From patchwork Mon Jul 27 08:59:41 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cyrille Pitchen X-Patchwork-Id: 500251 Return-Path: X-Original-To: incoming-dt@patchwork.ozlabs.org Delivered-To: patchwork-incoming-dt@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 0AFF014030D for ; Mon, 27 Jul 2015 19:00:20 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752508AbbG0JAS (ORCPT ); Mon, 27 Jul 2015 05:00:18 -0400 Received: from eusmtp01.atmel.com ([212.144.249.243]:36908 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752296AbbG0JAR (ORCPT ); Mon, 27 Jul 2015 05:00:17 -0400 Received: from tenerife.corp.atmel.com (10.161.101.13) by eusmtp01.atmel.com (10.161.101.31) with Microsoft SMTP Server id 14.3.235.1; Mon, 27 Jul 2015 11:00:14 +0200 From: Cyrille Pitchen To: , , , , , , , , , , CC: , , , , , , , , , Cyrille Pitchen Subject: [PATCH v3 2/5] Documentation: mtd: add a DT property to set the number of dummy cycles Date: Mon, 27 Jul 2015 10:59:41 +0200 Message-ID: <0740cb2056acc38a235045b211da8ece71b1a6f1.1437986785.git.cyrille.pitchen@atmel.com> X-Mailer: git-send-email 1.8.2.2 In-Reply-To: References: MIME-Version: 1.0 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Depending on the SPI clock frequency, the Fast Read op code and the Single/Dual Data Rate mode, the number of dummy cycles can be tuned to improve transfer speed. The actual number of dummy cycles is specific for each memory model and is provided by the manufacturer thanks to the memory datasheet. Signed-off-by: Cyrille Pitchen --- Documentation/devicetree/bindings/mtd/jedec,spi-nor.txt | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.txt b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.txt index 2bee68103b01..4387567d8024 100644 --- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.txt +++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.txt @@ -19,6 +19,11 @@ Optional properties: all chips and support for it can not be detected at runtime. Refer to your chips' datasheet to check if this is supported by your chip. +- m25p,num-dummy-cycles : Set the number of dummy cycles for Fast Read commands. + Depending on the manufacturer additional dedicated + commands are sent to the flash memory so the + controller and the memory can agree on the number of + dummy cycles to use. Example: @@ -29,4 +34,5 @@ Example: reg = <0>; spi-max-frequency = <40000000>; m25p,fast-read; + m25p,num-dummy-cycles = <8>; };