69d301fdd1
It is customary for GPIO controllers to support open drain/collector and open source/emitter configurations. Add standard GPIO line flags to account for this and augment the documentation to say that these are the most generic bindings. Several people approached me to add new flags to the lines, and this makes sense, but let's first bind up the most common cases before we start to add exotic stuff. Thanks to H. Nikolaus Schaller for ideas on how to encode single-ended wiring such as open drain/source and open collector/emitter. Cc: Tony Lindgren <tony@atomide.com> Cc: Grygorii Strashko <grygorii.strashko@ti.com> Cc: H. Nikolaus Schaller <hns@goldelico.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
28 lines
766 B
C
28 lines
766 B
C
/*
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* This header provides constants for most GPIO bindings.
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*
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* Most GPIO bindings include a flags cell as part of the GPIO specifier.
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* In most cases, the format of the flags cell uses the standard values
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* defined in this header.
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*/
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#ifndef _DT_BINDINGS_GPIO_GPIO_H
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#define _DT_BINDINGS_GPIO_GPIO_H
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/* Bit 0 express polarity */
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#define GPIO_ACTIVE_HIGH 0
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#define GPIO_ACTIVE_LOW 1
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/* Bit 1 express single-endedness */
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#define GPIO_PUSH_PULL 0
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#define GPIO_SINGLE_ENDED 2
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/*
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* Open Drain/Collector is the combination of single-ended active low,
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* Open Source/Emitter is the combination of single-ended active high.
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*/
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#define GPIO_OPEN_DRAIN (GPIO_SINGLE_ENDED | GPIO_ACTIVE_LOW)
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#define GPIO_OPEN_SOURCE (GPIO_SINGLE_ENDED | GPIO_ACTIVE_HIGH)
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#endif
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