/*
* 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.
*
* 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 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 [] = {
{ USB_DEVICE(0x4348, 0x5523) },
{ USB_DEVICE(0x1a86, 0x7523) },
{ },
};
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 */
};
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;
unsigned long factor;
short divisor;
dbg("ch341_set_baudrate(%d)", priv->baud_rate);
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);
return r;
}
static int ch341_set_handshake(struct usb_device *dev, u8 control)
{
dbg("ch341_set_handshake(0x%02x)", control);
return ch341_control_out(dev, 0xa4, ~control, 0);
}
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()");
buffer = kmalloc(size, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
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;
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, priv);
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->line_control);
if (r < 0)
goto out;
/* expect 0x9f 0xee */
r = ch341_get_status(dev, priv);
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;
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;
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;
}
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)
{
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->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->line_control);
if (r)
goto out;
r = ch341_set_baudrate(serial->dev, priv);
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;
}
/* Old_termios contains the original termios settings and
* tty->termios contains the new setting to be used.
*/
static void ch341_set_termios(struct tty_struct *tty,
struct usb_serial_port *port, struct ktermios *old_termios)
{
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);
}
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);
return result;
}
static int ch341_reset_resume(struct usb_interface *intf)
{
struct usb_device *dev = interface_to_usbdev(intf);
struct usb_serial *serial = NULL;
struct ch341_private *priv;
serial = usb_get_intfdata(intf);
priv = usb_get_serial_port_data(serial->port[0]);
/*reconfigure ch341 serial port after bus-reset*/
ch341_configure(dev, priv);
usb_serial_resume(intf);
return 0;
}
static struct usb_driver ch341_driver = {
.name = "ch341",
.probe = usb_serial_probe,
.disconnect = usb_serial_disconnect,
.suspend = usb_serial_suspend,
.resume = usb_serial_resume,
.reset_resume = ch341_reset_resume,
.id_table = id_table,
.no_dynamic_id = 1,
.supports_autosuspend = 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,
.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,
};
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 */
