Revision 8e37395c3a5dceff62a5010ebbbc107f4145935c authored by Linus Torvalds on 20 October 2021, 16:13:22 UTC, committed by Linus Torvalds on 20 October 2021, 16:13:22 UTC
Pull sound fixes from Takashi Iwai:
 "Again it became bigger than wished, unfortunately, as this contains
  quite a few ASoC fixes that came up a bit late. It also includes yet
  more HD- and USB-audio quirks: I decided to merge them now, as those
  are for stable, and we'll need them sooner or later.

  Although the volumes are a bit high, all changes are device-specific
  (and reasonably small) fixes, so it should be safe for the late rc"

* tag 'sound-5.15-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usb-audio: Fix microphone sound on Jieli webcam.
  ALSA: hda/realtek: Fixes HP Spectre x360 15-eb1xxx speakers
  ALSA: usb-audio: Provide quirk for Sennheiser GSP670 Headset
  ALSA: hda/realtek: Add quirk for Clevo PC50HS
  ALSA: usb-audio: add Schiit Hel device to quirk table
  ASoC: wm8960: Fix clock configuration on slave mode
  ASoC: cs42l42: Ensure 0dB full scale volume is used for headsets
  ASoC: soc-core: fix null-ptr-deref in snd_soc_del_component_unlocked()
  ASoC: codec: wcd938x: Add irq config support
  ASoC: DAPM: Fix missing kctl change notifications
  ASoC: Intel: bytcht_es8316: Utilize dev_err_probe() to avoid log saturation
  ASoC: Intel: bytcht_es8316: Switch to use gpiod_get_optional()
  ASoC: Intel: bytcht_es8316: Use temporary variable for struct device
  ASoC: Intel: bytcht_es8316: Get platform data via dev_get_platdata()
  ASoC: wcd938x: Fix jack detection issue
  ASoC: nau8824: Fix headphone vs headset, button-press detection no longer working
  ASoC: cs4341: Add SPI device ID table
  ASoC: pcm179x: Add missing entries SPI to device ID table
  ASoC: fsl_xcvr: Fix channel swap issue with ARC
  ASoC: pcm512x: Mend accesses to the I2S_1 and I2S_2 registers
2 parent s 6da52de + 2966492
Raw File
pc87427.rst
Kernel driver pc87427
=====================

Supported chips:

  * National Semiconductor PC87427

    Prefix: 'pc87427'

    Addresses scanned: none, address read from Super I/O config space

    Datasheet: No longer available

Author: Jean Delvare <jdelvare@suse.de>

Thanks to Amir Habibi at Candelis for setting up a test system, and to
Michael Kress for testing several iterations of this driver.


Description
-----------

The National Semiconductor Super I/O chip includes complete hardware
monitoring capabilities. It can monitor up to 18 voltages, 8 fans and
6 temperature sensors. Only the fans and temperatures are supported at
the moment, voltages aren't.

This chip also has fan controlling features (up to 4 PWM outputs),
which are partly supported by this driver.

The driver assumes that no more than one chip is present, which seems
reasonable.


Fan Monitoring
--------------

Fan rotation speeds are reported as 14-bit values from a gated clock
signal. Speeds down to 83 RPM can be measured.

An alarm is triggered if the rotation speed drops below a programmable
limit. Another alarm is triggered if the speed is too low to be measured
(including stalled or missing fan).


Fan Speed Control
-----------------

Fan speed can be controlled by PWM outputs. There are 4 possible modes:
always off, always on, manual and automatic. The latter isn't supported
by the driver: you can only return to that mode if it was the original
setting, and the configuration interface is missing.


Temperature Monitoring
----------------------

The PC87427 relies on external sensors (following the SensorPath
standard), so the resolution and range depend on the type of sensor
connected. The integer part can be 8-bit or 9-bit, and can be signed or
not. I couldn't find a way to figure out the external sensor data
temperature format, so user-space adjustment (typically by a factor 2)
may be required.
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