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Thu, 6 Mar 2025 16:05:05 -0500 Received: from ASHBMBX8.ad.analog.com (10.64.17.5) by ASHBMBX8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.14; Thu, 6 Mar 2025 16:05:05 -0500 Received: from zeus.spd.analog.com (10.66.68.11) by ashbmbx8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server id 15.2.986.14 via Frontend Transport; Thu, 6 Mar 2025 16:05:05 -0500 Received: from JSANTO12-L01.ad.analog.com ([10.65.60.206]) by zeus.spd.analog.com (8.15.1/8.15.1) with ESMTP id 526L4lDA011711; Thu, 6 Mar 2025 16:04:49 -0500 From: Jonathan Santos To: , , , CC: Jonathan Santos , , , , , , , , , , , , , , Subject: [PATCH v4 17/17] iio: adc: ad7768-1: add low pass -3dB cutoff attribute Date: Thu, 6 Mar 2025 18:04:47 -0300 Message-ID: <2aa347a97e7ea974951609b0bdf81cad0b21b993.1741268122.git.Jonathan.Santos@analog.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ADIRuleOP-NewSCL: Rule Triggered X-Proofpoint-GUID: b4hzi77df-eQY3lNKWTpVtvI309rP0lR X-Proofpoint-ORIG-GUID: b4hzi77df-eQY3lNKWTpVtvI309rP0lR X-Authority-Analysis: v=2.4 cv=VNcnn8PX c=1 sm=1 tr=0 ts=67ca0e03 cx=c_pps a=3WNzaoukacrqR9RwcOSAdA==:117 a=3WNzaoukacrqR9RwcOSAdA==:17 a=Vs1iUdzkB0EA:10 a=gAnH3GRIAAAA:8 a=ZkoTrUv0hqWFqrPu6skA:9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1093,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-03-06_07,2025-03-06_04,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 malwarescore=0 spamscore=0 clxscore=1015 priorityscore=1501 bulkscore=0 mlxlogscore=999 lowpriorityscore=0 impostorscore=0 suspectscore=0 adultscore=0 phishscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2502100000 definitions=main-2503060160 Ad7768-1 has a different -3db frequency multiplier depending on the filter type configured. The cutoff frequency also varies according to the current ODR. Add a readonly low pass -3dB frequency cutoff attribute to clarify to the user which bandwidth is being allowed depending on the filter configurations. Signed-off-by: Jonathan Santos Reviewed-by: Marcelo Schmitt --- v4 Changes: * None v3 Changes: * None v2 Changes: * New patch in v2. --- drivers/iio/adc/ad7768-1.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c index 664d0b535340..9ba00e9089bd 100644 --- a/drivers/iio/adc/ad7768-1.c +++ b/drivers/iio/adc/ad7768-1.c @@ -150,6 +150,17 @@ enum ad7768_scan_type { AD7768_SCAN_TYPE_HIGH_SPEED, }; +/* + * -3dB cutoff frequency multipliers (relative to ODR) for + * each filter type. Values are multiplied by 1000. + */ +static const int ad7768_filter_3db_odr_multiplier[] = { + [AD7768_FILTER_SINC5] = 204, + [AD7768_FILTER_SINC3] = 261, + [AD7768_FILTER_SINC3_REJ60] = 261, + [AD7768_FILTER_WIDEBAND] = 433, +}; + static const int ad7768_mclk_div_rates[4] = { 16, 8, 4, 2, }; @@ -228,7 +239,8 @@ static const struct iio_chan_spec ad7768_channels[] = { .type = IIO_VOLTAGE, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | - BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | + BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ), @@ -762,7 +774,7 @@ static int ad7768_read_raw(struct iio_dev *indio_dev, { struct ad7768_state *st = iio_priv(indio_dev); const struct iio_scan_type *scan_type; - int scale_uv, ret; + int scale_uv, ret, temp; scan_type = iio_get_current_scan_type(indio_dev, chan); if (IS_ERR(scan_type)) @@ -802,6 +814,12 @@ static int ad7768_read_raw(struct iio_dev *indio_dev, case IIO_CHAN_INFO_OVERSAMPLING_RATIO: *val = st->oversampling_ratio; + return IIO_VAL_INT; + + case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: + temp = st->samp_freq * ad7768_filter_3db_odr_multiplier[st->filter_type]; + *val = DIV_ROUND_CLOSEST(temp, 1000); + return IIO_VAL_INT; }