From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932651AbcGDX1L (ORCPT ); Mon, 4 Jul 2016 19:27:11 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:52441 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753366AbcGDX1J (ORCPT ); Mon, 4 Jul 2016 19:27:09 -0400 Subject: Re: [RFC PATCH] hwmon: (jc42) Add I2C_CLASS_HWMON to detection class To: Alison Schofield References: <20160704191908.GA9056@d830.WORKGROUP> <577ACF62.9030109@roeck-us.net> <20160704230414.GA10368@d830.WORKGROUP> Cc: Jean Delvare , "open list:JC42.4 TEMPERATURE SENSOR DRIVER" , linux-kernel@vger.kernel.org, daniel.baluta@gmail.com From: Guenter Roeck Message-ID: <577AF0CB.9020807@roeck-us.net> Date: Mon, 4 Jul 2016 16:27:07 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: <20160704230414.GA10368@d830.WORKGROUP> 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 On 07/04/2016 04:04 PM, Alison Schofield wrote: > On Mon, Jul 04, 2016 at 02:04:34PM -0700, Guenter Roeck wrote: >> On 07/04/2016 12:19 PM, Alison Schofield wrote: >>> In 2011, commit 774466add7c810fd7e4c8bcf41995b6799608880 changed >>> the detection class of these chips to I2C_CLASS_SPD based on this >>> premise: "makes more sense because these chips always live on >>> memory modules" >>> >>> Today these chips have applications beyond memory modules. >>> >> >> Do you have a specific example ? > The mcp9808 is popular among hobbyists and makers in projects that > monitor everything from their fish pond to their wine cellar. Beyond > that I'm just referring to Microchips datasheet and marketing words > saying that they target it for a wide range of apps beyond memory > devices. I guess the chance of one of them trying to use it, with a > Linux driver, and caring about auto detect are pretty slim. > A better example would be the MCP9085, which is officially JC42.4 compliant but also suggested for use as general purpose temperature sensor in its datasheet. I'll add your patch to -next. Thanks, Guenter > As you've guessed, I changed the Diolan for my purposes. I just found > it odd that jc42 was the only driver in hwmon, without I2C_CLASS_HWMON, > so I thought it was worth a look and rethink. > > So, no, nothing broken, nothing suspected incompatible. > > alisons > > >> >>> Add I2C_CLASS_HWMON as an additional detection class to allow >>> detection by hwmon class i2c adapters. >>> >> >> Practical impact should be limited, though. Most adapters have both >> I2C_CLASS_HWMON and I2C_CLASS_SPD flags set. Besides the Diolan adapters, >> which are experimental in nature anyway (and where it actually might make >> sense to add I2C_CLASS_SPD), do you have an example where a JC-42 compatible >> chip is used with an adapter which does not have I2C_CLASS_SPD set in >> its flags ? >> >>> Alternative is to replace the SPD w HWMON class, but that carries >>> risk for existing usage. >>> >> Yes, the driver would stop working on adapters which only have I2C_CLASS_SPD >> set. There are only two of those, but those two presumably _do_ have memory >> modules connected. >> >> Guenter >> >>> Signed-off-by: Alison Schofield >>> Cc: Daniel Baluta >>> --- >>> drivers/hwmon/jc42.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/hwmon/jc42.c b/drivers/hwmon/jc42.c >>> index 9887d32..1537ba0 100644 >>> --- a/drivers/hwmon/jc42.c >>> +++ b/drivers/hwmon/jc42.c >>> @@ -538,7 +538,7 @@ static const struct i2c_device_id jc42_id[] = { >>> MODULE_DEVICE_TABLE(i2c, jc42_id); >>> >>> static struct i2c_driver jc42_driver = { >>> - .class = I2C_CLASS_SPD, >>> + .class = I2C_CLASS_SPD | I2C_CLASS_HWMON, >>> .driver = { >>> .name = "jc42", >>> .pm = JC42_DEV_PM_OPS, >>> >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >