Message ID | 20221117105249.115649-8-tudor.ambarus@microchip.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show
Return-Path: <linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org> 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 144AAC4332F for <linux-arm-kernel@archiver.kernel.org>; Thu, 17 Nov 2022 11:04:02 +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=trSChD4khST41TtwB3TSlcjqBTyfQ/XYzU9US7I9Tk0=; b=tq3InGT58Nlp+X QrUGqOKAxnMSpmxBNVztmRUlLsTZp/x7DUtkMW6Zbz5E/C0gftf+KWtfKpPbXzrePw3G5mnFRxsjn rPzm8jdcQ81CC9SjUsCL+yhtIAEid4pgjFq3Bx8rf8GJGKOXoN475CG5ReE0cIW7A41yTMMk1/eCk F92jYdlMcVVhb2kaTJpLcFDVX/dVcmA01YX7QKxy9N7URROG4RyFqqUfALW4BAG+OxmN6vdiNX14L hKHrQpoc0wGM+nGaff7CVN2ZdPHlFL12QeQH/CzIj/c0mYIkT7uVWKR2gFAsZwdEnCsebdNztOP21 3uRCcBcgVAXTkyomvTxQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ovcfQ-00CtkH-Rv; Thu, 17 Nov 2022 11:02:49 +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 1ovcWG-00CoMz-2U; Thu, 17 Nov 2022 10:53:21 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1668682401; x=1700218401; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=pub4+zHZreJmfMrR4t0OMZDURmCLD6tCvA9jmlzzuIg=; b=sozHbAkZDpqgHG8Z2cJ3+h4fN+qXLDQCrar1UWtIJlGfEHpoWpREvmnD moDGG+wCCm0Njecm+TXSpkdfQnGM21WyyKlU/sQ681mwstE9Fl+o8cEvY qfu8zxPGmERjz3Aw2o0TK5klTFEoyFjq3jZ8pFbip81tgDItr9sSNZCjR dJB/HIOKHC/tlKIsztJltR1MvO2eUs9o+pyJBcdW47X13bkg5enzH8Pdq chaaY0ys2d2GLWnAPXDzwXodmhafEnKH4GgDZE13vT6M0yioOFc2nDlsR YCMb/eOsCGGWvcvDe5XsdODhdjVBP5UMP7ohKmCQ3wXQHqR5QIO4qxeni w==; X-IronPort-AV: E=Sophos;i="5.96,171,1665471600"; d="scan'208";a="183965652" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa4.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 17 Nov 2022 03:53:17 -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 03:53:14 -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 03:53:12 -0700 From: Tudor Ambarus <tudor.ambarus@microchip.com> To: <broonie@kernel.org>, <robh+dt@kernel.org>, <krzysztof.kozlowski+dt@linaro.org>, <nicolas.ferre@microchip.com>, <alexandre.belloni@bootlin.com>, <claudiu.beznea@microchip.com> CC: <linux-spi@vger.kernel.org>, <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <linux-mtd@lists.infradead.org>, Tudor Ambarus <tudor.ambarus@microchip.com> Subject: [PATCH 7/8] ARM: dts: at91: sama5d2_icp: Set sst26vf064b SPI NOR flash at its maximum frequency Date: Thu, 17 Nov 2022 12:52:48 +0200 Message-ID: <20221117105249.115649-8-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_025320_221114_3002B1B3 X-CRM114-Status: GOOD ( 10.02 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: <linux-arm-kernel.lists.infradead.org> List-Unsubscribe: <http://lists.infradead.org/mailman/options/linux-arm-kernel>, <mailto:linux-arm-kernel-request@lists.infradead.org?subject=unsubscribe> List-Archive: <http://lists.infradead.org/pipermail/linux-arm-kernel/> List-Post: <mailto:linux-arm-kernel@lists.infradead.org> List-Help: <mailto:linux-arm-kernel-request@lists.infradead.org?subject=help> List-Subscribe: <http://lists.infradead.org/mailman/listinfo/linux-arm-kernel>, <mailto:linux-arm-kernel-request@lists.infradead.org?subject=subscribe> Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org |
Series |
spi: Introduce spi-cs-setup-ns dt property
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expand
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diff --git a/arch/arm/boot/dts/at91-sama5d2_icp.dts b/arch/arm/boot/dts/at91-sama5d2_icp.dts index dd1dec9d4e07..ffd9627874c9 100644 --- a/arch/arm/boot/dts/at91-sama5d2_icp.dts +++ b/arch/arm/boot/dts/at91-sama5d2_icp.dts @@ -669,7 +669,8 @@ 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;
sama5d2_icp 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 <tudor.ambarus@microchip.com> --- arch/arm/boot/dts/at91-sama5d2_icp.dts | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)