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: NStefan Agner <stefan@agner.ch>
Link: https://lore.kernel.org/r/51830b2b24118eb0f77c5c9ac64ffb2f519dbb1d.1622218300.git.stefan@agner.ch
Fixes: c8acfe0a ("USB: serial: cp210x: implement GPIO support for CP2102N")
Cc: stable@vger.kernel.org	# 4.19
Signed-off-by: NJohan Hovold <johan@kernel.org>

Add a debug printk to dump the GPIO configuration stored in EEPROM
during probe.
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Use the new GPIO valid-mask feature to inform gpiolib which pins are
available for use instead of handling that in a request callback.

This also allows user space to figure out which pins are available
through the chardev interface without having to request each pin in
turn.

Note that the return value when requesting an unavailable pin will now
be -EINVAL instead of -ENODEV.
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NJohan Hovold <johan@kernel.org>

GE CS1000 has some more custom USB IDs for CP2102N; add them
to the driver to have working auto-probing.
Signed-off-by: NSebastian Reichel <sebastian.reichel@collabora.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJohan Hovold <johan@kernel.org>

IDs of nLight Air Adapter, Acuity Brands, Inc.:
vid: 10c4
pid: 88d8
Signed-off-by: NKaran Singhal <karan.singhal@acuitybrands.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJohan Hovold <johan@kernel.org>

All usb_serial drivers return 0 in their remove callbacks and driver
core ignores the value returned by usb_serial_device_remove(). So change
the remove callback to return void and return 0 unconditionally in
usb_serial_device_remove().
Signed-off-by: NUwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210208143149.963644-2-uwe@kleine-koenig.orgSigned-off-by: NJohan Hovold <johan@kernel.org>

Clear the RTS bits of the flow-control request before determining the
new value when updating the settings.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Clearing TIOCM_RTS should always deassert RTS and setting the same bit
should enable auto-RTS if hardware flow control is enabled.

This allows user space to throttle input directly at the source also
when hardware-assisted flow control is enabled and makes dtr_rts()
always deassert both lines during close (when HUPCL is set).
Signed-off-by: NJohan Hovold <johan@kernel.org>

Use the 0-flag and a field width to specify zero-padding consistently in
printk messages.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Shorten the flow-control debug message by abbreviating the field names
and reducing the value width to two characters. The latter improves
readability since all but the least significant byte will almost always
be zero anyway.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Drop the macros used to shift the flow-control settings to make the code
more readable for consistency with the other requests.
Signed-off-by: NJohan Hovold <johan@kernel.org>

The vendor request used to set the flow-control settings also sets the
state of the modem-control lines.

Add state variables to keep track of the modem-control lines to avoid
always asserting the lines whenever the flow-control settings are
updated.

This specifically also avoids asserting DTR/RTS when opening a port with
the line speed set to B0.
Signed-off-by: NJohan Hovold <johan@kernel.org>

The CP210X_SET_MHS request cannot be used to control RTS when hardware
flow control (auto-RTS) is enabled and instead returns an error which is
currently logged as:

	cp210x ttyUSB0: failed set request 0x7 status: -32

when opening and closing a port (and on TIOCMSET requests).

Add a crtscts flag to keep track of the hardware flow-control setting
and use it to suppress any request to change RTS when auto-RTS is
enabled.

Note that RTS is still deasserted when disabling the UART as part of
close.
Reported-by: NPho Tran <pho.tran@silabs.com>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Information pid/vid of WSDA-200-USB, Lord corporation company:
vid: 199b
pid: ba30
Signed-off-by: NPho Tran <pho.tran@silabs.com>
[ johan: amend comment with product name ]
Cc: stable@vger.kernel.org
Signed-off-by: NJohan Hovold <johan@kernel.org>

Add a copyright notice for myself.
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Drop include directives that are no longer used.
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

There's no need to check for short control transfers when sending data
so remove the redundant sanity checks.
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Update the XON/XOFF control characters also when no other flow-control
flag has changed and software flow control is enabled.
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

At least CP2102 requires the XON/XOFF limits to be initialised in order
for software input flow control (IXOFF) to work. Specifically, XOFF is
never sent if the XOFF limit is left at its default value of zero.

Set the limits so that input is throttled when the FIFO free level drops
below 128 bytes and restarted when the FIFO fill level drops below 128
bytes.

Note that the threshold values have been chosen so that they can be used
also with CP2105 which has the smallest FIFO of the currently supported
device types (288 byte for the SCI port). If needed the limits can be
made device specific later.
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

When data is transmitted between two serial ports, the phenomenon of
data loss often occurs. The two kinds of flow control commonly used in
serial communication are hardware flow control and software flow
control.

In serial communication, If you only use RX/TX/GND Pins, you can't do
hardware flow. So we often used software flow control and prevent data
loss. The user sets the software flow control through the application
program, and the application program sets the software flow control mode
for the serial port chip through the driver.

For the cp210 serial port chip, its driver lacks the software flow
control setting code, so the user cannot set the software flow control
function through the application program. This adds the missing software
flow control.
Signed-off-by: NWang Sheng Long <shenglong.wang.ext@siemens.com>
Link: https://lore.kernel.org/r/20210104094502.3942-1-china_shenglong@163.com
[ johan: rework properly on top of recent termios changes ]
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Teraoka AD2000 uses the CP210x driver, but the chip VID/PID is
customized with 0988/0578. We need the driver to support the new
VID/PID.
Signed-off-by: NChenxin Jin <bg4akv@hotmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJohan Hovold <johan@kernel.org>

Clean up dtr_rts() by renaming the port parameter and adding missing
whitespace.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Add a helper function to be used to configure flow control.

The flow-control code was the last caller that relied on the
memset-on-failure behaviour of cp210x_read_reg_block(), which we can now
drop in favour of bailing out on errors when retrieving the flow-control
settings.

This should also simplify adding support for software flow control.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Drop some unnecessary flow-control debugging.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Unlike other drivers cp210x have been retrieving the current terminal
settings from the device on open and reflecting those in termios.

Due to how set_termios() used to be implemented, this saved a few
control requests on open but has instead caused problems like broken
flow control and has required adding workarounds for swapped
line-control in cp2108 and line-speed initialisation on cp2104.

This unusual implementation also complicates adding new features for no
good reason.

Rip out the corresponding code and the above mentioned workarounds and
instead initialise the terminal settings unconditionally on open.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Update the line-control settings in one request unconditionally instead
of setting the word-length, parity and stop-bit settings separately.

This avoids multiple requests when several settings are changed even if
this scheme could potentially also be used to detect unsupported device
settings. Since all device types but CP2101 appears to support all
settings, let's handle that one specifically and also report back the
unsupported settings properly through termios by clearing the
corresponding bits.

Also drop the related unnecessary debug printks.
Signed-off-by: NJohan Hovold <johan@kernel.org>

Return early from set_termios() in case no relevant terminal settings
have changed.

This avoids testing each parameter in turn and specifically allows the
line-control handling to be cleaned up further.
Signed-off-by: NJohan 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.orgReviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Drop unnecessary packed attributes from structs without padding.

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

Try to disable the serial interface in the unlikely event that generic
open() fails.

Link: https://lore.kernel.org/r/20200713105517.27796-2-johan@kernel.orgReviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

CP210x hardware disables auto-RTS but leaves auto-CTS when in hardware
flow control mode and UART on cp210x hardware is disabled. When
re-opening the port, if auto-CTS is enabled on the cp210x, then auto-RTS
must be re-enabled in the driver.
Signed-off-by: NBrant Merryman <brant.merryman@silabs.com>
Co-developed-by: NPhu Luu <phu.luu@silabs.com>
Signed-off-by: NPhu Luu <phu.luu@silabs.com>
Link: https://lore.kernel.org/r/ECCF8E73-91F3-4080-BE17-1714BC8818FB@silabs.com
[ johan: fix up tags and problem description ]
Fixes: 39a66b8d ("[PATCH] USB: CP2101 Add support for flow control")
Cc: stable <stable@vger.kernel.org>     # 2.6.12
Signed-off-by: NJohan Hovold <johan@kernel.org>

Assign the .throttle and .unthrottle functions to be generic function
in the driver structure to prevent data loss that can otherwise occur
if the host does not enable USB throttling.
Signed-off-by: NBrant Merryman <brant.merryman@silabs.com>
Co-developed-by: NPhu Luu <phu.luu@silabs.com>
Signed-off-by: NPhu Luu <phu.luu@silabs.com>
Link: https://lore.kernel.org/r/57401AF3-9961-461F-95E1-F8AFC2105F5E@silabs.com
[ johan: fix up tags ]
Fixes: 39a66b8d ("[PATCH] USB: CP2101 Add support for flow control")
Cc: stable <stable@vger.kernel.org>     # 2.6.12
Signed-off-by: NJohan Hovold <johan@kernel.org>

Add support for the Mark-10 digital force gauge device to the cp201x
driver.

Based on a report and a larger patch from Joel Jennings
Reported-by: NJoel Jennings <joel.jennings@makeitlabs.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: NJohan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191118092119.GA153852@kroah.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Lorenz Messtechnik has a device that is controlled by the cp210x driver,
so add the device id to the driver.  The device id was provided by
Silicon-Labs for the devices from this vendor.
Reported-by: NUli <t9cpu@web.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Current GPIO code in cp210x fails to take USB autosuspend into account,
making it practically impossible to use GPIOs with autosuspend enabled
without user configuration. Fix this like for ftdi_sio in a previous patch.
Tested on a CP2102N.
Signed-off-by: NKaroly Pados <pados@pados.hu>
Fixes: cf5276ce ("USB: serial: cp210x: Adding GPIO support for CP2105")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Here is how this device appears in kernel log:

	usb 3-1: new full-speed USB device number 18 using xhci_hcd
	usb 3-1: New USB device found, idVendor=0b00, idProduct=3070
	usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
	usb 3-1: Product: Ingenico 3070
	usb 3-1: Manufacturer: Silicon Labs
	usb 3-1: SerialNumber: 0001

Apparently this is a POS terminal with embedded USB-to-Serial converter.

Cc: stable@vger.kernel.org
Signed-off-by: NIvan Mironov <mironov.ivan@gmail.com>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Add minimum baud rate to the cp210x driver.

According to the datasheet for CP2105, the SCI supports 2400 as the
lowest baud rate. As this is not heeded in the current code, an error
message 'failed set req 0x1e size 4 status: -32' when trying to set a
lower baud rate such as 300.
The other cp210x models to date supports a minimum baud rate of 300.
Signed-off-by: NJohanna Abrahamsson <johanna.abrahamsson@afconsult.com>
[ johan: simplify min_speed init, move clamp after comment, and drop
         unused serial-data pointer from cp210x_get_actual_rate() ]
Signed-off-by: NJohan Hovold <johan@kernel.org>

The CP2104 chips feature 4 controllable GPIO pins, which are similar to
the ones on CP2102N chip (output-only when push-pull, output or
simulated input mode when open-drain).

Add support for the GPIO pins for cp210x driver. The pin get/set routine
is shared with CP2102N, but the pinconf initialization code is not
shared because the acquisition of GPIO configuration in OTP ROM is
similar to CP2105, not CP2102N.
Signed-off-by: NIcenowy Zheng <icenowy@aosc.io>
Signed-off-by: NJohan Hovold <johan@kernel.org>