39 lines
1.8 KiB
ReStructuredText
39 lines
1.8 KiB
ReStructuredText
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==========================
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Touchscreen Device Drivers
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==========================
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NuttX supports a two-part touchscreen driver architecture.
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#. An "upper half", generic driver that provides the common
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touchscreen interface to application level code, and
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#. A "lower half", platform-specific driver that implements the
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low-level touchscreen controls to implement the touchscreen
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functionality.
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Files supporting the touchscreen controller (TSC) driver can be
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found in the following locations:
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- **Interface Definition**. The header files for NuttX
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touchscreen drivers reside in the
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``include/nuttx/include/input`` directory. The interface
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between the touchscreen controller "upper half" and "lower
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half" drivers are *not* common, but vary from
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controller-to-controller. Because of this, each touchscreen
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driver has its own unique header file that describes the "upper
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half"/"lower half" interface in that directory. The application
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level interface to each touchscreen driver, on the other hand,
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*is* the same for each touchscreen driver and is described
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``include/nuttx/include/input/touchscreen.h``. The touchscreen
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driver uses a standard character driver framework but read
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operations return specially formatted data.
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- **"Upper Half" Driver**. The controller-specific, "upper half"
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touchscreen drivers reside in the directory ``drivers/input``.
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- **"Lower Half" Drivers**. Platform-specific touchscreen drivers
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reside in either: (1) The
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``arch/``\ *<architecture>*\ ``/src/``\ *<hardware>* directory
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for the processor architectures that have build in touchscreen
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controllers or (2) the
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``boards/``\ *<arch>*\ ``/``\ *<chip>*\ ``/``\ *<board>*\ ``/src/``
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directory for boards that use an external touchscreen
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controller chip.
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