docs: ABI: sysfs-tty: close times are in centiseconds

The times for close_delay and closing_wait are in centiseconds, not
milliseconds. Fix the documentation and add details of special values.

Sign

docs: ABI: sysfs-tty: close times are in centiseconds

The times for close_delay and closing_wait are in centiseconds, not
milliseconds. Fix the documentation and add details of special values.

Signed-off-by: Simon Arlott <[email protected]>
Link: https://lore.kernel.org/r/30fa035a-709f-58cd-fc1e-fef1367dc6dd@0882a8b5-c6c3-11e9-b005-00805fc181fe.uuid.home.arpa
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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ABI: sysfs-tty: better document module name parameter

On almost all ABI documents, variable arguments are declared
as <foo_bar>. Change it here too, in order to allow replacing
such wildcards by reg

ABI: sysfs-tty: better document module name parameter

On almost all ABI documents, variable arguments are declared
as <foo_bar>. Change it here too, in order to allow replacing
such wildcards by regexes on a scriptable way.

Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Link: https://lore.kernel.org/r/6280edfacdbcbf8db1aeb7bf11e899187c11ac4c.1631782432.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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serial: core: Allow detach and attach serial device for console

In the future we would like to disable power management on the serial devices
used as kernel consoles to avoid weird behaviour in some

serial: core: Allow detach and attach serial device for console

In the future we would like to disable power management on the serial devices
used as kernel consoles to avoid weird behaviour in some cases. However,
disabling PM may prevent system to go to deep sleep states, which in its turn
leads to the higher power consumption.

Tony Lindgren proposed a work around, i.e. allow user to detach such consoles
to make PM working again. In case user wants to see what's going on, it also
provides a mechanism to attach console back.

Link: https://lists.openwall.net/linux-kernel/2018/09/29/65
Suggested-by: Tony Lindgren <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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Revert "serial:serial_core: Allow use of CTS for PPS line discipline"

This reverts commit c550f01c810f2197c98e6e3103f81797f5e063be.

Turns out the samsung tty driver is mucking around in the "unused

Revert "serial:serial_core: Allow use of CTS for PPS line discipline"

This reverts commit c550f01c810f2197c98e6e3103f81797f5e063be.

Turns out the samsung tty driver is mucking around in the "unused" port
fields and this patch breaks that code :(

So we need to fix that driver up before this can be accepted.

Reported-by: Stephen Rothwell <[email protected]>
Cc: Steve Sakoman <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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serial:serial_core: Allow use of CTS for PPS line discipline

Add a "pps_4wire" file to serial ports in sysfs in case the kernel is
configured with CONFIG_PPS_CLIENT_LDISC. Writing 1 to the file enab

serial:serial_core: Allow use of CTS for PPS line discipline

Add a "pps_4wire" file to serial ports in sysfs in case the kernel is
configured with CONFIG_PPS_CLIENT_LDISC. Writing 1 to the file enables
the use of CTS instead of DCD for PPS signal input. This is necessary
in case a serial port is not completely wired.
Though this affects PPS processing the patch is against the serial core
as the source of the serial port PPS event dispatching has to be
modified. Furthermore it should be possible to modify the source of
serial port PPS event dispatching before changing the line discipline.

Signed-off-by: Andreas Steinmetz <[email protected]>
Signed-off-by: Steve Sakoman <[email protected]>
Tested-by: Steve Sakoman <[email protected]>
Tested-by: Eric Gallimore <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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serial/uart/8250: Add tunable RX interrupt trigger I/F of FIFO buffers

Add tunable RX interrupt trigger I/F of FIFO buffers.

Serial devices are used as not only message communication devices but co

serial/uart/8250: Add tunable RX interrupt trigger I/F of FIFO buffers

Add tunable RX interrupt trigger I/F of FIFO buffers.

Serial devices are used as not only message communication devices but control
or sending communication devices. For the latter uses, normally small data
will be exchanged, so user applications want to receive data unit as soon as
possible for real-time tendency. If we have a sensor which sends a 1 byte data
each time and must control a device based on the sensor feedback, the RX
interrupt should be triggered for each data.

According to HW specification of serial UART devices, RX interrupt trigger
can be changed, but the trigger is hard-coded. For example, RX interrupt trigger
in 16550A can be set to 1, 4, 8, or 14 bytes for HW, but current driver sets
the trigger to only 8bytes.

This patch makes some devices change RX interrupt trigger from userland.

<How to use>
- Read current setting
# cat /sys/class/tty/ttyS0/rx_trig_bytes
8

- Write user setting
# echo 1 > /sys/class/tty/ttyS0/rx_trig_bytes
# cat /sys/class/tty/ttyS0/rx_trig_bytes
1

<Support uart devices>
- 16550A and Tegra (1, 4, 8, or 14 bytes)
- 16650V2 (8, 16, 24, or 28 bytes)
- 16654 (8, 16, 56, or 60 bytes)
- 16750 (1, 16, 32, or 56 bytes)

<Change log>
Changes in V9:
- Use attr_group instead of dev_spec_attr_group of uart_port structure

Changes in V8:
- Divide this patch from V7's patch based on Greg's comment

Changes in V7:
- Add Documentation
- Change I/F name from rx_int_trig to rx_trig_bytes because the name
rx_int_trig is hard to understand how users specify the value

Changes in V6:
- Move FCR_RX_TRIG_* definition in 8250.h to include/uapi/linux/serial_reg.h,
rename those to UART_FCR_R_TRIG_*, and use UART_FCR_TRIGGER_MASK to
UART_FCR_R_TRIG_BITS()
- Change following function names:
convert_fcr2val() => fcr_get_rxtrig_bytes()
convert_val2rxtrig() => bytes_to_fcr_rxtrig()
- Fix typo in serial8250_do_set_termios()
- Delete the verbose error message pr_info() in bytes_to_fcr_rxtrig()
- Rename *rx_int_trig/rx_trig* to *rxtrig* for several functions or variables
(but UI remains rx_int_trig)
- Change the meaningless variable name 'val' to 'bytes' following functions:
fcr_get_rxtrig_bytes(), bytes_to_fcr_rxtrig(), do_set_rxtrig(),
do_serial8250_set_rxtrig(), and serial8250_set_attr_rxtrig()
- Use up->fcr in order to get rxtrig_bytes instead of rx_trig_raw in
fcr_get_rxtrig_bytes()
- Use conf_type->rxtrig_bytes[0] instead of switch statement for support check
in register_dev_spec_attr_grp()
- Delete the checking whether a user changed FCR or not when minimum buffer
is needed in serial8250_do_set_termios()

Changes in V5.1:
- Fix FCR_RX_TRIG_MAX_STATE definition

Changes in V5:
- Support Tegra, 16650V2, 16654, and 16750
- Store default FCR value to up->fcr when the port is first created
- Add rx_trig_byte[] in uart_config[] for each device and use rx_trig_byte[]
in convert_fcr2val() and convert_val2rxtrig()

Changes in V4:
- Introduce fifo_bug flag in uart_8250_port structure
This is enabled only when parity is enabled and UART_BUG_PARITY is enabled
for up->bugs. If this flag is enabled, user cannot set RX trigger.
- Return -EOPNOTSUPP when it does not support device at convert_fcr2val() and
at convert_val2rxtrig()
- Set the nearest lower RX trigger when users input a meaningless value at
convert_val2rxtrig()
- Check whether p->fcr is existing at serial8250_clear_and_reinit_fifos()
- Set fcr = up->fcr in the begging of serial8250_do_set_termios()

Changes in V3:
- Change I/F from ioctl(2) to sysfs(rx_int_trig)

Changed in V2:
- Use _IOW for TIOCSFIFORTRIG definition
- Pass the interrupt trigger value itself

Signed-off-by: Yoshihiro YUNOMAE <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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Revert "tty: Set correct tty name in 'active' sysfs attribute"

This reverts commit d8a5dc3033af2fd6d16030d2ee4fbd073460fe54.

This breaks plymouth installs, either because plymouth is using the file

Revert "tty: Set correct tty name in 'active' sysfs attribute"

This reverts commit d8a5dc3033af2fd6d16030d2ee4fbd073460fe54.

This breaks plymouth installs, either because plymouth is using the file
"incorrectly" or because the patch is incorrect. Either way, this needs
to be reverted until it is all figured out.

Reported-by: Josh Boyer <[email protected]>
Reported-by: Ray Strode <[email protected]>
Cc: Lennart Poettering <[email protected]>
Cc: Kay Sievers <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: David Herrmann <[email protected]>
Cc: Werner Fink <[email protected]>
Cc: Hannes Reinecke <[email protected]>
Cc: stable <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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tty: Set correct tty name in 'active' sysfs attribute

The 'active' sysfs attribute should refer to the currently active tty
devices the console is running on, not the currently active console.

The

tty: Set correct tty name in 'active' sysfs attribute

The 'active' sysfs attribute should refer to the currently active tty
devices the console is running on, not the currently active console.

The console structure doesn't refer to any device in sysfs, only the tty
the console is running on has. So we need to print out the tty names in
'active', not the console names.

This resolves an issue on s390 platforms in determining the correct
console device to use.

Cc: Lennart Poettering <[email protected]>
Cc: Kay Sievers <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: David Herrmann <[email protected]>
Signed-off-by: Werner Fink <[email protected]>
Signed-off-by: Hannes Reinecke <[email protected]>
Cc: stable <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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uart: add other serial core layer get attributes

Signed-off-by: Alan Cox <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

tty: uartclk value from serial_core exposed to sysfs

Added file /sys/devices/.../tty/ttySX/uartclk to allow reading
uartclk value in struct uart_port in serial_core via sysfs.

tty_register_device()

tty: uartclk value from serial_core exposed to sysfs

Added file /sys/devices/.../tty/ttySX/uartclk to allow reading
uartclk value in struct uart_port in serial_core via sysfs.

tty_register_device() has been generalized and refactored in order
to add support for setting drvdata and attribute_group to the device.

Signed-off-by: Tomas Hlavacek <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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tty: add 'active' sysfs attribute to tty0 and console device

tty: add 'active' sysfs attribute to tty0 and console device

Userspace can query the actual virtual console, and the configured
console

tty: add 'active' sysfs attribute to tty0 and console device

tty: add 'active' sysfs attribute to tty0 and console device

Userspace can query the actual virtual console, and the configured
console devices behind /dev/tt0 and /dev/console.

The last entry in the list of devices is the active device, analog
to the console= kernel command line option.

The attribute supports poll(), which is raised when the virtual
console is changed or /dev/console is reconfigured.

Signed-off-by: Kay Sievers <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

index 0000000..b138b66

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