From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D21DFC4338F for ; Sat, 14 Aug 2021 16:09:37 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 95E6060F39 for ; Sat, 14 Aug 2021 16:09:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 95E6060F39 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Q9DADEQI4HYBOY+XHgLGkCllzjTwgt0ZA2iwOeK2DV8=; b=e+zmNz4+VTORw2 KQLvxACJaoHk48pwP4Vsreo5YpaZ4D9xH72+DHlFes9epUOJblbH6pTItZkJwYHO9raW5gUqC0UP/ kmQENFKSPjsqsLGy2hryV0AXrwwYzMgSnwvd999UtckpMhqfciUmX6ajmvN0Ih7hD9fRG25pglzJd VgAPgEL9CrXv9B4HkEpSPy1dcYoWxpC4CqwCsr5KLcsabb4BrqC6VCPjFKSyvpZ0W/d3IHwy5/HJS Wlt6Pp2TG5+r1J89cb3oAQjycOgCCw4toJQ2JU98REfCCqpuM2pOw2US8rDOFrHATWCJ83wIjPNwR dkSa1YF58+2fpwGXwLig==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mEwBr-00ENFC-IJ; Sat, 14 Aug 2021 16:07:19 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mEwBo-00ENEi-Fs; Sat, 14 Aug 2021 16:07:17 +0000 Received: from jic23-huawei (cpc108967-cmbg20-2-0-cust86.5-4.cable.virginm.net [81.101.6.87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D6B1660F21; Sat, 14 Aug 2021 16:07:10 +0000 (UTC) Date: Sat, 14 Aug 2021 17:10:07 +0100 From: Jonathan Cameron To: "hui.liu" Cc: Jonathan Cameron , , , , , , , , , , , , , , , Subject: Re: [PATCH v1 1/2] iio: mtk-auxadc: add support IIO_CHAN_INFO_RAW case Message-ID: <20210814171007.6892ae94@jic23-huawei> In-Reply-To: <042625639032bffe73b60a5c6274511e58e34ef4.camel@mediatek.com> References: <20210812054844.30575-1-hui.liu@mediatek.com> <20210812054844.30575-2-hui.liu@mediatek.com> <20210812190725.00007449@Huawei.com> <042625639032bffe73b60a5c6274511e58e34ef4.camel@mediatek.com> X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210814_090716_621423_051E445F X-CRM114-Status: GOOD ( 31.33 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 13 Aug 2021 11:46:24 +0800 hui.liu wrote: > On Thu, 2021-08-12 at 19:07 +0100, Jonathan Cameron wrote: > > On Thu, 12 Aug 2021 13:48:43 +0800 > > Hui Liu wrote: > > > > > Add support IIO_CHAN_INFO_RAW case. > > > > Why? > > > > We almost never support both RAW and PROCESSED as userspace should be > > fine to use either. There are a few reasons we've let drivers do > > this but I would like know why it matters to you and it definitely > > needs to be in the patch description. > > > Hi Jonathan, > > 1. To support ADC consumers' different types of requirement: some > consumers want to call iio_read_channel_raw to get raw data, the others > use iio_read_channel_processed to get voltage. Give an example of the consumer using the raw channel readback (without acess to any scaling information?) > 2. In our origin driver, if consumer call iio_read_channel_processed, > read back value is raw data. > > Could we use SCALE instead of PROCESSED in patch for next version, or > what's your suggestion? That would unfortunately be a userspace ABI change. We can add interfaces but taking them away is normally a problem :( Your reasons here are fine, subject to information on what consumer cares about having _RAW, please resend the patch with this information added to the description. Thanks, Jonathan > > Thanks. > > > > > > > Signed-off-by: Hui Liu > > > --- > > > drivers/iio/adc/mt6577_auxadc.c | 16 +++++++++++++++- > > > 1 file changed, 15 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/iio/adc/mt6577_auxadc.c > > > b/drivers/iio/adc/mt6577_auxadc.c > > > index 79c1dd68b909..e995d43287b2 100644 > > > --- a/drivers/iio/adc/mt6577_auxadc.c > > > +++ b/drivers/iio/adc/mt6577_auxadc.c > > > @@ -60,7 +60,8 @@ static const struct mtk_auxadc_compatible > > > mt6765_compat = { > > > .type = IIO_VOLTAGE, > > > \ > > > .indexed = 1, > > > \ > > > .channel = (idx), \ > > > - .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \ > > > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | > > > \ > > > + BIT(IIO_CHAN_INFO_PROCESSED), \ > > > } > > > > > > static const struct iio_chan_spec mt6577_auxadc_iio_channels[] = { > > > @@ -181,6 +182,19 @@ static int mt6577_auxadc_read_raw(struct > > > iio_dev *indio_dev, > > > struct mt6577_auxadc_device *adc_dev = iio_priv(indio_dev); > > > > > > switch (info) { > > > + case IIO_CHAN_INFO_RAW: > > > + *val = mt6577_auxadc_read(indio_dev, chan); > > > + if (*val < 0) { > > > + dev_notice(indio_dev->dev.parent, > > > + "failed to sample data on > > > channel[%d]\n", > > > + chan->channel); > > > + return *val; > > > + } > > > + if (adc_dev->dev_comp->sample_data_cali) > > > + *val = mt_auxadc_get_cali_data(*val, true); > > > + > > > + return IIO_VAL_INT; > > > + > > > case IIO_CHAN_INFO_PROCESSED: > > > *val = mt6577_auxadc_read(indio_dev, chan); > > > if (*val < 0) { > > > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel