From patchwork Tue Aug 24 09:12:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Billy Tsai X-Patchwork-Id: 12456209 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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MSGID_FROM_MTA_HEADER,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 D5886C4338F for ; Wed, 25 Aug 2021 01:57:24 +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 8BAF26127B for ; Wed, 25 Aug 2021 01:57:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8BAF26127B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=aspeedtech.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Date:Subject:CC:To:From:Message-Id:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ETijpCr5L3Zy1WuO5SPuQbpJPpcJ6uBVJG7jT72XqYY=; b=oUzeVBegla9s4p 6IQ1Sux9WjZUPBQewN1Lh6FWFBw+rPFQkHGFZ0Z7D8dmv8zfc/wL3iF8lYr8bvOH8+iQpIOxWFwWv hIYDize9Zp0mLuB+mcbTSybrFYjwq2VNX/G3yciSQxlJpAvyNMP9J7dzF2LqbiwRUMaj03xhWB8Nc HebHTfkW5925EoQH4DC+NatCEXzQPvKuGF7YSHDhRbO/VfKI6gdScQJoMMb8UmxNRrZ4naGf6c+JC X87LIIvMTg9XCjapPGd8GdCZAvSGVmJEM54QGw6I5BsMmh7gjLcWKDMrIHJclB4I2Co/US7yg08hp cjnnOjLedqvGKtYSmBQQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mIi8Q-005AHt-4y; Wed, 25 Aug 2021 01:55:22 +0000 Received: from desiato.infradead.org ([90.155.92.199]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mIi8H-005AGE-14 for linux-arm-kernel@bombadil.infradead.org; Wed, 25 Aug 2021 01:55:13 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:Content-Transfer-Encoding :MIME-Version:References:In-Reply-To:Date:Subject:CC:To:From:Message-Id: Sender:Reply-To:Content-ID:Content-Description; bh=DuBCCwmiWAtKHi9x6Kq0QwHrvwXHJhgIsjBc/aii61k=; b=e1nWoLiJTpZC56sALFLLxy0oxr l1xmBSiSD/LAfsaBnketvSiGk3TVizG0v+c68JHUAlTcVWE2eNmurjkeHxDQ4XO7XJGfMJAeA3b/Q fbt0IuHkp+Ttw0bVEnWdXTV6v8bVrJEdpsFKmglYSTlDWA8Gc8+Cwhk/NxGco9aUuzZyO46BIUwZp d3W8t5zhGyIwdwnyC/pIKza9cwbKos/5Waz9uFWfrkfRDpCof4v0LStd8e86UpM46i0Navja3/42h kdXBdkdE6TAEVyPAExA0ElxK/RTxWhGcwNtkiK0YMHrPXtrE1af7tYyPRQGNAiQWkQt43TcKbA0pC W1dZd0qA==; Received: from twspam01.aspeedtech.com ([211.20.114.71]) by desiato.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mIgft-00Ck18-Rx for linux-arm-kernel@lists.infradead.org; Wed, 25 Aug 2021 00:21:54 +0000 Received: (from root@localhost) by twspam01.aspeedtech.com id 17P036bM092211 for ; Wed, 25 Aug 2021 08:03:06 +0800 (GMT-8) (envelope-from billy_tsai@aspeedtech.com) Message-Id: <202108250003.17P036bM092211@twspam01.aspeedtech.com> Received: from mail.aspeedtech.com ([192.168.0.24]) by twspam01.aspeedtech.com with ESMTP id 17O8rHTG098403; Tue, 24 Aug 2021 16:53:17 +0800 (GMT-8) (envelope-from billy_tsai@aspeedtech.com) Received: from BillyTsai-pc.aspeed.com (192.168.2.149) by TWMBX02.aspeed.com (192.168.0.24) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 24 Aug 2021 17:11:49 +0800 From: Billy Tsai To: , , , , , , , , , , , , , CC: Subject: [RESEND v4 12/15] iio: adc: aspeed: Add func to set sampling rate. Date: Tue, 24 Aug 2021 17:12:40 +0800 X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210824091243.9393-1-billy_tsai@aspeedtech.com> References: <20210824091243.9393-1-billy_tsai@aspeedtech.com> MIME-Version: 1.0 X-Originating-IP: [192.168.2.149] X-ClientProxiedBy: TWMBX02.aspeed.com (192.168.0.24) To TWMBX02.aspeed.com (192.168.0.24) X-DNSRBL: X-MAIL: twspam01.aspeedtech.com 17P036bM092211 X-MSS: FORWARD@twspam01.aspeedtech.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210825_012150_593116_C44C7A1B X-CRM114-Status: GOOD ( 16.39 ) 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 Add the function to set the sampling rate and keep the sampling period for a driver used to wait the lastest value. Signed-off-by: Billy Tsai --- drivers/iio/adc/aspeed_adc.c | 58 +++++++++++++++++++++++++----------- 1 file changed, 40 insertions(+), 18 deletions(-) diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c index 8fe7da1a651f..4d979dd7fe88 100644 --- a/drivers/iio/adc/aspeed_adc.c +++ b/drivers/iio/adc/aspeed_adc.c @@ -65,6 +65,12 @@ #define ASPEED_ADC_INIT_POLLING_TIME 500 #define ASPEED_ADC_INIT_TIMEOUT 500000 +/* + * When the sampling rate is too high, the ADC may not have enough charging + * time, resulting in a low voltage value. Thus, default use slow sampling + * rate for most user case. + */ +#define ASPEED_ADC_DEF_SAMPLING_RATE 65000 struct aspeed_adc_model_data { const char *model_name; @@ -88,6 +94,7 @@ struct aspeed_adc_data { struct clk_hw *clk_scaler; struct reset_control *rst; int vref; + u32 sample_period_ns; }; #define ASPEED_CHAN(_idx, _data_reg_addr) { \ @@ -119,6 +126,24 @@ static const struct iio_chan_spec aspeed_adc_iio_channels[] = { ASPEED_CHAN(15, 0x2E), }; +static int aspeed_adc_set_sampling_rate(struct iio_dev *indio_dev, u32 rate) +{ + struct aspeed_adc_data *data = iio_priv(indio_dev); + + if (rate < data->model_data->min_sampling_rate || + rate > data->model_data->max_sampling_rate) + return -EINVAL; + /* Each sampling needs 12 clocks to covert.*/ + clk_set_rate(data->clk_scaler->clk, rate * ASPEED_CLOCKS_PER_SAMPLE); + rate = clk_get_rate(data->clk_scaler->clk); + data->sample_period_ns = DIV_ROUND_UP_ULL( + (u64)NSEC_PER_SEC * ASPEED_CLOCKS_PER_SAMPLE, rate); + dev_dbg(data->dev, "Adc clock = %d sample period = %d ns", rate, + data->sample_period_ns); + + return 0; +} + static int aspeed_adc_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) @@ -149,17 +174,10 @@ static int aspeed_adc_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask) { - struct aspeed_adc_data *data = iio_priv(indio_dev); switch (mask) { case IIO_CHAN_INFO_SAMP_FREQ: - if (val < data->model_data->min_sampling_rate || - val > data->model_data->max_sampling_rate) - return -EINVAL; - - clk_set_rate(data->clk_scaler->clk, - val * ASPEED_CLOCKS_PER_SAMPLE); - return 0; + return aspeed_adc_set_sampling_rate(indio_dev, val); case IIO_CHAN_INFO_SCALE: case IIO_CHAN_INFO_RAW: @@ -386,6 +404,20 @@ static int aspeed_adc_probe(struct platform_device *pdev) if (ret) return ret; + ret = clk_prepare_enable(data->clk_scaler->clk); + if (ret) + return ret; + + ret = devm_add_action_or_reset(data->dev, + aspeed_adc_clk_disable_unprepare, + data->clk_scaler->clk); + if (ret) + return ret; + + ret = aspeed_adc_set_sampling_rate(indio_dev, ASPEED_ADC_DEF_SAMPLING_RATE); + if (ret) + return ret; + ret = aspeed_adc_vref_config(indio_dev); if (ret) return ret; @@ -413,16 +445,6 @@ static int aspeed_adc_probe(struct platform_device *pdev) } /* Start all channels in normal mode. */ - ret = clk_prepare_enable(data->clk_scaler->clk); - if (ret) - return ret; - - ret = devm_add_action_or_reset(data->dev, - aspeed_adc_clk_disable_unprepare, - data->clk_scaler->clk); - if (ret) - return ret; - adc_engine_control_reg_val = readl(data->base + ASPEED_REG_ENGINE_CONTROL); adc_engine_control_reg_val |=