diff options
Diffstat (limited to 'drivers/usb/serial/cypress_m8.c')
| -rw-r--r-- | drivers/usb/serial/cypress_m8.c | 104 |
1 files changed, 59 insertions, 45 deletions
diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c index bdeda093695..4bf45c711b9 100644 --- a/drivers/usb/serial/cypress_m8.c +++ b/drivers/usb/serial/cypress_m8.c @@ -291,6 +291,59 @@ static struct usb_serial_driver cypress_ca42v2_device = { *****************************************************************************/ +static int analyze_baud_rate(struct usb_serial_port *port, unsigned baud_mask) +{ + int new_rate; + struct cypress_private *priv; + priv = usb_get_serial_port_data(port); + + /* + * The general purpose firmware for the Cypress M8 allows for + * a maximum speed of 57600bps (I have no idea whether DeLorme + * chose to use the general purpose firmware or not), if you + * need to modify this speed setting for your own project + * please add your own chiptype and modify the code likewise. + * The Cypress HID->COM device will work successfully up to + * 115200bps (but the actual throughput is around 3kBps). + */ + new_rate = mask_to_rate(baud_mask); + if (new_rate < 0) { + dbg("%s - failed setting baud rate, untranslatable speed", + __func__); + return -1; + } + if (port->serial->dev->speed == USB_SPEED_LOW) { + /* + * Mike Isely <isely@pobox.com> 2-Feb-2008: The + * Cypress app note that describes this mechanism + * states the the low-speed part can't handle more + * than 800 bytes/sec, in which case 4800 baud is the + * safest speed for a part like that. + */ + if (new_rate > 4800) { + dbg("%s - failed setting baud rate, device incapable " + "speed %d", __func__, new_rate); + return -1; + } + } + switch (priv->chiptype) { + case CT_EARTHMATE: + if (new_rate <= 600) { + /* 300 and 600 baud rates are supported under + * the generic firmware, but are not used with + * NMEA and SiRF protocols */ + dbg("%s - failed setting baud rate, unsupported speed " + "of %d on Earthmate GPS", __func__, new_rate); + return -1; + } + break; + default: + break; + } + return new_rate; +} + + /* This function can either set or retrieve the current serial line settings */ static int cypress_serial_control (struct usb_serial_port *port, unsigned baud_mask, int data_bits, int stop_bits, int parity_enable, int parity_type, int reset, int cypress_request_type) @@ -309,54 +362,15 @@ static int cypress_serial_control (struct usb_serial_port *port, unsigned baud_m switch(cypress_request_type) { case CYPRESS_SET_CONFIG: - - /* - * The general purpose firmware for the Cypress M8 allows for a maximum speed - * of 57600bps (I have no idea whether DeLorme chose to use the general purpose - * firmware or not), if you need to modify this speed setting for your own - * project please add your own chiptype and modify the code likewise. The - * Cypress HID->COM device will work successfully up to 115200bps (but the - * actual throughput is around 3kBps). - */ + new_baudrate = priv->baud_rate; if (baud_mask != priv->cbr_mask) { dbg("%s - baud rate is changing", __FUNCTION__); - if ( priv->chiptype == CT_EARTHMATE ) { - /* 300 and 600 baud rates are supported under the generic firmware, - * but are not used with NMEA and SiRF protocols */ - - if ( (baud_mask == B300) || (baud_mask == B600) ) { - err("%s - failed setting baud rate, unsupported speed", - __FUNCTION__); - new_baudrate = priv->baud_rate; - } else if ( (new_baudrate = mask_to_rate(baud_mask)) == -1) { - err("%s - failed setting baud rate, unsupported speed", - __FUNCTION__); - new_baudrate = priv->baud_rate; - } - } else if (priv->chiptype == CT_CYPHIDCOM) { - if ( (new_baudrate = mask_to_rate(baud_mask)) == -1) { - err("%s - failed setting baud rate, unsupported speed", - __FUNCTION__); - new_baudrate = priv->baud_rate; - } - } else if (priv->chiptype == CT_CA42V2) { - if ( (new_baudrate = mask_to_rate(baud_mask)) == -1) { - err("%s - failed setting baud rate, unsupported speed", - __FUNCTION__); - new_baudrate = priv->baud_rate; - } - } else if (priv->chiptype == CT_GENERIC) { - if ( (new_baudrate = mask_to_rate(baud_mask)) == -1) { - err("%s - failed setting baud rate, unsupported speed", - __FUNCTION__); - new_baudrate = priv->baud_rate; - } - } else { - info("%s - please define your chiptype", __FUNCTION__); - new_baudrate = priv->baud_rate; + retval = analyze_baud_rate(port, baud_mask); + if (retval >= 0) { + new_baudrate = retval; + dbg("%s - New baud rate set to %d", + __func__, new_baudrate); } - } else { /* baud rate not changing, keep the old */ - new_baudrate = priv->baud_rate; } dbg("%s - baud rate is being sent as %d", __FUNCTION__, new_baudrate); |