From patchwork Wed Feb 13 16:46:44 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Krzysztof Kozlowski X-Patchwork-Id: 1041446 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="dJpQiuaa"; dkim-atps=neutral Received: from lists.denx.de (dione.denx.de [81.169.180.215]) by ozlabs.org (Postfix) with ESMTP id 4405C50Klmz9s1l for ; Thu, 14 Feb 2019 03:51:28 +1100 (AEDT) Received: by lists.denx.de (Postfix, from userid 105) id ACBCFC21FDA; Wed, 13 Feb 2019 16:48:24 +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 1CB95C220A3; Wed, 13 Feb 2019 16:47:39 +0000 (UTC) Received: by lists.denx.de (Postfix, from userid 105) id 47E63C22019; Wed, 13 Feb 2019 16:47:12 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by lists.denx.de (Postfix) with ESMTPS id 4512AC220C0 for ; Wed, 13 Feb 2019 16:47:08 +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 B9344222CF; Wed, 13 Feb 2019 16:47:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550076426; bh=qio8BcMA0RQ3X3KeiBll7IyylxAVTHCV+ZqexJfUYBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dJpQiuaaHPfczgf+SvVONd5Av0uOaUj3+M+7+VSkpPOFLduxlQ+vrzORs855Ll70m QBg1hlE40WIHAjv5VfzOFgjm3QzvJ2maRUa32CPxi8aWJD9ElOa5t6Lz2WoTPNBxN/ nwvoNCvj5QG6NaHYpA8MXdNqQVCF9+fX8RKdw4Z0= From: Krzysztof Kozlowski To: Albert Aribaud , Jaehoon Chung , Lukasz Majewski , Simon Glass , Minkyu Kang , Marek Szyprowski , u-boot@lists.denx.de Date: Wed, 13 Feb 2019 17:46:44 +0100 Message-Id: <20190213164648.26579-6-krzk@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190213164648.26579-1-krzk@kernel.org> References: <20190213164648.26579-1-krzk@kernel.org> Cc: Krzysztof Kozlowski Subject: [U-Boot] [PATCH v2 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 af711e727a78..8aed64183837 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;