USB: Add driver for NXP ISP1301 USB transceiver

This new driver registers the NXP ISP1301 chip via the I2C subsystem.  The chip
is the USB transceiver shared by ohci-nxp, lpc32xx_udc (gadget) and
isp1301_omap.

ISP1301 is a very low-level driver that primarily separates out the I2C client
registration of the ISP1301 chip (including instantiation via DT), used by
other drivers, and declares the chip's registers. It's only a helper driver for
some OHCI and USB device drivers.  The driver can be considered as a register
set extension of ohci-nxp, lpc32xx-udc and isp1301_omap, which in turn know
best what to do with the low level functionality (individual ISP1301 registers
and timing, see the different initialization strategies in those drivers).
Those drivers previously internally duplicated ISP1301 register definitions
which is solved by this new isp1301 driver. The ISP1301 registers exposed via
isp1301.h can be accessed by other drivers using it with standard i2c_smbus_*()
accesses.

Following patches let the respective USB host and gadget drivers use this
driver, instead of duplicating ISP1301 handling.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

5 files changed, 104 insertions, 0 deletions

diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index 76316a3..4473ae5 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -177,6 +177,8 @@ source "drivers/usb/serial/Kconfig"
 
 source "drivers/usb/misc/Kconfig"
 
+source "drivers/usb/phy/Kconfig"
+
 source "drivers/usb/atm/Kconfig"
 
 source "drivers/usb/gadget/Kconfig"
diff --git a/drivers/usb/Makefile b/drivers/usb/Makefile
index 53a7bc0..77c835a 100644
--- a/drivers/usb/Makefile
+++ b/drivers/usb/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_USB_MICROTEK)	+= image/
 obj-$(CONFIG_USB_SERIAL)	+= serial/
 
 obj-$(CONFIG_USB)		+= misc/
+obj-$(CONFIG_USB)		+= phy/
 obj-$(CONFIG_EARLY_PRINTK_DBGP)	+= early/
 
 obj-$(CONFIG_USB_ATM)		+= atm/
diff --git a/drivers/usb/phy/Kconfig b/drivers/usb/phy/Kconfig
new file mode 100644
index 0000000..3cfabcb
--- /dev/null
+++ b/drivers/usb/phy/Kconfig
@@ -0,0 +1,17 @@
+#
+# Physical Layer USB driver configuration
+#
+comment "USB Physical Layer drivers"
+	depends on USB
+
+config USB_ISP1301
+	tristate "NXP ISP1301 USB transceiver support"
+	depends on USB
+	depends on I2C
+	help
+	  Say Y here to add support for the NXP ISP1301 USB transceiver driver.
+	  This chip is typically used as USB transceiver for USB host, gadget
+	  and OTG drivers (to be selected separately).
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called isp1301.
diff --git a/drivers/usb/phy/Makefile b/drivers/usb/phy/Makefile
new file mode 100644
index 0000000..eca095b
--- /dev/null
+++ b/drivers/usb/phy/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for physical layer USB drivers
+#
+
+ccflags-$(CONFIG_USB_DEBUG) := -DDEBUG
+
+obj-$(CONFIG_USB_ISP1301)		+= isp1301.o
diff --git a/drivers/usb/phy/isp1301.c b/drivers/usb/phy/isp1301.c
new file mode 100644
index 0000000..b19f493
--- /dev/null
+++ b/drivers/usb/phy/isp1301.c
@@ -0,0 +1,77 @@
+/*
+ * NXP ISP1301 USB transceiver driver
+ *
+ * Copyright (C) 2012 Roland Stigge
+ *
+ * Author: Roland Stigge <stigge@antcom.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+
+#define DRV_NAME		"isp1301"
+
+#define ISP1301_I2C_ADDR	0x2C
+
+static const unsigned short normal_i2c[] = {
+	ISP1301_I2C_ADDR, ISP1301_I2C_ADDR + 1, I2C_CLIENT_END
+};
+
+static const struct i2c_device_id isp1301_id[] = {
+	{ "isp1301", 0 },
+	{ }
+};
+
+static struct i2c_client *isp1301_i2c_client;
+
+static int isp1301_probe(struct i2c_client *client,
+			 const struct i2c_device_id *i2c_id)
+{
+	isp1301_i2c_client = client;
+	return 0;
+}
+
+static int isp1301_remove(struct i2c_client *client)
+{
+	return 0;
+}
+
+static struct i2c_driver isp1301_driver = {
+	.driver = {
+		.name = DRV_NAME,
+	},
+	.probe = isp1301_probe,
+	.remove = isp1301_remove,
+	.id_table = isp1301_id,
+};
+
+module_i2c_driver(isp1301_driver);
+
+static int match(struct device *dev, void *data)
+{
+	struct device_node *node = (struct device_node *)data;
+	return (dev->of_node == node) &&
+		(dev->driver == &isp1301_driver.driver);
+}
+
+struct i2c_client *isp1301_get_client(struct device_node *node)
+{
+	if (node) { /* reference of ISP1301 I2C node via DT */
+		struct device *dev = bus_find_device(&i2c_bus_type, NULL,
+						     node, match);
+		if (!dev)
+			return NULL;
+		return to_i2c_client(dev);
+	} else { /* non-DT: only one ISP1301 chip supported */
+		return isp1301_i2c_client;
+	}
+}
+EXPORT_SYMBOL_GPL(isp1301_get_client);
+
+MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
+MODULE_DESCRIPTION("NXP ISP1301 USB transceiver driver");
+MODULE_LICENSE("GPL");