Merge tag 'usb-serial-5.12-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-next

Johan writes:

USB-serial updates for 5.12-rc1

Here are the USB-serial updates for 5.12-rc1, including:

 - a line-speed fix for newer pl2303 devices
 - a line-speed fix for FTDI FT-X devices
 - a new xr_serial driver for MaxLinear/Exar devices (non-ACM mode)
 - a cdc-acm blacklist entry for when the xr_serial driver is enabled
 - cp210x support for software flow control
 - various cp210x modem-control fixes
 - an updated ZTE P685M modem entry to stop claiming the QMI interface
 - an update to drop the port_remove() driver-callback return value

Included are also various clean ups.

All have been in linux-next with no reported issues.

* tag 'usb-serial-5.12-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial: (41 commits)
  USB: serial: drop bogus to_usb_serial_port() checks
  USB: serial: make remove callback return void
  USB: serial: drop if with an always false condition
  USB: serial: option: update interface mapping for ZTE P685M
  USB: serial: ftdi_sio: restore divisor-encoding comments
  USB: serial: ftdi_sio: fix FTX sub-integer prescaler
  USB: serial: cp210x: clean up auto-RTS handling
  USB: serial: cp210x: fix RTS handling
  USB: serial: cp210x: clean up printk zero padding
  USB: serial: cp210x: clean up flow-control debug message
  USB: serial: cp210x: drop shift macros
  USB: serial: cp210x: fix modem-control handling
  USB: serial: cp210x: suppress modem-control errors
  USB: serial: mos7720: fix error code in mos7720_write()
  USB: serial: xr: fix B0 handling
  USB: serial: xr: fix pin configuration
  USB: serial: xr: fix gpio-mode handling
  USB: serial: xr: simplify line-speed logic
  USB: serial: xr: clean up line-settings handling
  USB: serial: xr: document vendor-request recipient
  ...

44 files changed, 888 insertions, 225 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 781905745812..37f824b59daa 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1901,6 +1901,12 @@ static const struct usb_device_id acm_ids[] = {
 	},
 #endif
 
+#if IS_ENABLED(CONFIG_USB_SERIAL_XR)
+	{ USB_DEVICE(0x04e2, 0x1410),   /* Ignore XR21V141X USB to Serial converter */
+	.driver_info = IGNORE_DEVICE,
+	},
+#endif
+
 	/*Samsung phone in firmware update mode */
 	{ USB_DEVICE(0x04e8, 0x685d),
 	.driver_info = IGNORE_DEVICE,
diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index a21ff5ab6df9..de5c01257060 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -633,6 +633,15 @@ config USB_SERIAL_UPD78F0730
 	  To compile this driver as a module, choose M here: the
 	  module will be called upd78f0730.
 
+config USB_SERIAL_XR
+	tristate "USB MaxLinear/Exar USB to Serial driver"
+	help
+	  Say Y here if you want to use MaxLinear/Exar USB to Serial converter
+	  devices.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called xr_serial.
+
 config USB_SERIAL_DEBUG
 	tristate "USB Debugging Device"
 	help
diff --git a/drivers/usb/serial/Makefile b/drivers/usb/serial/Makefile
index 50c53aed787a..c7bb1a88173e 100644
--- a/drivers/usb/serial/Makefile
+++ b/drivers/usb/serial/Makefile
@@ -61,4 +61,5 @@ obj-$(CONFIG_USB_SERIAL_UPD78F0730)		+= upd78f0730.o
 obj-$(CONFIG_USB_SERIAL_VISOR)			+= visor.o
 obj-$(CONFIG_USB_SERIAL_WISHBONE)		+= wishbone-serial.o
 obj-$(CONFIG_USB_SERIAL_WHITEHEAT)		+= whiteheat.o
+obj-$(CONFIG_USB_SERIAL_XR)			+= xr_serial.o
 obj-$(CONFIG_USB_SERIAL_XSENS_MT)		+= xsens_mt.o
diff --git a/drivers/usb/serial/ark3116.c b/drivers/usb/serial/ark3116.c
index 71a9206ea1e2..f0ac7bb07ac1 100644
--- a/drivers/usb/serial/ark3116.c
+++ b/drivers/usb/serial/ark3116.c
@@ -178,15 +178,13 @@ static int ark3116_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int ark3116_port_remove(struct usb_serial_port *port)
+static void ark3116_port_remove(struct usb_serial_port *port)
 {
 	struct ark3116_private *priv = usb_get_serial_port_data(port);
 
 	/* device is closed, so URBs and DMA should be down */
 	mutex_destroy(&priv->hw_lock);
 	kfree(priv);
-
-	return 0;
 }
 
 static void ark3116_set_termios(struct tty_struct *tty,
diff --git a/drivers/usb/serial/belkin_sa.c b/drivers/usb/serial/belkin_sa.c
index 9bb123ab9bc9..ed9193f3bb1a 100644
--- a/drivers/usb/serial/belkin_sa.c
+++ b/drivers/usb/serial/belkin_sa.c
@@ -37,7 +37,7 @@
 
 /* function prototypes for a Belkin USB Serial Adapter F5U103 */
 static int belkin_sa_port_probe(struct usb_serial_port *port);
-static int belkin_sa_port_remove(struct usb_serial_port *port);
+static void belkin_sa_port_remove(struct usb_serial_port *port);
 static int  belkin_sa_open(struct tty_struct *tty,
 			struct usb_serial_port *port);
 static void belkin_sa_close(struct usb_serial_port *port);
@@ -134,14 +134,12 @@ static int belkin_sa_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int belkin_sa_port_remove(struct usb_serial_port *port)
+static void belkin_sa_port_remove(struct usb_serial_port *port)
 {
 	struct belkin_sa_private *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static int belkin_sa_open(struct tty_struct *tty,
diff --git a/drivers/usb/serial/bus.c b/drivers/usb/serial/bus.c
index eb0195cf37dd..7133818a58b9 100644
--- a/drivers/usb/serial/bus.c
+++ b/drivers/usb/serial/bus.c
@@ -16,19 +16,13 @@
 static int usb_serial_device_match(struct device *dev,
 						struct device_driver *drv)
 {
-	struct usb_serial_driver *driver;
-	const struct usb_serial_port *port;
+	const struct usb_serial_port *port = to_usb_serial_port(dev);
+	struct usb_serial_driver *driver = to_usb_serial_driver(drv);
 
 	/*
 	 * drivers are already assigned to ports in serial_probe so it's
 	 * a simple check here.
 	 */
-	port = to_usb_serial_port(dev);
-	if (!port)
-		return 0;
-
-	driver = to_usb_serial_driver(drv);
-
 	if (driver == port->serial->type)
 		return 1;
 
@@ -37,16 +31,12 @@ static int usb_serial_device_match(struct device *dev,
 
 static int usb_serial_device_probe(struct device *dev)
 {
+	struct usb_serial_port *port = to_usb_serial_port(dev);
 	struct usb_serial_driver *driver;
-	struct usb_serial_port *port;
 	struct device *tty_dev;
 	int retval = 0;
 	int minor;
 
-	port = to_usb_serial_port(dev);
-	if (!port)
-		return -ENODEV;
-
 	/* make sure suspend/resume doesn't race against port_probe */
 	retval = usb_autopm_get_interface(port->serial->interface);
 	if (retval)
@@ -86,16 +76,11 @@ err_autopm_put:
 
 static int usb_serial_device_remove(struct device *dev)
 {
+	struct usb_serial_port *port = to_usb_serial_port(dev);
 	struct usb_serial_driver *driver;
-	struct usb_serial_port *port;
-	int retval = 0;
 	int minor;
 	int autopm_err;
 
-	port = to_usb_serial_port(dev);
-	if (!port)
-		return -ENODEV;
-
 	/*
 	 * Make sure suspend/resume doesn't race against port_remove.
 	 *
@@ -109,7 +94,7 @@ static int usb_serial_device_remove(struct device *dev)
 
 	driver = port->serial->type;
 	if (driver->port_remove)
-		retval = driver->port_remove(port);
+		driver->port_remove(port);
 
 	dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
 		 driver->description, minor);
@@ -117,7 +102,7 @@ static int usb_serial_device_remove(struct device *dev)
 	if (!autopm_err)
 		usb_autopm_put_interface(port->serial->interface);
 
-	return retval;
+	return 0;
 }
 
 static ssize_t new_id_store(struct device_driver *driver,
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 28deaaec581f..8d997b71056f 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -419,14 +419,12 @@ error:	kfree(priv);
 	return r;
 }
 
-static int ch341_port_remove(struct usb_serial_port *port)
+static void ch341_port_remove(struct usb_serial_port *port)
 {
 	struct ch341_private *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static int ch341_carrier_raised(struct usb_serial_port *port)
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 7bec1e730b20..9e1c609792fb 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -3,6 +3,7 @@
  * Silicon Laboratories CP210x USB to RS232 serial adaptor driver
  *
  * Copyright (C) 2005 Craig Shelley (craig@microtron.org.uk)
+ * Copyright (C) 2010-2021 Johan Hovold (johan@kernel.org)
  *
  * Support to set flow control line levels using TIOCMGET and TIOCMSET
  * thanks to Karl Hiramoto karl@hiramoto.org. RTSCTS hardware flow
@@ -16,9 +17,7 @@
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
 #include <linux/module.h>
-#include <linux/moduleparam.h>
 #include <linux/usb.h>
-#include <linux/uaccess.h>
 #include <linux/usb/serial.h>
 #include <linux/gpio/driver.h>
 #include <linux/bitops.h>
@@ -45,7 +44,7 @@ static int cp210x_attach(struct usb_serial *);
 static void cp210x_disconnect(struct usb_serial *);
 static void cp210x_release(struct usb_serial *);
 static int cp210x_port_probe(struct usb_serial_port *);
-static int cp210x_port_remove(struct usb_serial_port *);
+static void cp210x_port_remove(struct usb_serial_port *);
 static void cp210x_dtr_rts(struct usb_serial_port *port, int on);
 static void cp210x_process_read_urb(struct urb *urb);
 static void cp210x_enable_event_mode(struct usb_serial_port *port);
@@ -268,7 +267,12 @@ struct cp210x_port_private {
 	u8			bInterfaceNumber;
 	bool			event_mode;
 	enum cp210x_event_state event_state;
-	u8 lsr;
+	u8			lsr;
+
+	struct mutex		mutex;
+	bool			crtscts;
+	bool			dtr;
+	bool			rts;
 };
 
 static struct usb_serial_driver cp210x_device = {
@@ -379,6 +383,16 @@ static struct usb_serial_driver * const serial_drivers[] = {
 #define CONTROL_WRITE_DTR	0x0100
 #define CONTROL_WRITE_RTS	0x0200
 
+/* CP210X_(GET|SET)_CHARS */
+struct cp210x_special_chars {
+	u8	bEofChar;
+	u8	bErrorChar;
+	u8	bBreakChar;
+	u8	bEventChar;
+	u8	bXonChar;
+	u8	bXoffChar;
+};
+
 /* CP210X_VENDOR_SPECIFIC values */
 #define CP210X_READ_2NCONFIG	0x000E
 #define CP210X_READ_LATCH	0x00C2
@@ -437,17 +451,14 @@ struct cp210x_flow_ctl {
 
 /* cp210x_flow_ctl::ulControlHandshake */
 #define CP210X_SERIAL_DTR_MASK		GENMASK(1, 0)
-#define CP210X_SERIAL_DTR_SHIFT(_mode)	(_mode)
+#define CP210X_SERIAL_DTR_INACTIVE	(0 << 0)
+#define CP210X_SERIAL_DTR_ACTIVE	(1 << 0)
+#define CP210X_SERIAL_DTR_FLOW_CTL	(2 << 0)
 #define CP210X_SERIAL_CTS_HANDSHAKE	BIT(3)
 #define CP210X_SERIAL_DSR_HANDSHAKE	BIT(4)
 #define CP210X_SERIAL_DCD_HANDSHAKE	BIT(5)
 #define CP210X_SERIAL_DSR_SENSITIVITY	BIT(6)
 
-/* values for cp210x_flow_ctl::ulControlHandshake::CP210X_SERIAL_DTR_MASK */
-#define CP210X_SERIAL_DTR_INACTIVE	0
-#define CP210X_SERIAL_DTR_ACTIVE	1
-#define CP210X_SERIAL_DTR_FLOW_CTL	2
-
 /* cp210x_flow_ctl::ulFlowReplace */
 #define CP210X_SERIAL_AUTO_TRANSMIT	BIT(0)
 #define CP210X_SERIAL_AUTO_RECEIVE	BIT(1)
@@ -455,14 +466,11 @@ struct cp210x_flow_ctl {
 #define CP210X_SERIAL_NULL_STRIPPING	BIT(3)
 #define CP210X_SERIAL_BREAK_CHAR	BIT(4)
 #define CP210X_SERIAL_RTS_MASK		GENMASK(7, 6)
-#define CP210X_SERIAL_RTS_SHIFT(_mode)	(_mode << 6)
+#define CP210X_SERIAL_RTS_INACTIVE	(0 << 6)
+#define CP210X_SERIAL_RTS_ACTIVE	(1 << 6)
+#define CP210X_SERIAL_RTS_FLOW_CTL	(2 << 6)
 #define CP210X_SERIAL_XOFF_CONTINUE	BIT(31)
 
-/* values for cp210x_flow_ctl::ulFlowReplace::CP210X_SERIAL_RTS_MASK */
-#define CP210X_SERIAL_RTS_INACTIVE	0
-#define CP210X_SERIAL_RTS_ACTIVE	1
-#define CP210X_SERIAL_RTS_FLOW_CTL	2
-
 /* CP210X_VENDOR_SPECIFIC, CP210X_GET_DEVICEMODE call reads these 0x2 bytes. */
 struct cp210x_pin_mode {
 	u8	eci;
@@ -666,16 +674,13 @@ static int cp210x_write_reg_block(struct usb_serial_port *port, u8 req,
 
 	kfree(dmabuf);
 
-	if (result == bufsize) {
-		result = 0;
-	} else {
+	if (result < 0) {
 		dev_err(&port->dev, "failed set req 0x%x size %d status: %d\n",
 				req, bufsize, result);
-		if (result >= 0)
-			result = -EIO;
+		return result;
 	}
 
-	return result;
+	return 0;
 }
 
 /*
@@ -712,17 +717,14 @@ static int cp210x_write_vendor_block(struct usb_serial *serial, u8 type,
 
 	kfree(dmabuf);
 
-	if (result == bufsize) {
-		result = 0;
-	} else {
+	if (result < 0) {
 		dev_err(&serial->interface->dev,
 			"failed to set vendor val 0x%04x size %d: %d\n", val,
 			bufsize, result);
-		if (result >= 0)
-			result = -EIO;
+		return result;
 	}
 
-	return result;
+	return 0;
 }
 #endif
 
@@ -1076,30 +1078,80 @@ static void cp210x_disable_event_mode(struct usb_serial_port *port)
 	port_priv->event_mode = false;
 }
 
+static int cp210x_set_chars(struct usb_serial_port *port,
+		struct cp210x_special_chars *chars)
+{
+	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
+	struct usb_serial *serial = port->serial;
+	void *dmabuf;
+	int result;
+
+	dmabuf = kmemdup(chars, sizeof(*chars), GFP_KERNEL);
+	if (!dmabuf)
+		return -ENOMEM;
+
+	result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
+				CP210X_SET_CHARS, REQTYPE_HOST_TO_INTERFACE, 0,
+				port_priv->bInterfaceNumber,
+				dmabuf, sizeof(*chars), USB_CTRL_SET_TIMEOUT);
+
+	kfree(dmabuf);
+
+	if (result < 0) {
+		dev_err(&port->dev, "failed to set special chars: %d\n", result);
+		return result;
+	}
+
+	return 0;
+}
+
 static bool cp210x_termios_change(const struct ktermios *a, const struct ktermios *b)
 {
-	bool iflag_change;
+	bool iflag_change, cc_change;
 
-	iflag_change = ((a->c_iflag ^ b->c_iflag) & INPCK);
+	iflag_change = ((a->c_iflag ^ b->c_iflag) & (INPCK | IXON | IXOFF));
+	cc_change = a->c_cc[VSTART] != b->c_cc[VSTART] ||
+			a->c_cc[VSTOP] != b->c_cc[VSTOP];
 
-	return tty_termios_hw_change(a, b) || iflag_change;
+	return tty_termios_hw_change(a, b) || iflag_change || cc_change;
 }
 
 static void cp210x_set_flow_control(struct tty_struct *tty,
 		struct usb_serial_port *port, struct ktermios *old_termios)
 {
+	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
+	struct cp210x_special_chars chars;
 	struct cp210x_flow_ctl flow_ctl;
 	u32 flow_repl;
 	u32 ctl_hs;
 	int ret;
 
-	if (old_termios && C_CRTSCTS(tty) == (old_termios->c_cflag & CRTSCTS))
+	if (old_termios &&
+			C_CRTSCTS(tty) == (old_termios->c_cflag & CRTSCTS) &&
+			I_IXON(tty) == (old_termios->c_iflag & IXON) &&
+			I_IXOFF(tty) == (old_termios->c_iflag & IXOFF) &&
+			START_CHAR(tty) == old_termios->c_cc[VSTART] &&
+			STOP_CHAR(tty) == old_termios->c_cc[VSTOP]) {
 		return;
+	}
+
+	if (I_IXON(tty) || I_IXOFF(tty)) {
+		memset(&chars, 0, sizeof(chars));
+
+		chars.bXonChar = START_CHAR(tty);
+		chars.bXoffChar = STOP_CHAR(tty);
+
+		ret = cp210x_set_chars(port, &chars);
+		if (ret)
+			return;
+	}
+
+	mutex_lock(&port_priv->mutex);
 
 	ret = cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,
 			sizeof(flow_ctl));
 	if (ret)
-		return;
+		goto out_unlock;
 
 	ctl_hs = le32_to_cpu(flow_ctl.ulControlHandshake);
 	flow_repl = le32_to_cpu(flow_ctl.ulFlowReplace);
@@ -1108,26 +1160,51 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 	ctl_hs &= ~CP210X_SERIAL_DCD_HANDSHAKE;
 	ctl_hs &= ~CP210X_SERIAL_DSR_SENSITIVITY;
 	ctl_hs &= ~CP210X_SERIAL_DTR_MASK;
-	ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_ACTIVE);
+	if (port_priv->dtr)
+		ctl_hs |= CP210X_SERIAL_DTR_ACTIVE;
+	else
+		ctl_hs |= CP210X_SERIAL_DTR_INACTIVE;
 
+	flow_repl &= ~CP210X_SERIAL_RTS_MASK;
 	if (C_CRTSCTS(tty)) {
 		ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE;
-		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
-		flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_FLOW_CTL);
+		if (port_priv->rts)
+			flow_repl |= CP210X_SERIAL_RTS_FLOW_CTL;
+		else
+			flow_repl |= CP210X_SERIAL_RTS_INACTIVE;
+		port_priv->crtscts = true;
 	} else {
 		ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE;
-		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
-		flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_ACTIVE);
+		if (port_priv->rts)
+			flow_repl |= CP210X_SERIAL_RTS_ACTIVE;
+		else
+			flow_repl |= CP210X_SERIAL_RTS_INACTIVE;
+		port_priv->crtscts = false;
 	}
 
-	dev_dbg(&port->dev, "%s - ulControlHandshake=0x%08x, ulFlowReplace=0x%08x\n",
-			__func__, ctl_hs, flow_repl);
+	if (I_IXOFF(tty))
+		flow_repl |= CP210X_SERIAL_AUTO_RECEIVE;
+	else
+		flow_repl &= ~CP210X_SERIAL_AUTO_RECEIVE;
+
+	if (I_IXON(tty))
+		flow_repl |= CP210X_SERIAL_AUTO_TRANSMIT;
+	else
+		flow_repl &= ~CP210X_SERIAL_AUTO_TRANSMIT;
+
+	flow_ctl.ulXonLimit = cpu_to_le32(128);
+	flow_ctl.ulXoffLimit = cpu_to_le32(128);
+
+	dev_dbg(&port->dev, "%s - ctrl = 0x%02x, flow = 0x%02x\n", __func__,
+			ctl_hs, flow_repl);
 
 	flow_ctl.ulControlHandshake = cpu_to_le32(ctl_hs);
 	flow_ctl.ulFlowReplace = cpu_to_le32(flow_repl);
 
 	cp210x_write_reg_block(port, CP210X_SET_FLOW, &flow_ctl,
 			sizeof(flow_ctl));
+out_unlock:
+	mutex_unlock(&port_priv->mutex);
 }
 
 static void cp210x_set_termios(struct tty_struct *tty,
@@ -1212,28 +1289,77 @@ static int cp210x_tiocmset(struct tty_struct *tty,
 static int cp210x_tiocmset_port(struct usb_serial_port *port,
 		unsigned int set, unsigned int clear)
 {
+	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
+	struct cp210x_flow_ctl flow_ctl;
+	u32 ctl_hs, flow_repl;
 	u16 control = 0;
+	int ret;
+
+	mutex_lock(&port_priv->mutex);
 
 	if (set & TIOCM_RTS) {
+		port_priv->rts = true;
 		control |= CONTROL_RTS;
 		control |= CONTROL_WRITE_RTS;
 	}
 	if (set & TIOCM_DTR) {
+		port_priv->dtr = true;
 		control |= CONTROL_DTR;
 		control |= CONTROL_WRITE_DTR;
 	}
 	if (clear & TIOCM_RTS) {
+		port_priv->rts = false;
 		control &= ~CONTROL_RTS;
 		control |= CONTROL_WRITE_RTS;
 	}
 	if (clear & TIOCM_DTR) {
+		port_priv->dtr = false;
 		control &= ~CONTROL_DTR;
 		control |= CONTROL_WRITE_DTR;
 	}
 
-	dev_dbg(&port->dev, "%s - control = 0x%.4x\n", __func__, control);
+	/*
+	 * Use SET_FLOW to set DTR and enable/disable auto-RTS when hardware
+	 * flow control is enabled.
+	 */
+	if (port_priv->crtscts && control & CONTROL_WRITE_RTS) {
+		ret = cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,
+				sizeof(flow_ctl));
+		if (ret)
+			goto out_unlock;
+
+		ctl_hs = le32_to_cpu(flow_ctl.ulControlHandshake);
+		flow_repl = le32_to_cpu(flow_ctl.ulFlowReplace);
+
+		ctl_hs &= ~CP210X_SERIAL_DTR_MASK;
+		if (port_priv->dtr)
+			ctl_hs |= CP210X_SERIAL_DTR_ACTIVE;
+		else
+			ctl_hs |= CP210X_SERIAL_DTR_INACTIVE;
 
-	return cp210x_write_u16_reg(port, CP210X_SET_MHS, control);
+		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
+		if (port_priv->rts)
+			flow_repl |= CP210X_SERIAL_RTS_FLOW_CTL;
+		else
+			flow_repl |= CP210X_SERIAL_RTS_INACTIVE;
+
+		flow_ctl.ulControlHandshake = cpu_to_le32(ctl_hs);
+		flow_ctl.ulFlowReplace = cpu_to_le32(flow_repl);
+
+		dev_dbg(&port->dev, "%s - ctrl = 0x%02x, flow = 0x%02x\n",
+				__func__, ctl_hs, flow_repl);
+
+		ret = cp210x_write_reg_block(port, CP210X_SET_FLOW, &flow_ctl,
+				sizeof(flow_ctl));
+	} else {
+		dev_dbg(&port->dev, "%s - control = 0x%04x\n", __func__, control);
+
+		ret = cp210x_write_u16_reg(port, CP210X_SET_MHS, control);
+	}
+out_unlock:
+	mutex_unlock(&port_priv->mutex);
+
+	return ret;
 }
 
 static void cp210x_dtr_rts(struct usb_serial_port *port, int on)
@@ -1261,7 +1387,7 @@ static int cp210x_tiocmget(struct tty_struct *tty)
 		|((control & CONTROL_RING)? TIOCM_RI  : 0)
 		|((control & CONTROL_DCD) ? TIOCM_CD  : 0);
 
-	dev_dbg(&port->dev, "%s - control = 0x%.2x\n", __func__, control);
+	dev_dbg(&port->dev, "%s - control = 0x%02x\n", __func__, control);
 
 	return result;
 }
@@ -1710,20 +1836,19 @@ static int cp210x_port_probe(struct usb_serial_port *port)
 		return -ENOMEM;
 
 	port_priv->bInterfaceNumber = cp210x_interface_num(serial);
+	mutex_init(&port_priv->mutex);
 
 	usb_set_serial_port_data(port, port_priv);
 
 	return 0;
 }
 
-static int cp210x_port_remove(struct usb_serial_port *port)
+static void cp210x_port_remove(struct usb_serial_port *port)
 {
 	struct cp210x_port_private *port_priv;
 
 	port_priv = usb_get_serial_port_data(port);
 	kfree(port_priv);
-
-	return 0;
 }
 
 static void cp210x_init_max_speed(struct usb_serial *serial)
diff --git a/drivers/usb/serial/cyberjack.c b/drivers/usb/serial/cyberjack.c
index 2e40908963da..cf389224d528 100644
--- a/drivers/usb/serial/cyberjack.c
+++ b/drivers/usb/serial/cyberjack.c
@@ -47,7 +47,7 @@
 
 /* Function prototypes */
 static int cyberjack_port_probe(struct usb_serial_port *port);
-static int cyberjack_port_remove(struct usb_serial_port *port);
+static void cyberjack_port_remove(struct usb_serial_port *port);
 static int  cyberjack_open(struct tty_struct *tty,
 	struct usb_serial_port *port);
 static void cyberjack_close(struct usb_serial_port *port);
@@ -120,7 +120,7 @@ static int cyberjack_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int cyberjack_port_remove(struct usb_serial_port *port)
+static void cyberjack_port_remove(struct usb_serial_port *port)
 {
 	struct cyberjack_private *priv;
 
@@ -128,8 +128,6 @@ static int cyberjack_port_remove(struct usb_serial_port *port)
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static int  cyberjack_open(struct tty_struct *tty,
diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index cc028601c388..166ee2286fda 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -115,7 +115,7 @@ struct cypress_private {
 static int  cypress_earthmate_port_probe(struct usb_serial_port *port);
 static int  cypress_hidcom_port_probe(struct usb_serial_port *port);
 static int  cypress_ca42v2_port_probe(struct usb_serial_port *port);
-static int  cypress_port_remove(struct usb_serial_port *port);
+static void cypress_port_remove(struct usb_serial_port *port);
 static int  cypress_open(struct tty_struct *tty, struct usb_serial_port *port);
 static void cypress_close(struct usb_serial_port *port);
 static void cypress_dtr_rts(struct usb_serial_port *port, int on);
@@ -564,7 +564,7 @@ static int cypress_ca42v2_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int cypress_port_remove(struct usb_serial_port *port)
+static void cypress_port_remove(struct usb_serial_port *port)
 {
 	struct cypress_private *priv;
 
@@ -572,8 +572,6 @@ static int cypress_port_remove(struct usb_serial_port *port)
 
 	kfifo_free(&priv->write_fifo);
 	kfree(priv);
-
-	return 0;
 }
 
 static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port)
diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index 0ecd5316d85f..8b2f06539f2c 100644
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/