diff options
Diffstat (limited to 'drivers/usb/serial/mct_u232.h')
| -rw-r--r-- | drivers/usb/serial/mct_u232.h | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/usb/serial/mct_u232.h b/drivers/usb/serial/mct_u232.h index 73dd0d984cd3..a61bac8f224a 100644 --- a/drivers/usb/serial/mct_u232.h +++ b/drivers/usb/serial/mct_u232.h @@ -63,14 +63,15 @@ #define MCT_U232_SET_UNKNOWN1_REQUEST 11 /* Unknown functionality */ #define MCT_U232_SET_UNKNOWN1_SIZE 1 -/* This USB device request code is not well understood. It is transmitted by - the MCT-supplied Windows driver whenever the baud rate changes. +/* This USB device request code appears to control whether CTS is required + during transmission. - Without this USB device request, the USB/RS-232 adapter will not write to - RS-232 devices which do not assert the 'CTS' signal. + Sending a zero byte allows data transmission to a device which is not + asserting CTS. Sending a '1' byte will cause transmission to be deferred + until the device asserts CTS. */ -#define MCT_U232_SET_UNKNOWN2_REQUEST 12 /* Unknown functionality */ -#define MCT_U232_SET_UNKNOWN2_SIZE 1 +#define MCT_U232_SET_CTS_REQUEST 12 +#define MCT_U232_SET_CTS_SIZE 1 /* * Baud rate (divisor) @@ -439,7 +440,7 @@ static int mct_u232_calculate_baud_rate(struct usb_serial *serial, int value); * which says "U232-P9" ;-) * * The circuit board inside the adaptor contains a Philips PDIUSBD12 - * USB endpoint chip and a Phillips P87C52UBAA microcontroller with + * USB endpoint chip and a Philips P87C52UBAA microcontroller with * embedded UART. Exhaustive documentation for these is available at: * * http://www.semiconductors.philips.com/pip/p87c52ubaa |