From patchwork Wed Sep 22 08:15:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Billy Tsai X-Patchwork-Id: 12510213 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=-18.2 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,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 E75E9C433F5 for ; Wed, 22 Sep 2021 10:48:24 +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 AB4EE60F70 for ; Wed, 22 Sep 2021 10:48:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org AB4EE60F70 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: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=/CHcrXfA2pcukkV9rtAHcarTdJbzf9UKQ8CFfg3XQXA=; b=vCHkyej+xIN5Pg 5xs4kGIUSFoxV16ELhUR4JBeuXuMD5UrHaOfK2bPug800MKazPQar96pPLX7qWR4wGunkoLg+96F5 pARUz62VpeEMYbdO4btwyf3nvtYzAtFNfPtweOh4y69iRvNiSo28x72z8BMqxzYXRBpaTd8kh/dQx 8LMYTa8n3PBl18JugIWYpzcCeQUfKMP9ngoQMBjUbfFYO+oko/fEqMbruAWOhIhAdS7GfCSpG1M0L mwL6BXYFer/uK/J5XlbgcGF5p2v2NymlI4f87X7z9VYilGA4gMF0CwV38kbvt6TrnPW5sJD5B9Oo2 JpINCHuMRVxWyDWQLksg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mSzm0-0085ay-36; Wed, 22 Sep 2021 10:46:44 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mSzag-007qSO-Ec for linux-arm-kernel@bombadil.infradead.org; Wed, 22 Sep 2021 10:35:02 +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:Message-ID:Date:Subject:CC:To:From: Sender:Reply-To:Content-ID:Content-Description; bh=qjQFRrDUtxNiJiXNTejujNDmQ/qV4lpMuoqpzbBEEok=; b=EkPbQmW8ZmAq87m93DdAHbxgmp 5QE+j/LhH3IPGC6JixfxyueG5UyYBiA1yeTD/bO1sVoHEe4UDXdov67yjBGYq1erMk0wq7azUJA8P LGb129ATc8egzqxPdt+5KoA+Jr2YATelmlBOpn9OFc02jCXTM9LlU6RmL3ILAMJtwV+KY44oLijGP 0yZfg7oV0e2ks/3E5nRyQFI3VqkeJo+jeT4TKgdQOcpOC4F9nrL3/W7Vm6ic6GDrBaoUxhcHTM+IL HczJOfiI6jsrmCv0u/dAiGnnLdtH9qPmoHRmlPVPvTXrW6qIc/O3Q0Fa/QG9Q3GsW5U3q+aadLwuk vcuRMXaA==; Received: from twspam01.aspeedtech.com ([211.20.114.71]) by desiato.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mSxQ4-004x94-4K for linux-arm-kernel@lists.infradead.org; Wed, 22 Sep 2021 08:15:58 +0000 Received: from mail.aspeedtech.com ([192.168.0.24]) by twspam01.aspeedtech.com with ESMTP id 18M7sdaB099790; Wed, 22 Sep 2021 15:54:39 +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; Wed, 22 Sep 2021 16:14:57 +0800 From: Billy Tsai To: , , , , , , , , , , , , , CC: Subject: [v7 08/11] iio: adc: aspeed: Add func to set sampling rate. Date: Wed, 22 Sep 2021 16:15:17 +0800 Message-ID: <20210922081520.30580-9-billy_tsai@aspeedtech.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210922081520.30580-1-billy_tsai@aspeedtech.com> References: <20210922081520.30580-1-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 18M7sdaB099790 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210922_091556_749766_72A6542F X-CRM114-Status: GOOD ( 16.29 ) 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 fresh value. In addition, since the ADC clock is required when initializing the ADC device, move clk_prepare_enable ahead of the initialization phase. Signed-off-by: Billy Tsai --- drivers/iio/adc/aspeed_adc.c | 58 ++++++++++++++++++++++++------------ 1 file changed, 39 insertions(+), 19 deletions(-) diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c index a24be2a4f69c..f2226ba3144d 100644 --- a/drivers/iio/adc/aspeed_adc.c +++ b/drivers/iio/adc/aspeed_adc.c @@ -73,6 +73,12 @@ #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, the default uses a slow + * sampling rate for most use cases. + */ +#define ASPEED_ADC_DEF_SAMPLING_RATE 65000 struct aspeed_adc_model_data { const char *model_name; @@ -96,6 +102,7 @@ struct aspeed_adc_data { struct clk_hw *clk_scaler; struct reset_control *rst; int vref_mv; + u32 sample_period_ns; }; #define ASPEED_CHAN(_idx, _data_reg_addr) { \ @@ -127,6 +134,24 @@ 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 convert.*/ + 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) @@ -157,17 +182,9 @@ 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: @@ -392,6 +409,19 @@ 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; + adc_engine_control_reg_val = readl(data->base + ASPEED_REG_ENGINE_CONTROL); adc_engine_control_reg_val |= @@ -418,16 +448,6 @@ static int aspeed_adc_probe(struct platform_device *pdev) 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; - /* Start all channels in normal mode. */ adc_engine_control_reg_val = readl(data->base + ASPEED_REG_ENGINE_CONTROL);