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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 6F963C433FE for ; Thu, 17 Nov 2022 11:02:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=XvnfTF7zuPMdlIpUZYddttCXhV1GT+ln4IR6OttWs8k=; b=p0hXQ5cwRLi4PB ERIUwzTySAj14t6hrfGtwStm6C83Wl6dWfYp46qgvhY1SJBRvRjV3vVilhxj6f+9CYnK0hVQjbQ7N n6spRQDGuDRLuVgBKdC0uJ+6OeWNUPVchKnZuoVYGFPpdm+FUMOz3swkwWWOmXGRpQWiWMEnn+/qG JCPvZXeBN2zMP/2fzjVdtA89IzgmnRIHhjmxfpTsekIR7KLxbSSLx6FllxWx5ma2YxrZQFlUTZGsa arZM91AQ61LjhFQSmLeI2pJ8f7YJT3drZdY9Q/QpFzLxn/Zay6Zc3k6ChQl7bI4IfHjAdFMGmAqqr 4gyTgrU+x2X7Mxleq80g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ovcfF-00Cte6-4u; Thu, 17 Nov 2022 11:02:37 +0000 Received: from esa.microchip.iphmx.com ([68.232.154.123]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ovcWD-00CoMz-H2; Thu, 17 Nov 2022 10:53:19 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1668682398; x=1700218398; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=H6jfv/98Y/BHItdiM3LYtojQb8Xu3XwDeExUAi0R+zs=; b=z1cYFK+OLBZGxMMogW4KNZ2mZnOIBPB5I7ZKsfP0zBTAN4G8F0vZ2Qp6 27tt07qT2VKT4jd5iI7td9BzTtmwf5A7deukzgAZG1RudHILh/NQjGdvW THu9UVdrBYkVo8zkQZ2w17W8yK2PQumzXpb6vlfSFJL4UBjCh2v/bJEl3 qzBzn7ucOU7icbNNncN/4soQomq/qikfkeTbW8r/OW5QykpxtJcFhUxlj YQCHoEQyRCyVeULAGLRESxPhfSqPTUxbr02p2Pgw5SYdnqXvN+bRkodax IBAO897VxOHNiZwTe4eMFX4GMV+D+Hj5v32ju+9Mhg0TGDf5quD4+WAHy w==; X-IronPort-AV: E=Sophos;i="5.96,171,1665471600"; d="scan'208";a="183965650" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa4.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 17 Nov 2022 03:53:15 -0700 Received: from chn-vm-ex02.mchp-main.com (10.10.85.144) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.12; Thu, 17 Nov 2022 03:53:11 -0700 Received: from ROB-ULT-M18064N.mchp-main.com (10.10.115.15) by chn-vm-ex02.mchp-main.com (10.10.85.144) with Microsoft SMTP Server id 15.1.2507.12 via Frontend Transport; Thu, 17 Nov 2022 03:53:09 -0700 From: Tudor Ambarus To: , , , , , CC: , , , , , Tudor Ambarus Subject: [PATCH 6/8] ARM: dts: at91-sama5d27_som1: Set sst26vf064b SPI NOR flash at its maximum frequency Date: Thu, 17 Nov 2022 12:52:47 +0200 Message-ID: <20221117105249.115649-7-tudor.ambarus@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221117105249.115649-1-tudor.ambarus@microchip.com> References: <20221117105249.115649-1-tudor.ambarus@microchip.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221117_025317_751835_B56879C0 X-CRM114-Status: GOOD ( 10.02 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org sama5d27-som1 populates an sst26vf064b SPI NOR flash. Its maximum operating frequency for 2.7-3.6V is 104 MHz. As the flash is operated at 3.3V, increase its maximum supported frequency to 104MHz. The increasing of the spi-max-frequency value requires the setting of the "CE# Not Active Hold Time", thus set the spi-cs-setup-ns to a value of 7. The sst26vf064b datasheet specifies just a minimum value for the "CE# Not Active Hold Time" and it advertises it to 5 ns. There's no maximum time specified. I determined experimentally that 5 ns for the spi-cs-setup-ns is not enough when the flash is operated close to its maximum frequency and tests showed that 7 ns is just fine, so set the spi-cs-setup-ns dt property to 7. With the increase of frequency the reads are now faster with ~37%. Signed-off-by: Tudor Ambarus --- arch/arm/boot/dts/at91-sama5d27_som1.dtsi | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm/boot/dts/at91-sama5d27_som1.dtsi b/arch/arm/boot/dts/at91-sama5d27_som1.dtsi index 8aa9e8dea337..243f09f40761 100644 --- a/arch/arm/boot/dts/at91-sama5d27_som1.dtsi +++ b/arch/arm/boot/dts/at91-sama5d27_som1.dtsi @@ -43,7 +43,8 @@ flash@0 { #size-cells = <1>; compatible = "jedec,spi-nor"; reg = <0>; - spi-max-frequency = <80000000>; + spi-max-frequency = <104000000>; + spi-cs-setup-ns = /bits/ 16 <7>; spi-tx-bus-width = <4>; spi-rx-bus-width = <4>; m25p,fast-read; -- 2.25.1 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/