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 X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 27816C282C7 for ; Sat, 26 Jan 2019 16:32:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E40DF21906 for ; Sat, 26 Jan 2019 16:32:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=norrbonn-se.20150623.gappssmtp.com header.i=@norrbonn-se.20150623.gappssmtp.com header.b="HkUUTddO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726251AbfAZQc1 (ORCPT ); Sat, 26 Jan 2019 11:32:27 -0500 Received: from mail-lf1-f65.google.com ([209.85.167.65]:37943 "EHLO mail-lf1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726075AbfAZQc0 (ORCPT ); Sat, 26 Jan 2019 11:32:26 -0500 Received: by mail-lf1-f65.google.com with SMTP id a8so9024023lfk.5 for ; Sat, 26 Jan 2019 08:32:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=norrbonn-se.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=kS5H/aXW8GuV+ml679sxzZ/9wuuF0lVRxh23dupYwdQ=; b=HkUUTddOVU9DoiJ6tr9HDAPjUavOUN1er30Nt0VEC0kDHOOUnOJxkUo/R9laKhoZxj 7FWS+MIk0ZCTrK3Tr3lI121wEIc/JvCDV4nr6iJTEwdnmSpTKSnrvHkPg6bi/rWI37kK VFPFnjls23m40ElKlrniGukTJLoIaT1pi+ayHjNpobC+Dt16KcT4T5aGGaWqgx9dfaiG RLDjcar2I94LJg1zgW2K3Dz8VO0xmaxd0Am+YBZ8F33ZRguZgzU7eYLJ9XBWFowCmEbc UsFAD00yLrO4P2sLNVKgVR6zBHrKbJ9/HrnuFSUGHaxEfZHoMRZdzTxjsLgdZzx8TOBr jNlw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=kS5H/aXW8GuV+ml679sxzZ/9wuuF0lVRxh23dupYwdQ=; b=gwmHF3NVllBnijNrJHPeZGxMnxVwUuDhoP4GWw7lB0CZRE/vB8D4qBaX0ruoiKA2R4 w+cKGl/+aPsiV5ZWdezMl+7yACYFgFqlfEYLuYl0wxRjzAGvCxwBuOykQXGKGfcFV2BK w+uUCx1RVfEbDESLDePpUqojrnX3vxVVU/EbsWgPofnEzGcQ9kagImsWk13AbAjy9xiO WLgw86WqDq7kFRQ3WCUBth7CwobhobnccCxTaKkiiKl+G9p3BMMhOe6UKNq7gUqv9ZW/ iRav7a6ucm/YBDbGEyVh0r1EnUFGQaAXDCW9vQ7GKnVNnKZ3c9vMGgb2WjPgMHxTopnK EBVQ== X-Gm-Message-State: AJcUukdD4gvCgPbD2rL0Nz5eBrtBR6aKj60phEE9NdtQTnKHoadDto3b rfntNG7PMHoaqOLEWhUYl7nxc9mZHXM= X-Google-Smtp-Source: ALg8bN7auManVNcXvNC0adk6cLwS53omYHeXvQ3IKRI+5FPlGLjNBN/V6magOWSC8fouvtvyYSImCA== X-Received: by 2002:ac2:5599:: with SMTP id v25mr12652916lfg.169.1548520344420; Sat, 26 Jan 2019 08:32:24 -0800 (PST) Received: from mimer.lan (h-29-16.A159.priv.bahnhof.se. [79.136.29.16]) by smtp.gmail.com with ESMTPSA id e94sm2170532lfi.23.2019.01.26.08.32.23 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 26 Jan 2019 08:32:23 -0800 (PST) From: Jonas Bonn To: linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org Cc: Jonas Bonn Subject: [PATCH v3 0/2] spi: support inter-word delays Date: Sat, 26 Jan 2019 17:32:18 +0100 Message-Id: <20190126163220.26421-1-jonas@norrbonn.se> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Changed in v3: * Drop setting of inter-word delay via device tree Changed in v2: * Fix atmel-spi driver to not unconditionally set minimal delay if no delay is required (erroneous clamping) This short series adds support for SPI inter-word delays and configures the spi-atmel driver to honour the setting. Some SPI slaves are so slow that they are unable to keep up even at the SPI controller's lowest available clock frequency. I have such a configuration where an AVR-based SPI slave is unable to feed the SPI bus fast enough even the SPI master runs at the lowest possible clock speed. Jonas Bonn (2): spi: support inter-word delay requirement for devices spi-atmel: support inter-word delay drivers/spi/spi-atmel.c | 18 +++++++++++++----- include/linux/spi/spi.h | 3 +++ 2 files changed, 16 insertions(+), 5 deletions(-) -- 2.19.1