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_HIGH,DKIM_SIGNED, DKIM_VALID,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 0E37DC282D7 for ; Wed, 30 Jan 2019 17:15:31 +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 D33B22184D for ; Wed, 30 Jan 2019 17:15:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="T5zjebDZ"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="YO2hnQZa" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D33B22184D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Hsla/HC/ZCnYCdA1LzFLvIisTsRuTtGBNPZ3gA6Z8MI=; b=T5zjebDZBmNyqT sVFmdkKOMhU/WQzBk6Xwvr9ulXbrKjMbdr5LU6kQmWWCMR4Hf4cPc/F3cUXb3Atp0WPOoofkz0HXh KLm+LSLlQPcPes6W607TUPI5j35hVpQAlXHumm7gtzYQ8YxDFGe0msFYQB3xYPCwZYgY4HBUQOpf4 RLBkQsM/tigWBpzZR8AqLN+PQCck46Npn3PHY+n28yVg0R2++pGHtTohbiiWQPwuX1eI9AfFvTxfF 9TwSmT43r9s2DK6WVtVV6xRUbAYHAxXFV0rmyB+ZSPQ8cPQW/sfjpwDXscJzHjVyqsY+Q3RxSJFD5 Hk2cON5CpVZv7pHSRvnw==; 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 1gotST-0001HB-VC; Wed, 30 Jan 2019 17:15:29 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gotSQ-0001Go-KY; Wed, 30 Jan 2019 17:15:28 +0000 Received: from bbrezillon (91-160-177-164.subs.proxad.net [91.160.177.164]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7A9502087F; Wed, 30 Jan 2019 17:15:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548868525; bh=rL8MOHGzlA9uP8ZVfBxcHv6afRZ6IvHg9FHRaOPcosk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=YO2hnQZac79tNmomIgsJVI8OVsrSL2Qx3EndLyD28MP07Ics+sQpM5I9hBgLBYUZZ K9hT1fGkj+1ZQOHuJ11Ae1pH69bglZxftA/ej4r/u60uibd4BZ83hKrqUhu9plKZz4 z5dw4Av/dwlRfgAnpzErEbFw5xiMb+ev/WpIDOlU= Date: Wed, 30 Jan 2019 18:15:15 +0100 From: Boris Brezillon To: Subject: Re: [PATCH 1/9] spi: atmel-quadspi: optimize qspi init Message-ID: <20190130181505.4f495d3a@bbrezillon> In-Reply-To: <20190130150818.24902-2-tudor.ambarus@microchip.com> References: <20190130150818.24902-1-tudor.ambarus@microchip.com> <20190130150818.24902-2-tudor.ambarus@microchip.com> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190130_091526_806740_2CB908D7 X-CRM114-Status: GOOD ( 14.90 ) 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: alexandre.belloni@bootlin.com, linux-kernel@vger.kernel.org, Ludovic.Desroches@microchip.com, broonie@kernel.org, linux-mtd@lists.infradead.org, linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 30 Jan 2019 15:08:29 +0000 wrote: > From: Tudor Ambarus > > Set the QSPI controller in Serial Memory Mode at init and not > at each exec_op() call. If you ever want to support regular SPI you'll have to put it back to atmel_qspi_exec_op(), so I'm not sure this is a good move. Another approach would be to cache the MR value to avoid doing a write access on the bus when the value hasn't changed. > > Signed-off-by: Tudor Ambarus > --- > drivers/spi/atmel-quadspi.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c > index ddc712410812..f79b17792a11 100644 > --- a/drivers/spi/atmel-quadspi.c > +++ b/drivers/spi/atmel-quadspi.c > @@ -238,8 +238,6 @@ static int atmel_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op) > icr = QSPI_ICR_INST(op->cmd.opcode); > ifr = QSPI_IFR_INSTEN; > > - qspi_writel(aq, QSPI_MR, QSPI_MR_SMM); > - > mode = find_mode(op); > if (mode < 0) > return -ENOTSUPP; > @@ -381,6 +379,9 @@ static int atmel_qspi_init(struct atmel_qspi *aq) > /* Reset the QSPI controller */ > qspi_writel(aq, QSPI_CR, QSPI_CR_SWRST); > > + /* Set the QSPI controller in Serial Memory Mode */ > + qspi_writel(aq, QSPI_MR, QSPI_MR_SMM); > + > /* Enable the QSPI controller */ > qspi_writel(aq, QSPI_CR, QSPI_CR_QSPIEN); > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel