Johan writes:

USB-serial updates for 5.9-rc1

Here are the USB-serial updates for 5.9-rc1, including:

 - console flow-control support
 - simulated line-breaks on some ch341
 - hardware flow-control fixes for cp210x
 - break-detection and sysrq fixes for ftdi_sio
 - sysrq optimisations
 - input parity checking for cp210x

Included are also some new device ids and various clean ups.

All have been in linux-next with no reported issues.

* tag 'usb-serial-5.9-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial: (31 commits)
  USB: serial: qcserial: add EM7305 QDL product ID
  USB: serial: iuu_phoenix: fix led-activity helpers
  USB: serial: sierra: clean up special-interface handling
  USB: serial: cp210x: use in-kernel types in port data
  USB: serial: cp210x: drop unnecessary packed attributes
  USB: serial: cp210x: add support for TIOCGICOUNT
  USB: serial: cp210x: add support for line-status events
  USB: serial: cp210x: disable interface on errors in open
  USB: serial: drop redundant transfer-buffer casts
  USB: serial: drop extern keyword from function declarations
  USB: serial: drop unnecessary sysrq include
  USB: serial: add sysrq break-handler dummy
  USB: serial: inline sysrq dummy function
  USB: serial: only process sysrq when enabled
  USB: serial: only set sysrq timestamp for consoles
  USB: serial: ftdi_sio: fix break and sysrq handling
  USB: serial: ftdi_sio: clean up receive processing
  USB: serial: ftdi_sio: make process-packet buffer unsigned
  USB: serial: use fallthrough pseudo-keyword
  USB: serial: ch341: fix missing simulated-break margin
  ...

When running qmi-firmware-update on the Sierra Wireless EM7305 in a Toshiba
laptop, it changed product ID to 0x9062 when entering QDL mode:

usb 2-4: new high-speed USB device number 78 using xhci_hcd
usb 2-4: New USB device found, idVendor=1199, idProduct=9062, bcdDevice= 0.00
usb 2-4: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 2-4: Product: EM7305
usb 2-4: Manufacturer: Sierra Wireless, Incorporated

The upgrade could complete after running
 # echo 1199 9062 > /sys/bus/usb-serial/drivers/qcserial/new_id

qcserial 2-4:1.0: Qualcomm USB modem converter detected
usb 2-4: Qualcomm USB modem converter now attached to ttyUSB0

Signed-off-by: Erik Ekman <erik@kryo.se>
Link: https://lore.kernel.org/r/20200717185118.3640219-1-erik@kryo.se
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>

The set-led command is eight bytes long and starts with a command byte
followed by six bytes of RGB data and ends with a byte encoding a
frequency (see iuu_led() and iuu_rgbf_fill_buffer()).

The led activity helpers had a few long-standing bugs which corrupted
the command packets by inserting a second command byte and thereby
offsetting the RGB data and dropping the frequency in non-xmas mode.

In xmas mode, a related off-by-one error left the frequency field
uninitialised.

Fixes: 60a8fc017103 ("USB: add iuu_phoenix driver")
Reported-by: George Spelvin <lkml@sdf.org>
Link: https://lore.kernel.org/r/20200716085056.31471-1-johan@kernel.org
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

We need the USB fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The driver would happily overwrite its write buffer with user data in
256 byte increments due to a removed buffer-space sanity check.

Fixes: 5fcf62b0f1f2 ("tty: iuu_phoenix: fix locking.")
Cc: stable <stable@vger.kernel.org>     # 2.6.31
Signed-off-by: Johan Hovold <johan@kernel.org>

Clean up the handling of special interfaces that either should be
ignored or that need a larger number of URBs.

Commit 66f092ed3b94 ("USB: serial: sierra: unify quirk handling logic")
replaced the previous is_blacklisted() and is_highmemory() helpers with
a single is_quirk() helper which made it even harder to understand what
the interface lists were used for.

Rename the interface-list struct, its members and the interface-lookup
helper and restructure the code somewhat in order to make it more
self-explanatory.

Link: https://lore.kernel.org/r/20200713153936.18032-1-johan@kernel.org
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

The port data is not exported to user space so use the in-kernel u8
type.

Link: https://lore.kernel.org/r/20200713105517.27796-6-johan@kernel.org
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

Drop unnecessary packed attributes from structs without padding.

Link: https://lore.kernel.org/r/20200713105517.27796-5-johan@kernel.org
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

Enable TIOCGICOUNT to allow reading out the (unused) interrupt counters
and error statistics.

Note that modem-status events are currently left unimplemented as they
appear to be buffered on at least CP2102 and therefore cannot be used to
implement TIOCMIWAIT.

Link: https://lore.kernel.org/r/20200713105517.27796-4-johan@kernel.org
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

Add support for line-status events that specifically can be used to
detect and report parity errors.

Enable the device's event-insertion mode whenever input-parity checking
is requested. This will insert line and modem status events into the
data stream.

Note that modem-status changes appear to be buffered until a character
is received (at least on CP2102) and support is therefore left
unimplemented.

On at least one type of these chips (CP2102), line breaks are not
reported as expected either (regardless of whether SERIAL_BREAK_CHAR is
set) so do not enable event-mode when !IGNBRK is requested for now.

Link: https://lore.kernel.org/r/20200713105517.27796-3-johan@kernel.org
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>