set custom baud-rate for SCS P4 Dragon

[Robert Wolters <robert@xxxxxxxxxxxxxxxxx>]

|Why: FTDI USB serial speed issue with SCS P4 Dragon short-wave modems, 
a custom baud-rate is required Solution: set special baud-rate by 
setting a custom divisor on 38400B Signed-off-by: Robert Wolters 
<robert@xxxxxxxxxxxxxxxxx> | ||--- ftdi_sio.c 2021-04-21 
13:01:00.000000000 +0200| ||+++ ftdi_sio.c 2021-04-26 18:53:00.819175707 
+0200| ||@@ -97,6 +97,7 @@| |||static int ftdi_8u2232c_probe(struct 
usb_serial *serial);| ||static void ftdi_USB_UIRT_setup(struct 
ftdi_private *priv);||||static void ftdi_HE_TIRA1_setup(struct 
ftdi_private *priv);| |+static void ftdi_SCS_DR7X00_setup(struct 
ftdi_private *priv);| ||static const struct ftdi_sio_quirk 
ftdi_jtag_quirk = {| |||.probe  = ftdi_jtag_probe,| |||@@ -122,6 +123,10 
@@| |||.probe  = ftdi_8u2232c_probe,| |||}; ||||+static const struct 
ftdi_sio_quirk ftdi_SCS_DR7X00_quirk = {| |||+ .port_probe = 
ftdi_SCS_DR7X00_setup,| |||+};| |||+| |||/*| ||* The 8U232AM has the 
same API as the sio except for:| |* - it can support MUCH higher 
baudrates; up to:| |@@ -157,8 +162,12 @@| |{ USB_DEVICE(FTDI_VID, 
FTDI_EV3CON_PID) },| |{ USB_DEVICE(FTDI_VID, FTDI_SCS_DEVICE_0_PID) },| 
|{ USB_DEVICE(FTDI_VID, FTDI_SCS_DEVICE_1_PID) },| |- { 
USB_DEVICE(FTDI_VID, FTDI_SCS_DEVICE_2_PID) },| |- { 
USB_DEVICE(FTDI_VID, FTDI_SCS_DEVICE_3_PID) },| |+ { 
USB_DEVICE(FTDI_VID, FTDI_SCS_DEVICE_2_PID) ,| |+ .driver_info = 
(kernel_ulong_t)&ftdi_SCS_DR7X00_quirk },| |+ { USB_DEVICE(FTDI_VID, 
FTDI_SCS_DEVICE_3_PID) ,| |+ .driver_info = 
(kernel_ulong_t)&ftdi_SCS_DR7X00_quirk },| |{ USB_DEVICE(FTDI_VID, 
FTDI_SCS_DEVICE_4_PID) },| |{ USB_DEVICE(FTDI_VID, 
FTDI_SCS_DEVICE_5_PID) },| |{ USB_DEVICE(FTDI_VID, 
FTDI_SCS_DEVICE_6_PID) },| |@@ -2296,6 +2305,15 @@| |priv->force_rtscts 
= 1;| |}| |+/* Setup for the SCS P4dragon DR-7X00 devices, which 
require| |+ *hardwired baud-rate of 829440 (38400 gets mapped to 829440) 
*/| |+static void ftdi_SCS_DR7X00_setup(struct ftdi_private *priv)| |+{| 
|+ priv->flags |= ASYNC_SPD_CUST;| |+ priv->custom_divisor = 29;| |+ 
priv->force_baud = 38400;| |+}| |+| |||||/*| |* Module parameter to 
control latency timer for NDI FTDI-based USB devices.| |* If this value 
is not set in /etc/modprobe.d/ its value will be set|