diff options
| author | Linus Walleij <linus.walleij@linaro.org> | 2018-09-13 09:44:21 +0200 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2018-09-20 17:35:47 +0200 |
| commit | c02980d6bf061cc8d69940ed2f5d309c231920b2 (patch) | |
| tree | 26c2cfdd890845a47ba4c297ba2b6518dfd1bdf9 /Documentation | |
| parent | gpio: OF: Cut painful BNF experiments from bindings (diff) | |
| download | linux-c02980d6bf061cc8d69940ed2f5d309c231920b2.tar.xz linux-c02980d6bf061cc8d69940ed2f5d309c231920b2.zip | |
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>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio.txt | 24 |
1 files changed, 9 insertions, 15 deletions
diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt index 3afaa396adf7..f0ba154b5723 100644 --- a/Documentation/devicetree/bindings/gpio/gpio.txt +++ b/Documentation/devicetree/bindings/gpio/gpio.txt @@ -27,30 +27,24 @@ and bit-banged data signals: gpio-controller; #gpio-cells = <2>; }; - gpio2: gpio2 { - gpio-controller; - #gpio-cells = <1>; - }; [...] - enable-gpios = <&gpio2 2>; data-gpios = <&gpio1 12 0>, <&gpio1 13 0>, <&gpio1 14 0>, <&gpio1 15 0>; -Note that gpio-specifier length is controller dependent. In the -above example, &gpio1 uses 2 cells to specify a gpio, while &gpio2 -only uses one. - -gpio-specifier may encode: bank, pin position inside the bank, -whether pin is open-drain and whether pin is logically inverted. +In the above example, &gpio1 uses 2 cells to specify a gpio. The first cell is +a local offset to the GPIO line and the second cell represent consumer flags, +such as if the consumer desire the line to be active low (inverted) or open +drain. This is the recommended practice. -Exact meaning of each specifier cell is controller specific, and must -be documented in the device tree binding for the device. +The exact meaning of each specifier cell is controller specific, and must be +documented in the device tree binding for the device, but it is strongly +recommended to use the two-cell approach. -Most controllers are however specifying a generic flag bitfield -in the last cell, so for these, use the macros defined in +Most controllers are specifying a generic flag bitfield in the last cell, so +for these, use the macros defined in include/dt-bindings/gpio/gpio.h whenever possible: Example of a node using GPIOs: |