gpio: OF: Remove bad practice examples
We remove the references to anything but two-cell GPIO specifiers and just mention that controllers need to specify their bindings and that we strongly recommend two-cell bindings. Cc: devicetree@vger.kernel.org Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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@ -27,30 +27,24 @@ and bit-banged data signals:
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gpio-controller;
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#gpio-cells = <2>;
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};
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gpio2: gpio2 {
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gpio-controller;
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#gpio-cells = <1>;
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};
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[...]
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enable-gpios = <&gpio2 2>;
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data-gpios = <&gpio1 12 0>,
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<&gpio1 13 0>,
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<&gpio1 14 0>,
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<&gpio1 15 0>;
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Note that gpio-specifier length is controller dependent. In the
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above example, &gpio1 uses 2 cells to specify a gpio, while &gpio2
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only uses one.
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In the above example, &gpio1 uses 2 cells to specify a gpio. The first cell is
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a local offset to the GPIO line and the second cell represent consumer flags,
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such as if the consumer desire the line to be active low (inverted) or open
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drain. This is the recommended practice.
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gpio-specifier may encode: bank, pin position inside the bank,
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whether pin is open-drain and whether pin is logically inverted.
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The exact meaning of each specifier cell is controller specific, and must be
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documented in the device tree binding for the device, but it is strongly
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recommended to use the two-cell approach.
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Exact meaning of each specifier cell is controller specific, and must
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be documented in the device tree binding for the device.
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Most controllers are however specifying a generic flag bitfield
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in the last cell, so for these, use the macros defined in
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Most controllers are specifying a generic flag bitfield in the last cell, so
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for these, use the macros defined in
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include/dt-bindings/gpio/gpio.h whenever possible:
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Example of a node using GPIOs:
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