diff options
| -rw-r--r-- | drivers/usb/serial/cp210x.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index 9e5d5b016633..084033a568c2 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -38,6 +38,7 @@ static void cp210x_change_speed(struct tty_struct *, struct usb_serial_port *, struct ktermios *); static void cp210x_set_termios(struct tty_struct *, struct usb_serial_port *, struct ktermios*); +static bool cp210x_tx_empty(struct usb_serial_port *port); static int cp210x_tiocmget(struct tty_struct *); static int cp210x_tiocmset(struct tty_struct *, unsigned int, unsigned int); static int cp210x_tiocmset_port(struct usb_serial_port *port, @@ -215,6 +216,7 @@ static struct usb_serial_driver cp210x_device = { .close = cp210x_close, .break_ctl = cp210x_break_ctl, .set_termios = cp210x_set_termios, + .tx_empty = cp210x_tx_empty, .tiocmget = cp210x_tiocmget, .tiocmset = cp210x_tiocmset, .port_probe = cp210x_port_probe, @@ -301,6 +303,17 @@ static struct usb_serial_driver * const serial_drivers[] = { #define CONTROL_WRITE_DTR 0x0100 #define CONTROL_WRITE_RTS 0x0200 +/* CP210X_GET_COMM_STATUS returns these 0x13 bytes */ +struct cp210x_comm_status { + __le32 ulErrors; + __le32 ulHoldReasons; + __le32 ulAmountInInQueue; + __le32 ulAmountInOutQueue; + u8 bEofReceived; + u8 bWaitForImmediate; + u8 bReserved; +} __packed; + /* * CP210X_PURGE - 16 bits passed in wValue of USB request. * SiLabs app note AN571 gives a strange description of the 4 bits: @@ -550,6 +563,51 @@ static void cp210x_close(struct usb_serial_port *port) } /* + * Read how many bytes are waiting in the TX queue. + */ +static int cp210x_get_tx_queue_byte_count(struct usb_serial_port *port, + u32 *count) +{ + struct usb_serial *serial = port->serial; + struct cp210x_port_private *port_priv = usb_get_serial_port_data(port); + struct cp210x_comm_status *sts; + int result; + + sts = kmalloc(sizeof(*sts), GFP_KERNEL); + if (!sts) + return -ENOMEM; + + result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0), + CP210X_GET_COMM_STATUS, REQTYPE_INTERFACE_TO_HOST, + 0, port_priv->bInterfaceNumber, sts, sizeof(*sts), + USB_CTRL_GET_TIMEOUT); + if (result == sizeof(*sts)) { + *count = le32_to_cpu(sts->ulAmountInOutQueue); + result = 0; + } else { + dev_err(&port->dev, "failed to get comm status: %d\n", result); + if (result >= 0) + result = -EPROTO; + } + + kfree(sts); + + return result; +} + +static bool cp210x_tx_empty(struct usb_serial_port *port) +{ + int err; + u32 count; + + err = cp210x_get_tx_queue_byte_count(port, &count); + if (err) + return true; + + return !count; +} + +/* * cp210x_get_termios * Reads the baud rate, data bits, parity, stop bits and flow control mode * from the device, corrects any unsupported values, and configures the |