Documentation/leds/leds-lm3556.rst

Source file repositories/reference/linux-study-clean/Documentation/leds/leds-lm3556.rst

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System: Linux kernel
Corpus path: Documentation/leds/leds-lm3556.rst
Extension: .rst
Size: 3092 bytes
Lines: 138
Domain: Support Tooling And Documentation
Bucket: Documentation
Inferred role: Support Tooling And Documentation: documentation
Status: atlas-only

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Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

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Annotated Snippet

========================
Kernel driver for lm3556
========================

* Texas Instrument:
  1.5 A Synchronous Boost LED Flash Driver w/ High-Side Current Source
* Datasheet: http://www.national.com/ds/LM/LM3556.pdf

Authors:
      - Daniel Jeong

	Contact:Daniel Jeong(daniel.jeong-at-ti.com, gshark.jeong-at-gmail.com)

Description
-----------
There are 3 functions in LM3556, Flash, Torch and Indicator.

Flash Mode
^^^^^^^^^^

In Flash Mode, the LED current source(LED) provides 16 target current levels
from 93.75 mA to 1500 mA.The Flash currents are adjusted via the CURRENT
CONTROL REGISTER(0x09).Flash mode is activated by the ENABLE REGISTER(0x0A),
or by pulling the STROBE pin HIGH.

LM3556 Flash can be controlled through /sys/class/leds/flash/brightness file

* if STROBE pin is enabled, below example control brightness only, and
  ON / OFF will be controlled by STROBE pin.

Flash Example:

OFF::

	#echo 0 > /sys/class/leds/flash/brightness

93.75 mA::

	#echo 1 > /sys/class/leds/flash/brightness

...

1500  mA::

	#echo 16 > /sys/class/leds/flash/brightness

Torch Mode
^^^^^^^^^^

In Torch Mode, the current source(LED) is programmed via the CURRENT CONTROL
REGISTER(0x09).Torch Mode is activated by the ENABLE REGISTER(0x0A) or by the
hardware TORCH input.

LM3556 torch can be controlled through /sys/class/leds/torch/brightness file.
* if TORCH pin is enabled, below example control brightness only,
and ON / OFF will be controlled by TORCH pin.

Torch Example:

OFF::

	#echo 0 > /sys/class/leds/torch/brightness

46.88 mA::

	#echo 1 > /sys/class/leds/torch/brightness

...

375 mA::

Annotation

Atlas domain: Support Tooling And Documentation / Documentation.
Implementation status: atlas-only.

Implementation Notes

This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.