From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6DBE2C4332F for ; Mon, 4 Oct 2021 11:15:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5309D61381 for ; Mon, 4 Oct 2021 11:15:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232727AbhJDLRb (ORCPT ); Mon, 4 Oct 2021 07:17:31 -0400 Received: from mx1.tq-group.com ([93.104.207.81]:27097 "EHLO mx1.tq-group.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232413AbhJDLR3 (ORCPT ); Mon, 4 Oct 2021 07:17:29 -0400 X-IronPort-AV: E=Sophos;i="5.85,345,1624312800"; d="scan'208";a="19847137" Received: from unknown (HELO tq-pgp-pr1.tq-net.de) ([192.168.6.15]) by mx1-pgp.tq-group.com with ESMTP; 04 Oct 2021 13:15:38 +0200 Received: from mx1.tq-group.com ([192.168.6.7]) by tq-pgp-pr1.tq-net.de (PGP Universal service); Mon, 04 Oct 2021 13:15:38 +0200 X-PGP-Universal: processed; by tq-pgp-pr1.tq-net.de on Mon, 04 Oct 2021 13:15:38 +0200 X-IronPort-AV: E=Sophos;i="5.85,345,1624312800"; d="scan'208";a="19847134" Received: from vtuxmail01.tq-net.de ([10.115.0.20]) by mx1.tq-group.com with ESMTP; 04 Oct 2021 13:15:38 +0200 Received: from steina-w.tq-net.de (unknown [10.123.49.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by vtuxmail01.tq-net.de (Postfix) with ESMTPSA id 4FE09280065; Mon, 4 Oct 2021 13:15:38 +0200 (CEST) From: Alexander Stein To: Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Rob Herring , Pratyush Yadav , Michael Walle , Tudor Ambarus Cc: Alexander Stein , linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] dt-bindings: mtd: spi-nor: Add output-driver-strength property Date: Mon, 4 Oct 2021 13:15:28 +0200 Message-Id: <20211004111529.211089-1-Alexander.Stein@tq-systems.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexander Stein This property is for optimizing output voltage impedance and is specific to each board. Signed-off-by: Alexander Stein --- I checked Micron and Macronix datasheets. Both have similar but not identical supported values. Also the register locations are different. For those reasons I decided to specify the Ohms value directly and let the device specfic driver figure out if it is supported where to write it to. BTW: Are the Ohm values and the corresponding register bits standardized somewhere? Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml index ed590d7c6e37..7d7f20a741b5 100644 --- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml +++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml @@ -72,6 +72,12 @@ properties: be used on such systems, to denote the absence of a reliable reset mechanism. + output-driver-strength: + $ref: /schemas/types.yaml#/definitions/uint32 + description: + Output driver strength in Ohms which optimizes the impedance at Vcc/2 + output voltage. + label: true partitions: -- 2.25.1