Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755295AbbGPP1v (ORCPT ); Thu, 16 Jul 2015 11:27:51 -0400 Received: from eusmtp01.atmel.com ([212.144.249.243]:20589 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754545AbbGPP1t (ORCPT ); Thu, 16 Jul 2015 11:27:49 -0400 From: Cyrille Pitchen To: , , , , , , , , , , CC: , , , , , , , , , Cyrille Pitchen Subject: [PATCH 4/7] Documentation: mtd: add a DT property to set the latency code of Spansion memory Date: Thu, 16 Jul 2015 17:27:51 +0200 Message-ID: <398ca9f17bda638e05e97f258fb4e6d27ac828db.1437059658.git.cyrille.pitchen@atmel.com> X-Mailer: git-send-email 1.8.2.2 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2098 Lines: 50 Both the SPI controller and the NOR flash memory need to agree on the number of dummy cycles to use for Fast Read commands. For Spansion memories, this number of dummy cycles is not given directly but through a so called "latency code". The latency code can be found into the memory datasheet and depends on the SPI clock frequency, the Fast Read op code and the Single/Dual Data Rate mode. Signed-off-by: Cyrille Pitchen --- .../devicetree/bindings/mtd/spansion-nor.txt | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 Documentation/devicetree/bindings/mtd/spansion-nor.txt diff --git a/Documentation/devicetree/bindings/mtd/spansion-nor.txt b/Documentation/devicetree/bindings/mtd/spansion-nor.txt new file mode 100644 index 000000000000..a55c62db0e6f --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/spansion-nor.txt @@ -0,0 +1,22 @@ +* Spansion NOR flash + +Optional properties: +- spansion,latency-code : Only used when the "m25p,num-dummy-cycles" property is + set. The Spansion latency code tells the NOR flash + memory the number of dummy cycles to expect for each + Fast Read command. The value to be used is provided by + tables in the memory datasheet and depends on the SPI + clock frequency and on the Single/Dual Data Rate mode. + Then the value of "m25p,num-dummy-cycles" property + should match the (Fast) Read command to be used for + the chosen latency code. + +Example: + + m25p80@0 { + compatible = "spansion,s25fl512s"; + reg = <0>; + spi-max-frequency = <104000000>; + m25p,num-dummy-cycles = <8>; + spansion,latency-code = <2>; + }; -- 1.8.2.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/