[PATCH v8 1/2] usb: serial: add support for CH348

[Corentin Labbe]

The CH348 is an USB octo port serial adapter.
The device multiplexes all 8 ports in the same pair of Bulk endpoints.
Since there is no public datasheet, unfortunately it remains some magic values

Signed-off-by: Corentin Labbe <clabbe@xxxxxxxxxxxx>
---
 drivers/usb/serial/Kconfig  |   9 +
 drivers/usb/serial/Makefile |   1 +
 drivers/usb/serial/ch348.c  | 736 ++++++++++++++++++++++++++++++++++++
 3 files changed, 746 insertions(+)
 create mode 100644 drivers/usb/serial/ch348.c

diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index ef8d1c73c754..1e1842656b54 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -112,6 +112,15 @@ config USB_SERIAL_CH341
 	  To compile this driver as a module, choose M here: the
 	  module will be called ch341.
 
+config USB_SERIAL_CH348
+	tristate "USB Winchiphead CH348 Octo Port Serial Driver"
+	help
+	  Say Y here if you want to use a Winchiphead CH348 octo port
+	  USB to serial adapter.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ch348.
+
 config USB_SERIAL_WHITEHEAT
 	tristate "USB ConnectTech WhiteHEAT Serial Driver"
 	select USB_EZUSB_FX2
diff --git a/drivers/usb/serial/Makefile b/drivers/usb/serial/Makefile
index c7bb1a88173e..d16ff59fde68 100644
--- a/drivers/usb/serial/Makefile
+++ b/drivers/usb/serial/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_USB_SERIAL_AIRCABLE)		+= aircable.o
 obj-$(CONFIG_USB_SERIAL_ARK3116)		+= ark3116.o
 obj-$(CONFIG_USB_SERIAL_BELKIN)			+= belkin_sa.o
 obj-$(CONFIG_USB_SERIAL_CH341)			+= ch341.o
+obj-$(CONFIG_USB_SERIAL_CH348)			+= ch348.o
 obj-$(CONFIG_USB_SERIAL_CP210X)			+= cp210x.o
 obj-$(CONFIG_USB_SERIAL_CYBERJACK)		+= cyberjack.o
 obj-$(CONFIG_USB_SERIAL_CYPRESS_M8)		+= cypress_m8.o
diff --git a/drivers/usb/serial/ch348.c b/drivers/usb/serial/ch348.c
new file mode 100644
index 000000000000..01b61d74c4a4
--- /dev/null
+++ b/drivers/usb/serial/ch348.c
@@ -0,0 +1,736 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB serial driver for USB to Octal UARTs chip ch348.
+ *
+ * Copyright (C) 2023 Corentin Labbe <clabbe@xxxxxxxxxxxx>
+ * With the help of Neil Armstrong <neil.armstrong@xxxxxxxxxx>
+ * Copyright (C) 2024 Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
+ *
+ * Based on the ch9344 driver:
+ *   https://github.com/WCHSoftGroup/ch9344ser_linux/
+ *   Copyright (C) 2024 Nanjing Qinheng Microelectronics Co., Ltd.
+ */
+
+#include <linux/completion.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kfifo.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/overflow.h>
+#include <linux/serial.h>
+#include <linux/serial_reg.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+#include <linux/workqueue.h>
+
+#define CH348_CMD_TIMEOUT   2000
+
+#define CH348_CTO_D	0x01
+#define CH348_CTO_R	0x02
+
+#define CH348_CTI_C	0x10
+#define CH348_CTI_DSR	0x20
+#define CH348_CTI_R	0x40
+#define CH348_CTI_DCD	0x80
+
+#define CMD_W_R		0xC0
+#define CMD_W_BR	0x80
+
+#define CMD_WB_E	0x90
+#define CMD_RB_E	0xC0
+
+#define M_NOR		0x00
+#define M_HF		0x03
+
+#define R_MOD		0x97
+#define R_IO_D		0x98
+#define R_IO_O		0x99
+#define R_IO_I		0x9b
+#define R_TM_O		0x9c
+#define R_INIT		0xa1
+
+#define CMD_VER		0x96
+
+/* 0x10 is normally UART_MCR_LOOP but for CH348 it's UART_MCR_RTS */
+#define UART_MCR_RTS_CH348	0x10
+
+/*
+ * The CH348 multiplexes rx & tx into a pair of Bulk USB endpoints for the 8
+ * serial ports, and another pair of Bulk USB endpoints to set port settings
+ * and receive port status events.
+ *
+ * The USB serial cores ties every Bulk endpoints pairs to each ports, In our
+ * case it will set port 0 with the rx/tx endpoints and port 1 with the
+ * setup/status endpoints.
+ *
+ * For bulk writes we skip all of USB serial core's helpers and implement it on
+ * our own since for serial TX we need to not only wait for the URB to complete
+ * but also for the UART_IIR_THRI signal.
+ *
+ * For bulk reads we use USB serial core's helpers, even for the status/int
+ * handling as it simplifies our code.
+ */
+#define CH348_MAXPORT				8
+#define CH348_PORTNUM_SERIAL_RX_TX		0
+#define CH348_PORTNUM_STATUS_INT_CONFIG		1
+
+#define CH348_RX_PORT_MAX_LENGTH	30
+
+struct ch348_rxbuf {
+	u8 port;
+	u8 length;
+	u8 data[CH348_RX_PORT_MAX_LENGTH];
+} __packed;
+
+struct ch348_txbuf {
+	u8 port;
+	__le16 length;
+	u8 data[];
+} __packed;
+
+#define CH348_TX_HDRSIZE offsetof(struct ch348_txbuf, data)
+
+struct ch348_initbuf {
+	u8 cmd;
+	u8 reg;
+	u8 port;
+	__be32 baudrate;
+	u8 format;
+	u8 paritytype;
+	u8 databits;
+	u8 rate;
+	u8 unknown;
+} __packed;
+
+#define CH348_INITBUF_FORMAT_STOPBITS		0x2
+#define CH348_INITBUF_FORMAT_NO_STOPBITS	0x0
+
+/*
+ * struct ch348_port - per-port information
+ * @uartmode:		UART port current mode
+ * @baudrate:		A cached copy of current baudrate for the RX logic
+ */
+struct ch348_port {
+	u8 uartmode;
+	speed_t baudrate;
+};
+
+/*
+ * struct ch348 - main container for all this driver information
+ * @udev:		pointer to the CH348 USB device
+ * @ports:		List of per-port information
+ * @serial:		pointer to the serial structure
+ * @write_work:		worker for processing the write queues
+ * @txbuf_completion:	indicates that the TX buffer has been fully written out
+ * @tx_ep:		endpoint number for serial data transmit/write operation
+ * @config_ep:		endpoint number for configure operations
+ * @small_package:	indicates package size: small (CH348Q) or large (CH348L)
+ */
+struct ch348 {
+	struct usb_device *udev;
+	struct ch348_port ports[CH348_MAXPORT];
+	struct usb_serial *serial;
+
+	struct work_struct write_work;
+	struct completion txbuf_completion;
+
+	int tx_ep;
+	int config_ep;
+
+	bool small_package;
+};
+
+struct ch348_serial_config {
+	u8 action;
+	u8 reg;
+	u8 control;
+} __packed;
+
+struct ch348_status_entry {
+	u8 portnum;
+	u8 reg_iir;
+	union {
+		u8 lsr_signal;
+		u8 modem_signal;
+		u8 init_data[10];
+	};
+} __packed;
+
+#define CH348_STATUS_ENTRY_PORTNUM_MASK		0xf
+
+static void ch348_process_status_urb(struct usb_serial *serial, struct urb *urb)
+{
+	struct ch348 *ch348 = usb_get_serial_data(serial);
+	struct ch348_status_entry *status_entry;
+	struct usb_serial_port *port;
+	unsigned int i, status_len;
+	u8 portnum;
+
+	if (urb->actual_length < 3) {
+		dev_warn_ratelimited(&ch348->udev->dev,
+				     "Received too short status buffer with %u bytes\n",
+				     urb->actual_length);
+		return;
+	}
+
+	for (i = 0; i < urb->actual_length;) {
+		status_entry = urb->transfer_buffer + i;
+		portnum = status_entry->portnum & CH348_STATUS_ENTRY_PORTNUM_MASK;
+
+		if (portnum >= CH348_MAXPORT) {
+			dev_warn_ratelimited(&ch348->udev->dev,
+					     "Invalid port %d in status entry\n",
+					     portnum);
+			break;
+		}
+
+		port = serial->port[portnum];
+		status_len = 3;
+
+		if (!status_entry->reg_iir) {
+			dev_dbg(&port->dev, "Ignoring status with zero reg_iir\n");
+		} else if (status_entry->reg_iir == R_INIT) {
+			status_len = 12;
+		} else if ((status_entry->reg_iir & UART_IIR_ID) == UART_IIR_RLSI) {
+			if (status_entry->lsr_signal & UART_LSR_OE)
+				port->icount.overrun++;
+			if (status_entry->lsr_signal & UART_LSR_PE)
+				port->icount.parity++;
+			if (status_entry->lsr_signal & UART_LSR_FE)
+				port->icount.frame++;
+			if (status_entry->lsr_signal & UART_LSR_BI)
+				port->icount.brk++;
+		} else if ((status_entry->reg_iir & UART_IIR_ID) == UART_IIR_THRI) {
+			complete_all(&ch348->txbuf_completion);
+		} else {
+			dev_warn_ratelimited(&port->dev,
+					     "Unsupported status with reg_iir 0x%02x\n",
+					     status_entry->reg_iir);
+		}
+
+		i += status_len;
+	}
+}
+
+static void ch348_process_serial_rx_urb(struct usb_serial *serial,
+					struct urb *urb)
+{
+	unsigned int portnum, serial_rx_len, i;
+	struct usb_serial_port *port;
+	struct ch348_rxbuf *rxb;
+
+	if (urb->actual_length < 2) {
+		dev_dbg(&serial->dev->dev, "Empty rx buffer\n");
+		return;
+	}
+
+	for (i = 0; i < urb->actual_length; i += sizeof(*rxb)) {
+		rxb = urb->transfer_buffer + i;
+		portnum = rxb->port;
+		if (portnum >= CH348_MAXPORT) {
+			dev_dbg(&serial->dev->dev, "Invalid port %d\n", portnum);
+			break;
+		}
+
+		port = serial->port[portnum];
+
+		serial_rx_len = rxb->length;
+		if (serial_rx_len > CH348_RX_PORT_MAX_LENGTH) {
+			dev_dbg(&port->dev, "Invalid length %d for port %d\n",
+				serial_rx_len, portnum);
+			break;
+		}
+
+		tty_insert_flip_string(&port->port, rxb->data, serial_rx_len);
+		tty_flip_buffer_push(&port->port);
+
+		port->icount.rx += serial_rx_len;
+	}
+}
+
+static void ch348_process_read_urb(struct urb *urb)
+{
+	struct usb_serial_port *port = urb->context;
+
+	if (port->port_number == CH348_PORTNUM_SERIAL_RX_TX)
+		ch348_process_serial_rx_urb(port->serial, urb);
+	else if (port->port_number == CH348_PORTNUM_STATUS_INT_CONFIG)
+		ch348_process_status_urb(port->serial, urb);
+	else
+		dev_warn_ratelimited(&port->serial->dev->dev,
+				     "Ignoring read URB callback for unknown port/endpoint %u\n",
+				     port->port_number);
+}
+
+static int ch348_port_config(struct usb_serial_port *port, u8 action, u8 reg,
+			     u8 control)
+{
+	struct ch348 *ch348 = usb_get_serial_data(port->serial);
+	struct ch348_serial_config *buffer;
+	int ret;
+
+	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	if (port->port_number < 4)
+		reg += 0x10 * port->port_number;
+	else
+		reg += 0x10 * (port->port_number - 4) + 0x08;
+
+	buffer->action = action;
+	buffer->reg = reg;
+	buffer->control = control;
+
+	ret = usb_bulk_msg(ch348->udev, ch348->config_ep, buffer,
+			   sizeof(*buffer), NULL, CH348_CMD_TIMEOUT);
+	if (ret) {
+		dev_err(&ch348->udev->dev, "Failed to write port config: %d\n", ret);
+		goto out;
+	}
+
+out:
+	kfree(buffer);
+
+	return ret;
+}
+
+static int ch348_write(struct tty_struct *tty, struct usb_serial_port *port,
+		       const unsigned char *buf, int count)
+{
+	struct ch348 *ch348 = usb_get_serial_data(port->serial);
+
+	if (!count)
+		return 0;
+
+	count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
+
+	schedule_work(&ch348->write_work);
+
+	return count;
+}
+
+static int ch348_set_uartmode(struct usb_serial_port *port, u8 mode)
+{
+	struct ch348 *ch348 = usb_get_serial_data(port->serial);
+	unsigned int portnum = port->port_number;
+	int ret;
+
+	if (ch348->ports[portnum].uartmode == M_NOR && mode == M_HF) {
+		ret = ch348_port_config(port, CMD_W_BR, UART_MCR,
+					UART_MCR_DTR | UART_MCR_RTS_CH348 |
+					UART_MCR_TCRTLR);
+		if (ret)
+			return ret;
+		ch348->ports[portnum].uartmode = M_HF;
+	}
+
+	if (ch348->ports[portnum].uartmode == M_HF && mode == M_NOR) {
+		ret = ch348_port_config(port, CMD_W_BR, UART_MCR,
+					UART_MCR_RTS_CH348 | UART_MCR_TCRTLR);
+		if (ret)
+			return ret;
+		ch348->ports[portnum].uartmode = M_NOR;
+	}
+	return 0;
+}
+
+static void ch348_set_termios(struct tty_struct *tty, struct usb_serial_port *port,
+			      const struct ktermios *termios_old)
+{
+	struct ch348 *ch348 = usb_get_serial_data(port->serial);
+	struct ktermios *termios = &tty->termios;
+	int ret, portnum = port->port_number;
+	struct ch348_initbuf *buffer;
+	speed_t	baudrate;
+
+	if (termios_old && !tty_termios_hw_change(&tty->termios, termios_old))
+		return;
+
+	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
+	if (!buffer)
+		goto out;
+
+	/*
+	 * The datasheet states that only baud rates in range of 1200..6000000
+	 * are supported. Tests with an oscilloscope confirm that even when
+	 * configuring a baud rate slower than 1200 the output stays at around
+	 * 1200 baud.
+	 */
+	baudrate = clamp(tty_get_baud_rate(tty), 1200, 6000000);
+	tty_termios_encode_baud_rate(&tty->termios, baudrate, baudrate);
+	ch348->ports[port->port_number].baudrate = baudrate;
+
+	if (termios->c_cflag & PARENB) {
+		if  (termios->c_cflag & CMSPAR) {
+			if (termios->c_cflag & PARODD)
+				buffer->paritytype = 3;
+			else
+				buffer->paritytype = 4;
+		} else if (termios->c_cflag & PARODD) {
+			buffer->paritytype = 1;
+		} else {
+			buffer->paritytype = 2;
+		}
+	} else {
+		buffer->paritytype = 0;
+	}
+
+	switch (C_CSIZE(tty)) {
+	case CS5:
+		buffer->databits = 5;
+		break;
+	case CS6:
+		buffer->databits = 6;
+		break;
+	case CS7:
+		buffer->databits = 7;
+		break;
+	case CS8:
+	default:
+		buffer->databits = 8;
+		break;
+	}
+
+	buffer->cmd = CMD_WB_E | portnum;
+	buffer->reg = R_INIT;
+	buffer->port = portnum;
+	buffer->baudrate = cpu_to_be32(baudrate);
+
+	if (termios->c_cflag & CSTOPB)
+		buffer->format = CH348_INITBUF_FORMAT_STOPBITS;
+	else
+		buffer->format = CH348_INITBUF_FORMAT_NO_STOPBITS;
+
+	buffer->rate = max_t(speed_t, 5, (10000 * 15 / baudrate) + 1);
+
+	ret = usb_bulk_msg(ch348->udev, ch348->config_ep, buffer,
+			   sizeof(*buffer), NULL, CH348_CMD_TIMEOUT);
+	if (ret < 0) {
+		dev_err(&ch348->udev->dev, "Failed to change line settings: err=%d\n",
+			ret);
+		goto out_free;
+	}
+
+	ret = ch348_port_config(port, CMD_W_R, UART_IER, UART_IER_RDI |
+				UART_IER_THRI | UART_IER_RLSI | UART_IER_MSI);
+	if (ret < 0)
+		goto out_free;
+
+	if (C_CRTSCTS(tty))
+		ret = ch348_set_uartmode(port, M_HF);
+	else
+		ret = ch348_set_uartmode(port, M_NOR);
+
+out_free:
+	kfree(buffer);
+out:
+	if (ret && termios_old)
+		tty->termios = *termios_old;
+}
+
+static int ch348_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+	int ret;
+
+	clear_bit(USB_SERIAL_THROTTLED, &port->flags);
+
+	if (tty)
+		ch348_set_termios(tty, port, NULL);
+
+	ret = ch348_port_config(port, CMD_W_R, UART_FCR,
+				UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR |
+				UART_FCR_CLEAR_XMIT | UART_FCR_T_TRIG_00 |
+				UART_FCR_R_TRIG_10);
+	if (ret) {
+		dev_err(&port->serial->dev->dev,
+			"Failed to configure UART_FCR, err=%d\n", ret);
+		return ret;
+	}
+
+	ret = ch348_port_config(port, CMD_W_BR, UART_MCR, UART_MCR_OUT2);
+	if (ret) {
+		dev_err(&port->serial->dev->dev,
+			"Failed to configure UART_MCR, err=%d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void ch348_close(struct usb_serial_port *port)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	kfifo_reset_out(&port->write_fifo);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void ch348_write_work(struct work_struct *work)
+{
+	struct ch348 *ch348 = container_of(work, struct ch348, write_work);
+	struct usb_serial_port *port, *hw_tx_port;
+	unsigned int i, max_bytes;
+	struct ch348_txbuf *rxt;
+	unsigned long flags;
+	int ret, count;
+
+	reinit_completion(&ch348->txbuf_completion);
+
+	hw_tx_port = ch348->serial->port[CH348_PORTNUM_SERIAL_RX_TX];
+	rxt = hw_tx_port->write_urbs[0]->transfer_buffer;
+
+	for (i = 0; i < CH348_MAXPORT; i++) {
+		port = ch348->serial->port[i];
+
+		if (ch348->ports[i].baudrate < 9600)
+			/*
+			 * Writing larger buffers can take longer than the
+			 * hardware allows before discarding the write buffer.
+			 * Limit the transfer size in such cases.
+			 * These values have been found by empirical testing.
+			 */
+			max_bytes = 128;
+		else
+			/*
+			 * Only ingest as many bytes as we can transfer with
+			 * one URB at a time keeping the TX header in mind.
+			 */
+			max_bytes = hw_tx_port->bulk_out_size - CH348_TX_HDRSIZE;
+
+		count = kfifo_out_locked(&port->write_fifo, rxt->data,
+					 max_bytes, &port->lock);
+		if (count)
+			break;
+	}
+
+	if (!count)
+		return;
+
+	spin_lock_irqsave(&port->lock, flags);
+	port->tx_bytes += count;
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	rxt->port = port->port_number;
+	rxt->length = cpu_to_le16(count);
+
+	usb_serial_debug_data(&port->dev, __func__, count + CH348_TX_HDRSIZE,
+			      (const unsigned char *)rxt);
+
+	ret = usb_bulk_msg(ch348->udev, ch348->tx_ep, rxt,
+			   count + CH348_TX_HDRSIZE, NULL, CH348_CMD_TIMEOUT);
+	if (ret) {
+		dev_err_console(port,
+				"Failed to bulk write TX buffer, err=%d\n",
+				ret);
+		goto write_done;
+	}
+
+	if (!wait_for_completion_timeout(&ch348->txbuf_completion,
+					 msecs_to_jiffies(CH348_CMD_TIMEOUT)))
+		dev_err_console(port,
+				"Failed to wait for TX buffer to be fully written out\n");
+
+write_done:
+	spin_lock_irqsave(&port->lock, flags);
+	port->tx_bytes -= count;
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	port->icount.tx += count;
+
+	schedule_work(&ch348->write_work);
+	usb_serial_port_softint(port);
+}
+
+static int ch348_submit_urbs(struct usb_serial *serial)
+{
+	int ret;
+
+	ret = usb_serial_generic_open(NULL,
+				      serial->port[CH348_PORTNUM_SERIAL_RX_TX]);
+	if (ret) {
+		dev_err(&serial->dev->dev,
+			"Failed to open RX/TX port, err=%d\n", ret);
+		return ret;
+	}
+
+	ret = usb_serial_generic_open(NULL,
+				      serial->port[CH348_PORTNUM_STATUS_INT_CONFIG]);
+	if (ret) {
+		dev_err(&serial->dev->dev,
+			"Failed to submit STATUS/INT URB, err=%d\n", ret);
+		usb_serial_generic_close(serial->port[CH348_PORTNUM_SERIAL_RX_TX]);
+	}
+
+	return ret;
+}
+
+static void ch348_kill_urbs(struct usb_serial *serial)
+{
+	usb_serial_generic_close(serial->port[CH348_PORTNUM_STATUS_INT_CONFIG]);
+	usb_serial_generic_close(serial->port[CH348_PORTNUM_SERIAL_RX_TX]);
+}
+
+static int ch348_detect_version(struct usb_serial *serial)
+{
+	struct ch348 *ch348 = usb_get_serial_data(serial);
+	u8 *version_buf;
+	int ret;
+
+	version_buf = kzalloc(4, GFP_KERNEL);
+	if (!version_buf)
+		return -ENOMEM;
+
+	ret = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
+			      CMD_VER,
+			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+			      0, 0, version_buf, 4, CH348_CMD_TIMEOUT);
+	if (ret < 0) {
+		dev_err(&serial->dev->dev, "Failed to read CMD_VER: %d\n", ret);
+		goto out;
+	}
+
+	ret = 0;
+	ch348->small_package = !!(version_buf[1] & 0x80);
+
+	dev_info(&serial->dev->dev, "Found WCH CH348%c\n",
+		 ch348->small_package ? 'Q' : 'L');
+
+out:
+	kfree(version_buf);
+
+	return ret;
+}
+
+static int ch348_attach(struct usb_serial *serial)
+{
+	struct usb_serial_port *tx_port, *config_port;
+	struct ch348 *ch348;
+	int ret;
+
+	ch348 = kzalloc(sizeof(*ch348), GFP_KERNEL);
+	if (!ch348)
+		return -ENOMEM;
+
+	usb_set_serial_data(serial, ch348);
+
+	ch348->udev = serial->dev;
+	ch348->serial = serial;
+
+	INIT_WORK(&ch348->write_work, ch348_write_work);
+
+	init_completion(&ch348->txbuf_completion);
+
+	tx_port = ch348->serial->port[CH348_PORTNUM_SERIAL_RX_TX];
+	ch348->tx_ep = usb_sndbulkpipe(ch348->udev,
+				       tx_port->bulk_out_endpointAddress);
+
+	config_port = ch348->serial->port[CH348_PORTNUM_STATUS_INT_CONFIG];
+	ch348->config_ep = usb_sndbulkpipe(ch348->udev,
+					   config_port->bulk_out_endpointAddress);
+
+	ret = ch348_detect_version(serial);
+	if (ret)
+		goto err_free_ch348;
+
+	ret = ch348_submit_urbs(serial);
+	if (ret)
+		goto err_free_ch348;
+
+	return 0;
+
+err_free_ch348:
+	kfree(ch348);
+	return ret;
+}
+
+static void ch348_release(struct usb_serial *serial)
+{
+	struct ch348 *ch348 = usb_get_serial_data(serial);
+
+	cancel_work_sync(&ch348->write_work);
+	ch348_kill_urbs(serial);
+
+	kfree(ch348);
+}
+
+static int ch348_calc_num_ports(struct usb_serial *serial,
+				struct usb_serial_endpoints *epds)
+{
+	int i;
+
+	epds->num_bulk_out = CH348_MAXPORT;
+
+	for (i = serial->type->num_bulk_out; i < CH348_MAXPORT; ++i)
+		epds->bulk_out[i] = epds->bulk_out[0];
+
+	return CH348_MAXPORT;
+}
+
+static int ch348_suspend(struct usb_serial *serial, pm_message_t message)
+{
+	struct ch348 *ch348 = usb_get_serial_data(serial);
+
+	cancel_work_sync(&ch348->write_work);
+
+	return 0;
+}
+
+static int ch348_resume(struct usb_serial *serial)
+{
+	struct ch348 *ch348 = usb_get_serial_data(serial);
+	int ret;
+
+	ret = ch348_submit_urbs(serial);
+	if (ret)
+		return ret;
+
+	schedule_work(&ch348->write_work);
+
+	return 0;
+}
+
+static const struct usb_device_id ch348_ids[] = {
+	{ USB_DEVICE(0x1a86, 0x55d9), },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(usb, ch348_ids);
+
+static struct usb_serial_driver ch348_device = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = "ch348",
+	},
+	.id_table =		ch348_ids,
+	.num_ports =		CH348_MAXPORT,
+	.num_bulk_in =		2,
+	.num_bulk_out =		2,
+	.open =			ch348_open,
+	.close =		ch348_close,
+	.set_termios =		ch348_set_termios,
+	.process_read_urb =	ch348_process_read_urb,
+	.write =		ch348_write,
+	.calc_num_ports =	ch348_calc_num_ports,
+	.attach =		ch348_attach,
+	.release =		ch348_release,
+	.suspend =		ch348_suspend,
+	.resume =		ch348_resume,
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+	&ch348_device, NULL
+};
+
+module_usb_serial_driver(serial_drivers, ch348_ids);
+
+MODULE_AUTHOR("Corentin Labbe <clabbe@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("USB CH348 Octo port serial converter driver");
+MODULE_LICENSE("GPL");
-- 
2.45.2