<feed xmlns='http://www.w3.org/2005/Atom'>
<title>lwn.git/drivers/tty/serial, branch docs-4.17</title>
<subtitle>Linux kernel documentation tree maintained by Jonathan Corbet</subtitle>
<id>http://mirrors.hust.edu.cn/git/lwn.git/atom?h=docs-4.17</id>
<link rel='self' href='http://mirrors.hust.edu.cn/git/lwn.git/atom?h=docs-4.17'/>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/'/>
<updated>2018-02-09T17:44:25+00:00</updated>
<entry>
<title>Merge tag 'acpi-part2-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm</title>
<updated>2018-02-09T17:44:25+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-02-09T17:44:25+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=54ce685cae30c106f062d714c11e644ab1b93b51'/>
<id>urn:sha1:54ce685cae30c106f062d714c11e644ab1b93b51</id>
<content type='text'>
Pull more ACPI updates from Rafael Wysocki:
 "These are mostly fixes and cleanups, a few new quirks, a couple of
  updates related to the handling of ACPI tables and ACPICA copyrights
  refreshment.

  Specifics:

   - Update the ACPICA kernel code to upstream revision 20180105
     including:
       * Assorted fixes (Jung-uk Kim)
       * Support for X32 ABI compilation (Anuj Mittal)
       * Update of ACPICA copyrights to 2018 (Bob Moore)

   - Prepare for future modifications to avoid executing the _STA
     control method too early (Hans de Goede)

   - Make the processor performance control library code ignore _PPC
     notifications if they cannot be handled and fix up the C1 idle
     state definition when it is used as a fallback state (Chen Yu,
     Yazen Ghannam)

   - Make it possible to use the SPCR table on x86 and to replace the
     original IORT table with a new one from initrd (Prarit Bhargava,
     Shunyong Yang)

   - Add battery-related quirks for Asus UX360UA and UX410UAK and add
     quirks for table parsing on Dell XPS 9570 and Precision M5530 (Kai
     Heng Feng)

   - Address static checker warnings in the CPPC code (Gustavo Silva)

   - Avoid printing a raw pointer to the kernel log in the smart battery
     driver (Greg Kroah-Hartman)"

* tag 'acpi-part2-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: sbshc: remove raw pointer from printk() message
  ACPI: SPCR: Make SPCR available to x86
  ACPI / CPPC: Use 64-bit arithmetic instead of 32-bit
  ACPI / tables: Add IORT to injectable table list
  ACPI / bus: Parse tables as term_list for Dell XPS 9570 and Precision M5530
  ACPICA: Update version to 20180105
  ACPICA: All acpica: Update copyrights to 2018
  ACPI / processor: Set default C1 idle state description
  ACPI / battery: Add quirk for Asus UX360UA and UX410UAK
  ACPI: processor_perflib: Do not send _PPC change notification if not ready
  ACPI / scan: Use acpi_bus_get_status() to initialize ACPI_TYPE_DEVICE devs
  ACPI / bus: Do not call _STA on battery devices with unmet dependencies
  PCI: acpiphp_ibm: prepare for acpi_get_object_info() no longer returning status
  ACPI: export acpi_bus_get_status_handle()
  ACPICA: Add a missing pair of parentheses
  ACPICA: Prefer ACPI_TO_POINTER() over ACPI_ADD_PTR()
  ACPICA: Avoid NULL pointer arithmetic
  ACPICA: Linux: add support for X32 ABI compilation
  ACPI / video: Use true for boolean value
</content>
</entry>
<entry>
<title>ACPI: SPCR: Make SPCR available to x86</title>
<updated>2018-02-07T10:39:58+00:00</updated>
<author>
<name>Prarit Bhargava</name>
<email>prarit@redhat.com</email>
</author>
<published>2018-01-18T15:09:51+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=0231d00082f61cfe03f2b7c27e5356f8cdf0312c'/>
<id>urn:sha1:0231d00082f61cfe03f2b7c27e5356f8cdf0312c</id>
<content type='text'>
SPCR is currently only enabled or ARM64 and x86 can use SPCR to setup
an early console.

General fixes include updating Documentation &amp; Kconfig (for x86),
updating comments, and changing parse_spcr() to acpi_parse_spcr(),
and earlycon_init_is_deferred to earlycon_acpi_spcr_enable to be
more descriptive.

On x86, many systems have a valid SPCR table but the table version is
not 2 so the table version check must be a warning.

On ARM64 when the kernel parameter earlycon is used both the early console
and console are enabled.  On x86, only the earlycon should be enabled by
by default.  Modify acpi_parse_spcr() to allow options for initializing
the early console and console separately.

Signed-off-by: Prarit Bhargava &lt;prarit@redhat.com&gt;
Acked-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Reviewed-by: Mark Salter &lt;msalter@redhat.com&gt;
Tested-by: Mark Salter &lt;msalter@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'driver-core-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core</title>
<updated>2018-02-01T18:00:28+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-02-01T18:00:28+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=47fcc0360cfb3fe82e4daddacad3c1cd80b0b75d'/>
<id>urn:sha1:47fcc0360cfb3fe82e4daddacad3c1cd80b0b75d</id>
<content type='text'>
Pull driver core updates from Greg KH:
 "Here is the set of "big" driver core patches for 4.16-rc1.

  The majority of the work here is in the firmware subsystem, with
  reworks to try to attempt to make the code easier to handle in the
  long run, but no functional change. There's also some tree-wide sysfs
  attribute fixups with lots of acks from the various subsystem
  maintainers, as well as a handful of other normal fixes and changes.

  And finally, some license cleanups for the driver core and sysfs code.

  All have been in linux-next for a while with no reported issues"

* tag 'driver-core-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (48 commits)
  device property: Define type of PROPERTY_ENRTY_*() macros
  device property: Reuse property_entry_free_data()
  device property: Move property_entry_free_data() upper
  firmware: Fix up docs referring to FIRMWARE_IN_KERNEL
  firmware: Drop FIRMWARE_IN_KERNEL Kconfig option
  USB: serial: keyspan: Drop firmware Kconfig options
  sysfs: remove DEBUG defines
  sysfs: use SPDX identifiers
  drivers: base: add coredump driver ops
  sysfs: add attribute specification for /sysfs/devices/.../coredump
  test_firmware: fix missing unlock on error in config_num_requests_store()
  test_firmware: make local symbol test_fw_config static
  sysfs: turn WARN() into pr_warn()
  firmware: Fix a typo in fallback-mechanisms.rst
  treewide: Use DEVICE_ATTR_WO
  treewide: Use DEVICE_ATTR_RO
  treewide: Use DEVICE_ATTR_RW
  sysfs.h: Use octal permissions
  component: add debugfs support
  bus: simple-pm-bus: convert bool SIMPLE_PM_BUS to tristate
  ...
</content>
</entry>
<entry>
<title>tty: serial: exar: Relocate sleep wake-up handling</title>
<updated>2018-01-25T11:44:50+00:00</updated>
<author>
<name>Aaron Sierra</name>
<email>asierra@xes-inc.com</email>
</author>
<published>2018-01-25T00:19:23+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=c7e1b4059075c9e8eed101d7cc5da43e95eb5e18'/>
<id>urn:sha1:c7e1b4059075c9e8eed101d7cc5da43e95eb5e18</id>
<content type='text'>
Exar sleep wake-up handling has been done on a per-channel basis by
virtue of INT0 being accessible from each channel's address space. I
believe this was initially done out of necessity, but now that Exar
devices have their own driver, we can do things more efficiently by
registering a dedicated INT0 handler at the PCI device level.

I see this change providing the following benefits:

    1. If more than one port is active, eliminates the redundant bus
       cycles for reading INT0 on every interrupt.
    2. This note associated with hooking in the per-channel handler in
       8250_port.c is resolved:
        /* Fixme: probably not the best place for this */

Cc: Matt Schulte &lt;matts@commtech-fastcom.com&gt;
Signed-off-by: Aaron Sierra &lt;asierra@xes-inc.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>serial: imx: fix endless loop during suspend</title>
<updated>2018-01-22T13:20:56+00:00</updated>
<author>
<name>Martin Kaiser</name>
<email>martin@kaiser.cx</email>
</author>
<published>2018-01-05T16:46:43+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=09df0b3464e528c6a4ca2c48d9ff6d2fd7cbd775'/>
<id>urn:sha1:09df0b3464e528c6a4ca2c48d9ff6d2fd7cbd775</id>
<content type='text'>
Before we go into suspend mode, we enable the imx uart's interrupt for
the awake bit in the UART Status Register 1. If, for some reason, the
awake bit is already set before we enter suspend mode, we get an
interrupt immediately when we enable interrupts for awake. The uart's
clk_ipg is disabled at this point (unless there's an ongoing transfer).
We end up in the interrupt handler, which usually tries to clear the
awake bit. This doesn't work with the clock disabled. Therefore, we
keep getting interrupts forever, resulting in an endless loop.

Clear the awake bit before setting the awaken bit to signal that we want
an imx interrupt when the awake bit will be set. This ensures that we're
not woken up by events that happened before we started going into
suspend mode.

Change the clock handling so that suspend prepares and enables the clock
and suspend_noirq disables it. Revert these operations in resume_noirq and
resume.

With these preparations in place, we can now modify awake and awaken in
the suspend function when the actual imx interrupt is disabled and the
required clk_ipg is active.

Update the thaw and freeze functions to use the new clock handling since
we share the suspend_noirq function between suspend and hibernate.

Signed-off-by: Martin Kaiser &lt;martin@kaiser.cx&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>serial: core: mark port as initialized after successful IRQ change</title>
<updated>2018-01-22T13:20:56+00:00</updated>
<author>
<name>Sebastian Andrzej Siewior</name>
<email>bigeasy@linutronix.de</email>
</author>
<published>2018-01-11T17:57:26+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=44117a1d1732c513875d5a163f10d9adbe866c08'/>
<id>urn:sha1:44117a1d1732c513875d5a163f10d9adbe866c08</id>
<content type='text'>
setserial changes the IRQ via uart_set_info(). It invokes
uart_shutdown() which free the current used IRQ and clear
TTY_PORT_INITIALIZED. It will then update the IRQ number and invoke
uart_startup() before returning to the caller leaving
TTY_PORT_INITIALIZED cleared.

The next open will crash with
|  list_add double add: new=ffffffff839fcc98, prev=ffffffff839fcc98, next=ffffffff839fcc98.
since the close from the IOCTL won't free the IRQ (and clean the list)
due to the TTY_PORT_INITIALIZED check in uart_shutdown().

There is same pattern in uart_do_autoconfig() and I *think* it also
needs to set TTY_PORT_INITIALIZED there.
Is there a reason why uart_startup() does not set the flag by itself
after the IRQ has been acquired (since it is cleared in uart_shutdown)?

Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>serial: mxs-auart: don't use GPIOF_* with gpiod_get_direction</title>
<updated>2018-01-22T13:17:44+00:00</updated>
<author>
<name>Wolfram Sang</name>
<email>wsa+renesas@sang-engineering.com</email>
</author>
<published>2018-01-14T21:07:09+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=f8bdfe9d27350735d1cc787a5fd7c25078667496'/>
<id>urn:sha1:f8bdfe9d27350735d1cc787a5fd7c25078667496</id>
<content type='text'>
The documentation was wrong, gpiod_get_direction() returns 0/1 instead
of the GPIOF_* flags. The docs were fixed with commit 94fc73094abe47
("gpio: correct docs about return value of gpiod_get_direction"). Now,
fix this user (until a better, system-wide solution is in place). This
also means we can drop the deprecated use of 'linux/gpio.h'. Yay!

Signed-off-by: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>serial: 8250_dw: Revert "Improve clock rate setting"</title>
<updated>2018-01-22T13:13:40+00:00</updated>
<author>
<name>Andy Shevchenko</name>
<email>andriy.shevchenko@linux.intel.com</email>
</author>
<published>2018-01-19T16:02:05+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=c14b65feac9ebed649d6fe79c6b6d64d21d0287d'/>
<id>urn:sha1:c14b65feac9ebed649d6fe79c6b6d64d21d0287d</id>
<content type='text'>
The commit

  de9e33bdfa22 ("serial: 8250_dw: Improve clock rate setting")

obviously tries to cure symptoms, and not a root cause.

The root cause is the non-flexible rate calculation inside the
corresponding clock driver. What we need is to provide maximum UART
divisor value to the clock driver to allow it do the job transparently
to the caller.

Since from the initial commit message I have got no clue which clock
driver actually needs to be amended, I leave this exercise to the people
who know better the case.

Moreover, it seems [1] the fix introduced a regression. And possible
even one more [2].

Taking above, revert the commit de9e33bdfa22 for now.

[1]: https://www.spinics.net/lists/linux-serial/msg28872.html
[2]: https://github.com/Dunedan/mbp-2016-linux/issues/29#issuecomment-357583782

Fixes: de9e33bdfa22 ("serial: 8250_dw: Improve clock rate setting")
Cc: stable &lt;stable@vger.kernel.org&gt; # 4.15
Cc: Ed Blake &lt;ed.blake@sondrel.com&gt;
Cc: Heikki Krogerus &lt;heikki.krogerus@linux.intel.com&gt;
Cc: Lukas Wunner &lt;lukas@wunner.de&gt;
Signed-off-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>gpio: serial: max310x: Support open-drain configuration for GPIOs</title>
<updated>2018-01-09T18:36:51+00:00</updated>
<author>
<name>Jan Kundrát</name>
<email>jan.kundrat@cesnet.cz</email>
</author>
<published>2017-12-22T20:29:44+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=e397824bf0953344000101dc8994e92a98add0fe'/>
<id>urn:sha1:e397824bf0953344000101dc8994e92a98add0fe</id>
<content type='text'>
The push-pull vs. open-drain are the only supported output modes. The
inputs are always unconditionally equipped with weak pull-downs. That's
the only mode, so there's probably no point in exporting that. I wonder
if it's worthwhile to provide a custom dbg_show method to indicate the
current status of the outputs, though.

This patch and [1] for i2c-gpio together make it possible to bit-bang an
I2C bus over GPIOs of an UART which is connected via SPI :). Yes, this
is crazy, but it's fast enough (while on a 26Mhz SPI HW bus with a
dual-core 1.6GHz CPU) to drive an I2C bus at 200kHz, according to my
scope.

[1] https://patchwork.ozlabs.org/patch/852591/

Signed-off-by: Jan Kundrát &lt;jan.kundrat@cesnet.cz&gt;
Reviewed-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>serial: 8250_ingenic: Parse earlycon options</title>
<updated>2018-01-09T15:49:14+00:00</updated>
<author>
<name>Paul Cercueil</name>
<email>paul@crapouillou.net</email>
</author>
<published>2017-12-28T13:07:09+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=ea507ce3e05a462e170db4b6af1002fb0ed72916'/>
<id>urn:sha1:ea507ce3e05a462e170db4b6af1002fb0ed72916</id>
<content type='text'>
In the devicetree, it is possible to specify the baudrate, parity,
bits, flow of the early console, by passing a configuration string like
this:

aliases {
	serial0 = &amp;uart0;
};

chosen {
	stdout-path = "serial0:57600n8";
};

This, for instance, will configure the early console for a baudrate of
57600 bps, no parity, and 8 bits per baud.

This patches implements parsing of this configuration string in the
8250_ingenic driver, which previously just ignored it.

Signed-off-by: Paul Cercueil &lt;paul@crapouillou.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
</feed>
