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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 22AC9C3F2D7 for ; Wed, 4 Mar 2020 08:56:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EFD2A20870 for ; Wed, 4 Mar 2020 08:56:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="hz0b0Qz0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387726AbgCDI4A (ORCPT ); Wed, 4 Mar 2020 03:56:00 -0500 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:51062 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727734AbgCDIz7 (ORCPT ); Wed, 4 Mar 2020 03:55:59 -0500 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 0248s6Gp016466; Wed, 4 Mar 2020 09:55:50 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=STMicroelectronics; bh=/qiD8X3t4cPtlJawNy1q2Zqg0xWhtfmpQr6wgwRGjrM=; b=hz0b0Qz0JNlgGjP1cioYkf5IGoiRBgECEFc+UFw+3ZkktXnOidYT/kqNYTPSdyFu/W15 3c9Jvudx4NKmVAZscAkPTlEwDvgepIDzIiFBlC2psgIASwfVNIHwdjNLkaLXfwliyFbe 7kwLBhNJppeTrzb1BEfQgHaPOrD7Q6FizAX6dPzA0nfgc06HigMHv9Ut8j3lrHFabXPR qi42hY5070HPMsEP5vHDu3h5tUCSABYXYU9pWaGGfcEf8rTxksL/5AGKVDUwOE/il2N5 pYoZ6M6+nHxvenxN0qnW9GiXui7k3XrpkDoCjaYX5QxhPa5lWSY6gtw3CsQAL+mIh5Ex 8g== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 2yfea6yqap-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 04 Mar 2020 09:55:50 +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 01A0310003B; Wed, 4 Mar 2020 09:55:45 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag5node3.st.com [10.75.127.15]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 3DD1920F831; Wed, 4 Mar 2020 09:55:45 +0100 (CET) Received: from localhost (10.75.127.47) by SFHDAG5NODE3.st.com (10.75.127.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 4 Mar 2020 09:55:44 +0100 From: Fabrice Gasnier To: , CC: , , , , , Subject: [PATCH] regulator: stm32-vrefbuf: fix a possible overshoot when re-enabling Date: Wed, 4 Mar 2020 09:55:32 +0100 Message-ID: <1583312132-20932-1-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.75.127.47] X-ClientProxiedBy: SFHDAG2NODE2.st.com (10.75.127.5) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-03-04_01:2020-03-03,2020-03-04 signatures=0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There maybe an overshoot, when disabling, then re-enabling vrefbuf too quickly. VREFBUF is used by ADC/DAC on some boards. When re-enabling too quickly, an overshoot on the reference voltage make the conversions inaccurate for a short period of time. - Don't put the VREFBUF in HiZ when disabling, to force an active discharge. - Enforce a 1ms OFF/ON delay Fixes: 0cdbf481e927 ("regulator: Add support for stm32-vrefbuf") Signed-off-by: Fabrice Gasnier --- drivers/regulator/stm32-vrefbuf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/regulator/stm32-vrefbuf.c b/drivers/regulator/stm32-vrefbuf.c index bdfaf7e..992bc18 100644 --- a/drivers/regulator/stm32-vrefbuf.c +++ b/drivers/regulator/stm32-vrefbuf.c @@ -88,7 +88,7 @@ static int stm32_vrefbuf_disable(struct regulator_dev *rdev) } val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); - val = (val & ~STM32_ENVR) | STM32_HIZ; + val &= ~STM32_ENVR; writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); pm_runtime_mark_last_busy(priv->dev); @@ -175,6 +175,7 @@ static const struct regulator_desc stm32_vrefbuf_regu = { .volt_table = stm32_vrefbuf_voltages, .n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages), .ops = &stm32_vrefbuf_volt_ops, + .off_on_delay = 1000, .type = REGULATOR_VOLTAGE, .owner = THIS_MODULE, }; -- 2.7.4 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=-9.8 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_GIT 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 046A0C3F2D1 for ; Wed, 4 Mar 2020 08:56:00 +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 C9CB020870 for ; Wed, 4 Mar 2020 08:55:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="h6zsgcz5"; 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Wed, 04 Mar 2020 09:55:50 +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 01A0310003B; Wed, 4 Mar 2020 09:55:45 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag5node3.st.com [10.75.127.15]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 3DD1920F831; Wed, 4 Mar 2020 09:55:45 +0100 (CET) Received: from localhost (10.75.127.47) by SFHDAG5NODE3.st.com (10.75.127.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 4 Mar 2020 09:55:44 +0100 From: Fabrice Gasnier To: , Subject: [PATCH] regulator: stm32-vrefbuf: fix a possible overshoot when re-enabling Date: Wed, 4 Mar 2020 09:55:32 +0100 Message-ID: <1583312132-20932-1-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 X-Originating-IP: [10.75.127.47] X-ClientProxiedBy: SFHDAG2NODE2.st.com (10.75.127.5) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.572 definitions=2020-03-04_01:2020-03-03, 2020-03-04 signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200304_005555_688910_C884BF55 X-CRM114-Status: GOOD ( 14.60 ) 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: alexandre.torgue@st.com, linux-kernel@vger.kernel.org, mcoquelin.stm32@gmail.com, fabrice.gasnier@st.com, 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 There maybe an overshoot, when disabling, then re-enabling vrefbuf too quickly. VREFBUF is used by ADC/DAC on some boards. When re-enabling too quickly, an overshoot on the reference voltage make the conversions inaccurate for a short period of time. - Don't put the VREFBUF in HiZ when disabling, to force an active discharge. - Enforce a 1ms OFF/ON delay Fixes: 0cdbf481e927 ("regulator: Add support for stm32-vrefbuf") Signed-off-by: Fabrice Gasnier --- drivers/regulator/stm32-vrefbuf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/regulator/stm32-vrefbuf.c b/drivers/regulator/stm32-vrefbuf.c index bdfaf7e..992bc18 100644 --- a/drivers/regulator/stm32-vrefbuf.c +++ b/drivers/regulator/stm32-vrefbuf.c @@ -88,7 +88,7 @@ static int stm32_vrefbuf_disable(struct regulator_dev *rdev) } val = readl_relaxed(priv->base + STM32_VREFBUF_CSR); - val = (val & ~STM32_ENVR) | STM32_HIZ; + val &= ~STM32_ENVR; writel_relaxed(val, priv->base + STM32_VREFBUF_CSR); pm_runtime_mark_last_busy(priv->dev); @@ -175,6 +175,7 @@ static const struct regulator_desc stm32_vrefbuf_regu = { .volt_table = stm32_vrefbuf_voltages, .n_voltages = ARRAY_SIZE(stm32_vrefbuf_voltages), .ops = &stm32_vrefbuf_volt_ops, + .off_on_delay = 1000, .type = REGULATOR_VOLTAGE, .owner = THIS_MODULE, }; -- 2.7.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel