From patchwork Sat Feb 9 22:54:05 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Krzysztof Kozlowski X-Patchwork-Id: 1039303 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="z0k0IVQG"; dkim-atps=neutral Received: from lists.denx.de (dione.denx.de [81.169.180.215]) by ozlabs.org (Postfix) with ESMTP id 43xnT72t2Nz9s5c for ; Sun, 10 Feb 2019 09:55:38 +1100 (AEDT) Received: by lists.denx.de (Postfix, from userid 105) id 68011C21F3E; Sat, 9 Feb 2019 22:55:09 +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=KHOP_BIG_TO_CC, 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 77CC4C22026; Sat, 9 Feb 2019 22:54:51 +0000 (UTC) Received: by lists.denx.de (Postfix, from userid 105) id 44AD1C22049; Sat, 9 Feb 2019 22:54:32 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by lists.denx.de (Postfix) with ESMTPS id 8D02AC21FFA for ; Sat, 9 Feb 2019 22:54:29 +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 4AD3A2192C; Sat, 9 Feb 2019 22:54:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549752868; bh=iOcRyGZg82RQhMX1yZfqK95/vS26gtxrOZPGWLDaEtY=; h=From:To:Subject:Date:In-Reply-To:References:From; b=z0k0IVQGgX6cTie8hBGVZENONZbTQRbqTbPEhVGRTtkVB815x0Ci9W6igxHNk2H5b y/WVFPfZpb7ZwRvENNLcTg/T5fbtHccWtQF4plnZ7rInuAf7URm2F2EmLr8yzjtZqX 8x2e9plfCTO/1Qh3gUi8fQ8hSMkk6OyXto9FIe50= From: Krzysztof Kozlowski To: Albert Aribaud , Jaehoon Chung , Krzysztof Kozlowski , Simon Glass , Minkyu Kang , Marek Szyprowski , Lukasz Majewski , Dirk Meul , Patrice Chotard , Felix Brack , Jack Mitchell , Patrick Delaunay , Lokesh Vutla , u-boot@lists.denx.de Date: Sat, 9 Feb 2019 23:54:05 +0100 Message-Id: <20190209225411.32756-3-krzk@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190209225411.32756-1-krzk@kernel.org> References: <20190209225411.32756-1-krzk@kernel.org> Subject: [U-Boot] [RFT 2/8] 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 | 34 ++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) diff --git a/board/samsung/common/exynos5-dt-types.c b/board/samsung/common/exynos5-dt-types.c index 7a86e9187768..ba8584f1a5d8 100644 --- a/board/samsung/common/exynos5-dt-types.c +++ b/board/samsung/common/exynos5-dt-types.c @@ -57,12 +57,44 @@ 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 ((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;