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=-7.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS 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 8CB5FC282C0 for ; Fri, 25 Jan 2019 11:47:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5273E218F0 for ; Fri, 25 Jan 2019 11:47:22 +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="yKYWZX9o" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728238AbfAYLrU (ORCPT ); Fri, 25 Jan 2019 06:47:20 -0500 Received: from mail-lj1-f196.google.com ([209.85.208.196]:33514 "EHLO mail-lj1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726252AbfAYLrT (ORCPT ); Fri, 25 Jan 2019 06:47:19 -0500 Received: by mail-lj1-f196.google.com with SMTP id v1-v6so8156753ljd.0 for ; Fri, 25 Jan 2019 03:47:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=norrbonn-se.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=C31nlWpUsUu8j1iiazgCD439xBD7EbLuX36kiR/KNSI=; b=yKYWZX9oCKoMT2Fi/l3X1JV0wUphRDT2IxMzR7Wai8+fciGvOYKSaHLAVLUOkf9i8k +IOenP2MM0HMxoDWO1eyDwfybr44T5xVoWm9gczZDqyEoIIP1CnhylynJ4XKtnCrUpiB qdl7gQMAJCjBaSpDeZPn6gzZIonSYqworKlmxx7KZmKsCeByGwFFs/mVfWgMuiVjxnb/ UbbfZEX9yPx+2g5paDNDpQE1MtSWi26oMYcZd70vXS6MNBXzNXAB9W+C+DEeXgXdywg7 AEwH2VrWjT++EIY1hVl84fHsJmnAcyPP4+ecljFz0dQ3XMfSWVObLt5Q/4lUV6bnDj0X aMTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=C31nlWpUsUu8j1iiazgCD439xBD7EbLuX36kiR/KNSI=; b=OVB5NDDvW7Dw9gLzFidzokqSFIouwBwx/0BYmtjByvt8gJ9HqmIpM8FW29hASL40Ny 8nQ9dIEv26T3tmQuWcaShheTawxqlQjMpN905bt/9uPIR4NuTnkhbObFls9xxjMKg6xk RPK0ITcLAzJnqp11+KMG/pWCBkbEJOpiGIC1BQBSPmLM/gVjJw6EVK/lJlTl9RHJv8ha QKhdqMPTmkE5rhAfVoLTdtmBRCfAXwK4nUbWV2xDJjohGbr6AyyeSQ/2cYoYeaIpDvVQ cYKCMr98mufFg6qzd7APhSTmSaCNyO02HxzHtDpo1KLNuBYUt4nC+XJPYMaOiayn8Jvy MWnw== X-Gm-Message-State: AJcUukcyJURJwqSZ+YChLmzOHKmqS4N1T+R+Un/Sx9dD59ilMM/ehkqK gRxaVqJ4gVGkdGstCTu9VwEBwg== X-Google-Smtp-Source: ALg8bN57MEamk9wYy/GwFOX0tGuq2r4wbYBsROXpUqSD+7w1rimZDMdBR2dqSjH9QFH/sO/BXcq4xw== X-Received: by 2002:a2e:58b:: with SMTP id 133-v6mr8263289ljf.127.1548416837534; Fri, 25 Jan 2019 03:47:17 -0800 (PST) Received: from [192.168.1.169] (h-29-16.A159.priv.bahnhof.se. [79.136.29.16]) by smtp.gmail.com with ESMTPSA id 15-v6sm1611419lje.18.2019.01.25.03.47.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 25 Jan 2019 03:47:17 -0800 (PST) Subject: Re: [PATCH 2/2] spi-atmel: support inter-word delay To: linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org Cc: Nicolas Ferre , Mark Brown , Alexandre Belloni , Ludovic Desroches , linux-arm-kernel@lists.infradead.org References: <20190125114429.20066-1-jonas@norrbonn.se> <20190125114429.20066-3-jonas@norrbonn.se> From: Jonas Bonn Message-ID: <296f8326-a33d-8db1-ca71-c6aba21b1302@norrbonn.se> Date: Fri, 25 Jan 2019 12:47:15 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190125114429.20066-3-jonas@norrbonn.se> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25/01/2019 12:44, Jonas Bonn wrote: > If the SPI slave requires an inter-word delay, configure the DLYBCT > register accordingly. > > Tested on a SAMA5D2 board (derived from SAMA5D2-Xplained reference > board). > > Signed-off-by: Jonas Bonn > CC: Nicolas Ferre > CC: Mark Brown > CC: Alexandre Belloni > CC: Ludovic Desroches > CC: linux-spi@vger.kernel.org > CC: linux-arm-kernel@lists.infradead.org > --- > drivers/spi/spi-atmel.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c > index 74fddcd3282b..88ff3fef56e9 100644 > --- a/drivers/spi/spi-atmel.c > +++ b/drivers/spi/spi-atmel.c > @@ -1209,13 +1209,14 @@ static int atmel_spi_setup(struct spi_device *spi) > csr |= SPI_BIT(CSAAT); > > /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs. > - * > - * DLYBCT would add delays between words, slowing down transfers. > - * It could potentially be useful to cope with DMA bottlenecks, but > - * in those cases it's probably best to just use a lower bitrate. > */ > csr |= SPI_BF(DLYBS, 0); > - csr |= SPI_BF(DLYBCT, 0); > + > + /* DLYBCT adds delays between words. This is useful for slow devices > + * that need a bit of time to setup the next transfer. > + */ > + csr |= SPI_BF(DLYBCT, > + clamp_t(u8, (as->spi_clk/1000000*spi->word_delay)>>5, 1, 255)); Ah... this is stupid. The clamping here _always_ introduces a delay, which is not what we want... will resubmit this. /Jonas > > /* chipselect must have been muxed as GPIO (e.g. in board setup) */ > npcs_pin = (unsigned long)spi->controller_data; > 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=-8.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS 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 1E0F4C282C6 for ; Fri, 25 Jan 2019 11:47:24 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E0DCC218E2 for ; Fri, 25 Jan 2019 11:47:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="UIsU2NZI"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=norrbonn-se.20150623.gappssmtp.com header.i=@norrbonn-se.20150623.gappssmtp.com header.b="yKYWZX9o" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E0DCC218E2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=norrbonn.se Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=j/CdSv0icZthszhupODysGocCYVu9WS9VeQDqQC66fY=; b=UIsU2NZI/blFItfvDctTYk7ST GWBEl3iOyk2Qz+pe+7yn6EDWraakFYxWY+G6yZrsU0L8IxNhcsN1KlSn7wU83JotdOyj0vu4gEvgf 1jShEge49kD+7kmd79vDICY2P2JQTmHrH9cveFeslc5ZZagS98McWIDr5wQJdb+kM4yUill4i66+D ZCbhdbXksMn+86LpZTQl81Avcwp5uxqBfEYxRfDNBWXgXzeCA2s0xtyNXUfVesKhKhvAhfIg1phpR m3wCV+OluhM+YLWmT26+xOIlxNwS45qXtCu1fQfXK3M0m+43oh89oUVJDIwxSRtBk1iaHQ13FAp8H o+5uBCDJA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gmzxC-00016C-VY; Fri, 25 Jan 2019 11:47:22 +0000 Received: from mail-lj1-x244.google.com ([2a00:1450:4864:20::244]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gmzx9-00015r-SS for linux-arm-kernel@lists.infradead.org; Fri, 25 Jan 2019 11:47:21 +0000 Received: by mail-lj1-x244.google.com with SMTP id u89-v6so8165026lje.1 for ; Fri, 25 Jan 2019 03:47:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=norrbonn-se.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=C31nlWpUsUu8j1iiazgCD439xBD7EbLuX36kiR/KNSI=; b=yKYWZX9oCKoMT2Fi/l3X1JV0wUphRDT2IxMzR7Wai8+fciGvOYKSaHLAVLUOkf9i8k +IOenP2MM0HMxoDWO1eyDwfybr44T5xVoWm9gczZDqyEoIIP1CnhylynJ4XKtnCrUpiB qdl7gQMAJCjBaSpDeZPn6gzZIonSYqworKlmxx7KZmKsCeByGwFFs/mVfWgMuiVjxnb/ UbbfZEX9yPx+2g5paDNDpQE1MtSWi26oMYcZd70vXS6MNBXzNXAB9W+C+DEeXgXdywg7 AEwH2VrWjT++EIY1hVl84fHsJmnAcyPP4+ecljFz0dQ3XMfSWVObLt5Q/4lUV6bnDj0X aMTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=C31nlWpUsUu8j1iiazgCD439xBD7EbLuX36kiR/KNSI=; b=cE6hlFXvTfu5b22BxZQkCv0+TFY9TMx2Dmh4lKCJBiCUsNT6szi5lUIDmWxDSe5FVx 6RtmxJDc3XsNFxDYdSfuskV+1Cjdg5qn4sUgHGcI8bStTdA1cSVGRec/RPiFlx1LTYSE 9UItNpBbfDb9vgk8otwXO2DeYb9co7v8stu0s2CTVMArgDVcYddh0bbTf4nMabCJ37xa SkW+HUN4egfsa5c0j69JL3MoHQEHNNI/xF2uGcrZsgR2BPix232E9I8i5jiVESKbtIDw VHN6Pf/01itCXPq3oTo3GZp/+VdnZdGOJVlmF647zJIM//NF1AJbUQy6gUX302X3aMi4 Iaow== X-Gm-Message-State: AJcUukdtAUvhCKN+FDfmrftDwgF5qvtkBNLGtWykXntm9soTq+1/BCpl GPCeCS9cXSSRGiW1ujYNoQLvmIfZdXE= X-Google-Smtp-Source: ALg8bN57MEamk9wYy/GwFOX0tGuq2r4wbYBsROXpUqSD+7w1rimZDMdBR2dqSjH9QFH/sO/BXcq4xw== X-Received: by 2002:a2e:58b:: with SMTP id 133-v6mr8263289ljf.127.1548416837534; Fri, 25 Jan 2019 03:47:17 -0800 (PST) Received: from [192.168.1.169] (h-29-16.A159.priv.bahnhof.se. [79.136.29.16]) by smtp.gmail.com with ESMTPSA id 15-v6sm1611419lje.18.2019.01.25.03.47.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 25 Jan 2019 03:47:17 -0800 (PST) Subject: Re: [PATCH 2/2] spi-atmel: support inter-word delay To: linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org References: <20190125114429.20066-1-jonas@norrbonn.se> <20190125114429.20066-3-jonas@norrbonn.se> From: Jonas Bonn Message-ID: <296f8326-a33d-8db1-ca71-c6aba21b1302@norrbonn.se> Date: Fri, 25 Jan 2019 12:47:15 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190125114429.20066-3-jonas@norrbonn.se> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190125_034719_923138_8BB14065 X-CRM114-Status: GOOD ( 19.06 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ludovic Desroches , Alexandre Belloni , Mark Brown , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 25/01/2019 12:44, Jonas Bonn wrote: > If the SPI slave requires an inter-word delay, configure the DLYBCT > register accordingly. > > Tested on a SAMA5D2 board (derived from SAMA5D2-Xplained reference > board). > > Signed-off-by: Jonas Bonn > CC: Nicolas Ferre > CC: Mark Brown > CC: Alexandre Belloni > CC: Ludovic Desroches > CC: linux-spi@vger.kernel.org > CC: linux-arm-kernel@lists.infradead.org > --- > drivers/spi/spi-atmel.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c > index 74fddcd3282b..88ff3fef56e9 100644 > --- a/drivers/spi/spi-atmel.c > +++ b/drivers/spi/spi-atmel.c > @@ -1209,13 +1209,14 @@ static int atmel_spi_setup(struct spi_device *spi) > csr |= SPI_BIT(CSAAT); > > /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs. > - * > - * DLYBCT would add delays between words, slowing down transfers. > - * It could potentially be useful to cope with DMA bottlenecks, but > - * in those cases it's probably best to just use a lower bitrate. > */ > csr |= SPI_BF(DLYBS, 0); > - csr |= SPI_BF(DLYBCT, 0); > + > + /* DLYBCT adds delays between words. This is useful for slow devices > + * that need a bit of time to setup the next transfer. > + */ > + csr |= SPI_BF(DLYBCT, > + clamp_t(u8, (as->spi_clk/1000000*spi->word_delay)>>5, 1, 255)); Ah... this is stupid. The clamping here _always_ introduces a delay, which is not what we want... will resubmit this. /Jonas > > /* chipselect must have been muxed as GPIO (e.g. in board setup) */ > npcs_pin = (unsigned long)spi->controller_data; > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel