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/usb/otg.h>
  11 #include <linux/usb/ulpi.h>
  12
  13 #define ULPI_VIEW_WAKEUP        (1 << 31)
  14 #define ULPI_VIEW_RUN           (1 << 30)
  15 #define ULPI_VIEW_WRITE         (1 << 29)
  16 #define ULPI_VIEW_READ          (0 << 29)
  17 #define ULPI_VIEW_ADDR(x)       (((x) & 0xff) << 16)
  18 #define ULPI_VIEW_DATA_READ(x)  (((x) >> 8) & 0xff)
  19 #define ULPI_VIEW_DATA_WRITE(x) ((x) & 0xff)
  20
  21 static int ulpi_viewport_wait(void __iomem *view, u32 mask)
  22 {
  23         unsigned long usec = 2000;
  24
  25         while (usec--) {
  26                 if (!(readl(view) & mask))
  27                         return 0;
  28
  29                 udelay(1);
  30         }
  31
  32         return -ETIMEDOUT;
  33 }
  34
  35 static int ulpi_viewport_read(struct usb_phy *otg, u32 reg)
  36 {
  37         int ret;
  38         void __iomem *view = otg->io_priv;
  39
  40         writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
  41         ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
  42         if (ret)
  43                 return ret;
  44
  45         writel(ULPI_VIEW_RUN | ULPI_VIEW_READ | ULPI_VIEW_ADDR(reg), view);
  46         ret = ulpi_viewport_wait(view, ULPI_VIEW_RUN);
  47         if (ret)
  48                 return ret;
  49
  50         return ULPI_VIEW_DATA_READ(readl(view));
  51 }
  52
  53 static int ulpi_viewport_write(struct usb_phy *otg, u32 val, u32 reg)
  54 {
  55         int ret;
  56         void __iomem *view = otg->io_priv;
  57
  58         writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
  59         ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
  60         if (ret)
  61                 return ret;
  62
  63         writel(ULPI_VIEW_RUN | ULPI_VIEW_WRITE | ULPI_VIEW_DATA_WRITE(val) |
  64                                                  ULPI_VIEW_ADDR(reg), view);
  65
  66         return ulpi_viewport_wait(view, ULPI_VIEW_RUN);
  67 }
  68
  69 struct usb_phy_io_ops ulpi_viewport_access_ops = {
  70         .read   = ulpi_viewport_read,
  71         .write  = ulpi_viewport_write,
  72 };
  73 EXPORT_SYMBOL_GPL(ulpi_viewport_access_ops);