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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2011 Google, Inc.
   4  */
   5
   6 #include <linux/export.h>
   7 #include <linux/kernel.h>
   8 #include <linux/usb.h>
   9 #include <linux/io.h>
  10 #include <linux/iopoll.h>
  11 #include <linux/usb/otg.h>
  12 #include <linux/usb/ulpi.h>
  13
  14 #define ULPI_VIEW_WAKEUP        (1 << 31)
  15 #define ULPI_VIEW_RUN           (1 << 30)
  16 #define ULPI_VIEW_WRITE         (1 << 29)
  17 #define ULPI_VIEW_READ          (0 << 29)
  18 #define ULPI_VIEW_ADDR(x)       (((x) & 0xff) << 16)
  19 #define ULPI_VIEW_DATA_READ(x)  (((x) >> 8) & 0xff)
  20 #define ULPI_VIEW_DATA_WRITE(x) ((x) & 0xff)
  21
  22 static int ulpi_viewport_wait(void __iomem *view, u32 mask)
  23 {
  24         u32 val;
  25
  26         return readl_poll_timeout_atomic(view, val, !(val & mask), 1, 2000);
  27 }
  28
  29 static int ulpi_viewport_read(struct usb_phy *otg, u32 reg)
  30 {
  31         int ret;
  32         void __iomem *view = otg->io_priv;
  33
  34         writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
  35         ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
  36         if (ret)
  37                 return ret;
  38
  39         writel(ULPI_VIEW_RUN | ULPI_VIEW_READ | ULPI_VIEW_ADDR(reg), view);
  40         ret = ulpi_viewport_wait(view, ULPI_VIEW_RUN);
  41         if (ret)
  42                 return ret;
  43
  44         return ULPI_VIEW_DATA_READ(readl(view));
  45 }
  46
  47 static int ulpi_viewport_write(struct usb_phy *otg, u32 val, u32 reg)
  48 {
  49         int ret;
  50         void __iomem *view = otg->io_priv;
  51
  52         writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
  53         ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
  54         if (ret)
  55                 return ret;
  56
  57         writel(ULPI_VIEW_RUN | ULPI_VIEW_WRITE | ULPI_VIEW_DATA_WRITE(val) |
  58                                                  ULPI_VIEW_ADDR(reg), view);
  59
  60         return ulpi_viewport_wait(view, ULPI_VIEW_RUN);
  61 }
  62
  63 struct usb_phy_io_ops ulpi_viewport_access_ops = {
  64         .read   = ulpi_viewport_read,
  65         .write  = ulpi_viewport_write,
  66 };
  67 EXPORT_SYMBOL_GPL(ulpi_viewport_access_ops);