From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Grant Likely" Subject: Re: [PATCH 3/4] spi: Add OF binding support for SPI busses Date: Fri, 16 May 2008 14:51:45 -0600 Message-ID: References: <20080516193054.28030.35126.stgit@trillian.secretlab.ca> <20080516193613.28030.13950.stgit@trillian.secretlab.ca> <20080516134720.22d0569b.randy.dunlap@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linuxppc-dev@ozlabs.org, spi-devel-general@lists.sourceforge.net, linux-kernel@vger.kernel.org, dbrownell@users.sourceforge.net, fabrizio.garetto@gmail.com, jonsmirl@gmail.com To: "Randy Dunlap" Return-path: In-Reply-To: <20080516134720.22d0569b.randy.dunlap@oracle.com> Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org On Fri, May 16, 2008 at 2:47 PM, Randy Dunlap wrote: > 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? No problem. Cheers, g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd.