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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E01BC54EBE for ; Mon, 16 Jan 2023 15:39:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229817AbjAPPjD (ORCPT ); Mon, 16 Jan 2023 10:39:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231817AbjAPPih (ORCPT ); Mon, 16 Jan 2023 10:38:37 -0500 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADF841D933; Mon, 16 Jan 2023 07:38:21 -0800 (PST) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Nwbfp3TC5z6J6KT; Mon, 16 Jan 2023 23:34:26 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Mon, 16 Jan 2023 15:38:18 +0000 Date: Mon, 16 Jan 2023 15:38:17 +0000 From: Jonathan Cameron To: Olivier Moysan CC: Jonathan Cameron , Lars-Peter Clausen , Maxime Coquelin , "Alexandre Torgue" , Fabrice Gasnier , , , , Subject: Re: [PATCH] iio: adc: stm32: add oversampling support Message-ID: <20230116153817.00004770@Huawei.com> In-Reply-To: <20230116090333.33492-1-olivier.moysan@foss.st.com> References: <20230116090333.33492-1-olivier.moysan@foss.st.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500005.china.huawei.com (7.191.163.240) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 16 Jan 2023 10:03:33 +0100 Olivier Moysan wrote: > Add oversampling support for STM32H7, STM32MP15 & STM32MP13. > STM32F4 ADC has no oversampling feature. > > The current support of the oversampling feature aims at increasing > the data SNR, without changing the data resolution. > As the oversampling by itself increases data resolution, > a right shift is applied to keep initial resolution. > Only the oversampling ratio corresponding to a power of two are > supported here, to get a direct link between right shift and > oversampling ratio. (2exp(n) ratio <=> n right shift) > > The oversampling ratio is shared by all channels, whatever channel type. > (e.g. single ended or differential). > > Oversampling can be configured using IIO ABI: > - in_voltage_oversampling_ratio_available > - in_voltage_oversampling_ratio > > Signed-off-by: Olivier Moysan > Signed-off-by: Fabrice Gasnier Hi. A few minor suggestions inline. Also, what is relationship of Fabrice to this patch? I'd either expect him to have sent it on, or a Co-developed marking as appropriate. Thanks, Jonathan > --- > drivers/iio/adc/stm32-adc-core.h | 16 ++++ > drivers/iio/adc/stm32-adc.c | 144 +++++++++++++++++++++++++++++++ > 2 files changed, 160 insertions(+) > > diff --git a/drivers/iio/adc/stm32-adc-core.h b/drivers/iio/adc/stm32-adc-core.h > index 73b2c2e91c08..86a98286eeb3 100644 > --- a/drivers/iio/adc/stm32-adc-core.h > +++ b/drivers/iio/adc/stm32-adc-core.h > @@ -91,6 +91,7 @@ > #define STM32H7_ADC_IER 0x04 > #define STM32H7_ADC_CR 0x08 > #define STM32H7_ADC_CFGR 0x0C > +#define STM32H7_ADC_CFGR2 0x10 > #define STM32H7_ADC_SMPR1 0x14 > #define STM32H7_ADC_SMPR2 0x18 > #define STM32H7_ADC_PCSEL 0x1C > @@ -160,6 +161,14 @@ > #define STM32H7_DMNGT_SHIFT 0 > #define STM32H7_DMNGT_MASK GENMASK(1, 0) > > +/* STM32H7_ADC_CFGR2 bit fields */ > +#define STM32H7_OVSR_SHIFT 16 /* Correspond to OSVR field in datasheet */ > +#define STM32H7_OVSR_MASK GENMASK(25, 16) > +#define STM32H7_OVSR_BITS 10 > +#define STM32H7_OVSS_SHIFT 5 As below - mostly I'd expect FIELD_PREP / FIELD_GET to be used as they avoid the need for separate defines for MASK and SHIFT (only MASK ones are used). > +#define STM32H7_OVSS_MASK GENMASK(8, 5) > +#define STM32H7_ROVSE BIT(0) > + > enum stm32h7_adc_dmngt { > STM32H7_DMNGT_DR_ONLY, /* Regular data in DR only */ > STM32H7_DMNGT_DMA_ONESHOT, /* DMA one shot mode */ > @@ -226,6 +235,13 @@ enum stm32h7_adc_dmngt { > #define STM32MP13_RES_SHIFT 3 > #define STM32MP13_RES_MASK GENMASK(4, 3) > > +/* STM32MP13_ADC_CFGR2 bit fields */ > +#define STM32MP13_OVSR_SHIFT 2 > +#define STM32MP13_OVSR_MASK GENMASK(4, 2) > +#define STM32MP13_OVSR_BITS 3 > +#define STM32MP13_OVSS_SHIFT 5 > +#define STM32MP13_OVSS_MASK GENMASK(8, 5) > + > /* STM32MP13_ADC_DIFSEL - bit fields */ > #define STM32MP13_DIFSEL_MASK GENMASK(18, 0) > > diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c > index 45d4e79f8e55..17050875f23d 100644 > --- a/drivers/iio/adc/stm32-adc.c > +++ b/drivers/iio/adc/stm32-adc.c > @@ -6,6 +6,7 @@ > * Author: Fabrice Gasnier . > */ > > +#include > #include > #include > #include > @@ -13,6 +14,7 @@ > #include > #include > #include > +#include Why? That is only relevant for custom attributes. > #include > #include > #include > @@ -27,6 +29,7 @@ > #include > #include > #include > +#include I'm not immediately seeing anything from here being used. > > #include "stm32-adc-core.h" > > ... > > +static void stm32h7_adc_set_ovs(struct iio_dev *indio_dev, u32 ovs_idx) > +{ > + struct stm32_adc *adc = iio_priv(indio_dev); > + u32 ovsr_bits, bits, msk = STM32H7_ROVSE; > + > + msk |= STM32H7_OVSR_MASK | STM32H7_OVSS_MASK; As below. > + stm32_adc_clr_bits(adc, STM32H7_ADC_CFGR2, msk); > + > + if (!ovs_idx) > + return; > + > + bits = STM32H7_ROVSE; > + ovsr_bits = (1 << ovs_idx) - 1; > + bits |= ovsr_bits << STM32H7_OVSR_SHIFT; Good place to FIELD_PREP() and avoid need for SHIFT definitions. > + bits |= ovs_idx << STM32H7_OVSS_SHIFT; > + > + stm32_adc_set_bits(adc, STM32H7_ADC_CFGR2, bits & msk); > +} > + > +static void stm32mp13_adc_set_ovs(struct iio_dev *indio_dev, u32 ovs_idx) > +{ > + struct stm32_adc *adc = iio_priv(indio_dev); > + u32 bits, msk = STM32H7_ROVSE; > + > + msk |= STM32MP13_OVSR_MASK | STM32MP13_OVSS_MASK; u32 bits, msk; msk = STM32H7_ROVSE | STM32MP13_OVSR_MASK | STM32MP13_OVSS_MSK; is more readable. > + stm32_adc_clr_bits(adc, STM32H7_ADC_CFGR2, msk); > + > + if (!ovs_idx) > + return; > + > + bits = STM32H7_ROVSE; > + if (ovs_idx - 1) > + bits |= (ovs_idx - 1) << STM32MP13_OVSR_SHIFT; > + bits |= ovs_idx << STM32MP13_OVSS_SHIFT; FIELD_PREP() for all these. > + > + stm32_adc_set_bits(adc, STM32H7_ADC_CFGR2, bits & msk); > +} > + > static int stm32h7_adc_exit_pwr_down(struct iio_dev *indio_dev) > { > struct stm32_adc *adc = iio_priv(indio_dev); > @@ -1461,6 +1524,71 @@ static int stm32_adc_single_conv(struct iio_dev *indio_dev, > return ret; > } > > +static int stm32_adc_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + struct stm32_adc *adc = iio_priv(indio_dev); > + struct device *dev = indio_dev->dev.parent; > + int nb = adc->cfg->adc_info->num_ovs; > + u32 idx; > + int ret; > + > + switch (mask) { > + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: > + ret = iio_device_claim_direct_mode(indio_dev); > + if (ret) > + return ret; > + > + if (val2) { > + ret = -EINVAL; > + goto err; > + } Do as much as possible outside of the serialization caused by iio_device_claim_direct_mode. These sanity checks and indeed the array search can all be done outside of that and directly return on error. > + > + for (idx = 0; idx < nb; idx++) > + if (adc->cfg->adc_info->oversampling[idx] == val) > + break; > + > + if (idx >= nb) { > + ret = -EINVAL; > + goto err; > + } > + > + ret = pm_runtime_resume_and_get(dev); > + if (ret < 0) > + goto err; > + > + adc->cfg->set_ovs(indio_dev, idx); > + > + pm_runtime_mark_last_busy(dev); > + pm_runtime_put_autosuspend(dev); > + > + adc->ovs_idx = idx; > + > +err: > + iio_device_release_direct_mode(indio_dev); > + > + return ret; > + default: > + return -EINVAL; > + } > +} > + > +static int stm32_adc_read_avail(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, > + const int **vals, int *type, int *length, long m) Where it doesn't hurt readability, I'd prefer we keep lines under 80 chars. > +{ > + struct stm32_adc *adc = iio_priv(indio_dev); > + > + switch (m) { > + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: > + *type = IIO_VAL_INT; > + *length = adc->cfg->adc_info->num_ovs; > + *vals = adc->cfg->adc_info->oversampling; > + return IIO_AVAIL_LIST; > + default: > + return -EINVAL; > + } > +} > + Thanks, Jonathan