CP2102N revision A01 (firmware version <= 1.0.4) has a buggy
flow-control implementation that uses the ulXonLimit instead of
ulFlowReplace field of the flow-control settings structure (erratum
CP2102N_E104).

A recent change that set the input software flow-control limits
incidentally broke RTS control for these devices when CRTSCTS is not set
as the new limits would always enable hardware flow control.

Fix this by explicitly disabling flow control for the buggy firmware
versions and only updating the input software flow-control limits when
IXOFF is requested. This makes sure that the terminal settings matches
the default zero ulXonLimit (ulFlowReplace) for these devices.

Link: https://lore.kernel.org/r/20210609161509.9459-1-johan@kernel.org
Reported-by: David Frey <dpfrey@gmail.com>
Reported-by: Alex Villacís Lasso <a_villacis@palosanto.com>
Tested-by: Alex Villacís Lasso <a_villacis@palosanto.com>
Fixes: f61309d9c96a ("USB: serial: cp210x: set IXOFF thresholds")
Cc: stable@vger.kernel.org      # 5.12
Signed-off-by: Johan Hovold <johan@kernel.org>

The QFN20 part has a different GPIO/port function assignment. The
configuration struct bit field ordered as TX/RX/RS485/WAKEUP/CLK
which exactly matches GPIO0-3 for QFN24/28. However, QFN20 has a
different GPIO to primary function assignment.

Special case QFN20 to follow to properly detect which GPIOs are
available.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Link: https://lore.kernel.org/r/51830b2b24118eb0f77c5c9ac64ffb2f519dbb1d.1622218300.git.stefan@agner.ch
Fixes: c8acfe0aadbe ("USB: serial: cp210x: implement GPIO support for CP2102N")
Cc: stable@vger.kernel.org	# 4.19
Signed-off-by: Johan Hovold <johan@kernel.org>

Add PID for the NovaTech OrionMX so it can be automatically detected.

Signed-off-by: George McCollister <george.mccollister@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>

With the inclusion of Omni 56K Plus, this driver seem to be more common
among the family of Zyxel omni modem. Update the driver and module
descriptions.

Signed-off-by: Alexandre GRIVEAUX <agriveaux@deutnet.info>
[ johan: amend commit message ]
Signed-off-by: Johan Hovold <johan@kernel.org>

Add device id for Zyxel Omni 56K Plus modem, this modem include:

USB chip:
NetChip
NET2888

Main chip:
901041A
F721501APGF

Another modem using the same chips is the Zyxel Omni 56K DUO/NEO,
could be added with the right USB ID.

Signed-off-by: Alexandre GRIVEAUX <agriveaux@deutnet.info>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>

The direction of the pipe argument must match the request-type direction
bit or control requests may fail depending on the host-controller-driver
implementation.

Fix the three requests which erroneously used usb_rcvctrlpipe().

Fixes: f7a33e608d9a ("USB: serial: add quatech2 usb to serial driver")
Cc: stable@vger.kernel.org      # 3.5
Signed-off-by: Johan Hovold <johan@kernel.org>

This adds the device id for the ADLINK ND-6530 which is a PL2303GC based
device.

Signed-off-by: Zolton Jheng <s6668c2t@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>

This adds support for the Startech.com generic serial to USB converter.
It seems to be a bone stock TI_3410. I have been using this patch for
years.

Signed-off-by: Sean MacLennan <seanm@seanm.ca>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>

Add support for the following Telit LE910-S1 compositions:

0x7010: rndis, tty, tty, tty
0x7011: ecm, tty, tty, tty

Signed-off-by: Daniele Palmas <dnlplm@gmail.com>
Link: https://lore.kernel.org/r/20210428072634.5091-1-dnlplm@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>

Add the IDS GmbH Vendor ID and the Product IDs for SI31A (2xRS232)
and CM31A (LoRaWAN Modem).

Signed-off-by: Dominik Andreas Schorpp <dominik.a.schorpp@ids.de>
Signed-off-by: Juergen Borleis <jbe@pengutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>