353 lines
7.3 KiB
C
353 lines
7.3 KiB
C
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/*
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* Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
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*
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* ch341.c implements a serial port driver for the Winchiphead CH341.
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*
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* The CH341 device can be used to implement an RS232 asynchronous
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* serial port, an IEEE-1284 parallel printer port or a memory-like
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* interface. In all cases the CH341 supports an I2C interface as well.
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* This driver only supports the asynchronous serial interface.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/tty.h>
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#include <linux/module.h>
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#include <linux/usb.h>
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#include <linux/usb/serial.h>
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#include <linux/serial.h>
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#define DEFAULT_BAUD_RATE 2400
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#define DEFAULT_TIMEOUT 1000
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static int debug;
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static struct usb_device_id id_table [] = {
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{ USB_DEVICE(0x4348, 0x5523) },
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{ },
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};
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MODULE_DEVICE_TABLE(usb, id_table);
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struct ch341_private {
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unsigned baud_rate;
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u8 dtr;
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u8 rts;
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};
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static int ch341_control_out(struct usb_device *dev, u8 request,
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u16 value, u16 index)
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{
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int r;
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dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
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(int)request, (int)value, (int)index);
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r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
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USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
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value, index, NULL, 0, DEFAULT_TIMEOUT);
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return r;
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}
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static int ch341_control_in(struct usb_device *dev,
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u8 request, u16 value, u16 index,
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char *buf, unsigned bufsize)
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{
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int r;
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dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
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(int)request, (int)value, (int)index, buf, (int)bufsize);
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r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
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USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
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value, index, buf, bufsize, DEFAULT_TIMEOUT);
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return r;
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}
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int ch341_set_baudrate(struct usb_device *dev, struct ch341_private *priv)
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{
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short a, b;
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int r;
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dbg("ch341_set_baudrate(%d)", priv->baud_rate);
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switch (priv->baud_rate) {
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case 2400:
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a = 0xd901;
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b = 0x0038;
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break;
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case 4800:
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a = 0x6402;
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b = 0x001f;
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break;
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case 9600:
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a = 0xb202;
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b = 0x0013;
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break;
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case 19200:
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a = 0xd902;
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b = 0x000d;
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break;
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case 38400:
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a = 0x6403;
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b = 0x000a;
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break;
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case 115200:
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a = 0xcc03;
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b = 0x0008;
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break;
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default:
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return -EINVAL;
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}
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r = ch341_control_out(dev, 0x9a, 0x1312, a);
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if (!r)
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r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
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return r;
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}
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int ch341_set_handshake(struct usb_device *dev, struct ch341_private *priv)
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{
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dbg("ch341_set_handshake(%d,%d)", priv->dtr, priv->rts);
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return ch341_control_out(dev, 0xa4,
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~((priv->dtr?1<<5:0)|(priv->rts?1<<6:0)), 0);
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}
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int ch341_get_status(struct usb_device *dev)
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{
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char *buffer;
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int r;
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const unsigned size = 8;
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dbg("ch341_get_status()");
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buffer = kmalloc(size, GFP_KERNEL);
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if (!buffer)
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return -ENOMEM;
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r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
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if ( r < 0)
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goto out;
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/* Not having the datasheet for the CH341, we ignore the bytes returned
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* from the device. Return error if the device did not respond in time.
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*/
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r = 0;
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out: kfree(buffer);
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return r;
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}
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/* -------------------------------------------------------------------------- */
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int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
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{
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char *buffer;
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int r;
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const unsigned size = 8;
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dbg("ch341_configure()");
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buffer = kmalloc(size, GFP_KERNEL);
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if (!buffer)
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return -ENOMEM;
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/* expect two bytes 0x27 0x00 */
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r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
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if (r < 0)
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goto out;
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r = ch341_control_out(dev, 0xa1, 0, 0);
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if (r < 0)
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goto out;
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r = ch341_set_baudrate(dev, priv);
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if (r < 0)
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goto out;
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/* expect two bytes 0x56 0x00 */
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r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
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if (r < 0)
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goto out;
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r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
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if (r < 0)
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goto out;
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/* expect 0xff 0xee */
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r = ch341_get_status(dev);
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if (r < 0)
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goto out;
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r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
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if (r < 0)
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goto out;
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r = ch341_set_baudrate(dev, priv);
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if (r < 0)
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goto out;
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r = ch341_set_handshake(dev, priv);
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if (r < 0)
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goto out;
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/* expect 0x9f 0xee */
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r = ch341_get_status(dev);
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out: kfree(buffer);
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return r;
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}
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/* allocate private data */
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static int ch341_attach(struct usb_serial *serial)
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{
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struct ch341_private *priv;
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int r;
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dbg("ch341_attach()");
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/* private data */
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priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->baud_rate = DEFAULT_BAUD_RATE;
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priv->dtr = 1;
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priv->rts = 1;
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r = ch341_configure(serial->dev, priv);
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if (r < 0)
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goto error;
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usb_set_serial_port_data(serial->port[0], priv);
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return 0;
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error: kfree(priv);
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return r;
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}
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/* open this device, set default parameters */
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static int ch341_open(struct usb_serial_port *port, struct file *filp)
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{
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struct usb_serial *serial = port->serial;
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struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
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int r;
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dbg("ch341_open()");
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priv->baud_rate = DEFAULT_BAUD_RATE;
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priv->dtr = 1;
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priv->rts = 1;
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r = ch341_configure(serial->dev, priv);
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if (r)
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goto out;
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r = ch341_set_handshake(serial->dev, priv);
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if (r)
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goto out;
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r = ch341_set_baudrate(serial->dev, priv);
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if (r)
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goto out;
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r = usb_serial_generic_open(port, filp);
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out: return r;
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}
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/* Old_termios contains the original termios settings and
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* tty->termios contains the new setting to be used.
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*/
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static void ch341_set_termios(struct usb_serial_port *port,
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struct ktermios *old_termios)
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{
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struct ch341_private *priv = usb_get_serial_port_data(port);
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struct tty_struct *tty = port->tty;
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unsigned baud_rate;
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dbg("ch341_set_termios()");
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if (!tty || !tty->termios)
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return;
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baud_rate = tty_get_baud_rate(tty);
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switch (baud_rate) {
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case 2400:
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case 4800:
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case 9600:
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case 19200:
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case 38400:
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case 115200:
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priv->baud_rate = baud_rate;
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break;
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default:
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dbg("Rate %d not supported, using %d",
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baud_rate, DEFAULT_BAUD_RATE);
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priv->baud_rate = DEFAULT_BAUD_RATE;
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}
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ch341_set_baudrate(port->serial->dev, priv);
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/* Unimplemented:
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* (cflag & CSIZE) : data bits [5, 8]
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* (cflag & PARENB) : parity {NONE, EVEN, ODD}
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* (cflag & CSTOPB) : stop bits [1, 2]
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*/
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}
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static struct usb_driver ch341_driver = {
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.name = "ch341",
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.probe = usb_serial_probe,
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.disconnect = usb_serial_disconnect,
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.id_table = id_table,
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.no_dynamic_id = 1,
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};
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static struct usb_serial_driver ch341_device = {
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.driver = {
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.owner = THIS_MODULE,
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.name = "ch341-uart",
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},
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.id_table = id_table,
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.usb_driver = &ch341_driver,
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.num_interrupt_in = NUM_DONT_CARE,
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.num_bulk_in = 1,
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.num_bulk_out = 1,
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.num_ports = 1,
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.open = ch341_open,
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.set_termios = ch341_set_termios,
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.attach = ch341_attach,
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};
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static int __init ch341_init(void)
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{
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int retval;
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retval = usb_serial_register(&ch341_device);
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if (retval)
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return retval;
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retval = usb_register(&ch341_driver);
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if (retval)
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usb_serial_deregister(&ch341_device);
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return retval;
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}
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static void __exit ch341_exit(void)
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{
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usb_deregister(&ch341_driver);
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usb_serial_deregister(&ch341_device);
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}
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module_init(ch341_init);
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module_exit(ch341_exit);
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MODULE_LICENSE("GPL");
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module_param(debug, bool, S_IRUGO | S_IWUSR);
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MODULE_PARM_DESC(debug, "Debug enabled or not");
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/* EOF ch341.c */
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