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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 344B3CA0EDA for ; Tue, 12 Aug 2025 12:39:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=4fqFKZRX+VXRgMC+0U0SHSLoX7IVzWzQk49myeTjMC0=; b=1uKB2SvlM1a/9cfTbH2z6NHvP0 Hz64FQhDlwB5wvRZPX+rz+Hkp9sn2CqQjJ79m6hfmRGfq+/bJ5ERJAt2s3gv9ra0pZKtQ4iFHGqnu d6n8ukDMov8J7VUlN6M/qaonUYkbHJW3Mk39saNE7ib1SDuKUnP7O/THI3gJKykT3Cu9JUbZ0FDl4 ql170dNahsuxKoT30+aL4zvb6Hj9gK3gh5WKZiUIoDyuHDSi2u4F2x+3/zq56g9fWfn7KVeXLa1LX NsPU0gU+PjWGBNJgx/4Gmi5ru4c4anoByWxUizv4C0EkG3tzPymNtASteT6+e+QRKXXT3UbO7RgWA PflRpUHw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uloHT-0000000AlOh-47LG; Tue, 12 Aug 2025 12:39:08 +0000 Received: from cpanel.siel.si ([46.19.9.99]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1ulkdp-0000000AHe2-3api for linux-arm-kernel@lists.infradead.org; Tue, 12 Aug 2025 08:46:02 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=norik.com; s=default; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=4fqFKZRX+VXRgMC+0U0SHSLoX7IVzWzQk49myeTjMC0=; b=lng0be1EtH1NwTkyOrfJ1ypzjm Ddta3DOel3KELJHU7Ljf6sNwYidTcfJRFDolNYD4s4qiCTxkgCrn1Y1XPQAm+t/R1QPosqnglWg2P eoTtqS1uE6Mm2Z4KuWN2TqGNPwsI/qNiAtBT5l7PPRPOlAwkz9YUdQgc/AB9xsQMTAzsyJTUmr2Ji 6rVQjAgQ2fWxwnE/ZwXlpCWuwoPZG8AsXWfYRmMbZaYy6NR5kCfthx6GKrzajxmqgBSPqA/wp61cw KCS+JVHajYr1LZSW/2uQPtMLDxsRtKN3gpex3QBS5z74C8cLYHomnHe3omMdksCoTgSknxUaKp7OF TnXF1q+w==; Received: from [89.212.21.243] (port=39484 helo=[192.168.69.116]) by cpanel.siel.si with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.96.2) (envelope-from ) id 1ulkdj-00DLjg-0H; Tue, 12 Aug 2025 10:45:50 +0200 Message-ID: Date: Tue, 12 Aug 2025 10:45:48 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/2] iio: adc: imx93_adc: load calibrated values even calibration failed To: Haibo Chen , Jonathan Cameron , David Lechner , =?UTF-8?Q?Nuno_S=C3=A1?= , Andy Shevchenko , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam Cc: linux-iio@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, "upstream@lists.phytec.de" References: <20250812-adc-v2-0-0260833f13b8@nxp.com> <20250812-adc-v2-2-0260833f13b8@nxp.com> Content-Language: en-US From: Primoz Fiser Autocrypt: addr=primoz.fiser@norik.com; keydata= xjMEZrROOxYJKwYBBAHaRw8BAQdAADVOb5tiLVTUAC9nu/FUl4gj/+4fDLqbc3mk0Vz8riTN JVByaW1veiBGaXNlciA8cHJpbW96LmZpc2VyQG5vcmlrLmNvbT7CiQQTFggAMRYhBK2YFSAH ExsBZLCwJGoLbQEHbnBPBQJmtE47AhsDBAsJCAcFFQgJCgsFFgIDAQAACgkQagttAQducE+T gAD+K4fKlIuvH75fAFwGYG/HT3F9mN64majvqJqvp3gTB9YBAL12gu+cm11m9JMyOyN0l6Os jStsQFghPkzBSDWSDN0NzjgEZrROPBIKKwYBBAGXVQEFAQEHQP2xtEOhbgA+rfzvvcFkV1zK 6ym3/c/OUQObCp50BocdAwEIB8J4BBgWCAAgFiEErZgVIAcTGwFksLAkagttAQducE8FAma0 TjwCGwwACgkQagttAQducE8ucAD9F1sXtQD4iA7Qu+SwNUAp/9x7Cqr37CSb2p6hbRmPJP8B AMYR91JYlFmOJ+ScPhQ8/MgFO+V6pa7K2ebk5xYqsCgA Organization: Norik systems d.o.o. In-Reply-To: <20250812-adc-v2-2-0260833f13b8@nxp.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - cpanel.siel.si X-AntiAbuse: Original Domain - lists.infradead.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - norik.com X-Get-Message-Sender-Via: cpanel.siel.si: authenticated_id: primoz.fiser@norik.com X-Authenticated-Sender: cpanel.siel.si: primoz.fiser@norik.com X-Source: X-Source-Args: X-Source-Dir: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250812_014558_373194_47D6E5F8 X-CRM114-Status: GOOD ( 19.82 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Haibo, On 12. 08. 25 10:04, Haibo Chen wrote: > ADC calibration might fail because of the noise on reference voltage. > To avoid calibration fail, need to meet the following requirement: > ADC reference voltage Noise < 1.8V * 1/2^ENOB > > For the case which the ADC reference voltage on board do not meet > the requirement, still load the calibrated values, so ADC can also > work but maybe not that accurate. Reviewed-by: Primoz Fiser Thanks for fixing this. BR, Primoz > > Signed-off-by: Haibo Chen > --- > drivers/iio/adc/imx93_adc.c | 18 +++++++++++++++--- > 1 file changed, 15 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/adc/imx93_adc.c b/drivers/iio/adc/imx93_adc.c > index 8471737ac04a2bac0417a6397f20865f6a2c01ca..17b0a2548b0a3614ac537b01e28bc3144d17d6fc 100644 > --- a/drivers/iio/adc/imx93_adc.c > +++ b/drivers/iio/adc/imx93_adc.c > @@ -38,6 +38,7 @@ > #define IMX93_ADC_PCDR6 0x118 > #define IMX93_ADC_PCDR7 0x11C > #define IMX93_ADC_CALSTAT 0x39C > +#define IMX93_ADC_CALCFG0 0x3A0 > > /* ADC bit shift */ > #define IMX93_ADC_MCR_MODE_MASK BIT(29) > @@ -58,6 +59,8 @@ > #define IMX93_ADC_IMR_ECH_MASK BIT(0) > #define IMX93_ADC_PCDR_CDATA_MASK GENMASK(11, 0) > > +#define IMX93_ADC_CALCFG0_LDFAIL_MASK BIT(4) > + > /* ADC status */ > #define IMX93_ADC_MSR_ADCSTATUS_IDLE 0 > #define IMX93_ADC_MSR_ADCSTATUS_POWER_DOWN 1 > @@ -145,7 +148,7 @@ static void imx93_adc_config_ad_clk(struct imx93_adc *adc) > > static int imx93_adc_calibration(struct imx93_adc *adc) > { > - u32 mcr, msr; > + u32 mcr, msr, calcfg; > int ret; > > /* make sure ADC in power down mode */ > @@ -158,6 +161,11 @@ static int imx93_adc_calibration(struct imx93_adc *adc) > > imx93_adc_power_up(adc); > > + /* Enable loading of calibrated values even in fail condition */ > + calcfg = readl(adc->regs + IMX93_ADC_CALCFG0); > + calcfg |= IMX93_ADC_CALCFG0_LDFAIL_MASK; > + writel(calcfg, adc->regs + IMX93_ADC_CALCFG0); > + > /* > * TODO: we use the default TSAMP/NRSMPL/AVGEN in MCR, > * can add the setting of these bit if need in future. > @@ -180,9 +188,13 @@ static int imx93_adc_calibration(struct imx93_adc *adc) > /* check whether calbration is success or not */ > msr = readl(adc->regs + IMX93_ADC_MSR); > if (msr & IMX93_ADC_MSR_CALFAIL_MASK) { > + /* > + * Only give warning here, this means the noise of the > + * reference voltage do not meet the requirement: > + * ADC reference voltage Noise < 1.8V * 1/2^ENOB > + * And the resault of ADC is not that accurate. > + */ > dev_warn(adc->dev, "ADC calibration failed!\n"); > - imx93_adc_power_down(adc); > - return -EAGAIN; > } > > return 0; > -- Primoz Fiser phone: +386-41-390-545 email: primoz.fiser@norik.com -- Norik systems d.o.o. Your embedded software partner Slovenia, EU phone: +386-41-540-545 email: info@norik.com