USB: Add MSM OTG Controller driver

This driver implements PHY initialization, clock management, ULPI IO ops
and simple OTG state machine to kick host/peripheral based on Id/VBUS
line status.  VBUS/Id lines are tied to a reference voltage on some boards.
Hence provide debugfs interface to select host/peripheral mode.

Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 861 insertions, 0 deletions

diff --git a/drivers/usb/otg/Kconfig b/drivers/usb/otg/Kconfig
index 5ce07528cd0c..915c729872f8 100644
--- a/drivers/usb/otg/Kconfig
+++ b/drivers/usb/otg/Kconfig
@@ -81,4 +81,14 @@ config USB_LANGWELL_OTG
 	  To compile this driver as a module, choose M here: the
 	  module will be called langwell_otg.
 
+config USB_MSM_OTG_72K
+	tristate "OTG support for Qualcomm on-chip USB controller"
+	depends on (USB || USB_GADGET) && ARCH_MSM
+	select USB_OTG_UTILS
+	help
+	  Enable this to support the USB OTG transceiver on MSM chips. It
+	  handles PHY initialization, clock management, and workarounds
+	  required after resetting the hardware. This driver is required
+	  even for peripheral only or host only mode configuration.
+
 endif # USB || OTG
diff --git a/drivers/usb/otg/Makefile b/drivers/usb/otg/Makefile
index 66f1b83e4fa7..3b1b0960fb68 100644
--- a/drivers/usb/otg/Makefile
+++ b/drivers/usb/otg/Makefile
@@ -15,3 +15,4 @@ obj-$(CONFIG_TWL4030_USB)	+= twl4030-usb.o
 obj-$(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_MSM_OTG_72K)	+= msm72k_otg.o
diff --git a/drivers/usb/otg/msm72k_otg.c b/drivers/usb/otg/msm72k_otg.c
new file mode 100644
index 000000000000..46f468a912f4
--- /dev/null
+++ b/drivers/usb/otg/msm72k_otg.c
@@ -0,0 +1,850 @@
+/* Copyright (c) 2009-2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/uaccess.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+#include <linux/usb.h>
+#include <linux/usb/otg.h>
+#include <linux/usb/ulpi.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/hcd.h>
+#include <linux/usb/msm_hsusb.h>
+#include <linux/usb/msm_hsusb_hw.h>
+
+#include <mach/clk.h>
+
+#define MSM_USB_BASE	(motg->regs)
+#define DRIVER_NAME	"msm_otg"
+
+#define ULPI_IO_TIMEOUT_USEC	(10 * 1000)
+static int ulpi_read(struct otg_transceiver *otg, u32 reg)
+{
+	struct msm_otg *motg = container_of(otg, struct msm_otg, otg);
+	int cnt = 0;
+
+	/* initiate read operation */
+	writel(ULPI_RUN | ULPI_READ | ULPI_ADDR(reg),
+	       USB_ULPI_VIEWPORT);
+
+	/* wait for completion */
+	while (cnt < ULPI_IO_TIMEOUT_USEC) {
+		if (!(readl(USB_ULPI_VIEWPORT) & ULPI_RUN))
+			break;
+		udelay(1);
+		cnt++;
+	}
+
+	if (cnt >= ULPI_IO_TIMEOUT_USEC) {
+		dev_err(otg->dev, "ulpi_read: timeout %08x\n",
+			readl(USB_ULPI_VIEWPORT));
+		return -ETIMEDOUT;
+	}
+	return ULPI_DATA_READ(readl(USB_ULPI_VIEWPORT));
+}
+
+static int ulpi_write(struct otg_transceiver *otg, u32 val, u32 reg)
+{
+	struct msm_otg *motg = container_of(otg, struct msm_otg, otg);
+	int cnt = 0;
+
+	/* initiate write operation */
+	writel(ULPI_RUN | ULPI_WRITE |
+	       ULPI_ADDR(reg) | ULPI_DATA(val),
+	       USB_ULPI_VIEWPORT);
+
+	/* wait for completion */
+	while (cnt < ULPI_IO_TIMEOUT_USEC) {
+		if (!(readl(USB_ULPI_VIEWPORT) & ULPI_RUN))
+			break;
+		udelay(1);
+		cnt++;
+	}
+
+	if (cnt >= ULPI_IO_TIMEOUT_USEC) {
+		dev_err(otg->dev, "ulpi_write: timeout\n");
+		return -ETIMEDOUT;
+	}
+	return 0;
+}
+
+static struct otg_io_access_ops msm_otg_io_ops = {
+	.read = ulpi_read,
+	.write = ulpi_write,
+};
+
+static void ulpi_init(struct msm_otg *motg)
+{
+	struct msm_otg_platform_data *pdata = motg->pdata;
+	int *seq = pdata->phy_init_seq;
+
+	if (!seq)
+		return;
+
+	while (seq[0] >= 0) {
+		dev_vdbg(motg->otg.dev, "ulpi: write 0x%02x to 0x%02x\n",
+				seq[0], seq[1]);
+		ulpi_write(&motg->otg, seq[0], seq[1]);
+		seq += 2;
+	}
+}
+
+static int msm_otg_link_clk_reset(struct msm_otg *motg, bool assert)
+{
+	int ret;
+
+	if (assert) {
+		ret = clk_reset(motg->clk, CLK_RESET_ASSERT);
+		if (ret)
+			dev_err(motg->otg.dev, "usb hs_clk assert failed\n");
+	} else {
+		ret = clk_reset(motg->clk, CLK_RESET_DEASSERT);
+		if (ret)
+			dev_err(motg->otg.dev, "usb hs_clk deassert failed\n");
+	}
+	return ret;
+}
+
+static int msm_otg_phy_clk_reset(struct msm_otg *motg)
+{
+	int ret;
+
+	ret = clk_reset(motg->phy_reset_clk, CLK_RESET_ASSERT);
+	if (ret) {
+		dev_err(motg->otg.dev, "usb phy clk assert failed\n");
+		return ret;
+	}
+	usleep_range(10000, 12000);
+	ret = clk_reset(motg->phy_reset_clk, CLK_RESET_DEASSERT);
+	if (ret)
+		dev_err(motg->otg.dev, "usb phy clk deassert failed\n");
+	return ret;
+}
+
+static int msm_otg_phy_reset(struct msm_otg *motg)
+{
+	u32 val;
+	int ret;
+	int retries;
+
+	ret = msm_otg_link_clk_reset(motg, 1);
+	if (ret)
+		return ret;
+	ret = msm_otg_phy_clk_reset(motg);
+	if (ret)
+		return ret;
+	ret = msm_otg_link_clk_reset(motg, 0);
+	if (ret)
+		return ret;
+
+	val = readl(USB_PORTSC) & ~PORTSC_PTS_MASK;
+	writel(val | PORTSC_PTS_ULPI, USB_PORTSC);
+
+	for (retries = 3; retries > 0; retries--) {
+		ret = ulpi_write(&motg->otg, ULPI_FUNC_CTRL_SUSPENDM,
+				ULPI_CLR(ULPI_FUNC_CTRL));
+		if (!ret)
+			break;
+		ret = msm_otg_phy_clk_reset(motg);
+		if (ret)
+			return ret;
+	}
+	if (!retries)
+		return -ETIMEDOUT;
+
+	/* This reset calibrates the phy, if the above write succeeded */
+	ret = msm_otg_phy_clk_reset(motg);
+	if (ret)
+		return ret;
+
+	for (retries = 3; retries > 0; retries--) {
+		ret = ulpi_read(&motg->otg, ULPI_DEBUG);
+		if (ret != -ETIMEDOUT)
+			break;
+		ret = msm_otg_phy_clk_reset(motg);
+		if (ret)
+			return ret;
+	}
+	if (!retries)
+		return -ETIMEDOUT;
+
+	dev_info(motg->otg.dev, "phy_reset: success\n");
+	return 0;
+}
+
+#define LINK_RESET_TIMEOUT_USEC		(250 * 1000)
+static int msm_otg_reset(struct otg_transceiver *otg)
+{
+	struct msm_otg *motg = container_of(otg, struct msm_otg, otg);
+	struct msm_otg_platform_data *pdata = motg->pdata;
+	int cnt = 0;
+	int ret;
+	u32 val = 0;
+	u32 ulpi_val = 0;
+
+	ret = msm_otg_phy_reset(motg);
+	if (ret) {
+		dev_err(otg->dev, "phy_reset failed\n");
+		return ret;
+	}
+
+	ulpi_init(motg);
+
+	writel(USBCMD_RESET, USB_USBCMD);
+	while (cnt < LINK_RESET_TIMEOUT_USEC) {
+		if (!(readl(USB_USBCMD) & USBCMD_RESET))
+			break;
+		udelay(1);
+		cnt++;
+	}
+	if (cnt >= LINK_RESET_TIMEOUT_USEC)
+		return -ETIMEDOUT;
+
+	/* select ULPI phy */
+	writel(0x80000000, USB_PORTSC);
+
+	msleep(100);
+
+	writel(0x0, USB_AHBBURST);
+	writel(0x00, USB_AHBMODE);
+
+	if (pdata->otg_control == OTG_PHY_CONTROL) {
+		val = readl(USB_OTGSC);
+		if (pdata->mode == USB_OTG) {
+			ulpi_val = ULPI_INT_IDGRD | ULPI_INT_SESS_VALID;
+			val |= OTGSC_IDIE | OTGSC_BSVIE;
+		} else if (pdata->mode == USB_PERIPHERAL) {
+			ulpi_val = ULPI_INT_SESS_VALID;
+			val |= OTGSC_BSVIE;
+		}
+		writel(val, USB_OTGSC);
+		ulpi_write(otg, ulpi_val, ULPI_USB_INT_EN_RISE);
+		ulpi_write(otg, ulpi_val, ULPI_USB_INT_EN_FALL);
+	}
+
+	return 0;
+}
+
+static void msm_otg_start_host(struct otg_transceiver *otg, int on)
+{
+	struct msm_otg *motg = container_of(otg, struct msm_otg, otg);
+	struct msm_otg_platform_data *pdata = motg->pdata;
+	struct usb_hcd *hcd;
+
+	if (!otg->host)
+		return;
+
+	hcd = bus_to_hcd(otg->host);
+
+	if (on) {
+		dev_dbg(otg->dev, "host on\n");
+
+		if (pdata->vbus_power)
+			pdata->vbus_power(1);
+		/*
+		 * Some boards have a switch cotrolled by gpio
+		 * to enable/disable internal HUB. Enable internal
+		 * HUB before kicking the host.
+		 */
+		if (pdata->setup_gpio)
+			pdata->setup_gpio(OTG_STATE_A_HOST);
+#ifdef CONFIG_USB
+		usb_add_hcd(hcd, hcd->irq, IRQF_SHARED);
+#endif
+	} else {
+		dev_dbg(otg->dev, "host off\n");
+
+#ifdef CONFIG_USB
+		usb_remove_hcd(hcd);
+#endif
+		if (pdata->setup_gpio)
+			pdata->setup_gpio(OTG_STATE_UNDEFINED);
+		if (pdata->vbus_power)
+			pdata->vbus_power(0);
+	}
+}
+
+static int msm_otg_set_host(struct otg_transceiver *otg, struct usb_bus *host)
+{
+	struct msm_otg *motg = container_of(otg, struct msm_otg, otg);
+	struct usb_hcd *hcd;
+
+	/*
+	 * Fail host registration if this board can support
+	 * only peripheral configuration.
+	 */
+	if (motg->pdata->mode == USB_PERIPHERAL) {
+		dev_info(otg->dev, "Host mode is not supported\n");
+		return -ENODEV;
+	}
+
+	if (!host) {
+		if (otg->state == OTG_STATE_A_HOST) {
+			msm_otg_start_host(otg, 0);
+			otg->host = NULL;
+			otg->state = OTG_STATE_UNDEFINED;
+			schedule_work(&motg->sm_work);
+		} else {
+			otg->host = NULL;
+		}
+
+		return 0;
+	}
+
+	hcd = bus_to_hcd(host);
+	hcd->power_budget = motg->pdata->power_budget;
+
+	otg->host = host;
+	dev_dbg(otg->dev, "host driver registered w/ tranceiver\n");
+
+	/*
+	 * Kick the state machine work, if peripheral is not supported
+	 * or peripheral is already registered with us.
+	 */
+	if (motg->pdata->mode == USB_HOST || otg->gadget)
+		schedule_work(&motg->sm_work);
+
+	return 0;
+}
+
+static void msm_otg_start_peripheral(struct otg_transceiver *otg, int on)
+{
+	struct msm_otg *motg = container_of(otg, struct msm_otg, otg);
+	struct msm_otg_platform_data *pdata = motg->pdata;
+
+	if (!otg->gadget)
+		return;
+
+	if (on) {
+		dev_dbg(otg->dev, "gadget on\n");
+		/*
+		 * Some boards have a switch cotrolled by gpio
+		 * to enable/disable internal HUB. Disable internal
+		 * HUB before kicking the gadget.
+		 */
+		if (pdata->setup_gpio)
+			pdata->setup_gpio(OTG_STATE_B_PERIPHERAL);
+		usb_gadget_vbus_connect(otg->gadget);
+	} else {
+		dev_dbg(otg->dev, "gadget off\n");
+		usb_gadget_vbus_disconnect(otg->gadget);
+		if (pdata->setup_gpio)
+			pdata->setup_gpio(OTG_STATE_UNDEFINED);
+	}
+
+}
+
+static int msm_otg_set_peripheral(struct otg_transceiver *otg,
+			struct usb_gadget *gadget)
+{
+	struct msm_otg *motg = container_of(otg, struct msm_otg, otg);
+
+	/*
+	 * Fail peripheral registration if this board can support
+	 * only host configuration.
+	 */
+	if (motg->pdata->mode == USB_HOST) {
+		dev_info(otg->dev, "Peripheral mode is not supported\n");
+		return -ENODEV;
+	}
+
+	if (!gadget) {
+		if (otg->state == OTG_STATE_B_PERIPHERAL) {
+			msm_otg_start_peripheral(otg, 0);
+			otg->gadget = NULL;
+			otg->state = OTG_STATE_UNDEFINED;
+			schedule_work(&motg->sm_work);
+		} else {
+			otg->gadget = NULL;
+		}
+
+		return 0;
+	}
+	otg->gadget = gadget;
+	dev_dbg(otg->dev, "peripheral driver registered w/ tranceiver\n");
+
+	/*
+	 * Kick the state machine work, if host is not supported
+	 * or host is already registered with us.
+	 */
+	if (motg->pdata->mode == USB_PERIPHERAL || otg->host)
+		schedule_work(&motg->sm_work);
+
+	return 0;
+}
+
+/*
+ * We support OTG, Peripheral only and Host only configurations. In case
+ * of OTG, mode switch (host-->peripheral/peripheral-->host) can happen
+ * via Id pin status or user request (debugfs). Id/BSV interrupts are not
+ * enabled when switch is controlled by user and default mode is supplied
+ * by board file, which can be changed by userspace later.
+ */
+static void msm_otg_init_sm(struct msm_otg *motg)
+{
+	struct msm_otg_platform_data *pdata = motg->pdata;
+	u32 otgsc = readl(USB_OTGSC);
+
+	switch (pdata->mode) {
+	case USB_OTG:
+		if (pdata->otg_control == OTG_PHY_CONTROL) {
+			if (otgsc & OTGSC_ID)
+				set_bit(ID, &motg->inputs);
+			else
+				clear_bit(ID, &motg->inputs);
+
+			if (otgsc & OTGSC_BSV)
+				set_bit(B_SESS_VLD, &motg->inputs);
+			else
+				clear_bit(B_SESS_VLD, &motg->inputs);
+		} else if (pdata->otg_control == OTG_USER_CONTROL) {
+			if (pdata->default_mode == USB_HOST) {
+				clear_bit(ID, &motg->inputs);
+			} else if (pdata->default_mode == USB_PERIPHERAL) {
+				set_bit(ID, &motg->inputs);
+				set_bit(B_SESS_VLD, &motg->inputs);
+			} else {
+				set_bit(ID, &motg->inputs);
+				clear_bit(B_SESS_VLD, &motg->inputs);
+			}
+		}
+		break;
+	case USB_HOST:
+		clear_bit(ID, &motg->inputs);
+		break;
+	case USB_PERIPHERAL:
+		set_bit(ID, &motg->inputs);
+		if (otgsc & OTGSC_BSV)
+			set_bit(B_SESS_VLD, &motg->inputs);
+		else
+			clear_bit(B_SESS_VLD, &motg->inputs);
+		break;
+	default:
+		break;
+	}
+}
+
+static void msm_otg_sm_work(struct work_struct *w)
+{
+	struct msm_otg *motg = container_of(w, struct msm_otg, sm_work);
+	struct otg_transceiver *otg = &motg->otg;
+
+	switch (otg->state) {
+	case OTG_STATE_UNDEFINED:
+		dev_dbg(otg->dev, "OTG_STATE_UNDEFINED state\n");
+		msm_otg_reset(otg);
+		msm_otg_init_sm(motg);
+		otg->state = OTG_STATE_B_IDLE;
+		/* FALL THROUGH */
+	case OTG_STATE_B_IDLE:
+		dev_dbg(otg->dev, "OTG_STATE_B_IDLE state\n");
+		if (!test_bit(ID, &motg->inputs) && otg->host) {
+			/* disable BSV bit */
+			writel(readl(USB_OTGSC) & ~OTGSC_BSVIE, USB_OTGSC);
+			msm_otg_start_host(otg, 1);
+			otg->state = OTG_STATE_A_HOST;
+		} else if (test_bit(B_SESS_VLD, &motg->inputs) && otg->gadget) {
+			msm_otg_start_peripheral(otg, 1);
+			otg->state = OTG_STATE_B_PERIPHERAL;
+		}
+		break;
+	case OTG_STATE_B_PERIPHERAL:
+		dev_dbg(otg->dev, "OTG_STATE_B_PERIPHERAL state\n");
+		if (!test_bit(B_SESS_VLD, &motg->inputs) ||
+				!test_bit(ID, &motg->inputs)) {
+			msm_otg_start_peripheral(otg, 0);
+			otg->state = OTG_STATE_B_IDLE;
+			msm_otg_reset(otg);
+			schedule_work(w);
+		}
+		break;
+	case OTG_STATE_A_HOST:
+		dev_dbg(otg->dev, "OTG_STATE_A_HOST state\n");
+		if (test_bit(ID, &motg->inputs)) {
+			msm_otg_start_host(otg, 0);
+			otg->state = OTG_STATE_B_IDLE;
+			msm_otg_reset(otg);
+			schedule_work(w);
+		}
+		break;
+	default:
+		break;
+	}
+}
+
+static irqreturn_t msm_otg_irq(int irq, void *data)
+{
+	struct msm_otg *motg = data;
+	struct otg_transceiver *otg = &motg->otg;
+	u32 otgsc = 0;
+
+	otgsc = readl(USB_OTGSC);
+	if (!(otgsc & (OTGSC_IDIS | OTGSC_BSVIS)))
+		return IRQ_NONE;
+
+	if ((otgsc & OTGSC_IDIS) && (otgsc & OTGSC_IDIE)) {
+		if (otgsc & OTGSC_ID)
+			set_bit(ID, &motg->inputs);
+		else
+			clear_bit(ID, &motg->inputs);
+		dev_dbg(otg->dev, "ID set/clear\n");
+	} else if ((otgsc & OTGSC_BSVIS) && (otgsc & OTGSC_BSVIE)) {
+		if (otgsc & OTGSC_BSV)
+			set_bit(B_SESS_VLD, &motg->inputs);
+		else
+			clear_bit(B_SESS_VLD, &motg->inputs);
+		dev_dbg(otg->dev, "BSV set/clear\n");
+	}
+
+	writel(otgsc, USB_OTGSC);
+	schedule_work(&motg->sm_work);
+	return IRQ_HANDLED;
+}
+
+static int msm_otg_mode_show(struct seq_file *s, void *unused)
+{
+	struct msm_otg *motg = s->private;
+	struct otg_transceiver *otg = &motg->otg;
+
+	switch (otg->state) {
+	case OTG_STATE_A_HOST:
+		seq_printf(s, "host\n");
+		break;
+	case OTG_STATE_B_PERIPHERAL:
+		seq_printf(s, "peripheral\n");
+		break;
+	default:
+		seq_printf(s, "none\n");
+		break;
+	}
+
+	return 0;
+}
+
+static int msm_otg_mode_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, msm_otg_mode_show, inode->i_private);
+}
+
+static ssize_t msm_otg_mode_write(struct file *file, const char __user *ubuf,
+				size_t count, loff_t *ppos)
+{
+	struct msm_otg *motg = file->private_data;
+	char buf[16];
+	struct otg_transceiver *otg = &motg->otg;
+	int status = count;
+	enum usb_mode_type req_mode;
+
+	memset(buf, 0x00, sizeof(buf));
+
+	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count))) {
+		status = -EFAULT;
+		goto out;
+	}
+
+	if (!strncmp(buf, "host", 4)) {
+		req_mode = USB_HOST;
+	} else if (!strncmp(buf, "peripheral", 10)) {
+		req_mode = USB_PERIPHERAL;
+	} else if (!strncmp(buf, "none", 4)) {
+		req_mode = USB_NONE;
+	} else {
+		status = -EINVAL;
+		goto out;
+	}
+
+	switch (req_mode) {
+	case USB_NONE:
+		switch (otg->state) {
+		case OTG_STATE_A_HOST:
+		case OTG_STATE_B_PERIPHERAL:
+			set_bit(ID, &motg->inputs);
+			clear_bit(B_SESS_VLD, &motg->inputs);
+			break;
+		default:
+			goto out;
+		}
+		break;
+	case USB_PERIPHERAL:
+		switch (otg->state) {
+		case OTG_STATE_B_IDLE:
+		case OTG_STATE_A_HOST:
+			set_bit(ID, &motg->inputs);
+			set_bit(B_SESS_VLD, &motg->inputs);
+			break;
+		default:
+			goto out;
+		}
+		break;
+	case USB_HOST:
+		switch (otg->state) {
+		case OTG_STATE_B_IDLE:
+		case OTG_STATE_B_PERIPHERAL:
+			clear_bit(ID, &motg->inputs);
+			break;
+		default:
+			goto out;
+		}
+		break;
+	default:
+		goto out;
+	}
+
+	schedule_work(&motg->sm_work);
+out:
+	return status;
+}
+
+const struct file_operations msm_otg_mode_fops = {
+	.open = msm_otg_mode_open,
+	.read = seq_read,
+	.write = msm_otg_mode_write,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static struct dentry *msm_otg_dbg_root;
+static struct dentry *msm_otg_dbg_mode;
+
+static int msm_otg_debugfs_init(struct msm_otg *motg)
+{
+	msm_otg_dbg_root = debugfs_create_dir("msm_otg", NULL);
+
+	if (!msm_otg_dbg_root || IS_ERR(msm_otg_dbg_root))
+		return -ENODEV;
+
+	msm_otg_dbg_mode = debugfs_create_file("mode", S_IRUGO | S_IWUSR,
+				msm_otg_dbg_root, motg, &msm_otg_mode_fops);
+	if (!msm_otg_dbg_mode) {
+		debugfs_remove(msm_otg_dbg_root);
+		msm_otg_dbg_root = NULL;
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static void msm_otg_debugfs_cleanup(void)
+{
+	debugfs_remove(msm_otg_dbg_mode);
+	debugfs_remove(msm_otg_dbg_root);
+}
+
+static int __init msm_otg_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	struct resource *res;
+	struct msm_otg *motg;
+	struct otg_transceiver *otg;
+
+	dev_info(&pdev->dev, "msm_otg probe\n");
+	if (!pdev->dev.platform_data) {
+		dev_err(&pdev->dev, "No platform data given. Bailing out\n");
+		return -ENODEV;
+	}
+
+	motg = kzalloc(sizeof(struct msm_otg), GFP_KERNEL);
+	if (!motg) {
+		dev_err(&pdev->dev, "unable to allocate msm_otg\n");
+		return -ENOMEM;
+	}
+
+	motg->pdata = pdev->dev.platform_data;
+	otg = &motg->otg;
+	otg->dev = &pdev->dev;
+
+	motg->phy_reset_clk = clk_get(&pdev->dev, "usb_phy_clk");
+	if (IS_ERR(motg->phy_reset_clk)) {
+		dev_err(&pdev->dev, "failed to get usb_phy_clk\n");
+		ret = PTR_ERR(motg->phy_reset_clk);
+		goto free_motg;
+	}
+
+	motg->clk = clk_get(&pdev->dev, "usb_hs_clk");
+	if (IS_ERR(motg->clk)) {
+		dev_err(&pdev->dev, "failed to get usb_hs_clk\n");
+		ret = PTR_ERR(motg->clk);
+		goto put_phy_reset_clk;
+	}
+
+	motg->pclk = clk_get(&pdev->dev, "usb_hs_pclk");
+	if (IS_ERR(motg->pclk)) {
+		dev_err(&pdev->dev, "failed to get usb_hs_pclk\n");
+		ret = PTR_ERR(motg->pclk);
+		goto put_clk;
+	}
+
+	/*
+	 * USB core clock is not present on all MSM chips. This
+	 * clock is introduced to remove the dependency on AXI
+	 * bus frequency.
+	 */
+	motg->core_clk = clk_get(&pdev->dev, "usb_hs_core_clk");
+	if (IS_ERR(motg->core_clk))
+		motg->core_clk = NULL;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "failed to get platform resource mem\n");
+		ret = -ENODEV;
+		goto put_core_clk;
+	}
+
+	motg->regs = ioremap(res->start, resource_size(res));
+	if (!motg->regs) {
+		dev_err(&pdev->dev, "ioremap failed\n");
+		ret = -ENOMEM;
+		goto put_core_clk;
+	}
+	dev_info(&pdev->dev, "OTG regs = %p\n", motg->regs);
+
+	motg->irq = platform_get_irq(pdev, 0);
+	if (!motg->irq) {
+		dev_err(&pdev->dev, "platform_get_irq failed\n");
+		ret = -ENODEV;
+		goto free_regs;
+	}
+
+	clk_enable(motg->clk);
+	clk_enable(motg->pclk);
+	if (motg->core_clk)
+		clk_enable(motg->core_clk);
+
+	writel(0, USB_USBINTR);
+	writel(0, USB_OTGSC);
+
+	INIT_WORK(&motg->sm_work, msm_otg_sm_work);
+	ret = request_irq(motg->irq, msm_otg_irq, IRQF_SHARED,
+					"msm_otg", motg);
+	if (ret) {
+		dev_err(&pdev->dev, "request irq failed\n");
+		goto disable_clks;
+	}
+
+	otg->init = msm_otg_reset;
+	otg->set_host = msm_otg_set_host;
+	otg->set_peripheral = msm_otg_set_peripheral;
+
+	otg->io_ops = &msm_otg_io_ops;
+
+	ret = otg_set_transceiver(&motg->otg);
+	if (ret) {
+		dev_err(&pdev->dev, "otg_set_transceiver failed\n");
+		goto free_irq;
+	}
+
+	platform_set_drvdata(pdev, motg);
+	device_init_wakeup(&pdev->dev, 1);
+
+	if (motg->pdata->mode == USB_OTG &&
+			motg->pdata->otg_control == OTG_USER_CONTROL) {
+		ret = msm_otg_debugfs_init(motg);
+		if (ret)
+			dev_dbg(&pdev->dev, "mode debugfs file is"
+					"not available\n");
+	}
+
+	return 0;
+
+free_irq:
+	free_irq(motg->irq, motg);
+disable_clks:
+	clk_disable(motg->pclk);
+	clk_disable(motg->clk);
+free_regs:
+	iounmap(motg->regs);
+put_core_clk:
+	if (motg->core_clk)
+		clk_put(motg->core_clk);
+	clk_put(motg->pclk);
+put_clk:
+	clk_put(motg->clk);
+put_phy_reset_clk:
+	clk_put(motg->phy_reset_clk);
+free_motg:
+	kfree(motg);
+	return ret;
+}
+
+static int __devexit msm_otg_remove(struct platform_device *pdev)
+{
+	struct msm_otg *motg = platform_get_drvdata(pdev);
+	struct otg_transceiver *otg = &motg->otg;
+
+	if (otg->host || otg->gadget)
+		return -EBUSY;
+
+	msm_otg_debugfs_cleanup();
+	cancel_work_sync(&motg->sm_work);
+	device_init_wakeup(&pdev->dev, 0);
+	otg_set_transceiver(NULL);
+
+	free_irq(motg->irq, motg);
+
+	clk_disable(motg->pclk);
+	clk_disable(motg->clk);
+	if (motg->core_clk)
+		clk_disable(motg->core_clk);
+
+	iounmap(motg->regs);
+
+	clk_put(motg->phy_reset_clk);
+	clk_put(motg->pclk);
+	clk_put(motg->clk);
+	if (motg->core_clk)
+		clk_put(motg->core_clk);
+
+	kfree(motg);
+
+	return 0;
+}
+
+static struct platform_driver msm_otg_driver = {
+	.remove = __devexit_p(msm_otg_remove),
+	.driver = {
+		.name = DRIVER_NAME,
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init msm_otg_init(void)
+{
+	return platform_driver_probe(&msm_otg_driver, msm_otg_probe);
+}
+
+static void __exit msm_otg_exit(void)
+{
+	platform_driver_unregister(&msm_otg_driver);
+}
+
+module_init(msm_otg_init);
+module_exit(msm_otg_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MSM USB transceiver driver");