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Tue, 04 Feb 2020 11:10:37 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 5908310003B; Tue, 4 Feb 2020 11:10:33 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag6node2.st.com [10.75.127.17]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 49AFC2AD9D9; Tue, 4 Feb 2020 11:10:33 +0100 (CET) Received: from localhost (10.75.127.46) by SFHDAG6NODE2.st.com (10.75.127.17) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Tue, 4 Feb 2020 11:10:32 +0100 From: Olivier Moysan To: , , Subject: [PATCH 4/4] iio: adc: stm32-dfsdm: add scale and offset support Date: Tue, 4 Feb 2020 11:10:08 +0100 Message-ID: <20200204101008.11411-5-olivier.moysan@st.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200204101008.11411-1-olivier.moysan@st.com> References: <20200204101008.11411-1-olivier.moysan@st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.46] X-ClientProxiedBy: SFHDAG3NODE3.st.com (10.75.127.9) To SFHDAG6NODE2.st.com (10.75.127.17) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.572 definitions=2020-02-04_02:2020-02-04, 2020-02-04 signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200204_021046_533877_45432E1E X-CRM114-Status: GOOD ( 19.86 ) X-Spam-Score: -0.9 (/) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (-0.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at https://www.dnswl.org/, low trust [91.207.212.93 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, lars@metafoo.de, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, pmeerw@pmeerw.net, knaack.h@gmx.de, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Add scale and offset attributes support to STM32 DFSDM. Signed-off-by: Olivier Moysan --- drivers/iio/adc/stm32-dfsdm-adc.c | 105 +++++++++++++++++++++++++++++- 1 file changed, 102 insertions(+), 3 deletions(-) diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c index 07b9dfdf8e76..b85fd3e90496 100644 --- a/drivers/iio/adc/stm32-dfsdm-adc.c +++ b/drivers/iio/adc/stm32-dfsdm-adc.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -67,6 +68,13 @@ struct stm32_dfsdm_dev_data { const struct regmap_config *regmap_cfg; }; +struct stm32_dfsdm_sd_chan_info { + int scale_val; + int scale_val2; + int offset; + unsigned int differential; +}; + struct stm32_dfsdm_adc { struct stm32_dfsdm *dfsdm; const struct stm32_dfsdm_dev_data *dev_data; @@ -79,6 +87,7 @@ struct stm32_dfsdm_adc { struct iio_hw_consumer *hwc; struct completion completion; u32 *buffer; + struct stm32_dfsdm_sd_chan_info *sd_chan; /* Audio specific */ unsigned int spi_freq; /* SPI bus clock frequency */ @@ -1271,7 +1280,10 @@ static int stm32_dfsdm_read_raw(struct iio_dev *indio_dev, int *val2, long mask) { struct stm32_dfsdm_adc *adc = iio_priv(indio_dev); - int ret; + struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id]; + struct stm32_dfsdm_filter_osr *flo = &fl->flo[fl->fast]; + u32 max = flo->max << (flo->lshift - chan->scan_type.shift); + int ret, idx = chan->scan_index; switch (mask) { case IIO_CHAN_INFO_RAW: @@ -1307,6 +1319,41 @@ static int stm32_dfsdm_read_raw(struct iio_dev *indio_dev, *val = adc->sample_freq; return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + /* + * Scale is expressed in mV. + * When fast mode is disabled, actual resolution may be lower + * than 2^n, where n=realbits-1. + * This leads to underestimating input voltage. To + * compensate this deviation, the voltage reference can be + * corrected with a factor = realbits resolution / actual max + */ + *val = div_u64((u64)adc->sd_chan[idx].scale_val * + (u64)BIT(DFSDM_DATA_RES - 1), max); + *val2 = chan->scan_type.realbits; + if (adc->sd_chan[idx].differential) + *val *= 2; + + return IIO_VAL_FRACTIONAL_LOG2; + + case IIO_CHAN_INFO_OFFSET: + /* + * DFSDM output data are in the range [-2^n,2^n-1], + * with n=realbits-1. + * - Differential modulator: + * Offset correspond to SD modulator offset. + * - Single ended modulator: + * Input is in [0V,Vref] range, where 0V corresponds to -2^n. + * Add 2^n to offset. (i.e. middle of input range) + * offset = offset(sd) * vref / res(sd) * max / vref. + */ + *val = div_u64((u64)max * adc->sd_chan[idx].offset, + BIT(adc->sd_chan[idx].scale_val2 - 1)); + if (!adc->sd_chan[idx].differential) + *val += max; + + return IIO_VAL_INT; } return -EINVAL; @@ -1430,7 +1477,9 @@ static int stm32_dfsdm_adc_chan_init_one(struct iio_dev *indio_dev, * IIO_CHAN_INFO_RAW: used to compute regular conversion * IIO_CHAN_INFO_OVERSAMPLING_RATIO: used to set oversampling */ - ch->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); + ch->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE) | + BIT(IIO_CHAN_INFO_OFFSET); ch->info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | BIT(IIO_CHAN_INFO_SAMP_FREQ); @@ -1481,8 +1530,10 @@ static int stm32_dfsdm_adc_init(struct iio_dev *indio_dev) { struct iio_chan_spec *ch; struct stm32_dfsdm_adc *adc = iio_priv(indio_dev); + struct iio_channel *channels, *chan; + struct stm32_dfsdm_sd_chan_info *sd_chan; int num_ch; - int ret, chan_idx; + int ret, chan_idx, val2; adc->oversamp = DFSDM_DEFAULT_OVERSAMPLING; ret = stm32_dfsdm_compute_all_osrs(indio_dev, adc->oversamp); @@ -1506,6 +1557,22 @@ static int stm32_dfsdm_adc_init(struct iio_dev *indio_dev) if (!ch) return -ENOMEM; + /* Get SD modulator channels */ + channels = iio_channel_get_all(&indio_dev->dev); + if (IS_ERR(channels)) { + dev_err(&indio_dev->dev, "Failed to get channel %ld\n", + PTR_ERR(channels)); + return PTR_ERR(channels); + } + chan = &channels[0]; + + adc->sd_chan = devm_kzalloc(&indio_dev->dev, + sizeof(*adc->sd_chan) * num_ch, GFP_KERNEL); + if (!adc->sd_chan) + return -ENOMEM; + + sd_chan = adc->sd_chan; + for (chan_idx = 0; chan_idx < num_ch; chan_idx++) { ch[chan_idx].scan_index = chan_idx; ret = stm32_dfsdm_adc_chan_init_one(indio_dev, &ch[chan_idx]); @@ -1513,6 +1580,38 @@ static int stm32_dfsdm_adc_init(struct iio_dev *indio_dev) dev_err(&indio_dev->dev, "Channels init failed\n"); return ret; } + + if (!chan->indio_dev) + return -EINVAL; + + ret = iio_read_channel_scale(chan, &sd_chan->scale_val, + &sd_chan->scale_val2); + if (ret < 0) { + dev_err(&indio_dev->dev, + "Failed to get channel %d scale\n", chan_idx); + return ret; + } + + if (iio_channel_has_info(chan->channel, IIO_CHAN_INFO_OFFSET)) { + ret = iio_read_channel_offset(chan, &sd_chan->offset, + &val2); + if (ret < 0) { + dev_err(&indio_dev->dev, + "Failed to get channel %d offset\n", + chan_idx); + return ret; + } + } + + sd_chan->differential = chan->channel->differential; + + dev_dbg(&indio_dev->dev, "Channel %d %s scale ref=%d offset=%d", + chan_idx, chan->channel->differential ? + "differential" : "single-ended", + sd_chan->scale_val, sd_chan->offset); + + chan++; + sd_chan++; } indio_dev->num_channels = num_ch;