diff options
| -rw-r--r-- | drivers/usb/serial/cp210x.c | 70 |
1 files changed, 66 insertions, 4 deletions
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index 352fe63..9e5d5b0 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -199,6 +199,7 @@ MODULE_DEVICE_TABLE(usb, id_table); struct cp210x_port_private { __u8 bInterfaceNumber; + bool has_swapped_line_ctl; }; static struct usb_serial_driver cp210x_device = { @@ -419,6 +420,60 @@ static inline int cp210x_set_config_single(struct usb_serial_port *port, } /* + * Detect CP2108 GET_LINE_CTL bug and activate workaround. + * Write a known good value 0x800, read it back. + * If it comes back swapped the bug is detected. + * Preserve the original register value. + */ +static int cp210x_detect_swapped_line_ctl(struct usb_serial_port *port) +{ + struct cp210x_port_private *port_priv = usb_get_serial_port_data(port); + unsigned int line_ctl_save; + unsigned int line_ctl_test; + int err; + + err = cp210x_get_config(port, CP210X_GET_LINE_CTL, &line_ctl_save, 2); + if (err) + return err; + + line_ctl_test = 0x800; + err = cp210x_set_config(port, CP210X_SET_LINE_CTL, &line_ctl_test, 2); + if (err) + return err; + + err = cp210x_get_config(port, CP210X_GET_LINE_CTL, &line_ctl_test, 2); + if (err) + return err; + + if (line_ctl_test == 8) { + port_priv->has_swapped_line_ctl = true; + line_ctl_save = swab16((u16)line_ctl_save); + } + + return cp210x_set_config(port, CP210X_SET_LINE_CTL, &line_ctl_save, 2); +} + +/* + * Must always be called instead of cp210x_get_config(CP210X_GET_LINE_CTL) + * to workaround cp2108 bug and get correct value. + */ +static int cp210x_get_line_ctl(struct usb_serial_port *port, unsigned int *ctl) +{ + struct cp210x_port_private *port_priv = usb_get_serial_port_data(port); + int err; + + err = cp210x_get_config(port, CP210X_GET_LINE_CTL, ctl, 2); + if (err) + return err; + + /* Workaround swapped bytes in 16-bit value from CP210X_GET_LINE_CTL */ + if (port_priv->has_swapped_line_ctl) + *ctl = swab16((u16)(*ctl)); + + return 0; +} + +/* * cp210x_quantise_baudrate * Quantises the baud rate as per AN205 Table 1 */ @@ -535,7 +590,7 @@ static void cp210x_get_termios_port(struct usb_serial_port *port, cflag = *cflagp; - cp210x_get_config(port, CP210X_GET_LINE_CTL, &bits, 2); + cp210x_get_line_ctl(port, &bits); cflag &= ~CSIZE; switch (bits & BITS_DATA_MASK) { case BITS_DATA_5: @@ -703,7 +758,7 @@ static void cp210x_set_termios(struct tty_struct *tty, /* If the number of data bits is to be updated */ if ((cflag & CSIZE) != (old_cflag & CSIZE)) { - cp210x_get_config(port, CP210X_GET_LINE_CTL, &bits, 2); + cp210x_get_line_ctl(port, &bits); bits &= ~BITS_DATA_MASK; switch (cflag & CSIZE) { case CS5: @@ -737,7 +792,7 @@ static void cp210x_set_termios(struct tty_struct *tty, if ((cflag & (PARENB|PARODD|CMSPAR)) != (old_cflag & (PARENB|PARODD|CMSPAR))) { - cp210x_get_config(port, CP210X_GET_LINE_CTL, &bits, 2); + cp210x_get_line_ctl(port, &bits); bits &= ~BITS_PARITY_MASK; if (cflag & PARENB) { if (cflag & CMSPAR) { @@ -763,7 +818,7 @@ static void cp210x_set_termios(struct tty_struct *tty, } if ((cflag & CSTOPB) != (old_cflag & CSTOPB)) { - cp210x_get_config(port, CP210X_GET_LINE_CTL, &bits, 2); + cp210x_get_line_ctl(port, &bits); bits &= ~BITS_STOP_MASK; if (cflag & CSTOPB) { bits |= BITS_STOP_2; @@ -883,6 +938,7 @@ static int cp210x_port_probe(struct usb_serial_port *port) struct usb_serial *serial = port->serial; struct usb_host_interface *cur_altsetting; struct cp210x_port_private *port_priv; + int ret; port_priv = kzalloc(sizeof(*port_priv), GFP_KERNEL); if (!port_priv) @@ -893,6 +949,12 @@ static int cp210x_port_probe(struct usb_serial_port *port) usb_set_serial_port_data(port, port_priv); + ret = cp210x_detect_swapped_line_ctl(port); + if (ret) { + kfree(port_priv); + return ret; + } + return 0; } |
