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>

1 files changed, 80 insertions, 0 deletions

diff --git a/drivers/usb/otg/ulpi_viewport.c b/drivers/usb/otg/ulpi_viewport.c
new file mode 100644
index 000000000000..e9a37f90994f
--- /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,
+};