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Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
33 lines
906 B
ReStructuredText
33 lines
906 B
ReStructuredText
==============
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Device Drivers
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==============
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NuttX supports a variety of device drivers, which can be broadly
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divided in three classes:
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.. toctree::
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:maxdepth: 1
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character/index.rst
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block/index.rst
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special/index.rst
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.. note::
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Device driver support depends on the *in-memory*, *pseudo*
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file system that is enabled by default.
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Lower-half and upper-half
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=========================
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Drivers in NuttX generally work in two distinct layers:
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* An *upper half* which registers itself to NuttX using
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a call such as :c:func:`register_driver` or
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:c:func:`register_blockdriver` and implements the corresponding
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high-level interface (`read`, `write`, `close`, etc.).
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implements the interface. This *upper half* calls into
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the *lower half* via callbacks.
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* A "lower half" which is typically hardware-specific. This is
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usually implemented at the architecture or board level.
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