diff options
Diffstat (limited to 'doc/device-tree-bindings')
-rw-r--r-- | doc/device-tree-bindings/mtd/spi/spi-flash.txt | 25 | ||||
-rw-r--r-- | doc/device-tree-bindings/spi/soft-spi.txt | 34 |
2 files changed, 59 insertions, 0 deletions
diff --git a/doc/device-tree-bindings/mtd/spi/spi-flash.txt b/doc/device-tree-bindings/mtd/spi/spi-flash.txt new file mode 100644 index 0000000..85522d8 --- /dev/null +++ b/doc/device-tree-bindings/mtd/spi/spi-flash.txt @@ -0,0 +1,25 @@ +* MTD SPI driver for serial flash chips + +Required properties: +- #address-cells, #size-cells : Must be present if the device has sub-nodes + representing partitions. +- compatible : Should be the manufacturer and the name of the chip. Bear in + mind that the DT binding is not U-Boot-only, but in case of + U-Boot, see spi_flash_params_table table in + drivers/mtd/spi/sf_params.c for the list of supported chips. +- reg : Chip-Select number +- spi-max-frequency : Maximum frequency of the SPI bus the chip can operate at + +Optional properties: + - memory-map : Address and size of the flash, if memory mapped. This may + apply to Intel chipsets, which tend to memory-map flash. + +Example: + + flash: m25p80@0 { + #address-cells = <1>; + #size-cells = <1>; + compatible = "spansion,m25p80"; + reg = <0>; + spi-max-frequency = <40000000>; + }; diff --git a/doc/device-tree-bindings/spi/soft-spi.txt b/doc/device-tree-bindings/spi/soft-spi.txt new file mode 100644 index 0000000..d09c1a5 --- /dev/null +++ b/doc/device-tree-bindings/spi/soft-spi.txt @@ -0,0 +1,34 @@ +Soft SPI + +The soft SPI bus implementation allows the use of GPIO pins to simulate a +SPI bus. No SPI host is required for this to work. The down-side is that the +performance will typically be much lower than a real SPI bus. + +The soft SPI node requires the following properties: + +compatible: "u-boot,soft-spi" +soft_spi_cs: GPIO number to use for SPI chip select (output) +soft_spi_sclk: GPIO number to use for SPI clock (output) +soft_spi_mosi: GPIO number to use for SPI MOSI line (output) +soft_spi_miso GPIO number to use for SPI MISO line (input) +spi-delay-us: Number of microseconds of delay between each CS transition + +The GPIOs should be specified as required by the GPIO controller referenced. +The first cell holds the phandle of the controller and the second cell +typically holds the GPIO number. + + +Example: + + soft-spi { + compatible = "u-boot,soft-spi"; + cs-gpio = <&gpio 235 0>; /* Y43 */ + sclk-gpio = <&gpio 225 0>; /* Y31 */ + mosi-gpio = <&gpio 227 0>; /* Y33 */ + miso-gpio = <&gpio 224 0>; /* Y30 */ + spi-delay-us = <1>; + #address-cells = <1>; + #size-cells = <0>; + cs@0 { + }; + }; |