
  68         ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
  69         if (ret)
  70                 return ret;
  71
  72         writel(ULPI_VIEW_RUN | ULPI_VIEW_WRITE | ULPI_VIEW_DATA_WRITE(val) |
  73                                                  ULPI_VIEW_ADDR(reg), view);
  74
  75         return ulpi_viewport_wait(view, ULPI_VIEW_RUN);
  76 }
  77
  78 struct usb_phy_io_ops ulpi_viewport_access_ops = {
  79         .read   = ulpi_viewport_read,
  80         .write  = ulpi_viewport_write,
  81 };
  82 EXPORT_SYMBOL_GPL(ulpi_viewport_access_ops);