[PATCH 06/24] USB: serial: io_ti: fix TIOCGSERIAL implementation

From: Johan Hovold
Date: Wed Apr 07 2021 - 06:40:14 EST


TIOCSSERIAL is a horrid, underspecified, legacy interface which for most
serial devices is only useful for setting the close_delay and
closing_wait parameters.

The port parameter is used to set the I/O port and does not make any
sense to use for USB serial devices.

The xmit_fifo_size parameter could be used to set the hardware transmit
fifo size of a legacy UART when it could not be detected, but the
interface is limited to eight bits and should be left unset when not
used.

Similarly, baud_base could be used to set the UART base clock when it
could not be detected but might as well be left unset when it is not
known.

The close_delay and closing_wait parameters returned by TIOCGSERIAL are
specified in centiseconds (not jiffies). The driver does not yet support
changing close_delay, but let's report back the default value actually
used (0.5 seconds).

Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/usb/serial/io_ti.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index e800547be9e0..f5aab570fd05 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -2437,21 +2437,17 @@ static int get_serial_info(struct tty_struct *tty,
struct serial_struct *ss)
{
struct usb_serial_port *port = tty->driver_data;
- struct edgeport_port *edge_port = usb_get_serial_port_data(port);
unsigned cwait;

- cwait = edge_port->port->port.closing_wait;
+ cwait = port->port.closing_wait;
if (cwait != ASYNC_CLOSING_WAIT_NONE)
cwait = jiffies_to_msecs(cwait) / 10;

ss->type = PORT_16550A;
- ss->line = edge_port->port->minor;
- ss->port = edge_port->port->port_number;
- ss->irq = 0;
- ss->xmit_fifo_size = edge_port->port->bulk_out_size;
- ss->baud_base = 9600;
- ss->close_delay = 5*HZ;
+ ss->line = port->minor;
+ ss->close_delay = 50;
ss->closing_wait = cwait;
+
return 0;
}

--
2.26.3