Davinci SPI controller device bindings
Links on DM:
Keystone 2 -
https://www.ti.com/lit/ug/sprugp2a/sprugp2a.pdf
dm644x -
https://www.ti.com/lit/ug/sprue32a/sprue32a.pdf
OMAP-L138/da830 -
http://www.ti.com/lit/ug/spruh77a/spruh77a.pdf
Required properties:
- #address-cells: number of cells required to define a chip select
address on the SPI bus. Should be set to 1.
- #size-cells: should be zero.
- compatible:
- "ti,dm6441-spi" for SPI used similar to that on DM644x SoC family
- "ti,da830-spi" for SPI used similar to that on DA8xx SoC family
- "ti,keystone-spi" for SPI used similar to that on Keystone2 SoC
family
- reg: Offset and length of SPI controller register space
- num-cs: Number of chip selects. This includes internal as well as
GPIO chip selects.
- ti,davinci-spi-intr-line: interrupt line used to connect the SPI
IP to the interrupt controller within the SoC. Possible values
are 0 and 1. Manual says one of the two possible interrupt
lines can be tied to the interrupt controller. Set this
based on a specific SoC configuration.
- interrupts: interrupt number mapped to CPU.
- clocks: spi clk phandle
For 66AK2G this property should be set per binding,
Documentation/devicetree/bindings/clock/ti,sci-clk.yaml
SoC-specific Required Properties:
The following are mandatory properties for Keystone 2 66AK2G SoCs only:
- power-domains: Should contain a phandle to a PM domain provider node
and an args specifier containing the SPI device id
value. This property is as per the binding,
Optional:
- cs-gpios: gpio chip selects
For example to have 3 internal CS and 2 GPIO CS, user could define
cs-gpios = <0>, <0>, <0>, <&gpio1 30 0>, <&gpio1 31 0>;
where first three are internal CS and last two are GPIO CS.
Optional properties for slave devices:
SPI slave nodes can contain the following properties.
Not all SPI Peripherals from Texas Instruments support this.
Please check SPI peripheral documentation for a device before using these.
- ti,spi-wdelay : delay between transmission of words
(SPIFMTn.WDELAY, SPIDAT1.WDEL) must be specified in number of SPI module
clock periods.
delay = WDELAY * SPI_module_clock_period + 2 * SPI_module_clock_period
Below is timing diagram which shows functional meaning of
"ti,spi-wdelay" parameter.
+-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+
SPI_CLK | | | | | | | | | | | | | | | |
+----------+ +-+ +-+ +-+ +-+ +---------------------------+ +-+ +-+ +-
SPI_SOMI/SIMO+-----------------+ +-----------
+----------+ word1 +---------------------------+word2
+-----------------+ +-----------
WDELAY
<-------------------------->
Example of a NOR flash slave device (n25q032) connected to DaVinci
SPI controller device over the SPI bus.
spi0:spi@20bf0000 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "ti,dm6446-spi";
reg = <0x20BF0000 0x1000>;
num-cs = <4>;
ti,davinci-spi-intr-line = <0>;
interrupts = <338>;
clocks = <&clkspi>;
flash: flash@0 {
#address-cells = <1>;
#size-cells = <1>;
compatible = "st,m25p32";
spi-max-frequency = <25000000>;
reg = <0>;
ti,spi-wdelay = <8>;
partition@0 {
label = "u-boot-spl";
reg = <0x0 0x80000>;
read-only;
};
partition@1 {
label = "test";
reg = <0x80000 0x380000>;
};
};
};
