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 <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/otg/Kconfig

···
 	  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

drivers/usb/otg/Makefile

···
 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

drivers/usb/otg/ulpi_viewport.c

···
+/*
+ * 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,
+};

include/linux/usb/ulpi.h

···
 struct otg_transceiver *otg_ulpi_create(struct otg_io_access_ops *ops,
 					unsigned int flags);
 
+#ifdef CONFIG_USB_ULPI_VIEWPORT
+/* access ops for controllers with a viewport register */
+extern struct otg_io_access_ops ulpi_viewport_access_ops;
+#endif
+
 #endif /* __LINUX_USB_ULPI_H */