From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from co9ehsobe003.messaging.microsoft.com ([207.46.163.26] helo=co9outboundpool.messaging.microsoft.com) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TWkTS-0002M4-6e for linux-mtd@lists.infradead.org; Fri, 09 Nov 2012 09:02:03 +0000 From: Huang Shijie To: Subject: [PATCH] mtd: de-select the chip when it is not used Date: Fri, 9 Nov 2012 16:23:45 +0800 Message-ID: <1352449425-16496-1-git-send-email-b32955@freescale.com> MIME-Version: 1.0 Content-Type: text/plain Cc: Huang Shijie , computersforpeace@gmail.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, dedekind1@gmail.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , When we scan several nand chips with nand_scan(), such as ....................... nand_scan(*, 2); ....................... In nand_scan_ident(), the maxchips will become 2, so the current code will select chip 1 to read the device ID. But the chip 0 is still selected in this case. To make the logic clear, we'd better de-select the chip when it is not used. This patch de-select the nand chip if it is not used any more. Signed-off-by: Huang Shijie --- drivers/mtd/nand/nand_base.c | 10 ++++++---- 1 files changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index ec6841d..fd5fa3b 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -3325,6 +3325,8 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips, return PTR_ERR(type); } + chip->select_chip(mtd, -1); + /* Check for a chip array */ for (i = 1; i < maxchips; i++) { chip->select_chip(mtd, i); @@ -3334,8 +3336,11 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips, chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1); /* Read manufacturer and device IDs */ if (nand_maf_id != chip->read_byte(mtd) || - nand_dev_id != chip->read_byte(mtd)) + nand_dev_id != chip->read_byte(mtd)) { + chip->select_chip(mtd, -1); break; + } + chip->select_chip(mtd, -1); } if (i > 1) pr_info("%d NAND chips detected\n", i); @@ -3594,9 +3599,6 @@ int nand_scan_tail(struct mtd_info *mtd) /* Initialize state */ chip->state = FL_READY; - /* De-select the device */ - chip->select_chip(mtd, -1); - /* Invalidate the pagebuffer reference */ chip->pagebuf = -1; -- 1.7.0.4