From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753883AbYGCBEA (ORCPT ); Wed, 2 Jul 2008 21:04:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753458AbYGCBDN (ORCPT ); Wed, 2 Jul 2008 21:03:13 -0400 Received: from wf-out-1314.google.com ([209.85.200.170]:60541 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753358AbYGCBDM (ORCPT ); Wed, 2 Jul 2008 21:03:12 -0400 From: Grant Likely Subject: [PATCH v2 3/5] of-bindings: Add binding documentation for SPI busses and devices To: linuxppc-dev@ozlabs.org, spi-devel-general@lists.sourceforge.net, linux-kernel@vger.kernel.org Cc: fabrizio.garetto@gmail.com, jonsmirl@gmail.com, david-b@pacbell.net Date: Wed, 02 Jul 2008 19:03:08 -0600 Message-ID: <20080703010308.26187.23037.stgit@trillian.secretlab.ca> In-Reply-To: <20080703005749.26187.71719.stgit@trillian.secretlab.ca> References: <20080703005749.26187.71719.stgit@trillian.secretlab.ca> User-Agent: StGIT/0.13 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Grant Likely Add documentation about how to describe SPI busses in the device tree. Signed-off-by: Grant Likely --- Documentation/powerpc/booting-without-of.txt | 60 ++++++++++++++++++++++++++ 1 files changed, 60 insertions(+), 0 deletions(-) diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt index 1d2a772..7d3564f 100644 --- a/Documentation/powerpc/booting-without-of.txt +++ b/Documentation/powerpc/booting-without-of.txt @@ -58,6 +58,7 @@ Table of Contents o) Xilinx IP cores p) Freescale Synchronous Serial Interface q) USB EHCI controllers + t) SPI busses VII - Marvell Discovery mv64[345]6x System Controller chips 1) The /system-controller node @@ -2870,6 +2871,65 @@ platforms are moved over to use the flattened-device-tree model. reg = <0xe8000000 32>; }; + t) 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 - (required) 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. + + SPI example for an MPC5200 SPI bus: + spi@f00 { + #address-cells = <1>; + #size-cells = <0>; + compatible = "fsl,mpc5200b-spi","fsl,mpc5200-spi"; + reg = <0xf00 0x20>; + interrupts = <2 13 0 2 14 0>; + interrupt-parent = <&mpc5200_pic>; + + ethernet-switch@0 { + compatible = "micrel,ks8995m"; + linux,modalias = "ks8995"; + max-speed = <1000000>; + reg = <0>; + }; + + codec@1 { + compatible = "ti,tlv320aic26"; + max-speed = <100000>; + reg = <1>; + }; + }; + + VII - Marvell Discovery mv64[345]6x System Controller chips ===========================================================