Commit f4c1a837 authored by Werner Cornelius's avatar Werner Cornelius Committed by Greg Kroah-Hartman
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USB: usb-serial ch341: support for DTR/RTS/CTS 

commit 664d5df9 upstream.

Fixup of Werner Cornelius patch to the ch341 USB-serial driver, which adds:
- support all baudrates, not just a hard-coded set
- support for controlling DTR, RTS and CTS

Features still missing:
- character length other than 8 bits
- parity settings
- break control

I adapted his patch for the new usb_serial API introduced in 2.6.25-git8 by
Alan Cox on 22 July 2008. Non-compliance to the new API was a reason for
refusing a similar patch from Tollef Fog Heen.

Usage example by Tollef Fog Heen :
        TEMPer USB thermometer <http://err.no/src/TEMPer.c

>

based on a patch by:

	From: Tollef Fog Heen <tfheen@err.no>

	* Implement support for all baud rates rather than just a hard
	  coded set.
	* Make it possible to control status and control lines
	* Grab a bunch of #defines from FreeBSD to reduce the number of
	  magic numbers in the file

Signed-off-by: default avatarWerner Cornelius <Werner.Cornelius@cornelius-consult.de>
Signed-off-by: default avatarBoris Hajduk <boris@hajduk.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: default avatarTollef Fog Heen <tfheen@err.no>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent c7877e19

drivers/usb/serial/ch341.c

+302 −72
Original line number Diff line number Diff line 
/*

 * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>

 * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>

 * Copyright 2009, Boris Hajduk <boris@hajduk.org>

 *

 * ch341.c implements a serial port driver for the Winchiphead CH341.

 *
@@ -21,9 +23,39 @@ 
#include <linux/usb/serial.h>

#include <linux/serial.h>



#define DEFAULT_BAUD_RATE 2400

#define DEFAULT_BAUD_RATE 9600

#define DEFAULT_TIMEOUT   1000



/* flags for IO-Bits */

#define CH341_BIT_RTS (1 << 6)

#define CH341_BIT_DTR (1 << 5)



/******************************/

/* interrupt pipe definitions */

/******************************/

/* always 4 interrupt bytes */

/* first irq byte normally 0x08 */

/* second irq byte base 0x7d + below */

/* third irq byte base 0x94 + below */

/* fourth irq byte normally 0xee */



/* second interrupt byte */

#define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */



/* status returned in third interrupt answer byte, inverted in data

   from irq */

#define CH341_BIT_CTS 0x01

#define CH341_BIT_DSR 0x02

#define CH341_BIT_RI  0x04

#define CH341_BIT_DCD 0x08

#define CH341_BITS_MODEM_STAT 0x0f /* all bits */



/*******************************/

/* baudrate calculation factor */

/*******************************/

#define CH341_BAUDBASE_FACTOR 1532620800

#define CH341_BAUDBASE_DIVMAX 3



static int debug;



static struct usb_device_id id_table [] = {
@@ -34,9 +66,12 @@ static struct usb_device_id id_table [] = { 
MODULE_DEVICE_TABLE(usb, id_table);



struct ch341_private {

	unsigned baud_rate;

	u8 dtr;

	u8 rts;

	spinlock_t lock; /* access lock */

	wait_queue_head_t delta_msr_wait; /* wait queue for modem status */

	unsigned baud_rate; /* set baud rate */

	u8 line_control; /* set line control value RTS/DTR */

	u8 line_status; /* active status of modem control inputs */

	u8 multi_status_change; /* status changed multiple since last call */

};



static int ch341_control_out(struct usb_device *dev, u8 request,
@@ -72,37 +107,28 @@ static int ch341_set_baudrate(struct usb_device *dev, 
{

	short a, b;

	int r;

	unsigned long factor;

	short divisor;



	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:



	if (!priv->baud_rate)

		return -EINVAL;

	factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);

	divisor = CH341_BAUDBASE_DIVMAX;



	while ((factor > 0xfff0) && divisor) {

		factor >>= 3;

		divisor--;

	}



	if (factor > 0xfff0)

		return -EINVAL;



	factor = 0x10000 - factor;

	a = (factor & 0xff00) | divisor;

	b = factor & 0xff;



	r = ch341_control_out(dev, 0x9a, 0x1312, a);

	if (!r)

		r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
@@ -110,19 +136,18 @@ static int ch341_set_baudrate(struct usb_device *dev, 
	return r;

}



static int ch341_set_handshake(struct usb_device *dev,

			       struct ch341_private *priv)

static int ch341_set_handshake(struct usb_device *dev, u8 control)

{

	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);

	dbg("ch341_set_handshake(0x%02x)", control);

	return ch341_control_out(dev, 0xa4, ~control, 0);

}



static int ch341_get_status(struct usb_device *dev)

static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)

{

	char *buffer;

	int r;

	const unsigned size = 8;

	unsigned long flags;



	dbg("ch341_get_status()");
@@ -134,10 +159,15 @@ static int ch341_get_status(struct usb_device *dev) 
	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.

	 */

	/* setup the private status if available */

	if (r == 2) {

		r = 0;

		spin_lock_irqsave(&priv->lock, flags);

		priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;

		priv->multi_status_change = 0;

		spin_unlock_irqrestore(&priv->lock, flags);

	} else

		r = -EPROTO;



out:	kfree(buffer);

	return r;
@@ -180,7 +210,7 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 
		goto out;



	/* expect 0xff 0xee */

	r = ch341_get_status(dev);

	r = ch341_get_status(dev, priv);

	if (r < 0)

		goto out;
@@ -192,12 +222,12 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 
	if (r < 0)

		goto out;



	r = ch341_set_handshake(dev, priv);

	r = ch341_set_handshake(dev, priv->line_control);

	if (r < 0)

		goto out;



	/* expect 0x9f 0xee */

	r = ch341_get_status(dev);

	r = ch341_get_status(dev, priv);



out:	kfree(buffer);

	return r;
@@ -216,9 +246,10 @@ static int ch341_attach(struct usb_serial *serial) 
	if (!priv)

		return -ENOMEM;



	spin_lock_init(&priv->lock);

	init_waitqueue_head(&priv->delta_msr_wait);

	priv->baud_rate = DEFAULT_BAUD_RATE;

	priv->dtr = 1;

	priv->rts = 1;

	priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;



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

	if (r < 0)
@@ -231,6 +262,35 @@ error: kfree(priv); 
	return r;

}



static void ch341_close(struct tty_struct *tty, struct usb_serial_port *port,

				struct file *filp)

{

	struct ch341_private *priv = usb_get_serial_port_data(port);

	unsigned long flags;

	unsigned int c_cflag;



	dbg("%s - port %d", __func__, port->number);



	/* shutdown our urbs */

	dbg("%s - shutting down urbs", __func__);

	usb_kill_urb(port->write_urb);

	usb_kill_urb(port->read_urb);

	usb_kill_urb(port->interrupt_in_urb);



	if (tty) {

		c_cflag = tty->termios->c_cflag;

		if (c_cflag & HUPCL) {

			/* drop DTR and RTS */

			spin_lock_irqsave(&priv->lock, flags);

			priv->line_control = 0;

			spin_unlock_irqrestore(&priv->lock, flags);

			ch341_set_handshake(port->serial->dev, 0);

		}

	}

	wake_up_interruptible(&priv->delta_msr_wait);

}





/* open this device, set default parameters */

static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port,

				struct file *filp)
@@ -242,14 +302,13 @@ static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port, 
	dbg("ch341_open()");



	priv->baud_rate = DEFAULT_BAUD_RATE;

	priv->dtr = 1;

	priv->rts = 1;

	priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;



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

	if (r)

		goto out;



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

	r = ch341_set_handshake(serial->dev, priv->line_control);

	if (r)

		goto out;
@@ -257,6 +316,16 @@ static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port, 
	if (r)

		goto out;



	dbg("%s - submitting interrupt urb", __func__);

	port->interrupt_in_urb->dev = serial->dev;

	r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);

	if (r) {

		dev_err(&port->dev, "%s - failed submitting interrupt urb,"

			" error %d\n", __func__, r);

		ch341_close(tty, port, NULL);

		return -EPROTO;

	}



	r = usb_serial_generic_open(tty, port, filp);



out:	return r;
@@ -270,38 +339,194 @@ static void ch341_set_termios(struct tty_struct *tty, 
{

	struct ch341_private *priv = usb_get_serial_port_data(port);

	unsigned baud_rate;

	unsigned long flags;



	dbg("ch341_set_termios()");



	if (!tty || !tty->termios)

		return;



	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;

	}



	if (baud_rate) {

		spin_lock_irqsave(&priv->lock, flags);

		priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);

		spin_unlock_irqrestore(&priv->lock, flags);

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

	} else {

		spin_lock_irqsave(&priv->lock, flags);

		priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);

		spin_unlock_irqrestore(&priv->lock, flags);

	}



	ch341_set_handshake(port->serial->dev, priv->line_control);



	/* Unimplemented:

	 * (cflag & CSIZE) : data bits [5, 8]

	 * (cflag & PARENB) : parity {NONE, EVEN, ODD}

	 * (cflag & CSTOPB) : stop bits [1, 2]

	 */

}



static int ch341_tiocmset(struct tty_struct *tty, struct file *file,

			  unsigned int set, unsigned int clear)

{

	struct usb_serial_port *port = tty->driver_data;

	struct ch341_private *priv = usb_get_serial_port_data(port);

	unsigned long flags;

	u8 control;



	spin_lock_irqsave(&priv->lock, flags);

	if (set & TIOCM_RTS)

		priv->line_control |= CH341_BIT_RTS;

	if (set & TIOCM_DTR)

		priv->line_control |= CH341_BIT_DTR;

	if (clear & TIOCM_RTS)

		priv->line_control &= ~CH341_BIT_RTS;

	if (clear & TIOCM_DTR)

		priv->line_control &= ~CH341_BIT_DTR;

	control = priv->line_control;

	spin_unlock_irqrestore(&priv->lock, flags);



	return ch341_set_handshake(port->serial->dev, control);

}



static void ch341_read_int_callback(struct urb *urb)

{

	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;

	unsigned char *data = urb->transfer_buffer;

	unsigned int actual_length = urb->actual_length;

	int status;



	dbg("%s (%d)", __func__, port->number);



	switch (urb->status) {

	case 0:

		/* success */

		break;

	case -ECONNRESET:

	case -ENOENT:

	case -ESHUTDOWN:

		/* this urb is terminated, clean up */

		dbg("%s - urb shutting down with status: %d", __func__,

		    urb->status);

		return;

	default:

		dbg("%s - nonzero urb status received: %d", __func__,

		    urb->status);

		goto exit;

	}



	usb_serial_debug_data(debug, &port->dev, __func__,

			      urb->actual_length, urb->transfer_buffer);



	if (actual_length >= 4) {

		struct ch341_private *priv = usb_get_serial_port_data(port);

		unsigned long flags;



		spin_lock_irqsave(&priv->lock, flags);

		priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;

		if ((data[1] & CH341_MULT_STAT))

			priv->multi_status_change = 1;

		spin_unlock_irqrestore(&priv->lock, flags);

		wake_up_interruptible(&priv->delta_msr_wait);

	}



exit:

	status = usb_submit_urb(urb, GFP_ATOMIC);

	if (status)

		dev_err(&urb->dev->dev,

			"%s - usb_submit_urb failed with result %d\n",

			__func__, status);

}



static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)

{

	struct ch341_private *priv = usb_get_serial_port_data(port);

	unsigned long flags;

	u8 prevstatus;

	u8 status;

	u8 changed;

	u8 multi_change = 0;



	spin_lock_irqsave(&priv->lock, flags);

	prevstatus = priv->line_status;

	priv->multi_status_change = 0;

	spin_unlock_irqrestore(&priv->lock, flags);



	while (!multi_change) {

		interruptible_sleep_on(&priv->delta_msr_wait);

		/* see if a signal did it */

		if (signal_pending(current))

			return -ERESTARTSYS;



		spin_lock_irqsave(&priv->lock, flags);

		status = priv->line_status;

		multi_change = priv->multi_status_change;

		spin_unlock_irqrestore(&priv->lock, flags);



		changed = prevstatus ^ status;



		if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||

		    ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||

		    ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||

		    ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {

			return 0;

		}

		prevstatus = status;

	}



	return 0;

}



/*static int ch341_ioctl(struct usb_serial_port *port, struct file *file,*/

static int ch341_ioctl(struct tty_struct *tty, struct file *file,

			unsigned int cmd, unsigned long arg)

{

	struct usb_serial_port *port = tty->driver_data;

	dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);



	switch (cmd) {

	case TIOCMIWAIT:

		dbg("%s (%d) TIOCMIWAIT", __func__,  port->number);

		return wait_modem_info(port, arg);



	default:

		dbg("%s not supported = 0x%04x", __func__, cmd);

		break;

	}



	return -ENOIOCTLCMD;

}



static int ch341_tiocmget(struct tty_struct *tty, struct file *file)

{

	struct usb_serial_port *port = tty->driver_data;

	struct ch341_private *priv = usb_get_serial_port_data(port);

	unsigned long flags;

	u8 mcr;

	u8 status;

	unsigned int result;



	dbg("%s (%d)", __func__, port->number);



	spin_lock_irqsave(&priv->lock, flags);

	mcr = priv->line_control;

	status = priv->line_status;

	spin_unlock_irqrestore(&priv->lock, flags);



	result = ((mcr & CH341_BIT_DTR)		? TIOCM_DTR : 0)

		  | ((mcr & CH341_BIT_RTS)	? TIOCM_RTS : 0)

		  | ((status & CH341_BIT_CTS)	? TIOCM_CTS : 0)

		  | ((status & CH341_BIT_DSR)	? TIOCM_DSR : 0)

		  | ((status & CH341_BIT_RI)	? TIOCM_RI  : 0)

		  | ((status & CH341_BIT_DCD)	? TIOCM_CD  : 0);



	dbg("%s - result = %x", __func__, result);



	 /* 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);

	return result;

}
@@ -343,7 +568,12 @@ static struct usb_serial_driver ch341_device = { 
	.usb_driver        = &ch341_driver,

	.num_ports         = 1,

	.open              = ch341_open,

	.close             = ch341_close,

	.ioctl             = ch341_ioctl,

	.set_termios       = ch341_set_termios,

	.tiocmget          = ch341_tiocmget,

	.tiocmset          = ch341_tiocmset,

	.read_int_callback = ch341_read_int_callback,

	.attach            = ch341_attach,

};

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