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USb: Break support for WinChipHead CH341 340 USB->Serial "chip" 

Here is a patch to the ch341 driver which adds serial break support.

Signed-off-by: Tim Small <tim@seoss.co.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Tim Small 2009-08-17 13:21:57 +01:00 committed by Greg Kroah-Hartman
parent 823c3fd9cc
commit 492896f011
1 changed files with 52 additions and 0 deletions
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52
drivers/usb/serial/ch341.c
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@ -56,6 +56,18 @@
#define CH341_BAUDBASE_FACTOR 1532620800
#define CH341_BAUDBASE_DIVMAX 3
/* Break support - the information used to implement this was gleaned from
* the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
*/
#define CH341_REQ_WRITE_REG 0x9A
#define CH341_REQ_READ_REG 0x95
#define CH341_REG_BREAK1 0x05
#define CH341_REG_BREAK2 0x18
#define CH341_NBREAK_BITS_REG1 0x01
#define CH341_NBREAK_BITS_REG2 0x40
static int debug;
static struct usb_device_id id_table [] = {
@ -373,6 +385,45 @@ static void ch341_set_termios(struct tty_struct *tty,
*/
}
static void ch341_break_ctl(struct tty_struct *tty, int break_state)
{
const uint16_t ch341_break_reg =
CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
struct usb_serial_port *port = tty->driver_data;
int r;
uint16_t reg_contents;
uint8_t break_reg[2];
dbg("%s()", __func__);
r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
ch341_break_reg, 0, break_reg, sizeof(break_reg));
if (r < 0) {
printk(KERN_WARNING "%s: USB control read error whilst getting"
" break register contents.\n", __FILE__);
return;
}
dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
__func__, break_reg[0], break_reg[1]);
if (break_state != 0) {
dbg("%s - Enter break state requested", __func__);
break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
} else {
dbg("%s - Leave break state requested", __func__);
break_reg[0] |= CH341_NBREAK_BITS_REG1;
break_reg[1] |= CH341_NBREAK_BITS_REG2;
}
dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
__func__, break_reg[0], break_reg[1]);
reg_contents = (uint16_t)break_reg[0] | ((uint16_t)break_reg[1] << 8);
r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
ch341_break_reg, reg_contents);
if (r < 0)
printk(KERN_WARNING "%s: USB control write error whilst setting"
" break register contents.\n", __FILE__);
}
static int ch341_tiocmset(struct tty_struct *tty, struct file *file,
unsigned int set, unsigned int clear)
{
@ -576,6 +627,7 @@ static struct usb_serial_driver ch341_device = {
.close = ch341_close,
.ioctl = ch341_ioctl,
.set_termios = ch341_set_termios,
.break_ctl = ch341_break_ctl,
.tiocmget = ch341_tiocmget,
.tiocmset = ch341_tiocmset,
.read_int_callback = ch341_read_int_callback,