From patchwork Thu May 6 19:18:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pratyush Yadav X-Patchwork-Id: 431974 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, 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 4971AC43461 for ; Thu, 6 May 2021 19:18:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3146A61164 for ; Thu, 6 May 2021 19:18:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235152AbhEFTTw (ORCPT ); Thu, 6 May 2021 15:19:52 -0400 Received: from fllv0015.ext.ti.com ([198.47.19.141]:54840 "EHLO fllv0015.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235127AbhEFTTu (ORCPT ); Thu, 6 May 2021 15:19:50 -0400 Received: from fllv0034.itg.ti.com ([10.64.40.246]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 146JIin4080687; Thu, 6 May 2021 14:18:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1620328724; bh=YxdJ0KAQlULOSarEjigNBSaxhdxJcUTtoguFX6Vi1xY=; h=From:To:CC:Subject:Date:In-Reply-To:References; b=c0F6JEgYXJkRjwu7ik8WAAmdjETo8cyZg6E2rPbXz4todjem5H3ZMkHJA2074o2hA Vg7ZT17zUeG7y2fIiIa0CmTakPwb2PV+pvned4HzXfiih4AMU80HWcYb8wkC3F0CNK DIKxLTcYj++aPsPN8Nz8468m/erZn/hFfMsePglk= Received: from DLEE105.ent.ti.com (dlee105.ent.ti.com [157.170.170.35]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 146JIiDv097500 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 6 May 2021 14:18:44 -0500 Received: from DLEE110.ent.ti.com (157.170.170.21) by DLEE105.ent.ti.com (157.170.170.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Thu, 6 May 2021 14:18:43 -0500 Received: from lelv0326.itg.ti.com (10.180.67.84) by DLEE110.ent.ti.com (157.170.170.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2 via Frontend Transport; Thu, 6 May 2021 14:18:43 -0500 Received: from pratyush-OptiPlex-790.dhcp.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 146JIUNF026052; Thu, 6 May 2021 14:18:41 -0500 From: Pratyush Yadav To: Tudor Ambarus , Michael Walle , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Mark Brown , , , CC: Pratyush Yadav Subject: [PATCH 3/6] mtd: spi-nor: micron-st: write 2 bytes when disabling Octal DTR mode Date: Fri, 7 May 2021 00:48:26 +0530 Message-ID: <20210506191829.8271-4-p.yadav@ti.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210506191829.8271-1-p.yadav@ti.com> References: <20210506191829.8271-1-p.yadav@ti.com> MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org The Octal DTR configuration is stored in the CFR0V register. This register is 1 byte wide. But 1 byte long transactions are not allowed in 8D-8D-8D mode. The next byte address contains the CFR1V register, which contains the number of dummy cycles. This is very fortunate since the enable path changes the value of this register. Reset the value to its default when disabling Octal DTR mode. This way, both changes to the flash state made when enabling can be reverted in one single transaction. Signed-off-by: Pratyush Yadav --- drivers/mtd/spi-nor/micron-st.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/drivers/mtd/spi-nor/micron-st.c b/drivers/mtd/spi-nor/micron-st.c index c224e59820a1..e49bb2f142b3 100644 --- a/drivers/mtd/spi-nor/micron-st.c +++ b/drivers/mtd/spi-nor/micron-st.c @@ -13,6 +13,7 @@ #define SPINOR_OP_MT_WR_ANY_REG 0x81 /* Write volatile register */ #define SPINOR_REG_MT_CFR0V 0x00 /* For setting octal DTR mode */ #define SPINOR_REG_MT_CFR1V 0x01 /* For setting dummy cycles */ +#define SPINOR_REG_MT_CFR1V_DEF 0x1f /* Default dummy cycles */ #define SPINOR_MT_OCT_DTR 0xe7 /* Enable Octal DTR. */ #define SPINOR_MT_EXSPI 0xff /* Enable Extended SPI (default) */ @@ -48,17 +49,28 @@ static int spi_nor_micron_octal_dtr_enable(struct spi_nor *nor, bool enable) if (ret) return ret; - if (enable) - *buf = SPINOR_MT_OCT_DTR; - else - *buf = SPINOR_MT_EXSPI; + if (enable) { + buf[0] = SPINOR_MT_OCT_DTR; + } else { + /* + * The register is 1-byte wide, but 1-byte transactions are not + * allowed in 8D-8D-8D mode. The next register is the dummy + * cycle configuration register. Since the transaction needs to + * be at least 2 bytes wide, set the next register to its + * default value. This also makes sense because the value was + * changed when enabling 8D-8D-8D mode, it should be reset when + * disabling. + */ + buf[0] = SPINOR_MT_EXSPI; + buf[1] = SPINOR_REG_MT_CFR1V_DEF; + } op = (struct spi_mem_op) SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_MT_WR_ANY_REG, 1), SPI_MEM_OP_ADDR(enable ? 3 : 4, SPINOR_REG_MT_CFR0V, 1), SPI_MEM_OP_NO_DUMMY, - SPI_MEM_OP_DATA_OUT(1, buf, 1)); + SPI_MEM_OP_DATA_OUT(enable ? 1 : 2, buf, 1)); if (!enable) spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR);