[PATCH] USB: isp1301_omap driver (OTG core)

This adds the isp1301_omap driver, supporting USB OTG on OMAP systems.
The driver tightly couples two different chunks of hardware, which are
used to implement the OTG protocols:

 - The Philips ISP1301 OTG transceiver (an I2C device) senses voltage
   levels and sources VBUS current in the A-Device roles.

 - OMAP's OTG controller handles lots of OTG transitions, and
   tells the transceiver what to do.

The driver implements the abstract "otg_transceiver" API, since it's got to
talk to both the host controller (OHCI on current OMAPs) and the peripheral
controller (omap_udc) while hiding a variety of implementation details.  It
should be easy to tweak to work on other OMAP boards using the isp1301 chip;
OMAP boards with other transceivers, or non-OMAP boards using isp1301, will
probably find things to learn from.

Note that this also supports two non-OTG modes, with the OTG controller
disabled; very handy for debugging just the host side USB stack, or just the
peripheral side USB stack.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/i2c/chips/Kconfig

@@ -299,4 +299,16 @@ config SENSORS_RTC8564
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-rtc8564.
 
+config ISP1301_OMAP
+	tristate "Philips ISP1301 with OMAP OTG"
+	depends on I2C && ARCH_OMAP_OTG
+	help
+	  If you say yes here you get support for the Philips ISP1301
+	  USB-On-The-Go transceiver working with the OMAP OTG controller.
+	  The ISP1301 is used in products including H2 and H3 development
+	  boards for Texas Instruments OMAP processors.
+	  
+	  This driver can also be built as a module.  If so, the module
+	  will be called isp1301_omap.
+
 endmenu

drivers/i2c/chips/Makefile

@@ -29,7 +29,9 @@ obj-$(CONFIG_SENSORS_RTC8564)	+= rtc8564.o
 obj-$(CONFIG_SENSORS_SMSC47M1)	+= smsc47m1.o
 obj-$(CONFIG_SENSORS_VIA686A)	+= via686a.o
 obj-$(CONFIG_SENSORS_W83L785TS)	+= w83l785ts.o
+obj-$(CONFIG_ISP1301_OMAP)	+= isp1301_omap.o
 
 ifeq ($(CONFIG_I2C_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG
 endif
+

drivers/i2c/chips/isp1301_omap.c

+/*
+ * isp1301_omap - ISP 1301 USB transceiver, talking to OMAP OTG controller
+ *
+ * Copyright (C) 2004 Texas Instruments
+ * Copyright (C) 2004 David Brownell
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#undef	DEBUG
+#undef	VERBOSE
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/usb_ch9.h>
+#include <linux/usb_gadget.h>
+#include <linux/usb.h>
+#include <linux/usb_otg.h>
+#include <linux/i2c.h>
+#include <linux/workqueue.h>
+
+#include <asm/irq.h>
+#include <asm/arch/usb.h>
+
+
+#ifndef	DEBUG
+#undef	VERBOSE
+#endif
+
+
+#define	DRIVER_VERSION	"24 August 2004"
+#define	DRIVER_NAME	(isp1301_driver.name)
+
+MODULE_DESCRIPTION("ISP1301 USB OTG Transceiver Driver");
+MODULE_LICENSE("GPL");
+
+struct isp1301 {
+	struct otg_transceiver	otg;
+	struct i2c_client	client;
+	void			(*i2c_release)(struct device *dev);
+
+	int			irq;
+
+	u32			last_otg_ctrl;
+	unsigned		working:1;
+
+	struct timer_list	timer;
+
+	/* use keventd context to change the state for us */
+	struct work_struct	work;
+	
+	unsigned long		todo;
+#		define WORK_UPDATE_ISP	0	/* update ISP from OTG */
+#		define WORK_UPDATE_OTG	1	/* update OTG from ISP */
+#		define WORK_HOST_RESUME	4	/* resume host */
+#		define WORK_TIMER	6	/* timer fired */
+#		define WORK_STOP	7	/* don't resubmit */
+};
+
+
+/* bits in OTG_CTRL_REG */
+
+#define	OTG_XCEIV_OUTPUTS \
+	(OTG_ASESSVLD|OTG_BSESSEND|OTG_BSESSVLD|OTG_VBUSVLD|OTG_ID)
+#define	OTG_XCEIV_INPUTS \
+	(OTG_PULLDOWN|OTG_PULLUP|OTG_DRV_VBUS|OTG_PD_VBUS|OTG_PU_VBUS|OTG_PU_ID)
+#define	OTG_CTRL_BITS \
+	(OTG_A_BUSREQ|OTG_A_SETB_HNPEN|OTG_B_BUSREQ|OTG_B_HNPEN|OTG_BUSDROP)
+	/* and OTG_PULLUP is sometimes written */
+
+#define	OTG_CTRL_MASK	(OTG_DRIVER_SEL| \
+	OTG_XCEIV_OUTPUTS|OTG_XCEIV_INPUTS| \
+	OTG_CTRL_BITS)
+
+
+/*-------------------------------------------------------------------------*/
+
+#ifdef	CONFIG_MACH_OMAP_H2
+
+/* board-specific PM hooks */
+
+#include <asm/arch/gpio.h>
+#include <asm/arch/mux.h>
+#include <asm/mach-types.h>
+
+
+#if	defined(CONFIG_TPS65010) || defined(CONFIG_TPS65010_MODULE)
+
+#include <asm/arch/tps65010.h>
+
+#else
+
+static inline int tps65010_set_vbus_draw(unsigned mA)
+{
+	pr_debug("tps65010: draw %d mA (STUB)\n", mA);
+	return 0;
+}
+
+#endif
+
+static void enable_vbus_draw(struct isp1301 *isp, unsigned mA)
+{
+	int status = tps65010_set_vbus_draw(mA);
+	if (status < 0)
+		pr_debug("  VBUS %d mA error %d\n", mA, status);
+}
+
+static void enable_vbus_source(struct isp1301 *isp)
+{
+	/* this board won't supply more than 8mA vbus power.
+	 * some boards can switch a 100ma "unit load" (or more).
+	 */
+}
+
+
+/* products will deliver OTG messages with LEDs, GUI, etc */
+static inline void notresponding(struct isp1301 *isp)
+{
+	printk(KERN_NOTICE "OTG device not responding.\n");
+}
+
+
+#endif
+
+/*-------------------------------------------------------------------------*/
+
+/* only two addresses possible */
+#define	ISP_BASE		0x2c
+static unsigned short normal_i2c[] = {
+	ISP_BASE, ISP_BASE + 1,
+	I2C_CLIENT_END };
+static unsigned short normal_i2c_range[] = { I2C_CLIENT_END };
+
+I2C_CLIENT_INSMOD;
+
+static struct i2c_driver isp1301_driver;
+
+/* smbus apis are used for portability */
+
+static inline u8
+isp1301_get_u8(struct isp1301 *isp, u8 reg)
+{
+	return i2c_smbus_read_byte_data(&isp->client, reg + 0);
+}
+
+static inline int
+isp1301_get_u16(struct isp1301 *isp, u8 reg)
+{
+	return i2c_smbus_read_word_data(&isp->client, reg);
+}
+
+static inline int
+isp1301_set_bits(struct isp1301 *isp, u8 reg, u8 bits)
+{
+	return i2c_smbus_write_byte_data(&isp->client, reg + 0, bits);
+}
+
+static inline int
+isp1301_clear_bits(struct isp1301 *isp, u8 reg, u8 bits)
+{
+	return i2c_smbus_write_byte_data(&isp->client, reg + 1, bits);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* identification */
+#define	ISP1301_VENDOR_ID		0x00	/* u16 read */
+#define	ISP1301_PRODUCT_ID		0x02	/* u16 read */
+#define	ISP1301_BCD_DEVICE		0x14	/* u16 read */
+
+#define	I2C_VENDOR_ID_PHILIPS		0x04cc
+#define	I2C_PRODUCT_ID_PHILIPS_1301	0x1301
+
+/* operational registers */
+#define	ISP1301_MODE_CONTROL_1		0x04	/* u8 read, set, +1 clear */
+#	define	MC1_SPEED_REG		(1 << 0)
+#	define	MC1_SUSPEND_REG		(1 << 1)
+#	define	MC1_DAT_SE0		(1 << 2)
+#	define	MC1_TRANSPARENT		(1 << 3)
+#	define	MC1_BDIS_ACON_EN	(1 << 4)
+#	define	MC1_OE_INT_EN		(1 << 5)
+#	define	MC1_UART_EN		(1 << 6)
+#	define	MC1_MASK		0x7f
+#define	ISP1301_MODE_CONTROL_2		0x12	/* u8 read, set, +1 clear */
+#	define	MC2_GLOBAL_PWR_DN	(1 << 0)
+#	define	MC2_SPD_SUSP_CTRL	(1 << 1)
+#	define	MC2_BI_DI		(1 << 2)
+#	define	MC2_TRANSP_BDIR0	(1 << 3)
+#	define	MC2_TRANSP_BDIR1	(1 << 4)
+#	define	MC2_AUDIO_EN		(1 << 5)
+#	define	MC2_PSW_EN		(1 << 6)
+#	define	MC2_EN2V7		(1 << 7)
+#define	ISP1301_OTG_CONTROL_1		0x06	/* u8 read, set, +1 clear */
+#	define	OTG1_DP_PULLUP		(1 << 0)
+#	define	OTG1_DM_PULLUP		(1 << 1)
+#	define	OTG1_DP_PULLDOWN	(1 << 2)
+#	define	OTG1_DM_PULLDOWN	(1 << 3)
+#	define	OTG1_ID_PULLDOWN	(1 << 4)
+#	define	OTG1_VBUS_DRV		(1 << 5)
+#	define	OTG1_VBUS_DISCHRG	(1 << 6)
+#	define	OTG1_VBUS_CHRG		(1 << 7)
+#define	ISP1301_OTG_STATUS		0x10	/* u8 readonly */
+#	define	OTG_B_SESS_END		(1 << 6)
+#	define	OTG_B_SESS_VLD		(1 << 7)
+
+#define	ISP1301_INTERRUPT_SOURCE	0x08	/* u8 read */
+#define	ISP1301_INTERRUPT_LATCH		0x0A	/* u8 read, set, +1 clear */
+
+#define	ISP1301_INTERRUPT_FALLING	0x0C	/* u8 read, set, +1 clear */
+#define	ISP1301_INTERRUPT_RISING	0x0E	/* u8 read, set, +1 clear */
+
+/* same bitfields in all interrupt registers */
+#	define	INTR_VBUS_VLD		(1 << 0)
+#	define	INTR_SESS_VLD		(1 << 1)
+#	define	INTR_DP_HI		(1 << 2)
+#	define	INTR_ID_GND		(1 << 3)
+#	define	INTR_DM_HI		(1 << 4)
+#	define	INTR_ID_FLOAT		(1 << 5)
+#	define	INTR_BDIS_ACON		(1 << 6)
+#	define	INTR_CR_INT		(1 << 7)
+
+/*-------------------------------------------------------------------------*/
+
+static const char *state_string(enum usb_otg_state state)
+{
+	switch (state) {
+	case OTG_STATE_A_IDLE:		return "a_idle";
+	case OTG_STATE_A_WAIT_VRISE:	return "a_wait_vrise";
+	case OTG_STATE_A_WAIT_BCON:	return "a_wait_bcon";
+	case OTG_STATE_A_HOST:		return "a_host";
+	case OTG_STATE_A_SUSPEND:	return "a_suspend";
+	case OTG_STATE_A_PERIPHERAL:	return "a_peripheral";
+	case OTG_STATE_A_WAIT_VFALL:	return "a_wait_vfall";
+	case OTG_STATE_A_VBUS_ERR:	return "a_vbus_err";
+	case OTG_STATE_B_IDLE:		return "b_idle";
+	case OTG_STATE_B_SRP_INIT:	return "b_srp_init";
+	case OTG_STATE_B_PERIPHERAL:	return "b_peripheral";
+	case OTG_STATE_B_WAIT_ACON:	return "b_wait_acon";
+	case OTG_STATE_B_HOST:		return "b_host";
+	default:			return "UNDEFINED";
+	}
+}
+
+static inline const char *state_name(struct isp1301 *isp)
+{
+	return state_string(isp->otg.state);
+}
+
+#ifdef	VERBOSE
+#define	dev_vdbg			dev_dbg
+#else
+#define	dev_vdbg(dev, fmt, arg...)	do{}while(0)
+#endif
+
+/*-------------------------------------------------------------------------*/
+
+/* NOTE:  some of this ISP1301 setup is specific to H2 boards;
+ * not everything is guarded by board-specific checks, or even using
+ * omap_usb_config data to deduce MC1_DAT_SE0 and MC2_BI_DI.
+ *
+ * ALSO:  this currently doesn't use ISP1301 low-power modes
+ * while OTG is running.
+ */
+
+static void power_down(struct isp1301 *isp)
+{
+	isp->otg.state = OTG_STATE_UNDEFINED;
+
+	// isp1301_set_bits(isp, ISP1301_MODE_CONTROL_2, MC2_GLOBAL_PWR_DN);
+	isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1, MC1_SUSPEND_REG);
+
+	isp1301_clear_bits(isp, ISP1301_OTG_CONTROL_1, OTG1_ID_PULLDOWN);
+	isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_1, MC1_DAT_SE0);
+}
+
+static void power_up(struct isp1301 *isp)
+{
+	// isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_2, MC2_GLOBAL_PWR_DN);
+	isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_1, MC1_SUSPEND_REG);
+	
+	/* do this only when cpu is driving transceiver,
+	 * so host won't see a low speed device...
+	 */
+	isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1, MC1_DAT_SE0);
+}
+
+#define	NO_HOST_SUSPEND
+
+static int host_suspend(struct isp1301 *isp)
+{
+#ifdef	NO_HOST_SUSPEND
+	return 0;
+#else
+	struct device	*dev;
+
+	if (!isp->otg.host)
+		return -ENODEV;
+
+	/* Currently ASSUMES only the OTG port matters;
+	 * other ports could be active...
+	 */
+	dev = isp->otg.host->controller;
+	return dev->driver->suspend(dev, 3, 0);
+#endif
+}
+
+static int host_resume(struct isp1301 *isp)
+{
+#ifdef	NO_HOST_SUSPEND
+	return 0;
+#else
+	struct device	*dev;
+
+	if (!isp->otg.host)
+		return -ENODEV;
+
+	dev = isp->otg.host->controller;
+	return dev->driver->resume(dev, 0);
+#endif
+}
+
+static int gadget_suspend(struct isp1301 *isp)
+{
+	isp->otg.gadget->b_hnp_enable = 0;
+	isp->otg.gadget->a_hnp_support = 0;
+	isp->otg.gadget->a_alt_hnp_support = 0;
+	return usb_gadget_vbus_disconnect(isp->otg.gadget);
+}
+
+/*-------------------------------------------------------------------------*/
+
+#define	TIMER_MINUTES	10
+#define	TIMER_JIFFIES	(TIMER_MINUTES * 60 * HZ)
+
+/* Almost all our I2C messaging comes from a work queue's task context.
+ * NOTE: guaranteeing certain response times might mean we shouldn't
+ * share keventd's work queue; a realtime task might be safest.
+ */
+void
+isp1301_defer_work(struct isp1301 *isp, int work)
+{
+	int status;
+
+	if (isp && !test_and_set_bit(work, &isp->todo)) {
+		(void) get_device(&isp->client.dev);
+		status = schedule_work(&isp->work);
+		if (!status && !isp->working)
+			dev_vdbg(&isp->client.dev,
+				"work item %d may be lost\n", work);
+	}
+}
+
+/* called from irq handlers */
+static void a_idle(struct isp1301 *isp, const char *tag)
+{
+	if (isp->otg.state == OTG_STATE_A_IDLE)
+		return;
+
+	isp->otg.default_a = 1;
+	if (isp->otg.host) {
+		isp->otg.host->is_b_host = 0;
+		host_suspend(isp);
+	}
+	if (isp->otg.gadget) {
+		isp->otg.gadget->is_a_peripheral = 1;
+		gadget_suspend(isp);
+	}
+	isp->otg.state = OTG_STATE_A_IDLE;
+	isp->last_otg_ctrl = OTG_CTRL_REG = OTG_CTRL_REG & OTG_XCEIV_OUTPUTS;
+	pr_debug("  --> %s/%s\n", state_name(isp), tag);
+}
+
+/* called from irq handlers */
+static void b_idle(struct isp1301 *isp, const char *tag)
+{
+	if (isp->otg.state == OTG_STATE_B_IDLE)
+		return;
+
+	isp->otg.default_a = 0;
+	if (isp->otg.host) {
+		isp->otg.host->is_b_host = 1;
+		host_suspend(isp);
+	}
+	if (isp->otg.gadget) {
+		isp->otg.gadget->is_a_peripheral = 0;
+		gadget_suspend(isp);
+	}
+	isp->otg.state = OTG_STATE_B_IDLE;
+	isp->last_otg_ctrl = OTG_CTRL_REG = OTG_CTRL_REG & OTG_XCEIV_OUTPUTS;
+	pr_debug("  --> %s/%s\n", state_name(isp), tag);
+}
+
+static void
+dump_regs(struct isp1301 *isp, const char *label)
+{
+#ifdef	DEBUG
+	u8	ctrl = isp1301_get_u8(isp, ISP1301_OTG_CONTROL_1);
+	u8	status = isp1301_get_u8(isp, ISP1301_OTG_STATUS);
+	u8	src = isp1301_get_u8(isp, ISP1301_INTERRUPT_SOURCE);
+
+	pr_debug("otg: %06x, %s %s, otg/%02x stat/%02x.%02x\n",
+		OTG_CTRL_REG, label, state_name(isp),
+		ctrl, status, src);
+	/* mode control and irq enables don't change much */
+#endif
+}
+
+/*-------------------------------------------------------------------------*/
+
+#ifdef	CONFIG_USB_OTG
+
+/*
+ * The OMAP OTG controller handles most of the OTG state transitions.
+ *
+ * We translate isp1301 outputs (mostly voltage comparator status) into
+ * OTG inputs; OTG outputs (mostly pullup/pulldown controls) and HNP state
+ * flags into isp1301 inputs ... and infer state transitions.
+ */
+
+#ifdef	VERBOSE
+
+static void check_state(struct isp1301 *isp, const char *tag)
+{
+	enum usb_otg_state	state = OTG_STATE_UNDEFINED;
+	u8			fsm = OTG_TEST_REG & 0x0ff;
+	unsigned		extra = 0;
+
+	switch (fsm) {
+
+	/* default-b */
+	case 0x0:
+		state = OTG_STATE_B_IDLE;
+		break;
+	case 0x3:
+	case 0x7:
+		extra = 1;
+	case 0x1:
+		state = OTG_STATE_B_PERIPHERAL;
+		break;
+	case 0x11:
+		state = OTG_STATE_B_SRP_INIT;
+		break;
+
+	/* extra dual-role default-b states */
+	case 0x12:
+	case 0x13:
+	case 0x16:
+		extra = 1;
+	case 0x17:
+		state = OTG_STATE_B_WAIT_ACON;
+		break;
+	case 0x34:
+		state = OTG_STATE_B_HOST;
+		break;
+
+	/* default-a */
+	case 0x36:
+		state = OTG_STATE_A_IDLE;
+		break;
+	case 0x3c:
+		state = OTG_STATE_A_WAIT_VFALL;
+		break;
+	case 0x7d:
+		state = OTG_STATE_A_VBUS_ERR;
+		break;
+	case 0x9e:
+	case 0x9f:
+		extra = 1;
+	case 0x89:
+		state = OTG_STATE_A_PERIPHERAL;
+		break;
+	case 0xb7:
+		state = OTG_STATE_A_WAIT_VRISE;
+		break;
+	case 0xb8:
+		state = OTG_STATE_A_WAIT_BCON;
+		break;
+	case 0xb9:
+		state = OTG_STATE_A_HOST;
+		break;
+	case 0xba:
+		state = OTG_STATE_A_SUSPEND;
+		break;
+	default:
+		break;
+	}
+	if (isp->otg.state == state && !extra)
+		return;
+	pr_debug("otg: %s FSM %s/%02x, %s, %06x\n", tag,
+		state_string(state), fsm, state_name(isp), OTG_CTRL_REG);
+}
+
+#else
+
+static inline void check_state(struct isp1301 *isp, const char *tag) { }
+
+#endif
+
+/* outputs from ISP1301_INTERRUPT_SOURCE */
+static void update_otg1(struct isp1301 *isp, u8 int_src)
+{
+	u32	otg_ctrl;
+
+	otg_ctrl = OTG_CTRL_REG
+			& OTG_CTRL_MASK
+			& ~OTG_XCEIV_INPUTS
+			& ~(OTG_ID|OTG_ASESSVLD|OTG_VBUSVLD);
+	if (int_src & INTR_SESS_VLD)
+		otg_ctrl |= OTG_ASESSVLD;
+	else if (isp->otg.state == OTG_STATE_A_WAIT_VFALL) {
+		a_idle(isp, "vfall");
+		otg_ctrl &= ~OTG_CTRL_BITS;
+	}
+	if (int_src & INTR_VBUS_VLD)
+		otg_ctrl |= OTG_VBUSVLD;
+	if (int_src & INTR_ID_GND) {		/* default-A */
+		if (isp->otg.state == OTG_STATE_B_IDLE
+				|| isp->otg.state == OTG_STATE_UNDEFINED) {
+			a_idle(isp, "init");
+			return;
+		}
+	} else {				/* default-B */
+		otg_ctrl |= OTG_ID;
+		if (isp->otg.state == OTG_STATE_A_IDLE
+				|| isp->otg.state == OTG_STATE_UNDEFINED) {
+			b_idle(isp, "init");
+			return;
+		}
+	}
+	OTG_CTRL_REG = otg_ctrl;
+}
+
+/* outputs from ISP1301_OTG_STATUS */
+static void update_otg2(struct isp1301 *isp, u8 otg_status)
+{
+	u32	otg_ctrl;
+
+	otg_ctrl = OTG_CTRL_REG
+			& OTG_CTRL_MASK
+			& ~OTG_XCEIV_INPUTS
+			& ~(OTG_BSESSVLD|OTG_BSESSEND);
+	if (otg_status & OTG_B_SESS_VLD)
+		otg_ctrl |= OTG_BSESSVLD;
+	else if (otg_status & OTG_B_SESS_END)
+		otg_ctrl |= OTG_BSESSEND;
+	OTG_CTRL_REG = otg_ctrl;
+}
+
+/* inputs going to ISP1301 */
+static void otg_update_isp(struct isp1301 *isp)
+{
+	u32	otg_ctrl, otg_change;
+	u8	set = OTG1_DM_PULLDOWN, clr = OTG1_DM_PULLUP;
+
+	otg_ctrl = OTG_CTRL_REG;
+	otg_change = otg_ctrl ^ isp->last_otg_ctrl;
+	isp->last_otg_ctrl = otg_ctrl;
+	otg_ctrl = otg_ctrl & OTG_XCEIV_INPUTS;
+
+	switch (isp->otg.state) {
+	case OTG_STATE_B_IDLE:
+	case OTG_STATE_B_PERIPHERAL:
+	case OTG_STATE_B_SRP_INIT:
+		if (!(otg_ctrl & OTG_PULLUP)) {
+			// if (otg_ctrl & OTG_B_HNPEN) {
+			if (isp->otg.gadget->b_hnp_enable) {
+				isp->otg.state = OTG_STATE_B_WAIT_ACON;
+				pr_debug("  --> b_wait_acon\n");
+			}
+			goto pulldown;
+		}
+pullup:
+		set |= OTG1_DP_PULLUP;
+		clr |= OTG1_DP_PULLDOWN;
+		break;
+	case OTG_STATE_A_SUSPEND:
+	case OTG_STATE_A_PERIPHERAL:
+		if (otg_ctrl & OTG_PULLUP)
+			goto pullup;
+		/* FALLTHROUGH */
+	// case OTG_STATE_B_WAIT_ACON:
+	default:
+pulldown:
+		set |= OTG1_DP_PULLDOWN;
+		clr |= OTG1_DP_PULLUP;
+		break;
+	}
+
+#	define toggle(OTG,ISP) do { \
+		if (otg_ctrl & OTG) set |= ISP; \
+		else clr |= ISP; \
+		} while (0)
+
+	if (!(isp->otg.host))
+		otg_ctrl &= ~OTG_DRV_VBUS;
+
+	switch (isp->otg.state) {
+	case OTG_STATE_A_SUSPEND:
+		if (otg_ctrl & OTG_DRV_VBUS) {
+			set |= OTG1_VBUS_DRV;
+			break;
+		}
+		/* HNP failed for some reason (A_AIDL_BDIS timeout) */
+		notresponding(isp);
+
+		/* FALLTHROUGH */
+	case OTG_STATE_A_VBUS_ERR:
+		isp->otg.state = OTG_STATE_A_WAIT_VFALL;
+		pr_debug("  --> a_wait_vfall\n");
+		/* FALLTHROUGH */
+	case OTG_STATE_A_WAIT_VFALL:
+		/* FIXME usbcore thinks port power is still on ... */
+		clr |= OTG1_VBUS_DRV;
+		break;
+	case OTG_STATE_A_IDLE:
+		if (otg_ctrl & OTG_DRV_VBUS) {
+			isp->otg.state = OTG_STATE_A_WAIT_VRISE;
+			pr_debug("  --> a_wait_vrise\n");
+		}
+		/* FALLTHROUGH */
+	default:
+		toggle(OTG_DRV_VBUS, OTG1_VBUS_DRV);
+	}
+
+	toggle(OTG_PU_VBUS, OTG1_VBUS_CHRG);
+	toggle(OTG_PD_VBUS, OTG1_VBUS_DISCHRG);
+
+#	undef toggle
+
+	isp1301_set_bits(isp, ISP1301_OTG_CONTROL_1, set);
+	isp1301_clear_bits(isp, ISP1301_OTG_CONTROL_1, clr);
+
+	/* HNP switch to host or peripheral; and SRP */
+	if (otg_change & OTG_PULLUP) {
+		switch (isp->otg.state) {
+		case OTG_STATE_B_IDLE:
+			if (clr & OTG1_DP_PULLUP)
+				break;
+			isp->otg.state = OTG_STATE_B_PERIPHERAL;
+			pr_debug("  --> b_peripheral\n");
+			break;
+		case OTG_STATE_A_SUSPEND:
+			if (clr & OTG1_DP_PULLUP)
+				break;
+			isp->otg.state = OTG_STATE_A_PERIPHERAL;
+			pr_debug("  --> a_peripheral\n");
+			break;
+		default:
+			break;
+		}
+		OTG_CTRL_REG |= OTG_PULLUP;
+	}
+
+	check_state(isp, __FUNCTION__);
+	dump_regs(isp, "otg->isp1301");
+}
+
+static irqreturn_t omap_otg_irq(int irq, void *_isp, struct pt_regs *regs)
+{
+	u16		otg_irq = OTG_IRQ_SRC_REG;
+	u32		otg_ctrl;
+	int		ret = IRQ_NONE;
+	struct isp1301	*isp = _isp;
+
+	/* update ISP1301 transciever from OTG controller */
+	if (otg_irq & OPRT_CHG) {
+		OTG_IRQ_SRC_REG = OPRT_CHG;
+		isp1301_defer_work(isp, WORK_UPDATE_ISP);
+		ret = IRQ_HANDLED;
+
+	/* SRP to become b_peripheral failed */
+	} else if (otg_irq & B_SRP_TMROUT) {
+		pr_debug("otg: B_SRP_TIMEOUT, %06x\n", OTG_CTRL_REG);
+		notresponding(isp);
+
+		/* gadget drivers that care should monitor all kinds of
+		 * remote wakeup (SRP, normal) using their own timer
+		 * to give "check cable and A-device" messages.
+		 */
+		if (isp->otg.state == OTG_STATE_B_SRP_INIT)
+			b_idle(isp, "srp_timeout");
+
+		OTG_IRQ_SRC_REG = B_SRP_TMROUT;
+		ret = IRQ_HANDLED;
+
+	/* HNP to become b_host failed */
+	} else if (otg_irq & B_HNP_FAIL) {
+		pr_debug("otg: %s B_HNP_FAIL, %06x\n",
+				state_name(isp), OTG_CTRL_REG);
+		notresponding(isp);
+
+		otg_ctrl = OTG_CTRL_REG;
+		otg_ctrl |= OTG_BUSDROP;
+		otg_ctrl &= OTG_CTRL_MASK & ~OTG_XCEIV_INPUTS;
+		OTG_CTRL_REG = otg_ctrl;
+
+		/* subset of b_peripheral()... */
+		isp->otg.state = OTG_STATE_B_PERIPHERAL;
+		pr_debug("  --> b_peripheral\n");
+
+		OTG_IRQ_SRC_REG = B_HNP_FAIL;
+		ret = IRQ_HANDLED;
+
+	/* detect SRP from B-device ... */
+	} else if (otg_irq & A_SRP_DETECT) {
+		pr_debug("otg: %s SRP_DETECT, %06x\n",
+				state_name(isp), OTG_CTRL_REG);
+
+		isp1301_defer_work(isp, WORK_UPDATE_OTG);
+		switch (isp->otg.state) {
+		case OTG_STATE_A_IDLE:
+			if (!isp->otg.host)
+				break;
+			isp1301_defer_work(isp, WORK_HOST_RESUME);
+			otg_ctrl = OTG_CTRL_REG;
+			otg_ctrl |= OTG_A_BUSREQ;
+			otg_ctrl &= ~(OTG_BUSDROP|OTG_B_BUSREQ)
+					& ~OTG_XCEIV_INPUTS
+					& OTG_CTRL_MASK;
+			OTG_CTRL_REG = otg_ctrl;
+			break;
+		default:
+			break;
+		}
+
+		OTG_IRQ_SRC_REG = A_SRP_DETECT;
+		ret = IRQ_HANDLED;
+
+	/* timer expired:  T(a_wait_bcon) and maybe T(a_wait_vrise)
+	 * we don't track them separately
+	 */
+	} else if (otg_irq & A_REQ_TMROUT) {
+		otg_ctrl = OTG_CTRL_REG;
+		pr_info("otg: BCON_TMOUT from %s, %06x\n",
+				state_name(isp), otg_ctrl);
+		notresponding(isp);
+
+		otg_ctrl |= OTG_BUSDROP;
+		otg_ctrl &= ~OTG_A_BUSREQ & OTG_CTRL_MASK & ~OTG_XCEIV_INPUTS;
+		OTG_CTRL_REG = otg_ctrl;
+		isp->otg.state = OTG_STATE_A_WAIT_VFALL;
+
+		OTG_IRQ_SRC_REG = A_REQ_TMROUT;
+		ret = IRQ_HANDLED;
+
+	/* A-supplied voltage fell too low; overcurrent */
+	} else if (otg_irq & A_VBUS_ERR) {
+		otg_ctrl = OTG_CTRL_REG;
+		printk(KERN_ERR "otg: %s, VBUS_ERR %04x ctrl %06x\n",
+			state_name(isp), otg_irq, otg_ctrl);
+
+		otg_ctrl |= OTG_BUSDROP;
+		otg_ctrl &= ~OTG_A_BUSREQ & OTG_CTRL_MASK & ~OTG_XCEIV_INPUTS;
+		OTG_CTRL_REG = otg_ctrl;
+		isp->otg.state = OTG_STATE_A_VBUS_ERR;
+
+		OTG_IRQ_SRC_REG = A_VBUS_ERR;
+		ret = IRQ_HANDLED;
+
+	/* switch driver; the transciever code activates it,
+	 * ungating the udc clock or resuming OHCI.
+	 */
+	} else if (otg_irq & DRIVER_SWITCH) {
+		int	kick = 0;
+
+		otg_ctrl = OTG_CTRL_REG;
+		printk(KERN_NOTICE "otg: %s, SWITCH to %s, ctrl %06x\n",
+				state_name(isp),
+				(otg_ctrl & OTG_DRIVER_SEL)
+					? "gadget" : "host",
+				otg_ctrl);
+		isp1301_defer_work(isp, WORK_UPDATE_ISP);
+
+		/* role is peripheral */
+		if (otg_ctrl & OTG_DRIVER_SEL) {
+			switch (isp->otg.state) {
+			case OTG_STATE_A_IDLE:
+				b_idle(isp, __FUNCTION__);
+				break;
+			default:
+				break;
+			}
+			isp1301_defer_work(isp, WORK_UPDATE_ISP);
+
+		/* role is host */
+		} else {
+			if (!(otg_ctrl & OTG_ID)) {
+		 		otg_ctrl &= OTG_CTRL_MASK & ~OTG_XCEIV_INPUTS;
+				OTG_CTRL_REG = otg_ctrl | OTG_A_BUSREQ;
+			}
+
+			if (isp->otg.host) {
+				switch (isp->otg.state) {
+				case OTG_STATE_B_WAIT_ACON:
+					isp->otg.state = OTG_STATE_B_HOST;
+					pr_debug("  --> b_host\n");
+					kick = 1;
+					break;
+				case OTG_STATE_A_WAIT_BCON:
+					isp->otg.state = OTG_STATE_A_HOST;
+					pr_debug("  --> a_host\n");
+					break;
+				case OTG_STATE_A_PERIPHERAL:
+					isp->otg.state = OTG_STATE_A_WAIT_BCON;
+					pr_debug("  --> a_wait_bcon\n");
+					break;
+				default:
+					break;
+				}
+				isp1301_defer_work(isp, WORK_HOST_RESUME);
+			}
+		}
+
+		OTG_IRQ_SRC_REG = DRIVER_SWITCH;
+		ret = IRQ_HANDLED;
+
+		if (kick)
+			usb_bus_start_enum(isp->otg.host,
+						isp->otg.host->otg_port);
+	}
+
+	check_state(isp, __FUNCTION__);
+	return ret;
+}
+
+static struct platform_device *otg_dev;
+
+static int otg_init(struct isp1301 *isp)
+{
+	if (!otg_dev)
+		return -ENODEV;
+
+	dump_regs(isp, __FUNCTION__);
+	/* some of these values are board-specific... */
+	OTG_SYSCON_2_REG |= OTG_EN
+		/* for B-device: */
+		| SRP_GPDATA		/* 9msec Bdev D+ pulse */
+		| SRP_GPDVBUS		/* discharge after VBUS pulse */
+		// | (3 << 24)		/* 2msec VBUS pulse */
+		/* for A-device: */
+		| (0 << 20)		/* 200ms nominal A_WAIT_VRISE timer */
+		| SRP_DPW		/* detect 167+ns SRP pulses */
+		| SRP_DATA | SRP_VBUS	/* accept both kinds of SRP pulse */
+		;
+
+	update_otg1(isp, isp1301_get_u8(isp, ISP1301_INTERRUPT_SOURCE));
+	update_otg2(isp, isp1301_get_u8(isp, ISP1301_OTG_STATUS));
+
+	check_state(isp, __FUNCTION__);
+	pr_debug("otg: %s, %s %06x\n",
+			state_name(isp), __FUNCTION__, OTG_CTRL_REG);
+
+	OTG_IRQ_EN_REG = DRIVER_SWITCH | OPRT_CHG
+			| B_SRP_TMROUT | B_HNP_FAIL
+			| A_VBUS_ERR | A_SRP_DETECT | A_REQ_TMROUT;
+	OTG_SYSCON_2_REG |= OTG_EN;
+
+	return 0;
+}
+
+static int otg_probe(struct device *dev)
+{
+	// struct omap_usb_config *config = dev->platform_data;
+
+	otg_dev = to_platform_device(dev);
+	return 0;
+}
+
+static int otg_remove(struct device *dev)
+{
+	otg_dev = 0;
+	return 0;
+}
+
+struct device_driver omap_otg_driver = {
+	.name		= "omap_otg",
+	.bus		= &platform_bus_type,
+	.probe		= otg_probe,
+	.remove		= otg_remove,	
+};
+
+static int otg_bind(struct isp1301 *isp)
+{
+	int	status;
+
+	if (otg_dev)
+		return -EBUSY;
+
+	status = driver_register(&omap_otg_driver);
+	if (status < 0)
+		return status;
+
+	if (otg_dev)
+		status = request_irq(otg_dev->resource[1].start, omap_otg_irq,
+				SA_INTERRUPT, DRIVER_NAME, isp);
+	else
+		status = -ENODEV;
+
+	if (status < 0)
+		driver_unregister(&omap_otg_driver);
+	return status;
+}
+
+static void otg_unbind(struct isp1301 *isp)
+{
+	if (!otg_dev)
+		return;
+	free_irq(otg_dev->resource[1].start, isp);
+}
+
+#else
+
+/* OTG controller isn't clocked */
+
+#endif	/* CONFIG_USB_OTG */
+
+/*-------------------------------------------------------------------------*/
+
+static void b_peripheral(struct isp1301 *isp)
+{
+	enable_vbus_draw(isp, 8);
+	OTG_CTRL_REG = OTG_CTRL_REG & OTG_XCEIV_OUTPUTS;
+	usb_gadget_vbus_connect(isp->otg.gadget);
+
+#ifdef	CONFIG_USB_OTG
+	otg_update_isp(isp);
+#else
+	/* UDC driver just set OTG_BSESSVLD */
+	isp1301_set_bits(isp, ISP1301_OTG_CONTROL_1, OTG1_DP_PULLUP);
+	isp1301_clear_bits(isp, ISP1301_OTG_CONTROL_1, OTG1_DP_PULLDOWN);
+	isp->otg.state = OTG_STATE_B_PERIPHERAL;
+	pr_debug("  --> b_peripheral\n");
+	dump_regs(isp, "2periph");
+#endif
+}
+
+static int isp_update_otg(struct isp1301 *isp, u8 stat)
+{
+	u8			isp_stat, isp_bstat;
+	enum usb_otg_state	state = isp->otg.state;
+
+	if (stat & INTR_BDIS_ACON)
+		pr_debug("OTG:  BDIS_ACON, %s\n", state_name(isp));
+
+	/* start certain state transitions right away */
+	isp_stat = isp1301_get_u8(isp, ISP1301_INTERRUPT_SOURCE);
+	if (isp_stat & INTR_ID_GND) {
+		if (isp->otg.default_a) {
+			switch (state) {
+			case OTG_STATE_B_IDLE:
+				a_idle(isp, "idle");
+				/* FALLTHROUGH */
+			case OTG_STATE_A_IDLE:
+				enable_vbus_source(isp);
+				/* FALLTHROUGH */
+			case OTG_STATE_A_WAIT_VRISE:
+				/* we skip over OTG_STATE_A_WAIT_BCON, since
+				 * the HC will transition to A_HOST (or
+				 * A_SUSPEND!) without our noticing except
+				 * when HNP is used.
+				 */
+				if (isp_stat & INTR_VBUS_VLD)
+					isp->otg.state = OTG_STATE_A_HOST;
+				break;
+			case OTG_STATE_A_WAIT_VFALL:
+				if (!(isp_stat & INTR_SESS_VLD))
+					a_idle(isp, "vfell");
+				break;
+			default:
+				if (!(isp_stat & INTR_VBUS_VLD))
+					isp->otg.state = OTG_STATE_A_VBUS_ERR;
+				break;
+			}
+			isp_bstat = isp1301_get_u8(isp, ISP1301_OTG_STATUS);
+		} else {
+			switch (state) {
+			case OTG_STATE_B_PERIPHERAL:
+			case OTG_STATE_B_HOST:
+			case OTG_STATE_B_WAIT_ACON:
+				usb_gadget_vbus_disconnect(isp->otg.gadget);
+				break;
+			default:
+				break;
+			}
+			if (state != OTG_STATE_A_IDLE)
+				a_idle(isp, "id");
+			if (isp->otg.host && state == OTG_STATE_A_IDLE)
+				isp1301_defer_work(isp, WORK_HOST_RESUME);
+			isp_bstat = 0;
+		}
+	} else {
+		/* if user unplugged mini-A end of cable,
+		 * don't bypass A_WAIT_VFALL.
+		 */
+		if (isp->otg.default_a) {
+			switch (state) {
+			default:
+				isp->otg.state = OTG_STATE_A_WAIT_VFALL;
+				break;
+			case OTG_STATE_A_WAIT_VFALL:
+				state = OTG_STATE_A_IDLE;
+				/* khubd may take a while to notice and
+				 * handle this disconnect, so don't go
+				 * to B_IDLE quite yet.
+				 */
+				break;
+			case OTG_STATE_A_IDLE:
+				host_suspend(isp);
+				isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_1,
+						MC1_BDIS_ACON_EN);
+				isp->otg.state = OTG_STATE_B_IDLE;
+				OTG_CTRL_REG &= OTG_CTRL_REG & OTG_CTRL_MASK
+						& ~OTG_CTRL_BITS;
+				break;
+			case OTG_STATE_B_IDLE:
+				break;
+			}
+		}
+		isp_bstat = isp1301_get_u8(isp, ISP1301_OTG_STATUS);
+
+		switch (isp->otg.state) {
+		case OTG_STATE_B_PERIPHERAL:
+		case OTG_STATE_B_WAIT_ACON:
+		case OTG_STATE_B_HOST:
+			if (likely(isp_bstat & OTG_B_SESS_VLD))
+				break;
+			enable_vbus_draw(isp, 0);
+#ifndef	CONFIG_USB_OTG
+			/* UDC driver will clear OTG_BSESSVLD */
+			isp1301_set_bits(isp, ISP1301_OTG_CONTROL_1,
+						OTG1_DP_PULLDOWN);
+			isp1301_clear_bits(isp, ISP1301_OTG_CONTROL_1,
+						OTG1_DP_PULLUP);
+			dump_regs(isp, __FUNCTION__);
+#endif
+			/* FALLTHROUGH */
+		case OTG_STATE_B_SRP_INIT:
+			b_idle(isp, __FUNCTION__);
+			OTG_CTRL_REG &= OTG_CTRL_REG & OTG_XCEIV_OUTPUTS;
+			/* FALLTHROUGH */
+		case OTG_STATE_B_IDLE:
+			if (isp->otg.gadget && (isp_bstat & OTG_B_SESS_VLD)) {
+#ifdef	CONFIG_USB_OTG
+				update_otg1(isp, isp_stat);
+				update_otg2(isp, isp_bstat);
+#endif
+				b_peripheral(isp);
+			} else if (!(isp_stat & (INTR_VBUS_VLD|INTR_SESS_VLD)))
+				isp_bstat |= OTG_B_SESS_END;
+			break;
+		case OTG_STATE_A_WAIT_VFALL:
+			break;
+		default:
+			pr_debug("otg: unsupported b-device %s\n",
+				state_name(isp));
+			break;
+		}
+	}
+
+	if (state != isp->otg.state)
+		pr_debug("  isp, %s -> %s\n",
+				state_string(state), state_name(isp));
+
+#ifdef	CONFIG_USB_OTG
+	/* update the OTG controller state to match the isp1301; may
+	 * trigger OPRT_CHG irqs for changes going to the isp1301.
+	 */
+	update_otg1(isp, isp_stat);
+	update_otg2(isp, isp_bstat);
+	check_state(isp, __FUNCTION__);
+#endif
+
+	dump_regs(isp, "isp1301->otg");
+}
+
+/*-------------------------------------------------------------------------*/
+
+static u8 isp1301_clear_latch(struct isp1301 *isp)
+{
+	u8 latch = isp1301_get_u8(isp, ISP1301_INTERRUPT_LATCH);
+	isp1301_clear_bits(isp, ISP1301_INTERRUPT_LATCH, latch);
+	return latch;
+}
+
+static void
+isp1301_work(void *data)
+{
+	struct isp1301	*isp = data;
+	int		stop;
+
+	/* implicit lock:  we're the only task using this device */
+	isp->working = 1;
+	do {
+		stop = test_bit(WORK_STOP, &isp->todo);
+
+#ifdef	CONFIG_USB_OTG
+		/* transfer state from otg engine to isp1301 */
+		if (test_and_clear_bit(WORK_UPDATE_ISP, &isp->todo)) {
+			otg_update_isp(isp);
+			put_device(&isp->client.dev);
+		}
+#endif
+		/* transfer state from isp1301 to otg engine */
+		if (test_and_clear_bit(WORK_UPDATE_OTG, &isp->todo)) {
+			u8		stat = isp1301_clear_latch(isp);
+
+			isp_update_otg(isp, stat);
+			put_device(&isp->client.dev);
+		}
+
+		if (test_and_clear_bit(WORK_HOST_RESUME, &isp->todo)) {
+			u32	otg_ctrl;
+
+			/*
+			 * skip A_WAIT_VRISE; hc transitions invisibly
+			 * skip A_WAIT_BCON; same.
+			 */
+			switch (isp->otg.state) {
+			case OTG_STATE_A_WAIT_BCON:
+			case OTG_STATE_A_WAIT_VRISE:
+				isp->otg.state = OTG_STATE_A_HOST;
+				pr_debug("  --> a_host\n");
+				otg_ctrl = OTG_CTRL_REG;
+				otg_ctrl |= OTG_A_BUSREQ;
+				otg_ctrl &= ~(OTG_BUSDROP|OTG_B_BUSREQ)
+						& OTG_CTRL_MASK;
+				OTG_CTRL_REG = otg_ctrl;
+				break;
+			case OTG_STATE_B_WAIT_ACON:
+				isp->otg.state = OTG_STATE_B_HOST;
+				pr_debug("  --> b_host (acon)\n");
+				break;
+			case OTG_STATE_B_HOST:
+			case OTG_STATE_B_IDLE:
+			case OTG_STATE_A_IDLE:
+				break;
+			default:
+				pr_debug("  host resume in %s\n",
+						state_name(isp));
+			}
+			host_resume(isp);
+			// mdelay(10);
+			put_device(&isp->client.dev);
+		}
+
+		if (test_and_clear_bit(WORK_TIMER, &isp->todo)) {
+#ifdef	VERBOSE
+			dump_regs(isp, "timer");
+			if (!stop)
+				mod_timer(&isp->timer, jiffies + TIMER_JIFFIES);
+#endif
+			put_device(&isp->client.dev);
+		}
+
+		if (isp->todo)
+			dev_vdbg(&isp->client.dev,
+				"work done, todo = 0x%lx\n",
+				isp->todo);
+		if (stop) {
+			dev_dbg(&isp->client.dev, "stop\n");
+			break;
+		}
+	} while (isp->todo);
+	isp->working = 0;
+}
+
+static irqreturn_t isp1301_irq(int irq, void *isp, struct pt_regs *regs)
+{
+	isp1301_defer_work(isp, WORK_UPDATE_OTG);
+	return IRQ_HANDLED;
+}
+
+static void isp1301_timer(unsigned long _isp)
+{
+	isp1301_defer_work((void *)_isp, WORK_TIMER);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void isp1301_release(struct device *dev)
+{
+	struct isp1301	*isp;
+
+	isp = container_of(dev, struct isp1301, client.dev);
+
+	/* ugly -- i2c hijacks our memory hook to wait_for_completion() */
+	if (isp->i2c_release)
+		isp->i2c_release(dev);
+	kfree (isp);
+}
+
+static struct isp1301 *the_transceiver;
+
+static int isp1301_detach_client(struct i2c_client *i2c)
+{
+	struct isp1301	*isp;
+
+	isp = container_of(i2c, struct isp1301, client);
+
+	isp1301_clear_bits(isp, ISP1301_INTERRUPT_FALLING, ~0);
+	isp1301_clear_bits(isp, ISP1301_INTERRUPT_RISING, ~0);
+	free_irq(isp->irq, isp);
+#ifdef	CONFIG_USB_OTG
+	otg_unbind(isp);
+#endif
+	if (machine_is_omap_h2())
+		omap_free_gpio(2);
+
+	isp->timer.data = 0;
+	set_bit(WORK_STOP, &isp->todo);
+	del_timer_sync(&isp->timer);
+	flush_scheduled_work();
+
+	put_device(&i2c->dev);
+	the_transceiver = 0;
+
+	return i2c_detach_client(i2c);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* NOTE:  three modes are possible here, only one of which
+ * will be standards-conformant on any given system:
+ *
+ *  - OTG mode (dual-role), required if there's a Mini-AB connector
+ *  - HOST mode, for when there's one or more A (host) connectors
+ *  - DEVICE mode, for when there's a B/Mini-B (device) connector
+ *
+ * As a rule, you won't have an isp1301 chip unless it's there to
+ * support the OTG mode.  Other modes help testing USB controllers 
+ * in isolation from (full) OTG support, or maybe so later board
+ * revisions can help to support those feature.
+ */
+
+#ifdef	CONFIG_USB_OTG
+
+static int isp1301_otg_enable(struct isp1301 *isp)
+{
+	power_up(isp);
+	otg_init(isp);
+
+	/* NOTE:  since we don't change this, this provides
+	 * a few more interrupts than are strictly needed.
+	 */
+	isp1301_set_bits(isp, ISP1301_INTERRUPT_RISING,
+	 	INTR_VBUS_VLD | INTR_SESS_VLD | INTR_ID_GND);
+	isp1301_set_bits(isp, ISP1301_INTERRUPT_FALLING,
+	 	INTR_VBUS_VLD | INTR_SESS_VLD | INTR_ID_GND);
+
+	dev_info(&isp->client.dev, "ready for dual-role USB ...\n");
+
+	return 0;
+}
+
+#endif
+
+/* add or disable the host device+driver */
+static int
+isp1301_set_host(struct otg_transceiver *otg, struct usb_bus *host)
+{
+	struct isp1301	*isp = container_of(otg, struct isp1301, otg);
+
+	if (!otg || isp != the_transceiver)
+		return -ENODEV;
+
+	if (!host) {
+		OTG_IRQ_EN_REG = 0;
+		power_down(isp);
+		isp->otg.host = 0;
+		return 0;
+	}
+
+#ifdef	CONFIG_USB_OTG
+	isp->otg.host = host;
+	dev_dbg(&isp->client.dev, "registered host\n");
+	host_suspend(isp);
+	if (isp->otg.gadget)
+		return isp1301_otg_enable(isp);
+	return 0;
+
+#elif	!defined(CONFIG_USB_GADGET_OMAP)
+	// FIXME update its refcount
+	isp->otg.host = host;
+
+	power_up(isp);
+
+	if (machine_is_omap_h2())
+		isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1, MC1_DAT_SE0);
+
+	dev_info(&isp->client.dev, "A-Host sessions ok\n");
+	isp1301_set_bits(isp, ISP1301_INTERRUPT_RISING,
+	 	INTR_ID_GND);
+	isp1301_set_bits(isp, ISP1301_INTERRUPT_FALLING,
+	 	INTR_ID_GND);
+
+	/* If this has a Mini-AB connector, this mode is highly
+	 * nonstandard ... but can be handy for testing, especially with
+	 * the Mini-A end of an OTG cable.  (Or something nonstandard
+	 * like MiniB-to-StandardB, maybe built with a gender mender.)
+	 */
+	isp1301_set_bits(isp, ISP1301_OTG_CONTROL_1, OTG1_VBUS_DRV);
+
+	dump_regs(isp, __FUNCTION__);
+
+	return 0;
+
+#else
+	dev_dbg(&isp->client.dev, "host sessions not allowed\n");
+	return -EINVAL;
+#endif
+
+}
+
+static int
+isp1301_set_peripheral(struct otg_transceiver *otg, struct usb_gadget *gadget)
+{
+	struct isp1301	*isp = container_of(otg, struct isp1301, otg);
+
+	if (!otg || isp != the_transceiver)
+		return -ENODEV;
+
+	if (!gadget) {
+		OTG_IRQ_EN_REG = 0;
+		if (!isp->otg.default_a)
+			enable_vbus_draw(isp, 0);
+		usb_gadget_vbus_disconnect(isp->otg.gadget);
+		isp->otg.gadget = 0;
+		power_down(isp);
+		return 0;
+	}
+
+#ifdef	CONFIG_USB_OTG
+	isp->otg.gadget = gadget;
+	dev_dbg(&isp->client.dev, "registered gadget\n");
+	/* gadget driver may be suspended until vbus_connect () */
+	if (isp->otg.host)
+		return isp1301_otg_enable(isp);
+	return 0;
+
+#elif	!defined(CONFIG_USB_OHCI_HCD) && !defined(CONFIG_USB_OHCI_HCD_MODULE)
+	isp->otg.gadget = gadget;
+	// FIXME update its refcount
+
+	OTG_CTRL_REG = (OTG_CTRL_REG & OTG_CTRL_MASK
+				& ~(OTG_XCEIV_OUTPUTS|OTG_CTRL_BITS))
+			| OTG_ID;
+	power_up(isp);
+	isp->otg.state = OTG_STATE_B_IDLE;
+
+	if (machine_is_omap_h2())
+		isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1, MC1_DAT_SE0);
+
+	isp1301_set_bits(isp, ISP1301_INTERRUPT_RISING,
+	 	INTR_SESS_VLD);
+	isp1301_set_bits(isp, ISP1301_INTERRUPT_FALLING,
+	 	INTR_VBUS_VLD);
+	dev_info(&isp->client.dev, "B-Peripheral sessions ok\n");
+	dump_regs(isp, __FUNCTION__);
+
+	/* If this has a Mini-AB connector, this mode is highly
+	 * nonstandard ... but can be handy for testing, so long
+	 * as you don't plug a Mini-A cable into the jack.
+	 */
+	if (isp1301_get_u8(isp, ISP1301_INTERRUPT_SOURCE) & INTR_VBUS_VLD)
+		b_peripheral(isp);
+
+	return 0;
+
+#else
+	dev_dbg(&isp->client.dev, "peripheral sessions not allowed\n");
+	return -EINVAL;
+#endif
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int
+isp1301_set_power(struct otg_transceiver *dev, unsigned mA)
+{
+	if (!the_transceiver)
+		return -ENODEV;
+	if (dev->state == OTG_STATE_B_PERIPHERAL)
+		enable_vbus_draw(the_transceiver, mA);
+	return 0;
+}
+
+static int
+isp1301_start_srp(struct otg_transceiver *dev)
+{
+	struct isp1301	*isp = container_of(dev, struct isp1301, otg);
+	u32		otg_ctrl;
+
+	if (!dev || isp != the_transceiver
+			|| isp->otg.state != OTG_STATE_B_IDLE)
+		return -ENODEV;
+
+	otg_ctrl = OTG_CTRL_REG;
+	if (!(otg_ctrl & OTG_BSESSEND))
+		return -EINVAL;
+
+	otg_ctrl |= OTG_B_BUSREQ;
+	otg_ctrl &= ~OTG_A_BUSREQ & OTG_CTRL_MASK;
+	OTG_CTRL_REG = otg_ctrl;
+	isp->otg.state = OTG_STATE_B_SRP_INIT;
+
+	pr_debug("otg: SRP, %s ... %06x\n", state_name(isp), OTG_CTRL_REG);
+#ifdef	CONFIG_USB_OTG
+	check_state(isp, __FUNCTION__);
+#endif
+	return 0;
+}
+
+static int
+isp1301_start_hnp(struct otg_transceiver *dev)
+{
+#ifdef	CONFIG_USB_OTG
+	struct isp1301	*isp = container_of(dev, struct isp1301, otg);
+
+	if (!dev || isp != the_transceiver)
+		return -ENODEV;
+	if (isp->otg.default_a && (isp->otg.host == NULL
+			|| !isp->otg.host->b_hnp_enable))
+		return -ENOTCONN;
+	if (!isp->otg.default_a && (isp->otg.gadget == NULL
+			|| !isp->otg.gadget->b_hnp_enable))
+		return -ENOTCONN;
+
+	/* We want hardware to manage most HNP protocol timings.
+	 * So do this part as early as possible...
+	 */
+	switch (isp->otg.state) {
+	case OTG_STATE_B_HOST:
+		isp->otg.state = OTG_STATE_B_PERIPHERAL;
+		/* caller will suspend next */
+		break;
+	case OTG_STATE_A_HOST:
+#if 0
+		/* autoconnect mode avoids irq latency bugs */
+		isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1,
+				MC1_BDIS_ACON_EN);
+#endif
+		/* caller must suspend then clear A_BUSREQ */
+		usb_gadget_vbus_connect(isp->otg.gadget);
+		OTG_CTRL_REG |= OTG_A_SETB_HNPEN;
+
+		break;
+	case OTG_STATE_A_PERIPHERAL:
+		/* initiated by B-Host suspend */
+		break;
+	default:
+		return -EILSEQ;
+	}
+	pr_debug("otg: HNP %s, %06x ...\n",
+		state_name(isp), OTG_CTRL_REG);
+	check_state(isp, __FUNCTION__);
+	return 0;
+#else
+	/* srp-only */
+	return -EINVAL;
+#endif
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* no error returns, they'd just make bus scanning stop */
+static int isp1301_probe(struct i2c_adapter *bus, int address, int kind)
+{
+	int			status;
+	struct isp1301		*isp;
+	struct i2c_client	*i2c;
+
+	if (the_transceiver)
+		return 0;
+
+	isp = kmalloc(sizeof *isp, GFP_KERNEL);
+	if (!isp)
+		return 0;
+
+	memset(isp, 0, sizeof *isp);
+
+	INIT_WORK(&isp->work, isp1301_work, isp);
+	init_timer(&isp->timer);
+	isp->timer.function = isp1301_timer;
+	isp->timer.data = (unsigned long) isp;
+
+	isp->irq = -1;
+	isp->client.addr = address;
+	i2c_set_clientdata(&isp->client, isp);
+	isp->client.adapter = bus;
+	isp->client.id = 1301;
+	isp->client.driver = &isp1301_driver;
+	strlcpy(isp->client.name, DRIVER_NAME, I2C_NAME_SIZE);
+	i2c = &isp->client;
+
+	/* if this is a true probe, verify the chip ... */
+	if (kind < 0) {
+		status = isp1301_get_u16(isp, ISP1301_VENDOR_ID);
+		if (status != I2C_VENDOR_ID_PHILIPS) {
+			dev_dbg(&bus->dev, "addr %d not philips id: %d\n",
+				address, status);
+			goto fail1;
+		}
+		status = isp1301_get_u16(isp, ISP1301_PRODUCT_ID);
+		if (status != I2C_PRODUCT_ID_PHILIPS_1301) {
+			dev_dbg(&bus->dev, "%d not isp1301, %d\n",
+				address, status);
+			goto fail1;
+		}
+	}
+
+	status = i2c_attach_client(i2c);
+	if (status < 0) {
+		dev_dbg(&bus->dev, "can't attach %s to device %d, err %d\n",
+				DRIVER_NAME, address, status);
+fail1:
+		kfree(isp);
+		return 0;
+	}
+	isp->i2c_release = i2c->dev.release;
+	i2c->dev.release = isp1301_release;
+
+	/* initial development used chiprev 2.00 */
+	status = i2c_smbus_read_word_data(i2c, ISP1301_BCD_DEVICE);
+	dev_info(&i2c->dev, "chiprev %x.%02x, driver " DRIVER_VERSION "\n",
+		status >> 8, status & 0xff);
+
+	/* make like power-on reset */
+	isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_1, MC1_MASK);
+
+	isp1301_set_bits(isp, ISP1301_MODE_CONTROL_2, MC2_BI_DI);
+	isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_2, ~MC2_BI_DI);
+
+	isp1301_set_bits(isp, ISP1301_OTG_CONTROL_1,
+				OTG1_DM_PULLDOWN | OTG1_DP_PULLDOWN);
+	isp1301_clear_bits(isp, ISP1301_OTG_CONTROL_1,
+				~(OTG1_DM_PULLDOWN | OTG1_DP_PULLDOWN));
+
+	isp1301_clear_bits(isp, ISP1301_INTERRUPT_LATCH, ~0);
+	isp1301_clear_bits(isp, ISP1301_INTERRUPT_FALLING, ~0);
+	isp1301_clear_bits(isp, ISP1301_INTERRUPT_RISING, ~0);
+
+#ifdef	CONFIG_USB_OTG
+	status = otg_bind(isp);
+	if (status < 0) {
+		dev_dbg(&i2c->dev, "can't bind OTG\n");
+		goto fail2;
+	}
+#endif
+
+	if (machine_is_omap_h2()) {
+		/* full speed signaling by default */
+		isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1,
+			MC1_SPEED_REG);
+		isp1301_set_bits(isp, ISP1301_MODE_CONTROL_2,
+			MC2_SPD_SUSP_CTRL);
+
+		/* IRQ wired at M14 */
+		omap_cfg_reg(M14_1510_GPIO2);
+		isp->irq = OMAP_GPIO_IRQ(2);
+		omap_request_gpio(2);
+		omap_set_gpio_direction(2, 1);
+		omap_set_gpio_edge_ctrl(2, OMAP_GPIO_FALLING_EDGE);
+	}
+
+	status = request_irq(isp->irq, isp1301_irq,
+			SA_SAMPLE_RANDOM, DRIVER_NAME, isp);
+	if (status < 0) {
+		dev_dbg(&i2c->dev, "can't get IRQ %d, err %d\n",
+				isp->irq, status);
+#ifdef	CONFIG_USB_OTG
+fail2:
+#endif
+		i2c_detach_client(i2c);
+		goto fail1;
+	}
+
+	isp->otg.dev = &isp->client.dev;
+	isp->otg.label = DRIVER_NAME;
+
+	isp->otg.set_host = isp1301_set_host,
+	isp->otg.set_peripheral = isp1301_set_peripheral,
+	isp->otg.set_power = isp1301_set_power,
+	isp->otg.start_srp = isp1301_start_srp,
+	isp->otg.start_hnp = isp1301_start_hnp,
+
+	enable_vbus_draw(isp, 0);
+	power_down(isp);
+	the_transceiver = isp;
+
+#ifdef	CONFIG_USB_OTG
+	update_otg1(isp, isp1301_get_u8(isp, ISP1301_INTERRUPT_SOURCE));
+	update_otg2(isp, isp1301_get_u8(isp, ISP1301_OTG_STATUS));
+#endif
+
+	dump_regs(isp, __FUNCTION__);
+
+#ifdef	VERBOSE
+	mod_timer(&isp->timer, jiffies + TIMER_JIFFIES);
+	dev_dbg(&i2c->dev, "scheduled timer, %d min\n", TIMER_MINUTES);
+#endif
+
+	status = otg_set_transceiver(&isp->otg);
+	if (status < 0)
+		dev_err(&i2c->dev, "can't register transceiver, %d\n",
+			status);
+
+	return 0;
+}
+
+static int isp1301_scan_bus(struct i2c_adapter *bus)
+{
+	if (!i2c_check_functionality(bus, I2C_FUNC_SMBUS_BYTE_DATA
+			| I2C_FUNC_SMBUS_READ_WORD_DATA))
+		return -EINVAL;
+	return i2c_probe(bus, &addr_data, isp1301_probe);
+}
+
+static struct i2c_driver isp1301_driver = {
+	.owner		= THIS_MODULE,
+	.name		= "isp1301_omap",
+	.id		= 1301,		/* FIXME "official", i2c-ids.h */
+	.class		= I2C_CLASS_HWMON,
+	.flags		= I2C_DF_NOTIFY,
+	.attach_adapter	= isp1301_scan_bus,
+	.detach_client	= isp1301_detach_client,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int __init isp_init(void)
+{
+	return i2c_add_driver(&isp1301_driver);
+}
+module_init(isp_init);
+
+static void __exit isp_exit(void)
+{
+	if (the_transceiver)
+		otg_set_transceiver(0);
+	i2c_del_driver(&isp1301_driver);
+}
+module_exit(isp_exit);
+