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Tue, 23 Jun 2020 13:31:22 -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 15.1.1979.3; Tue, 23 Jun 2020 13:31:22 -0500 Received: from fllv0039.itg.ti.com (10.64.41.19) 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 15.1.1979.3 via Frontend Transport; Tue, 23 Jun 2020 13:31:22 -0500 Received: from pratyush-OptiPlex-790.dhcp.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id 05NIUVJN000942; Tue, 23 Jun 2020 13:31:17 -0500 From: Pratyush Yadav To: Tudor Ambarus , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Mark Brown , Nicolas Ferre , Alexandre Belloni , Ludovic Desroches , Matthias Brugger , Michal Simek , , , , , Subject: [PATCH v10 09/17] mtd: spi-nor: core: do 2 byte reads for SR and FSR in DTR mode Date: Wed, 24 Jun 2020 00:00:22 +0530 Message-ID: <20200623183030.26591-10-p.yadav@ti.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200623183030.26591-1-p.yadav@ti.com> References: <20200623183030.26591-1-p.yadav@ti.com> MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Boris Brezillon , Sekhar Nori , Pratyush Yadav 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 Some controllers, like the cadence qspi controller, have trouble reading only 1 byte in DTR mode. So, do 2 byte reads for SR and FSR commands in DTR mode, and then discard the second byte. Signed-off-by: Pratyush Yadav --- drivers/mtd/spi-nor/core.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c index f2748f1d9957..5f7e4a5c33bc 100644 --- a/drivers/mtd/spi-nor/core.c +++ b/drivers/mtd/spi-nor/core.c @@ -350,7 +350,7 @@ int spi_nor_write_disable(struct spi_nor *nor) * spi_nor_read_sr() - Read the Status Register. * @nor: pointer to 'struct spi_nor'. * @sr: pointer to a DMA-able buffer where the value of the - * Status Register will be written. + * Status Register will be written. Should be at least 2 bytes. * * Return: 0 on success, -errno otherwise. */ @@ -371,6 +371,11 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr) op.addr.nbytes = addr_bytes; op.addr.val = 0; op.dummy.nbytes = dummy; + /* + * We don't want to read only one byte in DTR mode. So, + * read 2 and then discard the second byte. + */ + op.data.nbytes = 2; } spi_nor_spimem_setup_op(nor, &op, nor->reg_proto); @@ -394,7 +399,8 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr) * spi_nor_read_fsr() - Read the Flag Status Register. * @nor: pointer to 'struct spi_nor' * @fsr: pointer to a DMA-able buffer where the value of the - * Flag Status Register will be written. + * Flag Status Register will be written. Should be at least 2 + * bytes. * * Return: 0 on success, -errno otherwise. */ @@ -415,6 +421,11 @@ static int spi_nor_read_fsr(struct spi_nor *nor, u8 *fsr) op.addr.nbytes = addr_bytes; op.addr.val = 0; op.dummy.nbytes = dummy; + /* + * We don't want to read only one byte in DTR mode. So, + * read 2 and then discard the second byte. + */ + op.data.nbytes = 2; } spi_nor_spimem_setup_op(nor, &op, nor->reg_proto); -- 2.27.0 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/