Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751445AbaKYR7Q (ORCPT ); Tue, 25 Nov 2014 12:59:16 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:60921 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751096AbaKYR7O (ORCPT ); Tue, 25 Nov 2014 12:59:14 -0500 Message-ID: <5474C36C.1020004@roeck-us.net> Date: Tue, 25 Nov 2014 09:59:08 -0800 From: Guenter Roeck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Bartosz Golaszewski CC: LKML , Benoit Cousson , Patrick Titiano Subject: Re: [PATCH 1/5] hwmon: ina2xx: bail-out from ina2xx_probe() in case of configuration errors References: <1416930423-12179-1-git-send-email-bgolaszewski@baylibre.com> <1416930423-12179-2-git-send-email-bgolaszewski@baylibre.com> <5474A72D.2000309@roeck-us.net> <5474B564.9080902@roeck-us.net> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-CTCH-PVer: 0000001 X-CTCH-Spam: Unknown X-CTCH-VOD: Unknown X-CTCH-Flags: 0 X-CTCH-RefID: str=0001.0A020207.5474C371.0325,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-CTCH-Score: 0.001 X-CTCH-ScoreCust: 0.000 X-CTCH-Rules: C_4847, X-CTCH-SenderID: linux@roeck-us.net X-CTCH-SenderID-Flags: 0 X-CTCH-SenderID-TotalMessages: 3 X-CTCH-SenderID-TotalSpam: 0 X-CTCH-SenderID-TotalSuspected: 0 X-CTCH-SenderID-TotalConfirmed: 0 X-CTCH-SenderID-TotalBulk: 0 X-CTCH-SenderID-TotalVirus: 0 X-CTCH-SenderID-TotalRecipients: 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: mailgid no entry from get_relayhosts_entry 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 11/25/2014 09:50 AM, Bartosz Golaszewski wrote: > 2014-11-25 17:59 GMT+01:00 Guenter Roeck : >> The new functions _might_ make a bit more sense if you would >> implement the necessary calculations in the functions, but you are >> not doing that. Instead, in the next patch, you introduce yet >> another function to do the calibration calculation, just to add it >> as parameter to the actual calibration function whenever you call it. > > This wasn't my intention, but I'll keep that in mind for the next version. > >> - I don't accept unnecessary ( ). >> - I don't accept unnecessary typecasts. >> - If you don't accept negative values, use kstrtoul(). >> - kstrtol can at least in theory return other errors besides -EINVAL. > > I'll fix those in the next version. > >> - Locking should be done in the calling code. It is not needed during >> probe and more appropriate in set functions. > > I don't use locks in probe - they're used directly in > ina2xx_set_value() or indirectly in ina226_update_avg(), but these > functions are never called from probe. > >> - Any reason for selecting "rshunt" as sysfs attribute name instead >> of, say, shunt-resistor or maybe shunt_resistor ? > > I'll change it to shunt_resistor for more readability. > >> - Returning -ENODEV from a set function doesn't make much sense. > > It does make sense in case of ACME (http://baylibre.com/acme/) - a > probe can be disconnected at run-time, which, even without these > patches, would cause ina2xx_update_device() to error out when called > by ina2xx_show_value(): > It seems to me this is a problem of your architecture. That doesn't make it a generic problem. Your architecture should detect that a probe was disconnected and de-instantiate the device automatically if so, and re-instantiate it if it is re-inserted. Ultimately this should be done with, for example, devicetree overlays. Even worse, the remove/reinsertion sequence results in a non-initialized chip. This makes me wonder: Is the shunt resistor value set by software, or by replacing one probe with another ? Guenter > 231 int rv = i2c_smbus_read_word_swapped(client, i); > 232 if (rv < 0) { > 233 ret = ERR_PTR(rv); > 234 goto abort; > > I just reproduced this behavior in ina2xx_set_value(). > >> - We don't overwrite error codes except in probe functions. > > I'll fix that too. > > Bart > -- 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/