mirror of
https://github.com/torvalds/linux.git
synced 2024-11-19 18:41:48 +00:00
1ada32ede9
These two properties were not documented but used in the spi dts. Add the related documentation. Suggested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Andi Shyti <andi.shyti@samsung.com> Reviewed-by: Michael Turquette <mturquette@baylibre.com> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Mark Brown <broonie@kernel.org>
123 lines
3.6 KiB
Plaintext
123 lines
3.6 KiB
Plaintext
* Samsung SPI Controller
|
|
|
|
The Samsung SPI controller is used to interface with various devices such as flash
|
|
and display controllers using the SPI communication interface.
|
|
|
|
Required SoC Specific Properties:
|
|
|
|
- compatible: should be one of the following.
|
|
- samsung,s3c2443-spi: for s3c2443, s3c2416 and s3c2450 platforms
|
|
- samsung,s3c6410-spi: for s3c6410 platforms
|
|
- samsung,s5pv210-spi: for s5pv210 and s5pc110 platforms
|
|
- samsung,exynos5433-spi: for exynos5433 compatible controllers
|
|
- samsung,exynos7-spi: for exynos7 platforms <DEPRECATED>
|
|
|
|
- reg: physical base address of the controller and length of memory mapped
|
|
region.
|
|
|
|
- interrupts: The interrupt number to the cpu. The interrupt specifier format
|
|
depends on the interrupt controller.
|
|
|
|
- dmas : Two or more DMA channel specifiers following the convention outlined
|
|
in bindings/dma/dma.txt
|
|
|
|
- dma-names: Names for the dma channels. There must be at least one channel
|
|
named "tx" for transmit and named "rx" for receive.
|
|
|
|
- clocks: specifies the clock IDs provided to the SPI controller; they are
|
|
required for interacting with the controller itself, for synchronizing the bus
|
|
and as I/O clock (the latter is required by exynos5433 and exynos7).
|
|
|
|
- clock-names: string names of the clocks in the 'clocks' property; for all the
|
|
the devices the names must be "spi", "spi_busclkN" (where N is determined by
|
|
"samsung,spi-src-clk"), while Exynos5433 should specify a third clock
|
|
"spi_ioclk" for the I/O clock.
|
|
|
|
Required Board Specific Properties:
|
|
|
|
- #address-cells: should be 1.
|
|
- #size-cells: should be 0.
|
|
|
|
Optional Board Specific Properties:
|
|
|
|
- samsung,spi-src-clk: If the spi controller includes a internal clock mux to
|
|
select the clock source for the spi bus clock, this property can be used to
|
|
indicate the clock to be used for driving the spi bus clock. If not specified,
|
|
the clock number 0 is used as default.
|
|
|
|
- num-cs: Specifies the number of chip select lines supported. If
|
|
not specified, the default number of chip select lines is set to 1.
|
|
|
|
- cs-gpios: should specify GPIOs used for chipselects (see spi-bus.txt)
|
|
|
|
- no-cs-readback: the CS line is disconnected, therefore the device should not
|
|
operate based on CS signalling.
|
|
|
|
SPI Controller specific data in SPI slave nodes:
|
|
|
|
- The spi slave nodes should provide the following information which is required
|
|
by the spi controller.
|
|
|
|
- samsung,spi-feedback-delay: The sampling phase shift to be applied on the
|
|
miso line (to account for any lag in the miso line). The following are the
|
|
valid values.
|
|
|
|
- 0: No phase shift.
|
|
- 1: 90 degree phase shift sampling.
|
|
- 2: 180 degree phase shift sampling.
|
|
- 3: 270 degree phase shift sampling.
|
|
|
|
Aliases:
|
|
|
|
- All the SPI controller nodes should be represented in the aliases node using
|
|
the following format 'spi{n}' where n is a unique number for the alias.
|
|
|
|
|
|
Example:
|
|
|
|
- SoC Specific Portion:
|
|
|
|
spi_0: spi@12d20000 {
|
|
compatible = "samsung,exynos4210-spi";
|
|
reg = <0x12d20000 0x100>;
|
|
interrupts = <0 66 0>;
|
|
dmas = <&pdma0 5
|
|
&pdma0 4>;
|
|
dma-names = "tx", "rx";
|
|
#address-cells = <1>;
|
|
#size-cells = <0>;
|
|
};
|
|
|
|
- Board Specific Portion:
|
|
|
|
spi_0: spi@12d20000 {
|
|
#address-cells = <1>;
|
|
#size-cells = <0>;
|
|
pinctrl-names = "default";
|
|
pinctrl-0 = <&spi0_bus>;
|
|
cs-gpios = <&gpa2 5 0>;
|
|
|
|
w25q80bw@0 {
|
|
#address-cells = <1>;
|
|
#size-cells = <1>;
|
|
compatible = "w25x80";
|
|
reg = <0>;
|
|
spi-max-frequency = <10000>;
|
|
|
|
controller-data {
|
|
samsung,spi-feedback-delay = <0>;
|
|
};
|
|
|
|
partition@0 {
|
|
label = "U-Boot";
|
|
reg = <0x0 0x40000>;
|
|
read-only;
|
|
};
|
|
|
|
partition@40000 {
|
|
label = "Kernel";
|
|
reg = <0x40000 0xc0000>;
|
|
};
|
|
};
|
|
};
|