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 ab4cc277aa65..d33d39d9b7e2 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)