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linux/drivers/usb/serial/ch341.c
Alan Cox 73f5930819 USB: ch341: fix termios handling 
The ch341 currently doesn't support most of the hardware setting.  So to keep
the termios data right we propogate the old termios hardware values back then
encode the speed.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-25 12:18:40 -07:00

356 lines
7.5 KiB
C
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/*
* 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) },
{ },
};
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_interrupt_in = NUM_DONT_CARE,
.num_bulk_in = 1,
.num_bulk_out = 1,
.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 */
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