diff options
Diffstat (limited to 'drivers/usb/serial/ftdi_sio.c')
| -rw-r--r-- | drivers/usb/serial/ftdi_sio.c | 41 |
1 files changed, 33 insertions, 8 deletions
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 72314734dfd0..2b9b5119ff13 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -1425,16 +1425,13 @@ static int write_latency_timer(struct usb_serial_port *port) return rv; } -static int read_latency_timer(struct usb_serial_port *port) +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 char *buf; int rv; - if (priv->chip_type == SIO || priv->chip_type == FT8U232AM) - return -EINVAL; - buf = kmalloc(1, GFP_KERNEL); if (!buf) return -ENOMEM; @@ -1446,11 +1443,10 @@ static int read_latency_timer(struct usb_serial_port *port) 0, priv->interface, buf, 1, WDR_TIMEOUT); if (rv < 1) { - dev_err(&port->dev, "Unable to read latency timer: %i\n", rv); if (rv >= 0) rv = -EIO; } else { - priv->latency = buf[0]; + rv = buf[0]; } kfree(buf); @@ -1458,6 +1454,25 @@ static int read_latency_timer(struct usb_serial_port *port) return rv; } +static int read_latency_timer(struct usb_serial_port *port) +{ + struct ftdi_private *priv = usb_get_serial_port_data(port); + int rv; + + if (priv->chip_type == SIO || priv->chip_type == FT8U232AM) + return -EINVAL; + + rv = _read_latency_timer(port); + if (rv < 0) { + dev_err(&port->dev, "Unable to read latency timer: %i\n", rv); + return rv; + } + + priv->latency = rv; + + return 0; +} + static int get_serial_info(struct usb_serial_port *port, struct serial_struct __user *retinfo) { @@ -1609,9 +1624,19 @@ static void ftdi_determine_type(struct usb_serial_port *port) priv->baud_base = 12000000 / 16; } else if (version < 0x400) { /* Assume it's an FT8U232AM (or FT8U245AM) */ - /* (It might be a BM because of the iSerialNumber bug, - * but it will still work as an AM device.) */ priv->chip_type = FT8U232AM; + /* + * It might be a BM type because of the iSerialNumber bug. + * If iSerialNumber==0 and the latency timer is readable, + * assume it is BM type. + */ + if (udev->descriptor.iSerialNumber == 0 && + _read_latency_timer(port) >= 0) { + dev_dbg(&port->dev, + "%s: has latency timer so not an AM type\n", + __func__); + priv->chip_type = FT232BM; + } } else if (version < 0x600) { /* Assume it's an FT232BM (or FT245BM) */ priv->chip_type = FT232BM; |