usb: otg: Add ulpi viewport access ops

Add generic access ops for controllers with a ulpi viewport register
(e.g. Chipidea/ARC based controllers).

Signed-off-by: Benoit Goby <benoit@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 88 insertions, 0 deletions

diff --git a/drivers/usb/otg/Kconfig b/drivers/usb/otg/Kconfig
index ceb24fee2ea..daf3e5f1a0e 100644
--- a/drivers/usb/otg/Kconfig
+++ b/drivers/usb/otg/Kconfig
@@ -49,6 +49,13 @@ config USB_ULPI
           Enable this to support ULPI connected USB OTG transceivers which
           are likely found on embedded boards.
 
+config USB_ULPI_VIEWPORT
+        bool
+        depends on USB_ULPI
+        help
+          Provides read/write operations to the ULPI phy register set for
+          controllers with a viewport register (e.g. Chipidea/ARC controllers).
+
 config TWL4030_USB
         tristate "TWL4030 USB Transceiver Driver"
         depends on TWL4030_CORE && REGULATOR_TWL4030
diff --git a/drivers/usb/otg/Makefile b/drivers/usb/otg/Makefile
index e516894260b..e22d917de01 100644
--- a/drivers/usb/otg/Makefile
+++ b/drivers/usb/otg/Makefile
@@ -16,5 +16,6 @@ obj-$(CONFIG_TWL6030_USB)	+= twl6030-usb.o
 obj-$(CONFIG_USB_LANGWELL_OTG)  += langwell_otg.o
 obj-$(CONFIG_NOP_USB_XCEIV)     += nop-usb-xceiv.o
 obj-$(CONFIG_USB_ULPI)          += ulpi.o
+obj-$(CONFIG_USB_ULPI_VIEWPORT) += ulpi_viewport.o
 obj-$(CONFIG_USB_MSM_OTG)       += msm_otg.o
 obj-$(CONFIG_AB8500_USB)        += ab8500-usb.o
diff --git a/drivers/usb/otg/ulpi_viewport.c b/drivers/usb/otg/ulpi_viewport.c
new file mode 100644
index 00000000000..e9a37f90994
--- /dev/null
+++ b/drivers/usb/otg/ulpi_viewport.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/usb.h>
+#include <linux/io.h>
+#include <linux/usb/otg.h>
+#include <linux/usb/ulpi.h>
+
+#define ULPI_VIEW_WAKEUP        (1 << 31)
+#define ULPI_VIEW_RUN           (1 << 30)
+#define ULPI_VIEW_WRITE         (1 << 29)
+#define ULPI_VIEW_READ          (0 << 29)
+#define ULPI_VIEW_ADDR(x)       (((x) & 0xff) << 16)
+#define ULPI_VIEW_DATA_READ(x)  (((x) >> 8) & 0xff)
+#define ULPI_VIEW_DATA_WRITE(x) ((x) & 0xff)
+
+static int ulpi_viewport_wait(void __iomem *view, u32 mask)
+{
+        unsigned long usec = 2000;
+
+        while (usec--) {
+                if (!(readl(view) & mask))
+                        return 0;
+
+                udelay(1);
+        };
+
+        return -ETIMEDOUT;
+}
+
+static int ulpi_viewport_read(struct otg_transceiver *otg, u32 reg)
+{
+        int ret;
+        void __iomem *view = otg->io_priv;
+
+        writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
+        ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
+        if (ret)
+                return ret;
+
+        writel(ULPI_VIEW_RUN | ULPI_VIEW_READ | ULPI_VIEW_ADDR(reg), view);
+        ret = ulpi_viewport_wait(view, ULPI_VIEW_RUN);
+        if (ret)
+                return ret;
+
+        return ULPI_VIEW_DATA_READ(readl(view));
+}
+
+static int ulpi_viewport_write(struct otg_transceiver *otg, u32 val, u32 reg)
+{
+        int ret;
+        void __iomem *view = otg->io_priv;
+
+        writel(ULPI_VIEW_WAKEUP | ULPI_VIEW_WRITE, view);
+        ret = ulpi_viewport_wait(view, ULPI_VIEW_WAKEUP);
+        if (ret)
+                return ret;
+
+        writel(ULPI_VIEW_RUN | ULPI_VIEW_WRITE | ULPI_VIEW_DATA_WRITE(val) |
+                                                 ULPI_VIEW_ADDR(reg), view);
+
+        return ulpi_viewport_wait(view, ULPI_VIEW_RUN);
+}
+
+struct otg_io_access_ops ulpi_viewport_access_ops = {
+        .read   = ulpi_viewport_read,
+        .write  = ulpi_viewport_write,
+};