1 files changed, 193 insertions, 141 deletions

diff --git a/drivers/media/rc/imon.c b/drivers/media/rc/imon.c
index 989d2554ec72..35b9e07003d8 100644
--- a/drivers/media/rc/imon.c
+++ b/drivers/media/rc/imon.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *   imon.c:	input and display driver for SoundGraph iMON IR/VFD/LCD
  *
@@ -10,16 +11,6 @@
  *   which the support for them wouldn't be nearly as good. Thanks
  *   also to the numerous 0xffdc device owners that tested auto-config
  *   support for me and provided debug dumps from their devices.
- *
- *   imon 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.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
@@ -48,11 +39,6 @@
 #define DISPLAY_MINOR_BASE	144
 #define DEVICE_NAME	"lcd%d"
 
-#define BUF_CHUNK_SIZE	8
-#define BUF_SIZE	128
-
-#define BIT_DURATION	250	/* each bit received is 250us */
-
 #define IMON_CLOCK_ENABLE_PACKETS	2
 
 /*** P R O T O T Y P E S ***/
@@ -92,6 +78,7 @@ struct imon_usb_dev_descr {
 	__u16 flags;
 #define IMON_NO_FLAGS 0
 #define IMON_NEED_20MS_PKT_DELAY 1
+#define IMON_SUPPRESS_REPEATED_KEYS 2
 	struct imon_panel_key_table key_table[];
 };
 
@@ -158,8 +145,27 @@ struct imon_context {
 	struct timer_list ttimer;	/* touch screen timer */
 	int touch_x;			/* x coordinate on touchscreen */
 	int touch_y;			/* y coordinate on touchscreen */
-	struct imon_usb_dev_descr *dev_descr; /* device description with key
-						 table for front panels */
+	const struct imon_usb_dev_descr *dev_descr;
+					/* device description with key */
+					/* table for front panels */
+	/*
+	 * Fields for deferring free_imon_context().
+	 *
+	 * Since reference to "struct imon_context" is stored into
+	 * "struct file"->private_data, we need to remember
+	 * how many file descriptors might access this "struct imon_context".
+	 */
+	refcount_t users;
+	/*
+	 * Use a flag for telling display_open()/vfd_write()/lcd_write() that
+	 * imon_disconnect() was already called.
+	 */
+	bool disconnected;
+	/*
+	 * We need to wait for RCU grace period in order to allow
+	 * display_open() to safely check ->disconnected and increment ->users.
+	 */
+	struct rcu_head rcu;
 };
 
 #define TOUCH_TIMEOUT	(HZ/30)
@@ -167,18 +173,18 @@ struct imon_context {
 /* vfd character device file operations */
 static const struct file_operations vfd_fops = {
 	.owner		= THIS_MODULE,
-	.open		= &display_open,
-	.write		= &vfd_write,
-	.release	= &display_close,
+	.open		= display_open,
+	.write		= vfd_write,
+	.release	= display_close,
 	.llseek		= noop_llseek,
 };
 
 /* lcd character device file operations */
 static const struct file_operations lcd_fops = {
 	.owner		= THIS_MODULE,
-	.open		= &display_open,
-	.write		= &lcd_write,
-	.release	= &display_close,
+	.open		= display_open,
+	.write		= lcd_write,
+	.release	= display_close,
 	.llseek		= noop_llseek,
 };
 
@@ -324,6 +330,32 @@ static const struct imon_usb_dev_descr imon_DH102 = {
 	}
 };
 
+/* imon ultrabay front panel key table */
+static const struct imon_usb_dev_descr ultrabay_table = {
+	.flags = IMON_SUPPRESS_REPEATED_KEYS,
+	.key_table = {
+		{ 0x0000000f0000ffeell, KEY_MEDIA },      /* Go */
+		{ 0x000000000100ffeell, KEY_UP },
+		{ 0x000000000001ffeell, KEY_DOWN },
+		{ 0x000000160000ffeell, KEY_ENTER },
+		{ 0x0000001f0000ffeell, KEY_AUDIO },      /* Music */
+		{ 0x000000200000ffeell, KEY_VIDEO },      /* Movie */
+		{ 0x000000210000ffeell, KEY_CAMERA },     /* Photo */
+		{ 0x000000270000ffeell, KEY_DVD },        /* DVD */
+		{ 0x000000230000ffeell, KEY_TV },         /* TV */
+		{ 0x000000050000ffeell, KEY_PREVIOUS },   /* Previous */
+		{ 0x000000070000ffeell, KEY_REWIND },
+		{ 0x000000040000ffeell, KEY_STOP },
+		{ 0x000000020000ffeell, KEY_PLAYPAUSE },
+		{ 0x000000080000ffeell, KEY_FASTFORWARD },
+		{ 0x000000060000ffeell, KEY_NEXT },       /* Next */
+		{ 0x000100000000ffeell, KEY_VOLUMEUP },
+		{ 0x010000000000ffeell, KEY_VOLUMEDOWN },
+		{ 0x000000010000ffeell, KEY_MUTE },
+		{ 0, KEY_RESERVED },
+	}
+};
+
 /*
  * USB Device ID for iMON USB Control Boards
  *
@@ -420,9 +452,6 @@ static struct usb_driver imon_driver = {
 	.id_table	= imon_usb_id_table,
 };
 
-/* to prevent races between open() and disconnect(), probing, etc */
-static DEFINE_MUTEX(driver_lock);
-
 /* Module bookkeeping bits */
 MODULE_AUTHOR(MOD_AUTHOR);
 MODULE_DESCRIPTION(MOD_DESC);
@@ -462,9 +491,11 @@ static void free_imon_context(struct imon_context *ictx)
 	struct device *dev = ictx->dev;
 
 	usb_free_urb(ictx->tx_urb);
+	WARN_ON(ictx->dev_present_intf0);
 	usb_free_urb(ictx->rx_urb_intf0);
+	WARN_ON(ictx->dev_present_intf1);
 	usb_free_urb(ictx->rx_urb_intf1);
-	kfree(ictx);
+	kfree_rcu(ictx, rcu);
 
 	dev_dbg(dev, "%s: iMON context freed\n", __func__);
 }
@@ -480,9 +511,6 @@ static int display_open(struct inode *inode, struct file *file)
 	int subminor;
 	int retval = 0;
 
-	/* prevent races with disconnect */
-	mutex_lock(&driver_lock);
-
 	subminor = iminor(inode);
 	interface = usb_find_interface(&imon_driver, subminor);
 	if (!interface) {
@@ -490,17 +518,22 @@ static int display_open(struct inode *inode, struct file *file)
 		retval = -ENODEV;
 		goto exit;
 	}
-	ictx = usb_get_intfdata(interface);
 
-	if (!ictx) {
+	rcu_read_lock();
+	ictx = usb_get_intfdata(interface);
+	if (!ictx || ictx->disconnected || !refcount_inc_not_zero(&ictx->users)) {
+		rcu_read_unlock();
 		pr_err("no context found for minor %d\n", subminor);
 		retval = -ENODEV;
 		goto exit;
 	}
+	rcu_read_unlock();
 
 	mutex_lock(&ictx->lock);
 
-	if (!ictx->display_supported) {
+	if (ictx->disconnected) {
+		retval = -ENODEV;
+	} else if (!ictx->display_supported) {
 		pr_err("display not supported by device\n");
 		retval = -ENODEV;
 	} else if (ictx->display_isopen) {
@@ -514,8 +547,10 @@ static int display_open(struct inode *inode, struct file *file)
 
 	mutex_unlock(&ictx->lock);
 
+	if (retval && refcount_dec_and_test(&ictx->users))
+		free_imon_context(ictx);
+
 exit:
-	mutex_unlock(&driver_lock);
 	return retval;
 }
 
@@ -525,16 +560,9 @@ exit:
  */
 static int display_close(struct inode *inode, struct file *file)
 {
-	struct imon_context *ictx = NULL;
+	struct imon_context *ictx = file->private_data;
 	int retval = 0;
 
-	ictx = file->private_data;
-
-	if (!ictx) {
-		pr_err("no context for device\n");
-		return -ENODEV;
-	}
-
 	mutex_lock(&ictx->lock);
 
 	if (!ictx->display_supported) {
@@ -549,6 +577,8 @@ static int display_close(struct inode *inode, struct file *file)
 	}
 
 	mutex_unlock(&ictx->lock);
+	if (refcount_dec_and_test(&ictx->users))
+		free_imon_context(ictx);
 	return retval;
 }
 
@@ -565,6 +595,11 @@ static int send_packet(struct imon_context *ictx)
 	int retval = 0;
 	struct usb_ctrlrequest *control_req = NULL;
 
+	lockdep_assert_held(&ictx->lock);
+
+	if (ictx->disconnected)
+		return -ENODEV;
+
 	/* Check if we need to use control or interrupt urb */
 	if (!ictx->tx_control) {
 		pipe = usb_sndintpipe(ictx->usbdev_intf0,
@@ -612,16 +647,18 @@ static int send_packet(struct imon_context *ictx)
 		smp_rmb(); /* ensure later readers know we're not busy */
 		pr_err_ratelimited("error submitting urb(%d)\n", retval);
 	} else {
-		/* Wait for transmission to complete (or abort) */
-		mutex_unlock(&ictx->lock);
-		retval = wait_for_completion_interruptible(
-				&ictx->tx.finished);
-		if (retval) {
+		/* Wait for transmission to complete (or abort or timeout) */
+		retval = wait_for_completion_interruptible_timeout(&ictx->tx.finished, 10 * HZ);
+		if (retval <= 0) {
 			usb_kill_urb(ictx->tx_urb);
 			pr_err_ratelimited("task interrupted\n");
+			if (retval < 0)
+				ictx->tx.status = retval;
+			else
+				ictx->tx.status = -ETIMEDOUT;
 		}
-		mutex_lock(&ictx->lock);
 
+		ictx->tx.busy = false;
 		retval = ictx->tx.status;
 		if (retval)
 			pr_err_ratelimited("packet tx failed (%d)\n", retval);
@@ -651,7 +688,6 @@ static int send_packet(struct imon_context *ictx)
  */
 static int send_associate_24g(struct imon_context *ictx)
 {
-	int retval;
 	const unsigned char packet[8] = { 0x01, 0x00, 0x00, 0x00,
 					  0x00, 0x00, 0x00, 0x20 };
 
@@ -666,9 +702,8 @@ static int send_associate_24g(struct imon_context *ictx)
 	}
 
 	memcpy(ictx->usb_tx_buf, packet, sizeof(packet));
-	retval = send_packet(ictx);
 
-	return retval;
+	return send_packet(ictx);
 }
 
 /*
@@ -761,7 +796,7 @@ static int send_set_imon_clock(struct imon_context *ictx,
 /*
  * These are the sysfs functions to handle the association on the iMON 2.4G LT.
  */
-static ssize_t show_associate_remote(struct device *d,
+static ssize_t associate_remote_show(struct device *d,
 				     struct device_attribute *attr,
 				     char *buf)
 {
@@ -776,12 +811,12 @@ static ssize_t show_associate_remote(struct device *d,
 	else
 		strscpy(buf, "closed\n", PAGE_SIZE);
 
-	dev_info(d, "Visit http://www.lirc.org/html/imon-24g.html for instructions on how to associate your iMON 2.4G DT/LT remote\n");
+	dev_info(d, "Visit https://www.lirc.org/html/imon-24g.html for instructions on how to associate your iMON 2.4G DT/LT remote\n");
 	mutex_unlock(&ictx->lock);
 	return strlen(buf);
 }
 
-static ssize_t store_associate_remote(struct device *d,
+static ssize_t associate_remote_store(struct device *d,
 				      struct device_attribute *attr,
 				      const char *buf, size_t count)
 {
@@ -803,7 +838,7 @@ static ssize_t store_associate_remote(struct device *d,
 /*
  * sysfs functions to control internal imon clock
  */
-static ssize_t show_imon_clock(struct device *d,
+static ssize_t imon_clock_show(struct device *d,
 			       struct device_attribute *attr, char *buf)
 {
 	struct imon_context *ictx = dev_get_drvdata(d);
@@ -815,13 +850,13 @@ static ssize_t show_imon_clock(struct device *d,
 	mutex_lock(&ictx->lock);
 
 	if (!ictx->display_supported) {
-		len = snprintf(buf, PAGE_SIZE, "Not supported.");
+		len = sysfs_emit(buf, "Not supported.");
 	} else {
-		len = snprintf(buf, PAGE_SIZE,
-			"To set the clock on your iMON display:\n"
-			"# date \"+%%y %%m %%d %%w %%H %%M %%S\" > imon_clock\n"
-			"%s", ictx->display_isopen ?
-			"\nNOTE: imon device must be closed\n" : "");
+		len = sysfs_emit(buf,
+				 "To set the clock on your iMON display:\n"
+				 "# date \"+%%y %%m %%d %%w %%H %%M %%S\" > imon_clock\n"
+				 "%s", ictx->display_isopen ?
+				 "\nNOTE: imon device must be closed\n" : "");
 	}
 
 	mutex_unlock(&ictx->lock);
@@ -829,7 +864,7 @@ static ssize_t show_imon_clock(struct device *d,
 	return len;
 }
 
-static ssize_t store_imon_clock(struct device *d,
+static ssize_t imon_clock_store(struct device *d,
 				struct device_attribute *attr,
 				const char *buf, size_t count)
 {
@@ -876,11 +911,8 @@ exit:
 }
 
 
-static DEVICE_ATTR(imon_clock, S_IWUSR | S_IRUGO, show_imon_clock,
-		   store_imon_clock);
-
-static DEVICE_ATTR(associate_remote, S_IWUSR | S_IRUGO, show_associate_remote,
-		   store_associate_remote);
+static DEVICE_ATTR_RW(imon_clock);
+static DEVICE_ATTR_RW(associate_remote);
 
 static struct attribute *imon_display_sysfs_entries[] = {
 	&dev_attr_imon_clock.attr,
@@ -918,17 +950,17 @@ static ssize_t vfd_write(struct file *file, const char __user *buf,
 	int offset;
 	int seq;
 	int retval = 0;
-	struct imon_context *ictx;
+	struct imon_context *ictx = file->private_data;
 	static const unsigned char vfd_packet6[] = {
 		0x01, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF };
 
-	ictx = file->private_data;
-	if (!ictx) {
-		pr_err_ratelimited("no context for device\n");
-		return -ENODEV;
-	}
+	if (mutex_lock_interruptible(&ictx->lock))
+		return -ERESTARTSYS;
 
-	mutex_lock(&ictx->lock);
+	if (ictx->disconnected) {
+		retval = -ENODEV;
+		goto exit;
+	}
 
 	if (!ictx->dev_present_intf0) {
 		pr_err_ratelimited("no iMON device present\n");
@@ -1002,16 +1034,15 @@ static ssize_t lcd_write(struct file *file, const char __user *buf,
 			 size_t n_bytes, loff_t *pos)
 {
 	int retval = 0;
-	struct imon_context *ictx;
-
-	ictx = file->private_data;
-	if (!ictx) {
-		pr_err_ratelimited("no context for device\n");
-		return -ENODEV;
-	}
+	struct imon_context *ictx = file->private_data;
 
 	mutex_lock(&ictx->lock);
 
+	if (ictx->disconnected) {
+		retval = -ENODEV;
+		goto exit;
+	}
+
 	if (!ictx->display_supported) {
 		pr_err_ratelimited("no iMON display present\n");
 		retval = -ENODEV;
@@ -1069,7 +1100,7 @@ static void usb_tx_callback(struct urb *urb)
  */
 static void imon_touch_display_timeout(struct timer_list *t)
 {
-	struct imon_context *ictx = from_timer(ictx, t, ttimer);
+	struct imon_context *ictx = timer_container_of(ictx, t, ttimer);
 
 	if (ictx->display_type != IMON_DISPLAY_TYPE_VGA)
 		return;
@@ -1099,7 +1130,7 @@ static int imon_ir_change_protocol(struct rc_dev *rc, u64 *rc_proto)
 	int retval;
 	struct imon_context *ictx = rc->priv;
 	struct device *dev = ictx->dev;
-	bool unlock = false;
+	const bool unlock = mutex_trylock(&ictx->lock);
 	unsigned char ir_proto_packet[] = {
 		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x86 };
 
@@ -1126,11 +1157,6 @@ static int imon_ir_change_protocol(struct rc_dev *rc, u64 *rc_proto)
 
 	memcpy(ictx->usb_tx_buf, &ir_proto_packet, sizeof(ir_proto_packet));
 
-	if (!mutex_is_locked(&ictx->lock)) {
-		unlock = true;
-		mutex_lock(&ictx->lock);
-	}
-
 	retval = send_packet(ictx);
 	if (retval)
 		goto out;
@@ -1273,9 +1299,11 @@ static u32 imon_mce_key_lookup(struct imon_context *ictx, u32 scancode)
 
 static u32 imon_panel_key_lookup(struct imon_context *ictx, u64 code)
 {
-	int i;
+	const struct imon_panel_key_table *key_table;
 	u32 keycode = KEY_RESERVED;
-	struct imon_panel_key_table *key_table = ictx->dev_descr->key_table;
+	int i;
+
+	key_table = ictx->dev_descr->key_table;
 
 	for (i = 0; key_table[i].hw_code != 0; i++) {
 		if (key_table[i].hw_code == (code | 0xffee)) {
@@ -1559,7 +1587,6 @@ static void imon_incoming_packet(struct imon_context *ictx,
 	u32 kc;
 	u64 scancode;
 	int press_type = 0;
-	long msec;
 	ktime_t t;
 	static ktime_t prev_time;
 	u8 ktype;
@@ -1607,8 +1634,7 @@ static void imon_incoming_packet(struct imon_context *ictx,
 	spin_unlock_irqrestore(&ictx->kc_lock, flags);
 
 	/* send touchscreen events through input subsystem if touchpad data */
-	if (ictx->display_type == IMON_DISPLAY_TYPE_VGA && len == 8 &&
-	    buf[7] == 0x86) {
+	if (ictx->touch && len == 8 && buf[7] == 0x86) {
 		imon_touch_event(ictx, buf);
 		return;
 
@@ -1662,14 +1688,16 @@ static void imon_incoming_packet(struct imon_context *ictx,
 	spin_lock_irqsave(&ictx->kc_lock, flags);
 
 	t = ktime_get();
-	/* KEY_MUTE repeats from knob need to be suppressed */
-	if (ictx->kc == KEY_MUTE && ictx->kc == ictx->last_keycode) {
-		msec = ktime_ms_delta(t, prev_time);
-		if (msec < ictx->idev->rep[REP_DELAY]) {
+	/* KEY repeats from knob and panel that need to be suppressed */
+	if (ictx->kc == KEY_MUTE ||
+	    ictx->dev_descr->flags & IMON_SUPPRESS_REPEATED_KEYS) {
+		if (ictx->kc == ictx->last_keycode &&
+		    ktime_ms_delta(t, prev_time) < ictx->idev->rep[REP_DELAY]) {
 			spin_unlock_irqrestore(&ictx->kc_lock, flags);
 			return;
 		}
 	}
+
 	prev_time = t;
 	kc = ictx->kc;
 
@@ -1724,14 +1752,6 @@ static void usb_rx_callback_intf0(struct urb *urb)
 	if (!ictx)
 		return;
 
-	/*
-	 * if we get a callback before we're done configuring the hardware, we
-	 * can't yet process the data, as there's nowhere to send it, but we
-	 * still need to submit a new rx URB to avoid wedging the hardware
-	 */
-	if (!ictx->dev_present_intf0)
-		goto out;
-
 	switch (urb->status) {
 	case -ENOENT:		/* usbcore unlink successful! */
 		return;
@@ -1740,16 +1760,29 @@ static void usb_rx_callback_intf0(struct urb *urb)
 		break;
 
 	case 0:
-		imon_incoming_packet(ictx, urb, intfnum);
+		/*
+		 * if we get a callback before we're done configuring the hardware, we
+		 * can't yet process the data, as there's nowhere to send it, but we
+		 * still need to submit a new rx URB to avoid wedging the hardware
+		 */
+		if (ictx->dev_present_intf0)
+			imon_incoming_packet(ictx, urb, intfnum);
 		break;
 
+	case -ECONNRESET:
+	case -EILSEQ:
+	case -EPROTO:
+	case -EPIPE:
+		dev_warn(ictx->dev, "imon %s: status(%d)\n",
+			 __func__, urb->status);
+		return;
+
 	default:
 		dev_warn(ictx->dev, "imon %s: status(%d): ignored\n",
 			 __func__, urb->status);
 		break;
 	}
 
-out:
 	usb_submit_urb(ictx->rx_urb_intf0, GFP_ATOMIC);
 }
 
@@ -1765,14 +1798,6 @@ static void usb_rx_callback_intf1(struct urb *urb)
 	if (!ictx)
 		return;
 
-	/*
-	 * if we get a callback before we're done configuring the hardware, we
-	 * can't yet process the data, as there's nowhere to send it, but we
-	 * still need to submit a new rx URB to avoid wedging the hardware
-	 */
-	if (!ictx->dev_present_intf1)
-		goto out;
-
 	switch (urb->status) {
 	case -ENOENT:		/* usbcore unlink successful! */
 		return;
@@ -1781,16 +1806,29 @@ static void usb_rx_callback_intf1(struct urb *urb)
 		break;
 
 	case 0:
-		imon_incoming_packet(ictx, urb, intfnum);
+		/*
+		 * if we get a callback before we're done configuring the hardware, we
+		 * can't yet process the data, as there's nowhere to send it, but we
+		 * still need to submit a new rx URB to avoid wedging the hardware
+		 */
+		if (ictx->dev_present_intf1)
+			imon_incoming_packet(ictx, urb, intfnum);
 		break;
 
+	case -ECONNRESET:
+	case -EILSEQ:
+	case -EPROTO:
+	case -EPIPE:
+		dev_warn(ictx->dev, "imon %s: status(%d)\n",
+			 __func__, urb->status);
+		return;
+
 	default:
 		dev_warn(ictx->dev, "imon %s: status(%d): ignored\n",
 			 __func__, urb->status);
 		break;
 	}
 
-out:
 	usb_submit_urb(ictx->rx_urb_intf1, GFP_ATOMIC);
 }
 
@@ -1835,12 +1873,17 @@ static void imon_get_ffdc_type(struct imon_context *ictx)
 		break;
 	/* iMON VFD, MCE IR */
 	case 0x46:
-	case 0x7e:
 	case 0x9e:
 		dev_info(ictx->dev, "0xffdc iMON VFD, MCE IR");
 		detected_display_type = IMON_DISPLAY_TYPE_VFD;
 		allowed_protos = RC_PROTO_BIT_RC6_MCE;
 		break;
+	/* iMON VFD, iMON or MCE IR */
+	case 0x7e:
+		dev_info(ictx->dev, "0xffdc iMON VFD, iMON or MCE IR");
+		detected_display_type = IMON_DISPLAY_TYPE_VFD;
+		allowed_protos |= RC_PROTO_BIT_RC6_MCE;
+		break;
 	/* iMON LCD, MCE IR */
 	case 0x9f:
 		dev_info(ictx->dev, "0xffdc iMON LCD, MCE IR");
@@ -1852,6 +1895,14 @@ static void imon_get_ffdc_type(struct imon_context *ictx)
 		dev_info(ictx->dev, "0xffdc iMON Inside, iMON IR");
 		ictx->display_supported = false;
 		break;
+	/* Soundgraph iMON UltraBay */
+	case 0x98:
+		dev_info(ictx->dev, "0xffdc iMON UltraBay, LCD + IR");
+		detected_display_type = IMON_DISPLAY_TYPE_LCD;
+		allowed_protos = RC_PROTO_BIT_IMON | RC_PROTO_BIT_RC6_MCE;
+		ictx->dev_descr = &ultrabay_table;
+		break;
+
 	default:
 		dev_info(ictx->dev, "Unknown 0xffdc device, defaulting to VFD and iMON IR");
 		detected_display_type = IMON_DISPLAY_TYPE_VFD;
@@ -1983,10 +2034,12 @@ out:
 
 static struct input_dev *imon_init_idev(struct imon_context *ictx)
 {
-	struct imon_panel_key_table *key_table = ictx->dev_descr->key_table;
+	const struct imon_panel_key_table *key_table;
 	struct input_dev *idev;
 	int ret, i;
 
+	key_table = ictx->dev_descr->key_table;
+
 	idev = input_allocate_device();
 	if (!idev)
 		goto out;
@@ -2325,8 +2378,10 @@ urb_submit_failed:
 touch_setup_failed:
 find_endpoint_failed:
 	usb_put_dev(ictx->usbdev_intf1);
+	ictx->usbdev_intf1 = NULL;
 	mutex_unlock(&ictx->lock);
 	usb_free_urb(rx_urb);
+	ictx->rx_urb_intf1 = NULL;
 rx_urb_alloc_failed:
 	dev_err(ictx->dev, "unable to initialize intf1, err %d\n", ret);
 
@@ -2369,7 +2424,6 @@ static int imon_probe(struct usb_interface *interface,
 	int ifnum, sysfs_err;
 	int ret = 0;
 	struct imon_context *ictx = NULL;
-	struct imon_context *first_if_ctx = NULL;
 	u16 vendor, product;
 
 	usbdev     = usb_get_dev(interface_to_usbdev(interface));
@@ -2381,16 +2435,17 @@ static int imon_probe(struct usb_interface *interface,
 	dev_dbg(dev, "%s: found iMON device (%04x:%04x, intf%d)\n",
 		__func__, vendor, product, ifnum);
 
-	/* prevent races probing devices w/multiple interfaces */
-	mutex_lock(&driver_lock);
-
 	first_if = usb_ifnum_to_if(usbdev, 0);
 	if (!first_if) {
 		ret = -ENODEV;
 		goto fail;
 	}
 
-	first_if_ctx = usb_get_intfdata(first_if);
+	if (first_if->dev.driver != interface->dev.driver) {
+		dev_err(&interface->dev, "inconsistent driver matching\n");
+		ret = -EINVAL;
+		goto fail;
+	}
 
 	if (ifnum == 0) {
 		ictx = imon_init_intf0(interface, id);
@@ -2399,9 +2454,11 @@ static int imon_probe(struct usb_interface *interface,
 			ret = -ENODEV;
 			goto fail;
 		}
+		refcount_set(&ictx->users, 1);
 
 	} else {
 		/* this is the secondary interface on the device */
+		struct imon_context *first_if_ctx = usb_get_intfdata(first_if);
 
 		/* fail early if first intf failed to register */
 		if (!first_if_ctx) {
@@ -2415,14 +2472,13 @@ static int imon_probe(struct usb_interface *interface,
 			ret = -ENODEV;
 			goto fail;
 		}
+		refcount_inc(&ictx->users);
 
 	}
 
 	usb_set_intfdata(interface, ictx);
 
 	if (ifnum == 0) {
-		mutex_lock(&ictx->lock);
-
 		if (product == 0xffdc && ictx->rf_device) {
 			sysfs_err = sysfs_create_group(&interface->dev.kobj,
 						       &imon_rf_attr_group);
@@ -2433,21 +2489,17 @@ static int imon_probe(struct usb_interface *interface,
 
 		if (ictx->display_supported)
 			imon_init_display(ictx, interface);
-
-		mutex_unlock(&ictx->lock);
 	}
 
 	dev_info(dev, "iMON device (%04x:%04x, intf%d) on usb<%d:%d> initialized\n",
 		 vendor, product, ifnum,
 		 usbdev->bus->busnum, usbdev->devnum);
 
-	mutex_unlock(&driver_lock);
 	usb_put_dev(usbdev);
 
 	return 0;
 
 fail:
-	mutex_unlock(&driver_lock);
 	usb_put_dev(usbdev);
 	dev_err(dev, "unable to register, err %d\n", ret);
 
@@ -2463,10 +2515,12 @@ static void imon_disconnect(struct usb_interface *interface)
 	struct device *dev;
 	int ifnum;
 
-	/* prevent races with multi-interface device probing and display_open */
-	mutex_lock(&driver_lock);
-
 	ictx = usb_get_intfdata(interface);
+
+	mutex_lock(&ictx->lock);
+	ictx->disconnected = true;
+	mutex_unlock(&ictx->lock);
+
 	dev = ictx->dev;
 	ifnum = interface->cur_altsetting->desc.bInterfaceNumber;
 
@@ -2488,7 +2542,6 @@ static void imon_disconnect(struct usb_interface *interface)
 	if (ifnum == 0) {
 		ictx->dev_present_intf0 = false;
 		usb_kill_urb(ictx->rx_urb_intf0);
-		usb_put_dev(ictx->usbdev_intf0);
 		input_unregister_device(ictx->idev);
 		rc_unregister_device(ictx->rdev);
 		if (ictx->display_supported) {
@@ -2497,21 +2550,20 @@ static void imon_disconnect(struct usb_interface *interface)
 			else if (ictx->display_type == IMON_DISPLAY_TYPE_VFD)
 				usb_deregister_dev(interface, &imon_vfd_class);
 		}
+		usb_put_dev(ictx->usbdev_intf0);
 	} else {
 		ictx->dev_present_intf1 = false;
 		usb_kill_urb(ictx->rx_urb_intf1);
-		usb_put_dev(ictx->usbdev_intf1);
 		if (ictx->display_type == IMON_DISPLAY_TYPE_VGA) {
+			timer_delete_sync(&ictx->ttimer);
 			input_unregister_device(ictx->touch);
-			del_timer_sync(&ictx->ttimer);
 		}
+		usb_put_dev(ictx->usbdev_intf1);
 	}
 
-	if (!ictx->dev_present_intf0 && !ictx->dev_present_intf1)
+	if (refcount_dec_and_test(&ictx->users))
 		free_imon_context(ictx);
 
-	mutex_unlock(&driver_lock);
-
 	dev_dbg(dev, "%s: iMON device (intf%d) disconnected\n",
 		__func__, ifnum);
 }
@@ -2543,7 +2595,7 @@ static int imon_resume(struct usb_interface *intf)
 			usb_rx_callback_intf0, ictx,
 			ictx->rx_endpoint_intf0->bInterval);
 
-		rc = usb_submit_urb(ictx->rx_urb_intf0, GFP_ATOMIC);
+		rc = usb_submit_urb(ictx->rx_urb_intf0, GFP_NOIO);
 
 	} else {
 		usb_fill_int_urb(ictx->rx_urb_intf1, ictx->usbdev_intf1,
@@ -2553,7 +2605,7 @@ static int imon_resume(struct usb_interface *intf)
 			usb_rx_callback_intf1, ictx,
 			ictx->rx_endpoint_intf1->bInterval);
 
-		rc = usb_submit_urb(ictx->rx_urb_intf1, GFP_ATOMIC);
+		rc = usb_submit_urb(ictx->rx_urb_intf1, GFP_NOIO);
 	}
 
 	return rc;