From patchwork Thu May 4 17:45:46 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 9712393 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 61E316020B for ; Thu, 4 May 2017 17:46:12 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 591B128698 for ; Thu, 4 May 2017 17:46:12 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4AEBF2869C; Thu, 4 May 2017 17:46:12 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 109CB28687 for ; Thu, 4 May 2017 17:46:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755604AbdEDRqJ (ORCPT ); Thu, 4 May 2017 13:46:09 -0400 Received: from laurent.telenet-ops.be ([195.130.137.89]:58154 "EHLO laurent.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752845AbdEDRqF (ORCPT ); Thu, 4 May 2017 13:46:05 -0400 Received: from ayla.of.borg ([84.193.137.253]) by laurent.telenet-ops.be with bizsmtp id GHm01v00G5UCtCs01Hm0At; Thu, 04 May 2017 19:46:04 +0200 Received: from ramsan.of.borg ([192.168.97.29] helo=ramsan) by ayla.of.borg with esmtp (Exim 4.86_2) (envelope-from ) id 1d6KpE-00061b-2W; Thu, 04 May 2017 19:46:00 +0200 Received: from geert by ramsan with local (Exim 4.86_2) (envelope-from ) id 1d6KpE-0008NK-1B; Thu, 04 May 2017 19:46:00 +0200 From: Geert Uytterhoeven To: Mark Brown , Rob Herring , Mark Rutland Cc: Magnus Damm , Wolfram Sang , Hiromitsu Yamasaki , Jiada Wang , Matt Porter , linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v3 1/6] spi: Document DT bindings for SPI controllers in slave mode Date: Thu, 4 May 2017 19:45:46 +0200 Message-Id: <1493919951-32122-2-git-send-email-geert+renesas@glider.be> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1493919951-32122-1-git-send-email-geert+renesas@glider.be> References: <1493919951-32122-1-git-send-email-geert+renesas@glider.be> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Signed-off-by: Geert Uytterhoeven Reviewed-by: Rob Herring --- v3: - In SPI slave mode, represent the (single) slave device again as a child of the controller node, which is now optional, and must be named "slave" if present, - Split slave node properties in master mode, slave mode, and common properties, v2: - Do not create a child node in SPI slave mode. Instead, add an "spi-slave" property, and put the mode properties in the controller node. --- Documentation/devicetree/bindings/spi/spi-bus.txt | 76 ++++++++++++++--------- 1 file changed, 45 insertions(+), 31 deletions(-) diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt index 4b1d6e74c744fe96..1f6e86f787efd229 100644 --- a/Documentation/devicetree/bindings/spi/spi-bus.txt +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt @@ -1,17 +1,23 @@ 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. +SPI busses can be described with a node for the SPI controller device +and a set of child nodes for each SPI slave on the bus. The system's SPI +controller may be described for use in SPI master mode or in SPI slave mode, +but not for both at the same time. -The SPI master node requires the following properties: +The SPI controller node requires the following properties: +- compatible - Name of SPI bus controller following generic names + recommended practice. + +In master mode, the SPI controller node requires the following additional +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. + +In slave mode, the SPI controller node requires one additional property: +- spi-slave - Empty property. + 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 @@ -21,7 +27,7 @@ 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. -Optional properties: +Optional properties (master mode only): - cs-gpios - gpios chip select. - num-cs - total number of chipselects. @@ -41,28 +47,36 @@ cs1 : native cs2 : &gpio1 1 0 cs3 : &gpio1 2 0 -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. -- spi-max-frequency - (required) Maximum SPI clocking speed of device in Hz. -- spi-cpol - (optional) Empty property indicating device requires - inverse clock polarity (CPOL) mode. -- spi-cpha - (optional) Empty property indicating device requires - shifted clock phase (CPHA) mode. -- spi-cs-high - (optional) Empty property indicating device requires - chip select active high. -- spi-3wire - (optional) Empty property indicating device requires - 3-wire mode. -- spi-lsb-first - (optional) Empty property indicating device requires - LSB first mode. -- spi-tx-bus-width - (optional) The bus width (number of data wires) that is - used for MOSI. Defaults to 1 if not present. -- spi-rx-bus-width - (optional) The bus width (number of data wires) that is - used for MISO. Defaults to 1 if not present. -- spi-rx-delay-us - (optional) Microsecond delay after a read transfer. -- spi-tx-delay-us - (optional) Microsecond delay after a write transfer. + +SPI slave nodes must be children of the SPI controller node. + +In master mode, one or more slave nodes (up to the number of chip selects) can +be present. Required properties are: +- compatible - Name of SPI device following generic names recommended + practice. +- reg - Chip select address of device. +- spi-max-frequency - Maximum SPI clocking speed of device in Hz. + +In slave mode, the (single) slave node is optional. +If present, it must be called "slave". Required properties are: +- compatible - Name of SPI device following generic names recommended + practice. + +All slave nodes can contain the following optional properties: +- spi-cpol - Empty property indicating device requires inverse clock + polarity (CPOL) mode. +- spi-cpha - Empty property indicating device requires shifted clock + phase (CPHA) mode. +- spi-cs-high - Empty property indicating device requires chip select + active high. +- spi-3wire - Empty property indicating device requires 3-wire mode. +- spi-lsb-first - Empty property indicating device requires LSB first mode. +- spi-tx-bus-width - The bus width (number of data wires) that is used for MOSI. + Defaults to 1 if not present. +- spi-rx-bus-width - The bus width (number of data wires) that is used for MISO. + Defaults to 1 if not present. +- spi-rx-delay-us - Microsecond delay after a read transfer. +- spi-tx-delay-us - Microsecond delay after a write transfer. Some SPI controllers and devices support Dual and Quad SPI transfer mode. It allows data in the SPI system to be transferred using 2 wires (DUAL) or 4