USB-serial updates for 5.7-rc1

Here are the USB-serial updates for 5.7-rc1, including: - support for a new family of Fintek devices - fix for an io-edgeport slab-out-of-bounds access - fixes for a couple of kernel-doc issues Included are also various clean ups and some new modem device ids. All but the io-edgeport fix have been in linux-next with no reported issues. -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQQHbPq+cpGvN/peuzMLxc3C7H1lCAUCXnx+TQAKCRALxc3C7H1l CEGnAQCCITnwkGkLZe64yyEM9txUw5oXSRFvoURs7en/2+2YZQD/br8Ygn24NgFh Qg0dZKSoh7FLGGlJm2Dnny31Edz7kAY= =k8M6 -----END PGP SIGNATURE----- Merge tag 'usb-serial-5.7-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-next Johan writes: USB-serial updates for 5.7-rc1 Here are the USB-serial updates for 5.7-rc1, including: - support for a new family of Fintek devices - fix for an io-edgeport slab-out-of-bounds access - fixes for a couple of kernel-doc issues Included are also various clean ups and some new modem device ids. All but the io-edgeport fix have been in linux-next with no reported issues. * tag 'usb-serial-5.7-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial: USB: serial: io_edgeport: fix slab-out-of-bounds read in edge_interrupt_callback USB: serial: option: add Wistron Neweb D19Q1 USB: serial: option: add BroadMobi BM806U USB: serial: option: add support for ASKEY WWHC050 USB: serial: f81232: add control driver for F81534A USB: serial: fix tty cleanup-op kernel-doc USB: serial: clean up carrier-detect helper USB: serial: f81232: set F81534A serial port with RS232 mode USB: serial: f81232: add F81534A support USB: serial: f81232: use devm_kzalloc for port data USB: serial: f81232: add tx_empty function USB: serial: f81232: extract LSR handler USB: serial: digi_acceleport: remove redundant assignment to pointer priv USB: serial: relax unthrottle memory barrier
2020-03-26 11:15:30 +01:00 · 2020-03-26 11:15:30 +01:00 · 0fa84af850
commit 0fa84af850
parent a599a0fb62 57aa9f294b
6 changed files with 332 additions and 46 deletions
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@ -1472,7 +1472,7 @@ static int digi_read_oob_callback(struct urb *urb)
 	struct usb_serial_port *port = urb->context;
 	struct usb_serial *serial = port->serial;
 	struct tty_struct *tty;
-	struct digi_port *priv = usb_get_serial_port_data(port);
+	struct digi_port *priv;
 	unsigned char *buf = urb->transfer_buffer;
 	int opcode, line, status, val;
 	unsigned long flags;
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
 * Fintek F81232 USB to serial adaptor driver
+ * Fintek F81532A/534A/535/536 USB to 2/4/8/12 serial adaptor driver
 *
 * Copyright (C) 2012 Greg Kroah-Hartman (gregkh@linuxfoundation.org)
 * Copyright (C) 2012 Linux Foundation
@ -21,11 +22,45 @@
 #include <linux/usb/serial.h>
 #include <linux/serial_reg.h>

-static const struct usb_device_id id_table[] = {
-	{ USB_DEVICE(0x1934, 0x0706) },
+#define F81232_ID		\
+	{ USB_DEVICE(0x1934, 0x0706) }	/* 1 port UART device */
+
+#define F81534A_SERIES_ID	\
+	{ USB_DEVICE(0x2c42, 0x1602) },	/* In-Box 2 port UART device */	\
+	{ USB_DEVICE(0x2c42, 0x1604) },	/* In-Box 4 port UART device */	\
+	{ USB_DEVICE(0x2c42, 0x1605) },	/* In-Box 8 port UART device */	\
+	{ USB_DEVICE(0x2c42, 0x1606) },	/* In-Box 12 port UART device */ \
+	{ USB_DEVICE(0x2c42, 0x1608) },	/* Non-Flash type */ \
+	{ USB_DEVICE(0x2c42, 0x1632) },	/* 2 port UART device */ \
+	{ USB_DEVICE(0x2c42, 0x1634) },	/* 4 port UART device */ \
+	{ USB_DEVICE(0x2c42, 0x1635) },	/* 8 port UART device */ \
+	{ USB_DEVICE(0x2c42, 0x1636) }	/* 12 port UART device */
+
+#define F81534A_CTRL_ID		\
+	{ USB_DEVICE(0x2c42, 0x16f8) }	/* Global control device */
+
+static const struct usb_device_id f81232_id_table[] = {
+	F81232_ID,
 	{ }					/* Terminating entry */
 };
-MODULE_DEVICE_TABLE(usb, id_table);
+
+static const struct usb_device_id f81534a_id_table[] = {
+	F81534A_SERIES_ID,
+	{ }					/* Terminating entry */
+};
+
+static const struct usb_device_id f81534a_ctrl_id_table[] = {
+	F81534A_CTRL_ID,
+	{ }					/* Terminating entry */
+};
+
+static const struct usb_device_id combined_id_table[] = {
+	F81232_ID,
+	F81534A_SERIES_ID,
+	F81534A_CTRL_ID,
+	{ }					/* Terminating entry */
+};
+MODULE_DEVICE_TABLE(usb, combined_id_table);

 /* Maximum baudrate for F81232 */
 #define F81232_MAX_BAUDRATE		1500000
@ -35,6 +70,7 @@ MODULE_DEVICE_TABLE(usb, id_table);
 #define F81232_REGISTER_REQUEST		0xa0
 #define F81232_GET_REGISTER		0xc0
 #define F81232_SET_REGISTER		0x40
+#define F81534A_ACCESS_REG_RETRY	2

 #define SERIAL_BASE_ADDRESS		0x0120
 #define RECEIVE_BUFFER_REGISTER		(0x00 + SERIAL_BASE_ADDRESS)
@ -61,6 +97,22 @@ MODULE_DEVICE_TABLE(usb, id_table);
 #define F81232_CLK_14_77_MHZ		(BIT(1) | BIT(0))
 #define F81232_CLK_MASK			GENMASK(1, 0)

+#define F81534A_MODE_REG		0x107
+#define F81534A_TRIGGER_MASK		GENMASK(3, 2)
+#define F81534A_TRIGGER_MULTIPLE_4X	BIT(3)
+#define F81534A_FIFO_128BYTE		(BIT(1) | BIT(0))
+
+/* Serial port self GPIO control, 2bytes [control&output data][input data] */
+#define F81534A_GPIO_REG		0x10e
+#define F81534A_GPIO_MODE2_DIR		BIT(6) /* 1: input, 0: output */
+#define F81534A_GPIO_MODE1_DIR		BIT(5)
+#define F81534A_GPIO_MODE0_DIR		BIT(4)
+#define F81534A_GPIO_MODE2_OUTPUT	BIT(2)
+#define F81534A_GPIO_MODE1_OUTPUT	BIT(1)
+#define F81534A_GPIO_MODE0_OUTPUT	BIT(0)
+
+#define F81534A_CTRL_CMD_ENABLE_PORT	0x116
+
 struct f81232_private {
 	struct mutex lock;
 	u8 modem_control;
@ -322,10 +374,38 @@ exit:
 			__func__, retval);
 }

+static char f81232_handle_lsr(struct usb_serial_port *port, u8 lsr)
+{
+	struct f81232_private *priv = usb_get_serial_port_data(port);
+	char tty_flag = TTY_NORMAL;
+
+	if (!(lsr & UART_LSR_BRK_ERROR_BITS))
+		return tty_flag;
+
+	if (lsr & UART_LSR_BI) {
+		tty_flag = TTY_BREAK;
+		port->icount.brk++;
+		usb_serial_handle_break(port);
+	} else if (lsr & UART_LSR_PE) {
+		tty_flag = TTY_PARITY;
+		port->icount.parity++;
+	} else if (lsr & UART_LSR_FE) {
+		tty_flag = TTY_FRAME;
+		port->icount.frame++;
+	}
+
+	if (lsr & UART_LSR_OE) {
+		port->icount.overrun++;
+		schedule_work(&priv->lsr_work);
+		tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
+	}
+
+	return tty_flag;
+}
+
 static void f81232_process_read_urb(struct urb *urb)
 {
 	struct usb_serial_port *port = urb->context;
-	struct f81232_private *priv = usb_get_serial_port_data(port);
 	unsigned char *data = urb->transfer_buffer;
 	char tty_flag;
 	unsigned int i;
@ -341,29 +421,8 @@ static void f81232_process_read_urb(struct urb *urb)
 	/* bulk-in data: [LSR(1Byte)+DATA(1Byte)][LSR(1Byte)+DATA(1Byte)]... */

 	for (i = 0; i < urb->actual_length; i += 2) {
-		tty_flag = TTY_NORMAL;
 		lsr = data[i];
-
-		if (lsr & UART_LSR_BRK_ERROR_BITS) {
-			if (lsr & UART_LSR_BI) {
-				tty_flag = TTY_BREAK;
-				port->icount.brk++;
-				usb_serial_handle_break(port);
-			} else if (lsr & UART_LSR_PE) {
-				tty_flag = TTY_PARITY;
-				port->icount.parity++;
-			} else if (lsr & UART_LSR_FE) {
-				tty_flag = TTY_FRAME;
-				port->icount.frame++;
-			}
-
-			if (lsr & UART_LSR_OE) {
-				port->icount.overrun++;
-				schedule_work(&priv->lsr_work);
-				tty_insert_flip_char(&port->port, 0,
-						TTY_OVERRUN);
-			}
-		}
+		tty_flag = f81232_handle_lsr(port, lsr);

 		if (port->port.console && port->sysrq) {
 			if (usb_serial_handle_sysrq_char(port, data[i + 1]))
@ -376,6 +435,47 @@ static void f81232_process_read_urb(struct urb *urb)
 	tty_flip_buffer_push(&port->port);
 }

+static void f81534a_process_read_urb(struct urb *urb)
+{
+	struct usb_serial_port *port = urb->context;
+	unsigned char *data = urb->transfer_buffer;
+	char tty_flag;
+	unsigned int i;
+	u8 lsr;
+	u8 len;
+
+	if (urb->actual_length < 3) {
+		dev_err(&port->dev, "short message received: %d\n",
+				urb->actual_length);
+		return;
+	}
+
+	len = data[0];
+	if (len != urb->actual_length) {
+		dev_err(&port->dev, "malformed message received: %d (%d)\n",
+				urb->actual_length, len);
+		return;
+	}
+
+	/* bulk-in data: [LEN][Data.....][LSR] */
+	lsr = data[len - 1];
+	tty_flag = f81232_handle_lsr(port, lsr);
+
+	if (port->port.console && port->sysrq) {
+		for (i = 1; i < len - 1; ++i) {
+			if (!usb_serial_handle_sysrq_char(port, data[i])) {
+				tty_insert_flip_char(&port->port, data[i],
+						tty_flag);
+			}
+		}
+	} else {
+		tty_insert_flip_string_fixed_flag(&port->port, &data[1],
+							tty_flag, len - 2);
+	}
+
+	tty_flip_buffer_push(&port->port);
+}
+
 static void f81232_break_ctl(struct tty_struct *tty, int break_state)
 {
 	struct usb_serial_port *port = tty->driver_data;
@ -659,6 +759,24 @@ static int f81232_open(struct tty_struct *tty, struct usb_serial_port *port)
 	return 0;
 }

+static int f81534a_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+	int status;
+	u8 mask;
+	u8 val;
+
+	val = F81534A_TRIGGER_MULTIPLE_4X | F81534A_FIFO_128BYTE;
+	mask = F81534A_TRIGGER_MASK | F81534A_FIFO_128BYTE;
+
+	status = f81232_set_mask_register(port, F81534A_MODE_REG, mask, val);
+	if (status) {
+		dev_err(&port->dev, "failed to set MODE_REG: %d\n", status);
+		return status;
+	}
+
+	return f81232_open(tty, port);
+}
+
 static void f81232_close(struct usb_serial_port *port)
 {
 	struct f81232_private *port_priv = usb_get_serial_port_data(port);
@ -678,6 +796,20 @@ static void f81232_dtr_rts(struct usb_serial_port *port, int on)
 		f81232_set_mctrl(port, 0, TIOCM_DTR | TIOCM_RTS);
 }

+static bool f81232_tx_empty(struct usb_serial_port *port)
+{
+	int status;
+	u8 tmp;
+
+	status = f81232_get_register(port, LINE_STATUS_REGISTER, &tmp);
+	if (!status) {
+		if ((tmp & UART_LSR_TEMT) != UART_LSR_TEMT)
+			return false;
+	}
+
+	return true;
+}
+
 static int f81232_carrier_raised(struct usb_serial_port *port)
 {
 	u8 msr;
@ -728,11 +860,98 @@ static void f81232_lsr_worker(struct work_struct *work)
 		dev_warn(&port->dev, "read LSR failed: %d\n", status);
 }

+static int f81534a_ctrl_set_register(struct usb_interface *intf, u16 reg,
+					u16 size, void *val)
+{
+	struct usb_device *dev = interface_to_usbdev(intf);
+	int retry = F81534A_ACCESS_REG_RETRY;
+	int status;
+	u8 *tmp;
+
+	tmp = kmemdup(val, size, GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	while (retry--) {
+		status = usb_control_msg(dev,
+					usb_sndctrlpipe(dev, 0),
+					F81232_REGISTER_REQUEST,
+					F81232_SET_REGISTER,
+					reg,
+					0,
+					tmp,
+					size,
+					USB_CTRL_SET_TIMEOUT);
+		if (status < 0) {
+			status = usb_translate_errors(status);
+			if (status == -EIO)
+				continue;
+		} else if (status != size) {
+			/* Retry on short transfers */
+			status = -EIO;
+			continue;
+		} else {
+			status = 0;
+		}
+
+		break;
+	}
+
+	if (status) {
+		dev_err(&intf->dev, "failed to set register 0x%x: %d\n",
+				reg, status);
+	}
+
+	kfree(tmp);
+	return status;
+}
+
+static int f81534a_ctrl_enable_all_ports(struct usb_interface *intf, bool en)
+{
+	unsigned char enable[2] = {0};
+	int status;
+
+	/*
+	 * Enable all available serial ports, define as following:
+	 * bit 15	: Reset behavior (when HUB got soft reset)
+	 *			0: maintain all serial port enabled state.
+	 *			1: disable all serial port.
+	 * bit 0~11	: Serial port enable bit.
+	 */
+	if (en) {
+		enable[0] = 0xff;
+		enable[1] = 0x8f;
+	}
+
+	status = f81534a_ctrl_set_register(intf, F81534A_CTRL_CMD_ENABLE_PORT,
+			sizeof(enable), enable);
+	if (status)
+		dev_err(&intf->dev, "failed to enable ports: %d\n", status);
+
+	return status;
+}
+
+static int f81534a_ctrl_probe(struct usb_interface *intf,
+				const struct usb_device_id *id)
+{
+	return f81534a_ctrl_enable_all_ports(intf, true);
+}
+
+static void f81534a_ctrl_disconnect(struct usb_interface *intf)
+{
+	f81534a_ctrl_enable_all_ports(intf, false);
+}
+
+static int f81534a_ctrl_resume(struct usb_interface *intf)
+{
+	return f81534a_ctrl_enable_all_ports(intf, true);
+}
+
 static int f81232_port_probe(struct usb_serial_port *port)
 {
 	struct f81232_private *priv;

-	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	priv = devm_kzalloc(&port->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

@ -748,14 +967,17 @@ static int f81232_port_probe(struct usb_serial_port *port)
 	return 0;
 }

-static int f81232_port_remove(struct usb_serial_port *port)
+static int f81534a_port_probe(struct usb_serial_port *port)
 {
-	struct f81232_private *priv;
+	int status;

-	priv = usb_get_serial_port_data(port);
-	kfree(priv);
+	/* tri-state with pull-high, default RS232 Mode */
+	status = f81232_set_register(port, F81534A_GPIO_REG,
+					F81534A_GPIO_MODE2_DIR);
+	if (status)
+		return status;

-	return 0;
+	return f81232_port_probe(port);
 }

 static int f81232_suspend(struct usb_serial *serial, pm_message_t message)
@ -799,7 +1021,7 @@ static struct usb_serial_driver f81232_device = {
 		.owner =	THIS_MODULE,
 		.name =		"f81232",
 	},
-	.id_table =		id_table,
+	.id_table =		f81232_id_table,
 	.num_ports =		1,
 	.bulk_in_size =		256,
 	.bulk_out_size =	256,
@ -813,22 +1035,82 @@ static struct usb_serial_driver f81232_device = {
 	.tiocmget =		f81232_tiocmget,
 	.tiocmset =		f81232_tiocmset,
 	.tiocmiwait =		usb_serial_generic_tiocmiwait,
+	.tx_empty =		f81232_tx_empty,
 	.process_read_urb =	f81232_process_read_urb,
 	.read_int_callback =	f81232_read_int_callback,
 	.port_probe =		f81232_port_probe,
-	.port_remove =		f81232_port_remove,
+	.suspend =		f81232_suspend,
+	.resume =		f81232_resume,
+};
+
+static struct usb_serial_driver f81534a_device = {
+	.driver = {
+		.owner =	THIS_MODULE,
+		.name =		"f81534a",
+	},
+	.id_table =		f81534a_id_table,
+	.num_ports =		1,
+	.open =			f81534a_open,
+	.close =		f81232_close,
+	.dtr_rts =		f81232_dtr_rts,
+	.carrier_raised =	f81232_carrier_raised,
+	.get_serial =		f81232_get_serial_info,
+	.break_ctl =		f81232_break_ctl,
+	.set_termios =		f81232_set_termios,
+	.tiocmget =		f81232_tiocmget,
+	.tiocmset =		f81232_tiocmset,
+	.tiocmiwait =		usb_serial_generic_tiocmiwait,
+	.tx_empty =		f81232_tx_empty,
+	.process_read_urb =	f81534a_process_read_urb,
+	.read_int_callback =	f81232_read_int_callback,
+	.port_probe =		f81534a_port_probe,
 	.suspend =		f81232_suspend,
 	.resume =		f81232_resume,
 };

 static struct usb_serial_driver * const serial_drivers[] = {
 	&f81232_device,
+	&f81534a_device,
 	NULL,
 };

-module_usb_serial_driver(serial_drivers, id_table);
+static struct usb_driver f81534a_ctrl_driver = {
+	.name =		"f81534a_ctrl",
+	.id_table =	f81534a_ctrl_id_table,
+	.probe =	f81534a_ctrl_probe,
+	.disconnect =	f81534a_ctrl_disconnect,
+	.resume =	f81534a_ctrl_resume,
+};

-MODULE_DESCRIPTION("Fintek F81232 USB to serial adaptor driver");
+static int __init f81232_init(void)
+{
+	int status;
+
+	status = usb_register_driver(&f81534a_ctrl_driver, THIS_MODULE,
+			KBUILD_MODNAME);
+	if (status)
+		return status;
+
+	status = usb_serial_register_drivers(serial_drivers, KBUILD_MODNAME,
+			combined_id_table);
+	if (status) {
+		usb_deregister(&f81534a_ctrl_driver);
+		return status;
+	}
+
+	return 0;
+}
+
+static void __exit f81232_exit(void)
+{
+	usb_serial_deregister_drivers(serial_drivers);
+	usb_deregister(&f81534a_ctrl_driver);
+}
+
+module_init(f81232_init);
+module_exit(f81232_exit);
+
+MODULE_DESCRIPTION("Fintek F81232/532A/534A/535/536 USB to serial driver");
 MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>");
 MODULE_AUTHOR("Peter Hong <peter_hong@fintek.com.tw>");
 MODULE_LICENSE("GPL v2");
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@ -417,7 +417,7 @@ void usb_serial_generic_read_bulk_callback(struct urb *urb)
 	/*
 	 * Make sure URB is marked as free before checking the throttled flag
 	 * to avoid racing with unthrottle() on another CPU. Matches the
-	 * smp_mb() in unthrottle().
+	 * smp_mb__after_atomic() in unthrottle().
 	 */
 	smp_mb__after_atomic();

@ -489,7 +489,7 @@ void usb_serial_generic_unthrottle(struct tty_struct *tty)
 	 * Matches the smp_mb__after_atomic() in
 	 * usb_serial_generic_read_bulk_callback().
 	 */
-	smp_mb();
+	smp_mb__after_atomic();

 	usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 }
@ -609,12 +609,10 @@ EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 * @tty: tty for the port
 * @status: new carrier detect status, nonzero if active
 */
-void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
+void usb_serial_handle_dcd_change(struct usb_serial_port *port,
 				struct tty_struct *tty, unsigned int status)
 {
-	struct tty_port *port = &usb_port->port;
-
-	dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status);
+	dev_dbg(&port->dev, "%s - status %d\n", __func__, status);

 	if (tty) {
 		struct tty_ldisc *ld = tty_ldisc_ref(tty);
@ -627,7 +625,7 @@ void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 	}

 	if (status)
-		wake_up_interruptible(&port->open_wait);
+		wake_up_interruptible(&port->port.open_wait);
 	else if (tty && !C_CLOCAL(tty))
 		tty_hangup(tty);
 }
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@ -710,7 +710,7 @@ static void edge_interrupt_callback(struct urb *urb)
 		/* grab the txcredits for the ports if available */
 		position = 2;
 		portNumber = 0;
-		while ((position < length) &&
+		while ((position < length - 1) &&
 				(portNumber < edge_serial->serial->num_ports)) {
 			txCredits = data[position] | (data[position+1] << 8);
 			if (txCredits) {
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@ -1992,8 +1992,14 @@ static const struct usb_device_id option_ids[] = {
 	{ USB_DEVICE_AND_INTERFACE_INFO(0x07d1, 0x3e01, 0xff, 0xff, 0xff) },	/* D-Link DWM-152/C1 */
 	{ USB_DEVICE_AND_INTERFACE_INFO(0x07d1, 0x3e02, 0xff, 0xff, 0xff) },	/* D-Link DWM-156/C1 */
 	{ USB_DEVICE_AND_INTERFACE_INFO(0x07d1, 0x7e11, 0xff, 0xff, 0xff) },	/* D-Link DWM-156/A3 */
+	{ USB_DEVICE_INTERFACE_CLASS(0x1435, 0xd191, 0xff),			/* Wistron Neweb D19Q1 */
+	  .driver_info = RSVD(1) | RSVD(4) },
+	{ USB_DEVICE_INTERFACE_CLASS(0x1690, 0x7588, 0xff),			/* ASKEY WWHC050 */
+	  .driver_info = RSVD(1) | RSVD(4) },
 	{ USB_DEVICE_INTERFACE_CLASS(0x2020, 0x2031, 0xff),			/* Olicard 600 */
 	  .driver_info = RSVD(4) },
+	{ USB_DEVICE_INTERFACE_CLASS(0x2020, 0x2033, 0xff),			/* BroadMobi BM806U */
+	  .driver_info = RSVD(4) },
 	{ USB_DEVICE_INTERFACE_CLASS(0x2020, 0x2060, 0xff),			/* BroadMobi BM818 */
 	  .driver_info = RSVD(4) },
 	{ USB_DEVICE_INTERFACE_CLASS(0x2020, 0x4000, 0xff) },			/* OLICARD300 - MT6225 */
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@ -288,7 +288,7 @@ static void serial_close(struct tty_struct *tty, struct file *filp)

 /**
 * serial_cleanup - free resources post close/hangup
- * @port: port to free up
+ * @tty: tty to clean up
 *
 * Do the resource freeing and refcount dropping for the port.
 * Avoid freeing the console.