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| author | Iker Pedrosa <ikerpedrosam@gmail.com> | 2024-12-16 12:57:33 +0300 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2024-12-17 18:37:14 +0300 |
| commit | 7b4035ebf2af2c2f1450e8c38bf4f41acd3f01bf (patch) | |
| tree | f7fbebf7ffc42eda6e1a7ea06cf8ef902ddb5490 | |
| parent | e490ceff433fbc111404ce040bd9e8f41f12af16 (diff) | |
| download | linux-7b4035ebf2af2c2f1450e8c38bf4f41acd3f01bf.tar.xz | |
spi: dt-bindings: Document CS active-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>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20241216095739.27320-1-ikerpedrosam@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
| -rw-r--r-- | Documentation/devicetree/bindings/spi/spi-controller.yaml | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/spi/spi-controller.yaml b/Documentation/devicetree/bindings/spi/spi-controller.yaml index 093150c0cb87..82d051f7bd6e 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 +194,23 @@ examples: stacked-memories = /bits/ 64 <0x10000000 0x10000000>; }; }; + + - | + #include <dt-bindings/gpio/gpio.h> + + 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 = "lg,lg4573"; + spi-max-frequency = <1000000>; + reg = <0>; + spi-cs-high; + }; + }; |