From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-gw2-out.broadcom.com ([216.31.210.63]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1aDh6a-00079Z-Sk for linux-mtd@lists.infradead.org; Mon, 28 Dec 2015 23:21:33 +0000 CC: "linux-kernel@vger.kernel.org" , "linux-mtd@lists.infradead.org" To: Greg Kroah-Hartman , Arnd Bergmann , Brian Norris From: Scott Branden Subject: Adding OTP-only device to MTD or CHAR subsystem? Message-ID: <5681C3E4.4090506@broadcom.com> Date: Mon, 28 Dec 2015 15:21:08 -0800 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Greg/Brian/Arnd, We have OTP device drivers for accessing OTP memory in our SoCs. I looking for the right place and model to place such OTP device drivers. 1) Should we follow the bfin-otp model in drivers/char? This doesn't seem like the right place to put it although following the bfin example is quite simple to implement. We actually had a custom set of Ioctl's that I changed to use the standard file access model used by the bfin driver. But a custom util is still needed to issue an OTPLOCK command. I'm guess mtd-utils has such abilities (or should). 2) Instead, should we start adding OTP-only drivers into the MTD subsystem? Onenand and CFI based MTD devices already have OTP programmable regions. If we created a new OTP device type in the MTD subsystem this looks like a good thing to do. mtd-utils could/should be used to access the OTP device then along with standard fileio operations. 3) Or some other suggestion of where to place OTP device drivers? Regards, Scott