Commit 82a29bf9 authored by Amelie Delaunay's avatar Amelie Delaunay Committed by Mark Brown

spi: Document the STM32 SPI bindings

This patch adds the documentation of device tree bindings
for the STM32 SPI controller.
Signed-off-by: default avatarAmelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 2ea659a9
STMicroelectronics STM32 SPI Controller
The STM32 SPI controller is used to communicate with external devices using
the Serial Peripheral Interface. It supports full-duplex, half-duplex and
simplex synchronous serial communication with external devices. It supports
from 4 to 32-bit data size. Although it can be configured as master or slave,
only master is supported by the driver.
Required properties:
- compatible: Must be "st,stm32-spi".
- reg: Offset and length of the device's register set.
- interrupts: Must contain the interrupt id.
- clocks: Must contain an entry for spiclk (which feeds the internal clock
generator).
- #address-cells: Number of cells required to define a chip select address.
- #size-cells: Should be zero.
Optional properties:
- resets: Must contain the phandle to the reset controller.
- A pinctrl state named "default" may be defined to set pins in mode of
operation for SPI transfer.
- dmas: DMA specifiers for tx and rx dma. DMA fifo mode must be used. See the
STM32 DMA bindings, Documentation/devicetree/bindings/dma/stm32-dma.txt.
- dma-names: DMA request names should include "tx" and "rx" if present.
- cs-gpios: list of GPIO chip selects. See the SPI bus bindings,
Documentation/devicetree/bindings/spi/spi-bus.txt
Child nodes represent devices on the SPI bus
See ../spi/spi-bus.txt
Optional properties:
- st,spi-midi-ns: (Master Inter-Data Idleness) minimum time delay in
nanoseconds inserted between two consecutive data frames.
Example:
spi2: spi@40003800 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "st,stm32-spi";
reg = <0x40003800 0x400>;
interrupts = <36>;
clocks = <&rcc SPI2_CK>;
resets = <&rcc 1166>;
dmas = <&dmamux1 0 39 0x400 0x01>,
<&dmamux1 1 40 0x400 0x01>;
dma-names = "rx", "tx";
pinctrl-0 = <&spi2_pins_b>;
pinctrl-names = "default";
status = "okay";
cs-gpios = <&gpioa 11 0>;
spidev@0 {
compatible = "spidev";
reg = <0>;
spi-max-frequency = <4000000>;
st,spi-midi = <4000>;
};
};
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