| Message ID | 20241211134023.222473-1-ikerpedrosam@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | dt-bindings: devicetree: explain how to get CS active-high | expand |
On Wed, 11 Dec 2024 14:40:17 +0100, Iker Pedrosa wrote: > The current documentation does not clearly explain how to invert the SPI > CS signal to make it active-high. This makes it very difficult to > understand. > > This patch adds a simple explanation on how to set the CS line in > active-high and adds an example to make it easier for users who need > that setup for their SPI peripherals. > > Link: https://forums.raspberrypi.com/viewtopic.php?t=378222 > Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com> > --- > .../bindings/spi/spi-controller.yaml | 24 +++++++++++++++++++ > 1 file changed, 24 insertions(+) > My bot found errors running 'make dt_binding_check' on your patch: yamllint warnings/errors: dtschema/dtc warnings/errors: Error: Documentation/devicetree/bindings/spi/spi-controller.example.dts:82.33-34 syntax error FATAL ERROR: Unable to parse input tree make[2]: *** [scripts/Makefile.dtbs:131: Documentation/devicetree/bindings/spi/spi-controller.example.dtb] Error 1 make[2]: *** Waiting for unfinished jobs.... make[1]: *** [/builds/robherring/dt-review-ci/linux/Makefile:1506: dt_binding_check] Error 2 make: *** [Makefile:251: __sub-make] Error 2 doc reference errors (make refcheckdocs): See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20241211134023.222473-1-ikerpedrosam@gmail.com The base for the series is generally the latest rc1. A different dependency should be noted in *this* patch. If you already ran 'make dt_binding_check' and didn't see the above error(s), then make sure 'yamllint' is installed and dt-schema is up to date: pip3 install dtschema --upgrade Please check and re-submit after running the above command yourself. Note that DT_SCHEMA_FILES can be set to your schema file to speed up checking your schema. However, it must be unset to test all examples with your schema.
diff --git a/Documentation/devicetree/bindings/spi/spi-controller.yaml b/Documentation/devicetree/bindings/spi/spi-controller.yaml index 093150c0cb87..02dc3e1abcad 100644 --- a/Documentation/devicetree/bindings/spi/spi-controller.yaml +++ b/Documentation/devicetree/bindings/spi/spi-controller.yaml @@ -69,6 +69,11 @@ properties: Should be generally avoided and be replaced by spi-cs-high + ACTIVE_HIGH. + The simplest way to obtain an active-high CS signal is to configure the + controller's cs-gpio property with the ACTIVE_HIGH flag and set the + peripheral's spi-cs-high property. See example below for a better + understanding. + fifo-depth: $ref: /schemas/types.yaml#/definitions/uint32 description: @@ -189,3 +194,22 @@ examples: stacked-memories = /bits/ 64 <0x10000000 0x10000000>; }; }; + + - | + spi@20204000 { + #address-cells = <1>; + #size-cells = <0>; + compatible = "brcm,bcm2835-spi"; + reg = <0x7e204000 0x1000>; + interrupts = <2 22>; + clocks = <&clk_spi>; + cs-gpios = <&gpio 8 GPIO_ACTIVE_HIGH>; + + display@0 { + compatible = "sitronix,st7920"; + spi-max-frequency = <600000>; + reg = <0>; + spi-cs-high; + }; + }; +
The current documentation does not clearly explain how to invert the SPI CS signal to make it active-high. This makes it very difficult to understand. This patch adds a simple explanation on how to set the CS line in active-high and adds an example to make it easier for users who need that setup for their SPI peripherals. Link: https://forums.raspberrypi.com/viewtopic.php?t=378222 Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com> --- .../bindings/spi/spi-controller.yaml | 24 +++++++++++++++++++ 1 file changed, 24 insertions(+)