drivers/usb/serial/ch341.c - arm/linux-arm64-legacy - Git at Google

 /*
  * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
  *
  * ch341.c implements a serial port driver for the Winchiphead CH341.
  *
  * The CH341 device can be used to implement an RS232 asynchronous
  * serial port, an IEEE-1284 parallel printer port or a memory-like
  * interface. In all cases the CH341 supports an I2C interface as well.
  * This driver only supports the asynchronous serial interface.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License version
  * 2 as published by the Free Software Foundation.
  */

 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/tty.h>
 #include <linux/module.h>
 #include <linux/usb.h>
 #include <linux/usb/serial.h>
 #include <linux/serial.h>

 #define DEFAULT_BAUD_RATE 2400
 #define DEFAULT_TIMEOUT   1000

 static int debug;

 static struct usb_device_id id_table [] = {
 	{ USB_DEVICE(0x4348, 0x5523) },
 	{ USB_DEVICE(0x1a86, 0x7523) },
 	{ },
 };
 MODULE_DEVICE_TABLE(usb, id_table);

 struct ch341_private {
 	unsigned baud_rate;
 	u8 dtr;
 	u8 rts;
 };

 static int ch341_control_out(struct usb_device *dev, u8 request,
 			     u16 value, u16 index)
 {
 	int r;
 	dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
 		(int)request, (int)value, (int)index);

 	r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
 			    USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 			    value, index, NULL, 0, DEFAULT_TIMEOUT);

 	return r;
 }

 static int ch341_control_in(struct usb_device *dev,
 			    u8 request, u16 value, u16 index,
 			    char *buf, unsigned bufsize)
 {
 	int r;
 	dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
 		(int)request, (int)value, (int)index, buf, (int)bufsize);

 	r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
 			    USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 			    value, index, buf, bufsize, DEFAULT_TIMEOUT);
 	return r;
 }

 static int ch341_set_baudrate(struct usb_device *dev,
 			      struct ch341_private *priv)
 {
 	short a, b;
 	int r;

 	dbg("ch341_set_baudrate(%d)", priv->baud_rate);
 	switch (priv->baud_rate) {
 	case 2400:
 		a = 0xd901;
 		b = 0x0038;
 		break;
 	case 4800:
 		a = 0x6402;
 		b = 0x001f;
 		break;
 	case 9600:
 		a = 0xb202;
 		b = 0x0013;
 		break;
 	case 19200:
 		a = 0xd902;
 		b = 0x000d;
 		break;
 	case 38400:
 		a = 0x6403;
 		b = 0x000a;
 		break;
 	case 115200:
 		a = 0xcc03;
 		b = 0x0008;
 		break;
 	default:
 		return -EINVAL;
 	}

 	r = ch341_control_out(dev, 0x9a, 0x1312, a);
 	if (!r)
 		r = ch341_control_out(dev, 0x9a, 0x0f2c, b);

 	return r;
 }

 static int ch341_set_handshake(struct usb_device *dev,
 			       struct ch341_private *priv)
 {
 	dbg("ch341_set_handshake(%d,%d)", priv->dtr, priv->rts);
 	return ch341_control_out(dev, 0xa4,
 		~((priv->dtr?1<<5:0)|(priv->rts?1<<6:0)), 0);
 }

 static int ch341_get_status(struct usb_device *dev)
 {
 	char *buffer;
 	int r;
 	const unsigned size = 8;

 	dbg("ch341_get_status()");

 	buffer = kmalloc(size, GFP_KERNEL);
 	if (!buffer)
 		return -ENOMEM;

 	r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
 	if (r < 0)
 		goto out;

 	/* Not having the datasheet for the CH341, we ignore the bytes returned
 	 * from the device. Return error if the device did not respond in time.
 	 */
 	r = 0;

 out:	kfree(buffer);
 	return r;
 }

 /* -------------------------------------------------------------------------- */

 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 {
 	char *buffer;
 	int r;
 	const unsigned size = 8;

 	dbg("ch341_configure()");

 	buffer = kmalloc(size, GFP_KERNEL);
 	if (!buffer)
 		return -ENOMEM;

 	/* expect two bytes 0x27 0x00 */
 	r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
 	if (r < 0)
 		goto out;

 	r = ch341_control_out(dev, 0xa1, 0, 0);
 	if (r < 0)
 		goto out;

 	r = ch341_set_baudrate(dev, priv);
 	if (r < 0)
 		goto out;

 	/* expect two bytes 0x56 0x00 */
 	r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
 	if (r < 0)
 		goto out;

 	r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
 	if (r < 0)
 		goto out;

 	/* expect 0xff 0xee */
 	r = ch341_get_status(dev);
 	if (r < 0)
 		goto out;

 	r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
 	if (r < 0)
 		goto out;

 	r = ch341_set_baudrate(dev, priv);
 	if (r < 0)
 		goto out;

 	r = ch341_set_handshake(dev, priv);
 	if (r < 0)
 		goto out;

 	/* expect 0x9f 0xee */
 	r = ch341_get_status(dev);

 out:	kfree(buffer);
 	return r;
 }

 /* allocate private data */
 static int ch341_attach(struct usb_serial *serial)
 {
 	struct ch341_private *priv;
 	int r;

 	dbg("ch341_attach()");

 	/* private data */
 	priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	priv->baud_rate = DEFAULT_BAUD_RATE;
 	priv->dtr = 1;
 	priv->rts = 1;

 	r = ch341_configure(serial->dev, priv);
 	if (r < 0)
 		goto error;

 	usb_set_serial_port_data(serial->port[0], priv);
 	return 0;

 error:	kfree(priv);
 	return r;
 }

 /* open this device, set default parameters */
 static int ch341_open(struct usb_serial_port *port, struct file *filp)
 {
 	struct usb_serial *serial = port->serial;
 	struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
 	int r;

 	dbg("ch341_open()");

 	priv->baud_rate = DEFAULT_BAUD_RATE;
 	priv->dtr = 1;
 	priv->rts = 1;

 	r = ch341_configure(serial->dev, priv);
 	if (r)
 		goto out;

 	r = ch341_set_handshake(serial->dev, priv);
 	if (r)
 		goto out;

 	r = ch341_set_baudrate(serial->dev, priv);
 	if (r)
 		goto out;

 	r = usb_serial_generic_open(port, filp);

 out:	return r;
 }

 /* Old_termios contains the original termios settings and
  * tty->termios contains the new setting to be used.
  */
 static void ch341_set_termios(struct usb_serial_port *port,
 			      struct ktermios *old_termios)
 {
 	struct ch341_private *priv = usb_get_serial_port_data(port);
 	struct tty_struct *tty = port->tty;
 	unsigned baud_rate;

 	dbg("ch341_set_termios()");

 	baud_rate = tty_get_baud_rate(tty);

 	switch (baud_rate) {
 	case 2400:
 	case 4800:
 	case 9600:
 	case 19200:
 	case 38400:
 	case 115200:
 		priv->baud_rate = baud_rate;
 		break;
 	default:
 		dbg("Rate %d not supported, using %d",
 			baud_rate, DEFAULT_BAUD_RATE);
 		priv->baud_rate = DEFAULT_BAUD_RATE;
 	}

 	ch341_set_baudrate(port->serial->dev, priv);

 	/* Unimplemented:
 	 * (cflag & CSIZE) : data bits [5, 8]
 	 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
 	 * (cflag & CSTOPB) : stop bits [1, 2]
 	 */

 	 /* Copy back the old hardware settings */
 	 tty_termios_copy_hw(tty->termios, old_termios);
 	 /* And re-encode with the new baud */
 	 tty_encode_baud_rate(tty, baud_rate, baud_rate);
 }

 static struct usb_driver ch341_driver = {
 	.name		= "ch341",
 	.probe		= usb_serial_probe,
 	.disconnect	= usb_serial_disconnect,
 	.id_table	= id_table,
 	.no_dynamic_id	= 1,
 };

 static struct usb_serial_driver ch341_device = {
 	.driver = {
 		.owner	= THIS_MODULE,
 		.name	= "ch341-uart",
 	},
 	.id_table         = id_table,
 	.usb_driver       = &ch341_driver,
 	.num_ports        = 1,
 	.open             = ch341_open,
 	.set_termios      = ch341_set_termios,
 	.attach           = ch341_attach,
 };

 static int __init ch341_init(void)
 {
 	int retval;

 	retval = usb_serial_register(&ch341_device);
 	if (retval)
 		return retval;
 	retval = usb_register(&ch341_driver);
 	if (retval)
 		usb_serial_deregister(&ch341_device);
 	return retval;
 }

 static void __exit ch341_exit(void)
 {
 	usb_deregister(&ch341_driver);
 	usb_serial_deregister(&ch341_device);
 }

 module_init(ch341_init);
 module_exit(ch341_exit);
 MODULE_LICENSE("GPL");

 module_param(debug, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(debug, "Debug enabled or not");

 /* EOF ch341.c */
	/*
	* Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
	*
	* ch341.c implements a serial port driver for the Winchiphead CH341.
	*
	* The CH341 device can be used to implement an RS232 asynchronous
	* serial port, an IEEE-1284 parallel printer port or a memory-like
	* interface. In all cases the CH341 supports an I2C interface as well.
	* This driver only supports the asynchronous serial interface.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License version
	* 2 as published by the Free Software Foundation.
	*/

	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/tty.h>
	#include <linux/module.h>
	#include <linux/usb.h>
	#include <linux/usb/serial.h>
	#include <linux/serial.h>

	#define DEFAULT_BAUD_RATE 2400
	#define DEFAULT_TIMEOUT 1000

	static int debug;

	static struct usb_device_id id_table [] = {
	{ USB_DEVICE(0x4348, 0x5523) },
	{ USB_DEVICE(0x1a86, 0x7523) },
	{ },
	};
	MODULE_DEVICE_TABLE(usb, id_table);

	struct ch341_private {
	unsigned baud_rate;
	u8 dtr;
	u8 rts;
	};

	static int ch341_control_out(struct usb_device *dev, u8 request,
	u16 value, u16 index)
	{
	int r;
	dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT\|0x40,
	(int)request, (int)value, (int)index);

	r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_OUT,
	value, index, NULL, 0, DEFAULT_TIMEOUT);

	return r;
	}

	static int ch341_control_in(struct usb_device *dev,
	u8 request, u16 value, u16 index,
	char *buf, unsigned bufsize)
	{
	int r;
	dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN\|0x40,
	(int)request, (int)value, (int)index, buf, (int)bufsize);

	r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
	USB_TYPE_VENDOR \| USB_RECIP_DEVICE \| USB_DIR_IN,
	value, index, buf, bufsize, DEFAULT_TIMEOUT);
	return r;
	}

	static int ch341_set_baudrate(struct usb_device *dev,
	struct ch341_private *priv)
	{
	short a, b;
	int r;

	dbg("ch341_set_baudrate(%d)", priv->baud_rate);
	switch (priv->baud_rate) {
	case 2400:
	a = 0xd901;
	b = 0x0038;
	break;
	case 4800:
	a = 0x6402;
	b = 0x001f;
	break;
	case 9600:
	a = 0xb202;
	b = 0x0013;
	break;
	case 19200:
	a = 0xd902;
	b = 0x000d;
	break;
	case 38400:
	a = 0x6403;
	b = 0x000a;
	break;
	case 115200:
	a = 0xcc03;
	b = 0x0008;
	break;
	default:
	return -EINVAL;
	}

	r = ch341_control_out(dev, 0x9a, 0x1312, a);
	if (!r)
	r = ch341_control_out(dev, 0x9a, 0x0f2c, b);

	return r;
	}

	static int ch341_set_handshake(struct usb_device *dev,
	struct ch341_private *priv)
	{
	dbg("ch341_set_handshake(%d,%d)", priv->dtr, priv->rts);
	return ch341_control_out(dev, 0xa4,
	~((priv->dtr?1<<5:0)\|(priv->rts?1<<6:0)), 0);
	}

	static int ch341_get_status(struct usb_device *dev)
	{
	char *buffer;
	int r;
	const unsigned size = 8;

	dbg("ch341_get_status()");

	buffer = kmalloc(size, GFP_KERNEL);
	if (!buffer)
	return -ENOMEM;

	r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
	if (r < 0)
	goto out;

	/* Not having the datasheet for the CH341, we ignore the bytes returned
	* from the device. Return error if the device did not respond in time.
	*/
	r = 0;

	out: kfree(buffer);
	return r;
	}

	/* -------------------------------------------------------------------------- */

	static int ch341_configure(struct usb_device dev, struct ch341_private priv)
	{
	char *buffer;
	int r;
	const unsigned size = 8;

	dbg("ch341_configure()");

	buffer = kmalloc(size, GFP_KERNEL);
	if (!buffer)
	return -ENOMEM;

	/* expect two bytes 0x27 0x00 */
	r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
	if (r < 0)
	goto out;

	r = ch341_control_out(dev, 0xa1, 0, 0);
	if (r < 0)
	goto out;

	r = ch341_set_baudrate(dev, priv);
	if (r < 0)
	goto out;

	/* expect two bytes 0x56 0x00 */
	r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
	if (r < 0)
	goto out;

	r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
	if (r < 0)
	goto out;

	/* expect 0xff 0xee */
	r = ch341_get_status(dev);
	if (r < 0)
	goto out;

	r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
	if (r < 0)
	goto out;

	r = ch341_set_baudrate(dev, priv);
	if (r < 0)
	goto out;

	r = ch341_set_handshake(dev, priv);
	if (r < 0)
	goto out;

	/* expect 0x9f 0xee */
	r = ch341_get_status(dev);

	out: kfree(buffer);
	return r;
	}

	/* allocate private data */
	static int ch341_attach(struct usb_serial *serial)
	{
	struct ch341_private *priv;
	int r;

	dbg("ch341_attach()");

	/* private data */
	priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	priv->baud_rate = DEFAULT_BAUD_RATE;
	priv->dtr = 1;
	priv->rts = 1;

	r = ch341_configure(serial->dev, priv);
	if (r < 0)
	goto error;

	usb_set_serial_port_data(serial->port[0], priv);
	return 0;

	error: kfree(priv);
	return r;
	}

	/* open this device, set default parameters */
	static int ch341_open(struct usb_serial_port port, struct file filp)
	{
	struct usb_serial *serial = port->serial;
	struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
	int r;

	dbg("ch341_open()");

	priv->baud_rate = DEFAULT_BAUD_RATE;
	priv->dtr = 1;
	priv->rts = 1;

	r = ch341_configure(serial->dev, priv);
	if (r)
	goto out;

	r = ch341_set_handshake(serial->dev, priv);
	if (r)
	goto out;

	r = ch341_set_baudrate(serial->dev, priv);
	if (r)
	goto out;

	r = usb_serial_generic_open(port, filp);

	out: return r;
	}

	/* Old_termios contains the original termios settings and
	* tty->termios contains the new setting to be used.
	*/
	static void ch341_set_termios(struct usb_serial_port *port,
	struct ktermios *old_termios)
	{
	struct ch341_private *priv = usb_get_serial_port_data(port);
	struct tty_struct *tty = port->tty;
	unsigned baud_rate;

	dbg("ch341_set_termios()");

	baud_rate = tty_get_baud_rate(tty);

	switch (baud_rate) {
	case 2400:
	case 4800:
	case 9600:
	case 19200:
	case 38400:
	case 115200:
	priv->baud_rate = baud_rate;
	break;
	default:
	dbg("Rate %d not supported, using %d",
	baud_rate, DEFAULT_BAUD_RATE);
	priv->baud_rate = DEFAULT_BAUD_RATE;
	}

	ch341_set_baudrate(port->serial->dev, priv);

	/* Unimplemented:
	* (cflag & CSIZE) : data bits [5, 8]
	* (cflag & PARENB) : parity {NONE, EVEN, ODD}
	* (cflag & CSTOPB) : stop bits [1, 2]
	*/

	/* Copy back the old hardware settings */
	tty_termios_copy_hw(tty->termios, old_termios);
	/* And re-encode with the new baud */
	tty_encode_baud_rate(tty, baud_rate, baud_rate);
	}

	static struct usb_driver ch341_driver = {
	.name = "ch341",
	.probe = usb_serial_probe,
	.disconnect = usb_serial_disconnect,
	.id_table = id_table,
	.no_dynamic_id = 1,
	};

	static struct usb_serial_driver ch341_device = {
	.driver = {
	.owner = THIS_MODULE,
	.name = "ch341-uart",
	},
	.id_table = id_table,
	.usb_driver = &ch341_driver,
	.num_ports = 1,
	.open = ch341_open,
	.set_termios = ch341_set_termios,
	.attach = ch341_attach,
	};

	static int __init ch341_init(void)
	{
	int retval;

	retval = usb_serial_register(&ch341_device);
	if (retval)
	return retval;
	retval = usb_register(&ch341_driver);
	if (retval)
	usb_serial_deregister(&ch341_device);
	return retval;
	}

	static void __exit ch341_exit(void)
	{
	usb_deregister(&ch341_driver);
	usb_serial_deregister(&ch341_device);
	}

	module_init(ch341_init);
	module_exit(ch341_exit);
	MODULE_LICENSE("GPL");

	module_param(debug, bool, S_IRUGO \| S_IWUSR);
	MODULE_PARM_DESC(debug, "Debug enabled or not");

	/* EOF ch341.c */