From mboxrd@z Thu Jan 1 00:00:00 1970 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=-15.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 82F78C432BE for ; Sun, 29 Aug 2021 15:35:39 +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 5710760F3A for ; Sun, 29 Aug 2021 15:35:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5710760F3A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=SM85WvkkgwMFmracdKaIJ42oIOcocjIAoiLnlg0J70c=; b=f+ME8TPXML51+b L2n3SXIktHZ/VxeQ7g7CKcYXITlI5QsZ/LcC47YIlDePgX4IRNvB6RA+3PIYxXNznokhh+OX0/8Li fg0ZBooZ2Q9w2sIFkOzjnlOwWLBS5xeofIzQvW859OBbRhVOlzP5QHNWetRXUyHbO5VtHAjEg+TF+ kOxrjHaWa4UYiRQA+MTXCVYwDyPcpvzop3SEZAffVq6q8BC2IV2lK5/a7jWYFuaP9yHf8EfK07dxW dJR3eAzpW0IWoGPgpUTBIyLKHirGF21tsu4Qdsy5sP8HjkevPQKcVo1FiB01eVFrSyBdpOExwuKFW Y57zybl6mZrtHyhdHQog==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mKMol-00Fhea-Cz; Sun, 29 Aug 2021 15:33:55 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mKMog-00Fhdk-Qp for linux-arm-kernel@lists.infradead.org; Sun, 29 Aug 2021 15:33:52 +0000 Received: from jic23-huawei (cpc108967-cmbg20-2-0-cust86.5-4.cable.virginm.net [81.101.6.87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2557760F3A; Sun, 29 Aug 2021 15:33:44 +0000 (UTC) Date: Sun, 29 Aug 2021 16:36:59 +0100 From: Jonathan Cameron To: Billy Tsai Cc: , , , , , , , , , , , , , Subject: Re: [RESEND v4 12/15] iio: adc: aspeed: Add func to set sampling rate. Message-ID: <20210829163659.2f7f5974@jic23-huawei> In-Reply-To: <202108250003.17P03KRU092474@twspam01.aspeedtech.com> References: <20210824091243.9393-1-billy_tsai@aspeedtech.com> <202108250003.17P03KRU092474@twspam01.aspeedtech.com> X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210829_083350_957711_651D2139 X-CRM114-Status: GOOD ( 27.19 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 24 Aug 2021 17:12:40 +0800 Billy Tsai wrote: > 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 Why move the code as well as factoring out the setter function? I doubt it does any harm, but I'd like to understand why you did it. Jonathan > --- > 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.*/ convert. Please run a spell checker over these patches. > + 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. */ Why move this code up? > - 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 |= _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel