From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pa0-x22e.google.com ([2607:f8b0:400e:c03::22e]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WiQP3-00039V-8p for linux-mtd@lists.infradead.org; Thu, 08 May 2014 15:38:33 +0000 Received: by mail-pa0-f46.google.com with SMTP id kx10so2974007pab.19 for ; Thu, 08 May 2014 08:38:10 -0700 (PDT) Date: Thu, 8 May 2014 23:37:58 +0800 From: Huang Shijie To: Hugo Villeneuve Subject: Re: imx6 NAND chip selects Message-ID: <20140508153756.GA2572@localhost.localdomain> References: <536A5FEE.9090705@hugovil.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <536A5FEE.9090705@hugovil.com> Cc: b32955@freescale.com, linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, May 07, 2014 at 12:31:42PM -0400, Hugo Villeneuve wrote: > Hi, > I am trying to connect a NAND flash device (Micron MT29F8G08) to a > Wandboard Dual. > > Here is the pin mapping: > > i.MX6 NAND flash > ---------------------------- > NANDF_CS0 --> CE# > NANDF_RB0 --> R/B# > NANDF_WP_B --> WP# > NANDF_CLE --> CLE > NANDF_ALE --> ALE > NANDF_WE --> WE# > NANDF_RE --> RE# > NANDF_D[0-7] --> I/O[0-7] > > This NAND flash has a single chip-select. > > I'm testing it using Linux kernel 3.15.0-rc3. > > In the wandboard device tree file, I have added all the above gpmi > pins as GPMI pins. > > I am still booting from the SD card, so at this point I am only > trying to detect the NAND device. Unfortunately, when the kernel > boots, the GPMI driver fails to register (error -19). > > If I monitor the NANDF_CS0 line, I can see that it is pulsed low, > but I am not seing any activity on the NANDF_WE line. > > However, If I monitor the NANDF_CS1 line, I can see that it is > pulsed low, and during the time it is low the NANDF_WE line is also > going low. > > I then made sure to reconfigure the unused pins NANDF_CS[1-3] as > GPIOs (ALT5 function) in my device tree file. I have confirmed with > kernel debug traces that the iomux register for NANDF_CS1 have the > value 0x05, which means ALT5 function (GPIO). But I am still seeing > the same behavior as before on the oscilloscope. > > So how can I configure the GPMI driver to only use NANDF_CS0 and not > NANDF_CS1? > > And is it normal that NANDF_CS1 is still used by the GPMI driver > when configured as GPIO? It is not normal at all. Please disable the GPIO pinctrl, and only enable the pinctrl for gpmi and try again. I am sure that you did not configure the PADs correctly. thanks Huang Shijie