diff options
| -rw-r--r-- | drivers/usb/serial/ftdi_sio.c | 94 |
1 files changed, 60 insertions, 34 deletions
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index d9d87111f9a..21c053c31b9 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -89,6 +89,7 @@ struct ftdi_private { int force_rtscts; /* if non-zero, force RTS-CTS to always be enabled */ + unsigned int latency; /* latency setting in use */ spinlock_t tx_lock; /* spinlock for transmit state */ unsigned long tx_bytes; unsigned long tx_outstanding_bytes; @@ -1038,7 +1039,54 @@ static int change_speed(struct tty_struct *tty, struct usb_serial_port *port) return rv; } +static int write_latency_timer(struct usb_serial_port *port) +{ + struct ftdi_private *priv = usb_get_serial_port_data(port); + struct usb_device *udev = port->serial->dev; + char buf[1]; + int rv = 0; + int l = priv->latency; + + if (priv->flags & ASYNC_LOW_LATENCY) + l = 1; + + dbg("%s: setting latency timer = %i", __func__, l); + + rv = usb_control_msg(udev, + usb_sndctrlpipe(udev, 0), + FTDI_SIO_SET_LATENCY_TIMER_REQUEST, + FTDI_SIO_SET_LATENCY_TIMER_REQUEST_TYPE, + l, priv->interface, + buf, 0, WDR_TIMEOUT); + if (rv < 0) + dev_err(&port->dev, "Unable to write latency timer: %i\n", rv); + return rv; +} + +static int read_latency_timer(struct usb_serial_port *port) +{ + struct ftdi_private *priv = usb_get_serial_port_data(port); + struct usb_device *udev = port->serial->dev; + unsigned short latency = 0; + int rv = 0; + + + dbg("%s", __func__); + + rv = usb_control_msg(udev, + usb_rcvctrlpipe(udev, 0), + FTDI_SIO_GET_LATENCY_TIMER_REQUEST, + FTDI_SIO_GET_LATENCY_TIMER_REQUEST_TYPE, + 0, priv->interface, + (char *) &latency, 1, WDR_TIMEOUT); + + if (rv < 0) { + dev_err(&port->dev, "Unable to read latency timer: %i\n", rv); + return -EIO; + } + return latency; +} static int get_serial_info(struct usb_serial_port *port, struct serial_struct __user *retinfo) @@ -1098,6 +1146,7 @@ static int set_serial_info(struct tty_struct *tty, priv->custom_divisor = new_serial.custom_divisor; tty->low_latency = (priv->flags & ASYNC_LOW_LATENCY) ? 1 : 0; + write_latency_timer(port); check_and_exit: if ((old_priv.flags & ASYNC_SPD_MASK) != @@ -1193,27 +1242,13 @@ static ssize_t show_latency_timer(struct device *dev, { struct usb_serial_port *port = to_usb_serial_port(dev); struct ftdi_private *priv = usb_get_serial_port_data(port); - struct usb_device *udev = port->serial->dev; - unsigned short latency = 0; - int rv = 0; - - - dbg("%s", __func__); - - rv = usb_control_msg(udev, - usb_rcvctrlpipe(udev, 0), - FTDI_SIO_GET_LATENCY_TIMER_REQUEST, - FTDI_SIO_GET_LATENCY_TIMER_REQUEST_TYPE, - 0, priv->interface, - (char *) &latency, 1, WDR_TIMEOUT); - - if (rv < 0) { - dev_err(dev, "Unable to read latency timer: %i\n", rv); - return -EIO; - } - return sprintf(buf, "%i\n", latency); + if (priv->flags & ASYNC_LOW_LATENCY) + return sprintf(buf, "1\n"); + else + return sprintf(buf, "%i\n", priv->latency); } + /* Write a new value of the latency timer, in units of milliseconds. */ static ssize_t store_latency_timer(struct device *dev, struct device_attribute *attr, const char *valbuf, @@ -1221,25 +1256,13 @@ static ssize_t store_latency_timer(struct device *dev, { struct usb_serial_port *port = to_usb_serial_port(dev); struct ftdi_private *priv = usb_get_serial_port_data(port); - struct usb_device *udev = port->serial->dev; - char buf[1]; int v = simple_strtoul(valbuf, NULL, 10); int rv = 0; - dbg("%s: setting latency timer = %i", __func__, v); - - rv = usb_control_msg(udev, - usb_sndctrlpipe(udev, 0), - FTDI_SIO_SET_LATENCY_TIMER_REQUEST, - FTDI_SIO_SET_LATENCY_TIMER_REQUEST_TYPE, - v, priv->interface, - buf, 0, WDR_TIMEOUT); - - if (rv < 0) { - dev_err(dev, "Unable to write latency timer: %i\n", rv); + priv->latency = v; + rv = write_latency_timer(port); + if (rv < 0) return -EIO; - } - return count; } @@ -1393,6 +1416,7 @@ static int ftdi_sio_port_probe(struct usb_serial_port *port) usb_set_serial_port_data(port, priv); ftdi_determine_type(port); + read_latency_timer(port); create_sysfs_attrs(port); return 0; } @@ -1515,6 +1539,8 @@ static int ftdi_open(struct tty_struct *tty, if (tty) tty->low_latency = (priv->flags & ASYNC_LOW_LATENCY) ? 1 : 0; + write_latency_timer(port); + /* No error checking for this (will get errors later anyway) */ /* See ftdi_sio.h for description of what is reset */ usb_control_msg(dev, usb_sndctrlpipe(dev, 0), |