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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 C5619C352A3 for ; Tue, 11 Feb 2020 15:22:31 +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 78C4A206DB for ; Tue, 11 Feb 2020 15:22:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="bgWZmGkX"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=st.com header.i=@st.com header.b="ScAg1fvL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 78C4A206DB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=st.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Content-ID:In-Reply-To: References:Message-ID:Date:Subject:To:From:Reply-To:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ZHUB9x8kr23SzJbwt2kG7it9XJmrFE+u8wEb4ooxTzg=; b=bgWZmGkXlOHec5 dSkv75L+K0zi+7wsaDjTK77UL1qtQYLKCa9LoVhJM1r9GKeSUb7b+6KDmiqS4XlNAhCAY8htpPWoR QGFAkXT9MEyaIvbC1nVh8fmvFULzJ0AKbtEl9zf0j0MoengPoyM+rX4q039utlX/qenKHrl/EpNp4 SX6Vq3QSPnDg/OcblDF1g7pur9kSgBFbGNjT426qwUswnRzFehikNkzBxH4V/ivV+kym7aX0PfNny JdtSLBczC6hS3SQ9gfdabum+cnzhfdhbEzU2HFfUYUJOlq458DjVhWgO4NzZelDsFZWH4G72qwP6r BZmmm2dq0STt0okBiVMw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j1XMl-00013l-TZ; Tue, 11 Feb 2020 15:22:23 +0000 Received: from mx07-00178001.pphosted.com ([62.209.51.94]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1j1XMi-00011k-J7 for linux-arm-kernel@lists.infradead.org; Tue, 11 Feb 2020 15:22:22 +0000 Received: from pps.filterd (m0046668.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 01BFESwq030309; Tue, 11 Feb 2020 16:22:15 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=from : to : cc : subject : date : message-id : references : in-reply-to : content-type : content-id : content-transfer-encoding : mime-version; s=STMicroelectronics; bh=8FH4GMVMTuncapNMvYvyQMea4jBp3XjADEQ2jECszFU=; b=ScAg1fvLVaFAAZXimfYb21JBP1d4QQQj1s0uks6rBNnzfQLuHQXsUNtylpyjkgcUYJVn Njozwi8ONYzJLKyL6RX2VwsabBjM0dLcKHN4yDkcU/wFf8tQAO0QZiQ6HZJyvG068lDh EyUzGDrvKSYPJqdsdJup1blUtb2C+ISMFrgKwXAKsFs1NqakT6y9w4AJU4NXLVLpBH1v Ly/dg27xrTNb4rlIa+asVVTsMWHm5rYf4ICihUnXU8+PoomtKJypfKrJfXpVSOPA4uUa fErCgGiQUud1hIk1p/LpbfohBl6F+a8/6MTLbcUQneLQF2NVlKMlLYKZpVRTG744wVFo ew== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 2y1ufh6cdj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 11 Feb 2020 16:22:15 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id BAF28100034; Tue, 11 Feb 2020 16:22:10 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag6node2.st.com [10.75.127.17]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id A50532BEC61; Tue, 11 Feb 2020 16:22:10 +0100 (CET) Received: from SFHDAG6NODE2.st.com (10.75.127.17) by SFHDAG6NODE2.st.com (10.75.127.17) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Tue, 11 Feb 2020 16:22:10 +0100 Received: from SFHDAG6NODE2.st.com ([fe80::a56f:c186:bab7:13d6]) by SFHDAG6NODE2.st.com ([fe80::a56f:c186:bab7:13d6%20]) with mapi id 15.00.1347.000; Tue, 11 Feb 2020 16:22:10 +0100 From: Olivier MOYSAN To: Jonathan Cameron Subject: Re: [PATCH 2/4] iio: adc: sd modulator: add scale support Thread-Topic: [PATCH 2/4] iio: adc: sd modulator: add scale support Thread-Index: AQHV3plRO+Mdv2KS6Eiey+LjbbRUC6gWEBeA Date: Tue, 11 Feb 2020 15:22:10 +0000 Message-ID: <740eb007-3428-f336-fbe5-3713faaa6f4c@st.com> References: <20200204101008.11411-1-olivier.moysan@st.com> <20200204101008.11411-3-olivier.moysan@st.com> <20200208160327.334da020@archlinux> In-Reply-To: <20200208160327.334da020@archlinux> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.75.127.46] Content-ID: <8FAC793B44188043905F2B2F239FEEA3@st.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.572 definitions=2020-02-11_04:2020-02-10, 2020-02-11 signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200211_072220_937608_B22A2728 X-CRM114-Status: GOOD ( 26.65 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , "lars@metafoo.de" , "linux-iio@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "robh+dt@kernel.org" , "pmeerw@pmeerw.net" , "knaack.h@gmx.de" , "linux-stm32@st-md-mailman.stormreply.com" , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Jonathan, On 2/8/20 5:03 PM, Jonathan Cameron wrote: > On Tue, 4 Feb 2020 11:10:06 +0100 > Olivier Moysan wrote: > >> Add scale support to sigma delta modulator. >> >> Signed-off-by: Olivier Moysan > I note below that there are probably some complexities around > whether vref is used as you have it here or not. > > A few other bits inline around a race condition introduced in probe / remove. > > Thanks, > > Jonathan > >> --- >> drivers/iio/adc/sd_adc_modulator.c | 108 ++++++++++++++++++++++++++--- >> 1 file changed, 100 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/iio/adc/sd_adc_modulator.c b/drivers/iio/adc/sd_adc_modulator.c >> index 560d8c7d9d86..a83f35832050 100644 >> --- a/drivers/iio/adc/sd_adc_modulator.c >> +++ b/drivers/iio/adc/sd_adc_modulator.c >> @@ -10,8 +10,7 @@ >> #include >> #include >> #include >> - >> -static const struct iio_info iio_sd_mod_iio_info; >> +#include >> >> static const struct iio_chan_spec iio_sd_mod_ch = { >> .type = IIO_VOLTAGE, >> @@ -21,34 +20,126 @@ static const struct iio_chan_spec iio_sd_mod_ch = { >> .realbits = 1, >> .shift = 0, >> }, >> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), > This relies on generic sigma delta modulators using an external vref. > They might have an internal always on regulator... > I would suggest we only support scale for devices with explicitly > defined compatibles where we can know what regulators are used etc. > > For many devices, there will be a single powersupply called vdd-supply > or similar in DT. It may also provide a reference voltage. I will remove scale support for generic sd-modulator, according to your comment on sd modulator bindings. The DFSDM driver expects scale attribute from sd-modulator. So, some rework of DFSDM driver will be required to also support raw data reading. >> +}; >> + >> +static const struct iio_chan_spec iio_sd_mod_ch_ads = { >> + .type = IIO_VOLTAGE, >> + .indexed = 1, >> + .scan_type = { >> + .sign = 'u', >> + .realbits = 1, >> + .shift = 0, >> + }, >> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), >> + .differential = 1, >> +}; >> + >> +struct iio_sd_mod_priv { >> + struct regulator *vref; >> + int vref_mv; >> +}; >> + >> +static int iio_sd_mod_read_raw(struct iio_dev *indio_dev, >> + struct iio_chan_spec const *chan, int *val, >> + int *val2, long mask) >> +{ >> + struct iio_sd_mod_priv *priv = iio_priv(indio_dev); >> + >> + switch (mask) { >> + case IIO_CHAN_INFO_SCALE: >> + *val = priv->vref_mv; >> + *val2 = chan->scan_type.realbits; >> + return IIO_VAL_INT; >> + } >> + >> + return -EINVAL; >> +} >> + >> +static const struct iio_info iio_sd_mod_iio_info = { >> + .read_raw = iio_sd_mod_read_raw, >> }; >> >> static int iio_sd_mod_probe(struct platform_device *pdev) >> { >> struct device *dev = &pdev->dev; >> + struct iio_sd_mod_priv *priv; >> struct iio_dev *iio; >> + int ret; >> >> - iio = devm_iio_device_alloc(dev, 0); >> + iio = devm_iio_device_alloc(dev, sizeof(*priv)); >> if (!iio) >> return -ENOMEM; >> >> + iio->channels = (const struct iio_chan_spec *) >> + of_device_get_match_data(&pdev->dev); >> + >> + priv = iio_priv(iio); >> + >> iio->dev.parent = dev; >> iio->dev.of_node = dev->of_node; >> iio->name = dev_name(dev); >> iio->info = &iio_sd_mod_iio_info; >> iio->modes = INDIO_BUFFER_HARDWARE; >> - >> iio->num_channels = 1; >> - iio->channels = &iio_sd_mod_ch; >> >> platform_set_drvdata(pdev, iio); >> >> - return devm_iio_device_register(&pdev->dev, iio); >> + priv->vref = devm_regulator_get_optional(dev, "vref"); >> + if (IS_ERR(priv->vref)) { >> + ret = PTR_ERR(priv->vref); >> + if (ret != -ENODEV) { >> + if (ret != -EPROBE_DEFER) >> + dev_err(dev, "vref get failed, %d\n", ret); >> + return ret; >> + } >> + } >> + >> + if (!IS_ERR(priv->vref)) { >> + ret = regulator_enable(priv->vref); >> + if (ret < 0) { >> + dev_err(dev, "vref enable failed %d\n", ret); >> + return ret; >> + } >> + >> + ret = regulator_get_voltage(priv->vref); >> + if (ret < 0) { >> + dev_err(dev, "vref get failed, %d\n", ret); >> + goto err_regulator_disable; >> + } >> + >> + priv->vref_mv = ret / 1000; >> + dev_dbg(dev, "vref+=%dmV\n", priv->vref_mv); >> + } >> + >> + ret = devm_iio_device_register(&pdev->dev, iio); > This exposes the userspace and in kernel interfaces. Those > are partly dependent on the regulator enable you have above. > > Using devm_ version fo this interface leaves you with a race in remove. > The regulator is disabled before you have remove the interfaces that > will only work if we assume it is still on. > > Hence, you should either use devm_add_action_or_reset magic > to ensure we still do everything in the right order, or do it > manually by using iio_device_register and iio_device_unregister. > I will fix this in v2. Regards Olivier >> + if (ret < 0) { >> + dev_err(dev, "Failed to register sd-modulator, %d\n", ret); >> + goto err_regulator_disable; >> + } >> + >> + return 0; >> + >> +err_regulator_disable: >> + regulator_disable(priv->vref); >> + >> + return ret; >> +} >> + >> +static int iio_sd_mod_remove(struct platform_device *pdev) >> +{ >> + struct iio_dev *indio_dev = platform_get_drvdata(pdev); >> + struct iio_sd_mod_priv *priv = iio_priv(indio_dev); >> + >> + if (priv->vref) >> + return regulator_disable(priv->vref); >> + >> + return 0; >> } >> >> static const struct of_device_id sd_adc_of_match[] = { >> - { .compatible = "sd-modulator" }, >> - { .compatible = "ads1201" }, >> + { .compatible = "sd-modulator", .data = &iio_sd_mod_ch }, >> + { .compatible = "ads1201", .data = &iio_sd_mod_ch_ads }, >> { } >> }; >> MODULE_DEVICE_TABLE(of, sd_adc_of_match); >> @@ -59,6 +150,7 @@ static struct platform_driver iio_sd_mod_adc = { >> .of_match_table = of_match_ptr(sd_adc_of_match), >> }, >> .probe = iio_sd_mod_probe, >> + .remove = iio_sd_mod_remove, >> }; >> >> module_platform_driver(iio_sd_mod_adc); _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel