Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752342AbbLJQmB (ORCPT ); Thu, 10 Dec 2015 11:42:01 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:54375 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751199AbbLJQmA (ORCPT ); Thu, 10 Dec 2015 11:42:00 -0500 Subject: Re: LM90 driver and ti tmp461 detection To: Andreas Werner , linux-kernel@vger.kernel.org References: <20151210120856.GA27765@awelinux> Cc: jdelvare@suse.com, lm-sensors@lm-sensors.org, wni@nvidia.com From: Guenter Roeck Message-ID: <5669AB55.5030309@roeck-us.net> Date: Thu, 10 Dec 2015 08:41:57 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <20151210120856.GA27765@awelinux> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2938 Lines: 64 On 12/10/2015 04:08 AM, Andreas Werner wrote: > Hi, > i have a temperature sensor device named "TI TMP461" which is quite the > same than the tmp451 which is already included in the lm90 driver. > > I just want to add the tmp461 to the driver but currently i have no way > to differ between the tmp461 and tmp451. > > The main different is that the tmp461 address can be configured by to Pins > whereas the tmp451 has a fixed address. > > The register layout is quite the same except that the tmp461 has one > register more (0x16 Channel Enable Register). > > Every zero bit is the same for both bits, so we cannot use these bits for > identification. > > Does anybody of you have a tmp451 to read out the register 0x16 (which is > not implement but i expect a value). May be we can use this to > identify the tmp461. > Here is a register dump. 00: 5d 69 00 04 08 bf 00 ff 53 00 00 00 00 00 00 00 ]i.???..S....... 10: a0 00 00 00 00 f0 00 00 00 a9 00 00 00 00 00 00 ?....?...?...... 20: b8 0a 01 00 00 XX 00 00 00 00 0e 00 00 00 00 00 ???..X....?..... 30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 00 ..............U. there is nothing to distinguish the two chips as far as I can see. Is your system a devicetree system ? If so, you can just provide a compatible statement such as compatible = "ti,tmp461", "ti,tmp451"; or simply instantiate the chip as tmp451. Feel free to provide a patch adding '{ "tmp461", tmp451 },' to lm90_id as well as the necessary documentation, but I don't think there is anything we can do to detect the chip. On the other side, I am a bit concerned that the chip detection doesn't work well, since the chip ID register is really unsupported and just happens to return 0 for both chips. I wonder if there are other TI chips which may be mis-detected as TMP451. Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/