Revert USB: usb-serial ch341: support for DTR/RTS/CTS

Reverts commit 664d5df92e88b6ef091048a802b3750f4e989180 as the commit
log information was not complete, and we didn't have a proper
signed-off-by by the author of the original BSD code.

Cc: Werner Cornelius <Werner.Cornelius@cornelius-consult.de>
Cc: Boris Hajduk <boris@hajduk.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 72 insertions, 302 deletions

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index ab4cc27..d33d39d 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -1,7 +1,5 @@
 /*
  * 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.
  *
@@ -23,39 +21,9 @@
 #include <linux/usb/serial.h>
 #include <linux/serial.h>
 
-#define DEFAULT_BAUD_RATE 9600
+#define DEFAULT_BAUD_RATE 2400
 #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 [] = {
@@ -66,12 +34,9 @@ static struct usb_device_id id_table [] = {
 MODULE_DEVICE_TABLE(usb, id_table);
 
 struct ch341_private {
-	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 */
+	unsigned baud_rate;
+	u8 dtr;
+	u8 rts;
 };
 
 static int ch341_control_out(struct usb_device *dev, u8 request,
@@ -107,28 +72,37 @@ 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);
-
-	if (!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;
-	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);
@@ -136,18 +110,19 @@ static int ch341_set_baudrate(struct usb_device *dev,
 	return r;
 }
 
-static int ch341_set_handshake(struct usb_device *dev, u8 control)
+static int ch341_set_handshake(struct usb_device *dev,
+			       struct ch341_private *priv)
 {
-	dbg("ch341_set_handshake(0x%02x)", control);
-	return ch341_control_out(dev, 0xa4, ~control, 0);
+	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, struct ch341_private *priv)
+static int ch341_get_status(struct usb_device *dev)
 {
 	char *buffer;
 	int r;
 	const unsigned size = 8;
-	unsigned long flags;
 
 	dbg("ch341_get_status()");
 
@@ -159,15 +134,10 @@ static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
 	if (r < 0)
 		goto out;
 
-	/* 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;
+	/* 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;
@@ -210,7 +180,7 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 		goto out;
 
 	/* expect 0xff 0xee */
-	r = ch341_get_status(dev, priv);
+	r = ch341_get_status(dev);
 	if (r < 0)
 		goto out;
 
@@ -222,12 +192,12 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 	if (r < 0)
 		goto out;
 
-	r = ch341_set_handshake(dev, priv->line_control);
+	r = ch341_set_handshake(dev, priv);
 	if (r < 0)
 		goto out;
 
 	/* expect 0x9f 0xee */
-	r = ch341_get_status(dev, priv);
+	r = ch341_get_status(dev);
 
 out:	kfree(buffer);
 	return r;
@@ -246,10 +216,9 @@ 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->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
+	priv->dtr = 1;
+	priv->rts = 1;
 
 	r = ch341_configure(serial->dev, priv);
 	if (r < 0)
@@ -262,35 +231,6 @@ 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)
@@ -302,13 +242,14 @@ static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port,
 	dbg("ch341_open()");
 
 	priv->baud_rate = DEFAULT_BAUD_RATE;
-	priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
+	priv->dtr = 1;
+	priv->rts = 1;
 
 	r = ch341_configure(serial->dev, priv);
 	if (r)
 		goto out;
 
-	r = ch341_set_handshake(serial->dev, priv->line_control);
+	r = ch341_set_handshake(serial->dev, priv);
 	if (r)
 		goto out;
 
@@ -316,16 +257,6 @@ 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;
@@ -339,194 +270,38 @@ 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);
 
-	priv->baud_rate = 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);
+	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_handshake(port->serial->dev, priv->line_control);
+	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]
 	 */
-}
-
-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);
 
-	return 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);
 }
 
 
@@ -564,17 +339,12 @@ static struct usb_serial_driver ch341_device = {
 		.owner	= THIS_MODULE,
 		.name	= "ch341-uart",
 	},
-	.id_table          = id_table,
-	.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,
+	.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)