diff options
Diffstat (limited to 'drivers/usb/serial')
| -rw-r--r-- | drivers/usb/serial/ch341.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index 8c894a7d5dc..59eff721fcc 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -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, |