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From:   Pratyush Yadav <p.yadav@ti.com>
To:     Tudor Ambarus <tudor.ambarus@microchip.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Mark Brown <broonie@kernel.org>,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Ludovic Desroches <ludovic.desroches@microchip.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        <linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
        <linux-spi@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-mediatek@lists.infradead.org>
CC:     Pratyush Yadav <p.yadav@ti.com>, Sekhar Nori <nsekhar@ti.com>,
        Boris Brezillon <boris.brezillon@collabora.com>,
        Mason Yang <masonccyang@mxic.com.tw>
Subject: [PATCH v5 13/19] mtd: spi-nor: sfdp: do not make invalid quad enable fatal
Date:   Tue, 19 May 2020 19:56:35 +0530
Message-ID: <20200519142642.24131-14-p.yadav@ti.com>
In-Reply-To: <20200519142642.24131-1-p.yadav@ti.com>
References: <20200519142642.24131-1-p.yadav@ti.com>
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The Micron MT35XU512ABA flash does not support the quad enable bit. But
instead of programming the Quad Enable Require field to 000b ("Device
does not have a QE bit"), it is programmed to 111b ("Reserved").

While this is technically incorrect, it is not reason enough to abort
BFPT parsing. Instead, continue BFPT parsing assuming there is no quad
enable bit present.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
---
 drivers/mtd/spi-nor/sfdp.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
index 4e5e0eabe2d9..be9c6c3d6590 100644
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c
@@ -569,10 +569,6 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
 
 	/* Quad Enable Requirements. */
 	switch (bfpt.dwords[BFPT_DWORD(15)] & BFPT_DWORD15_QER_MASK) {
-	case BFPT_DWORD15_QER_NONE:
-		params->quad_enable = NULL;
-		break;
-
 	case BFPT_DWORD15_QER_SR2_BIT1_BUGGY:
 		/*
 		 * Writing only one byte to the Status Register has the
@@ -609,8 +605,10 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
 		params->quad_enable = spi_nor_sr2_bit1_quad_enable;
 		break;
 
+	case BFPT_DWORD15_QER_NONE:
 	default:
-		return -EINVAL;
+		params->quad_enable = NULL;
+		break;
 	}
 
 	/* Stop here if JESD216 rev B. */
-- 
2.26.2