From mboxrd@z Thu Jan 1 00:00:00 1970 From: marex@denx.de (Marek Vasut) Date: Mon, 20 Jul 2015 10:15:06 +0200 Subject: [PATCH V4 RFC 2/3] nvmem: add driver for ocotp in i.MX23 and i.MX28 In-Reply-To: <55AC9901.1040402@i2se.com> References: <1437343499-16422-1-git-send-email-stefan.wahren@i2se.com> <201507200012.13608.marex@denx.de> <55AC9901.1040402@i2se.com> Message-ID: <201507201015.07075.marex@denx.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Monday, July 20, 2015 at 08:45:21 AM, Stefan Wahren wrote: > Hi Marek, Hi! > Am 20.07.2015 um 00:12 schrieb Marek Vasut: > > On Monday, July 20, 2015 at 12:04:58 AM, Stefan Wahren wrote: > >> This patch brings read-only support for the On-Chip OTP cells > >> in the i.MX23 and i.MX28 processor. The driver implements the > >> new NVMEM provider API. > >> > >> Signed-off-by: Stefan Wahren > > > > How come this driver isn't doing any manipulation with the VDDIO > > voltage -- or did I miss that? I seem to remember that the VDDIO > > had to be lowered to 2.8V before the fuses could be programmed > > and restored to 3.3V afterward. See for example recent mainline > > u-boot, drivers/misc/mxs_ocotp.c . > > Why should the driver implement VDDIO manipulation when there is only > read-only support for the OTP bits? There is no ambition to implement > write support. Maybe i should clarify that in the comments. Urm, sorry, I missed that read-only part. I apologize. > Btw i'm on your side that because programming the OTP from userspace is > to dangerous. :) Best regards, Marek Vasut