Re: [PATCH 3/4] spi: Add OF binding support for SPI busses

Randy Dunlap
2008-05-16T20:49:06Z

On Fri, 16 May 2008 13:36:13 -0600 Grant Likely wrote:

> diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt
> index 1d2a772..452c242 100644
> --- a/Documentation/powerpc/booting-without-of.txt
> +++ b/Documentation/powerpc/booting-without-of.txt
> @@ -2870,6 +2871,66 @@ platforms are moved over to use the flattened-device-tree model.
> reg = <0xe8000000 32>;
> };
>
> + s) SPI (Serial Peripheral Interface) busses
> +
> + SPI busses can be described with a node for the SPI master device
> + and a set of child nodes for each SPI slave on the bus. For this
> + discussion, it is assumed that the system's SPI controller is in
> + SPI master mode. This binding does not describe SPI controllers
> + in slave mode.
> +
> + The SPI master node requires the following properties:
> + - #address-cells - number of cells required to define a chip select
> + address on the SPI bus.
> + - #size-cells - should be zero.
> + - compatible - name of SPI bus controller following generic names
> + recommended practice.
> + No other properties are required in the spi bus node. It is assumed
~~~

> + that a driver for an SPI bus device will understand that it is an SPI bus.
> + However, the binding does not attempt to define the specific method for
> + assigning chip select numbers. Since SPI chip select configuration is
> + flexible and non-standardized, it is left out of this binding with the
> + assumption that board specific platform code will be used to manage
> + chip selects. Individual drivers can define additional properties to
> + support describing the chip select layout.
> +
> + SPI slave nodes must be children of the spi master node and can
~~~

> + contain the following properties.
> + - reg - (required) chip select address of device.
> + - compatible - (required) name of SPI device following generic names
> + recommended practice
> + - max-speed - (optional) Maximum SPI clocking speed of device in Hz
> + - spi,cpol - (optional) Device requires inverse clock polarity
> + - spi,cpha - (optional) Device requires shifted clock phase
> + - linux,modalias - (optional, Linux specific) Force binding of SPI device
> + to a particular spi_device driver. Useful for changing
> + driver binding between spidev and a kernel spi driver.
~~~

Hi,
You mostly capitalize "SPI" in sentences (i.e., when it's not part of
a function name or OF data), so could the 3 underlined instances of it
also be all caps?

Thanks,
---
~Randy