From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-180.mta1.migadu.com (out-180.mta1.migadu.com [95.215.58.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0639C1A01BC for ; Mon, 24 Jun 2024 19:34:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719257694; cv=none; b=TBZsKWVA0l/tTsG1IXTRzLsQne16d36jL4dI/gn9UQ85uhVhDYO04Jgqfj33pb0lCM9lJWGD4pK5a2KVrNc82bg1+BupU+fmo39QLlJmbUWWTAPhKYeiYIDRw7mQXsHDBX45po/erqCpsITNNDxHMpFMcaAOtfG3ILM5wPyUmEY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719257694; c=relaxed/simple; bh=QTn1WRuA4hsCw/k8adDN6Jh64KjHr3yyO5fpW6vGjHU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=htgYewvVWbSyk1n/Won8Xp+LgZYl4o6VUdgc3EmT1noI/7jIam/jhUHvBnPfiTxVy3KPMOc1bxADvqqNrmzpW9G2CJJ8Z+5kcbyA/v6yDe98FkwVTjInvjkQdBbwQJ/fWKr5sxKa5iO8GaAnZ+T6AWUZwTPm5MyUV4t2z9i5uxw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=xgH3D7Fr; arc=none smtp.client-ip=95.215.58.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="xgH3D7Fr" X-Envelope-To: linux@roeck-us.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1719257691; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+Gm2PDGMMowWzUmm56U0hh5D/fJqNhmzLuHu2GZApjI=; b=xgH3D7FrktYrIkdGVYTAYPboDDd8QmQu52MF5MVVEc7wPvjFMAsusnlG26IB6k9NmqGUgq D2K8edbAy8hKIczFb1hPujNTQaaBenZuoE3drW9gaweZyP0nsWo7cIn8hFYFc+3kHgirnm /77XfMiFjxeIUOykPJK6lFBo1MoIjDQ= X-Envelope-To: jic23@kernel.org X-Envelope-To: jdelvare@suse.com X-Envelope-To: linux-iio@vger.kernel.org X-Envelope-To: linux-hwmon@vger.kernel.org X-Envelope-To: linux-kernel@vger.kernel.org X-Envelope-To: lars@metafoo.de Message-ID: <63046df2-e1fb-442b-a55f-2a9847c6c59e@linux.dev> Date: Mon, 24 Jun 2024 15:34:46 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v2 2/2] hwmon: iio: Add labels from IIO channels To: Guenter Roeck , Jonathan Cameron , Jean Delvare , linux-iio@vger.kernel.org, linux-hwmon@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Lars-Peter Clausen References: <20240624174601.1527244-1-sean.anderson@linux.dev> <20240624174601.1527244-3-sean.anderson@linux.dev> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sean Anderson In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 6/24/24 14:47, Guenter Roeck wrote: > On 6/24/24 10:46, Sean Anderson wrote: >> Add labels from IIO channels to our channels. This allows userspace to >> display more meaningful names instead of "in0" or "temp5". >> >> Although lm-sensors gracefully handles errors when reading channel >> labels, the ABI says the label attribute >> >>> Should only be created if the driver has hints about what this voltage >>> channel is being used for, and user-space doesn't. >> >> Therefore, we test to see if the channel has a label before >> creating the attribute. >> > > FWIW, complaining about an ABI really does not belong into a commit > message. Maybe you and lm-sensors don't care about error returns when > reading a label, but there are other userspace applications which may > expect drivers to follow the ABI. Last time I checked, the basic rule > was still "Don't break userspace", and that doesn't mean "it's ok to > violate / break an ABI as long as no one notices". This isn't complaining about the ABI, just documenting the reason it was done this way... >> Signed-off-by: Sean Anderson >> --- >> >> Changes in v2: >> - Check if the label exists before creating the attribute >> >>   drivers/hwmon/iio_hwmon.c | 45 ++++++++++++++++++++++++++++++++++----- >>   1 file changed, 40 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/hwmon/iio_hwmon.c b/drivers/hwmon/iio_hwmon.c >> index 4c8a80847891..5722cb9d81f9 100644 >> --- a/drivers/hwmon/iio_hwmon.c >> +++ b/drivers/hwmon/iio_hwmon.c >> @@ -33,6 +33,17 @@ struct iio_hwmon_state { >>       struct attribute **attrs; >>   }; >>   +static ssize_t iio_hwmon_read_label(struct device *dev, >> +                  struct device_attribute *attr, >> +                  char *buf) >> +{ >> +    struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr); >> +    struct iio_hwmon_state *state = dev_get_drvdata(dev); >> +    struct iio_channel *chan = &state->channels[sattr->index]; >> + >> +    return iio_read_channel_label(chan, buf); >> +} >> + > > I personally find it a bit kludgy that an in-kernel API would do a > sysfs write like this and expect a page-aligned buffer as parameter, > but since Jonathan is fine with it: This is also how the in-kernel iio_read_channel_ext_info API works. I agree that it is a strange API, but I do not want to rewrite all the implementing drivers. --Sean > Acked-by: Guenter Roeck > > Jonathan, please apply through your tree. > > Thanks, > Guenter >