From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris brezillon Subject: Re: [RFC PATCH 3/9] of: mtd: add NAND timings retrieval support Date: Wed, 15 Jan 2014 18:03:01 +0100 Message-ID: <52D6BF45.80407@overkiz.com> References: <1389190924-26226-1-git-send-email-b.brezillon@overkiz.com> <1389190924-26226-4-git-send-email-b.brezillon@overkiz.com> <20140108183418.GA12358@obsidianresearch.com> <52CDA032.3010804@overkiz.com> <20140108191339.GB12358@obsidianresearch.com> <52CE5F82.6070802@overkiz.com> <20140109173505.GB8899@obsidianresearch.com> <52D6A48D.4080302@overkiz.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <52D6A48D.4080302-ZNYIgs0QAGpBDgjK7y7TUQ@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jason Gunthorpe Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Russell King , linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dev-3kdeTeqwOZ9EV1b7eY7vFQ@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Rob Landley , Grant Likely , Maxime Ripard , David Woodhouse , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On 15/01/2014 16:09, boris brezillon wrote: > Hello Jason, > > On 09/01/2014 18:35, Jason Gunthorpe wrote: >> On Thu, Jan 09, 2014 at 09:36:18AM +0100, boris brezillon wrote: >> >>>> You might want to check if you can boil down the DT timings from t= he >>>> huge list to just an ONFI mode number.. >>> Sure, but the sunxi driver needs at least 19 of them... >> So does mvebu's NAND driver.. >> >> What I ment was you could have a >> >> onfi,nand-timing-mode =3D 0 >> >> in the DT. Each of the modes defines all ~19 parameters, higher mode= s >> are faster. >> >> Pick a mode value that fits all the parameters of the connected >> non-ONFI flash. >> >> This would be instead of defining each parameter >> individually.. Provide some helpers to convert from a onfi mode numb= er >> to all the onfi defined timing parameters so that drivers can >> configure the HW.. > > Are you suggesting we should provide a function that converts these > modes into a nand_timings struct, or just use the timing modes and > let the NAND controller drivers configure its IP accordingly ? > > I found the ONFI timing tables in this document: > > www.*onfi*.org/~/media/*ONFI*/specs/*onfi*_3_1_spec.pdf=E2=80=8E (cha= pter 4.16). > > I suppose my nand_timings struct should use the names described > page 110-111 (at least if we decide to use nand_timings and not > nand_timing_modes), right ? After taking a closer look at this document, the only parameter=20 available in my nand_timings struct that is not defined in the standard is tR_max (data= =20 transfer from cell to register). And the ONFI standard defines 4 more timings: - tCEA_max - tCEH_min - tFEAT_max - tITC_max > > Best Regards, > > Boris > >> >> Jason > -- To unsubscribe from this list: send the line "unsubscribe devicetree" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html