From patchwork Sat Feb 16 09:45:44 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Krzysztof Kozlowski X-Patchwork-Id: 1043402 X-Patchwork-Delegate: promsoft@gmail.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lists.denx.de (client-ip=81.169.180.215; helo=lists.denx.de; envelope-from=u-boot-bounces@lists.denx.de; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="YI8EK2OZ"; dkim-atps=neutral Received: from lists.denx.de (dione.denx.de [81.169.180.215]) by ozlabs.org (Postfix) with ESMTP id 441lgM3hYzz9s4Z for ; Sat, 16 Feb 2019 20:48:15 +1100 (AEDT) Received: by lists.denx.de (Postfix, from userid 105) id 273F2C21DE8; Sat, 16 Feb 2019 09:47:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lists.denx.de X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=T_DKIM_INVALID autolearn=unavailable autolearn_force=no version=3.4.0 Received: from lists.denx.de (localhost [IPv6:::1]) by lists.denx.de (Postfix) with ESMTP id 2D59CC21D65; Sat, 16 Feb 2019 09:46:35 +0000 (UTC) Received: by lists.denx.de (Postfix, from userid 105) id C74D1C21E42; Sat, 16 Feb 2019 09:46:12 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by lists.denx.de (Postfix) with ESMTPS id DF2FDC21EE3 for ; Sat, 16 Feb 2019 09:46:08 +0000 (UTC) Received: from localhost.localdomain (unknown [194.230.155.153]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C7E8A222E0; Sat, 16 Feb 2019 09:46:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550310367; bh=YH6BOm2EotAvSdn7hqkT2Tu0ZuuDUMfsgaXPGX8bTPw=; h=From:To:Subject:Date:In-Reply-To:References:From; b=YI8EK2OZrwCDpvdeoq6xAompmZkqgur21JWTENBPAxriQ/koh/FvSfSPlqbw8kT/S 0/FnwIn8N0giXoK2g7sqUsiUKlX95haaRvLUgQSTGnB8TkeRiLtLBV6lgaz8XFEkr1 vMAD+bgoiDX4Z4+i4EBQfjVuvAX+bQKoEkRUBf1Q= From: Krzysztof Kozlowski To: Albert Aribaud , Jaehoon Chung , Lukasz Majewski , Krzysztof Kozlowski , Minkyu Kang , Simon Glass , Marek Szyprowski , u-boot@lists.denx.de Date: Sat, 16 Feb 2019 10:45:44 +0100 Message-Id: <20190216094548.911-6-krzk@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190216094548.911-1-krzk@kernel.org> References: <20190216094548.911-1-krzk@kernel.org> Subject: [U-Boot] [PATCH v3 5/9] arm: exynos: Wait till ADC stabilizes before checking Odroid HC1 revision X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.18 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: u-boot-bounces@lists.denx.de Sender: "U-Boot" Fix detection of Odroid HC1 (Exynos5422) after reboot if kernel disabled the LDO4/VDD_ADC regulator. The LDO4 supplies both ADC block and the ADC input AIN9. Voltage on AIN9 will rise slowly, so be patient and wait for it to stabilize. First reads on Odroid HC1 return 305, 1207, 1297 and finally 1308 (reference value is 1309). Signed-off-by: Krzysztof Kozlowski --- board/samsung/common/exynos5-dt-types.c | 38 ++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-) diff --git a/board/samsung/common/exynos5-dt-types.c b/board/samsung/common/exynos5-dt-types.c index 7c1271d6547a..516c32923e44 100644 --- a/board/samsung/common/exynos5-dt-types.c +++ b/board/samsung/common/exynos5-dt-types.c @@ -57,12 +57,48 @@ static unsigned int odroid_get_rev(void) return 0; } +/* + * Read ADC at least twice and check the resuls. If regulator providing voltage + * on to measured point was just turned on, first reads might require time + * to stabilize. + */ +static int odroid_get_adc_val(unsigned int *adcval) +{ + unsigned int adcval_prev = 0; + int ret, retries = 20; + + ret = adc_channel_single_shot("adc", CONFIG_ODROID_REV_AIN, + &adcval_prev); + if (ret) + return ret; + + while (retries--) { + mdelay(5); + + ret = adc_channel_single_shot("adc", CONFIG_ODROID_REV_AIN, + adcval); + if (ret) + return ret; + + /* + * If difference between ADC reads is less than 3%, + * accept the result + */ + if ((100 * abs(*adcval - adcval_prev) / adcval_prev) < 3) + return ret; + + adcval_prev = *adcval; + } + + return ret; +} + static int odroid_get_board_type(void) { unsigned int adcval; int ret, i; - ret = adc_channel_single_shot("adc", CONFIG_ODROID_REV_AIN, &adcval); + ret = odroid_get_adc_val(&adcval); if (ret) goto rev_default;