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Wed, 11 Jun 2025 07:52:20 -0400 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 15.2.1748.10; Wed, 11 Jun 2025 07:52:20 -0400 Received: from zeus.spd.analog.com (10.66.68.11) by ashbmbx8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server id 15.2.1748.10 via Frontend Transport; Wed, 11 Jun 2025 07:52:20 -0400 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 55BBq5P2008952; Wed, 11 Jun 2025 07:52:08 -0400 From: Jonathan Santos To: , , , CC: Jonathan Santos , , , , , , , , , , , , , , , Subject: [PATCH v11 11/11] iio: adc: ad7768-1: add low pass -3dB cutoff attribute Date: Wed, 11 Jun 2025 08:52:03 -0300 Message-ID: <804d66f1858014d7278aec3344d81c223661e878.1749569957.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: vgMbvfqAqX-kArYpl0uX7CHp_vR_oTaR X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNjExMDEwMSBTYWx0ZWRfXyJ4XMfagPp8u YopnYcjE8oY+G5emYpQVghHy6t8dcrJfZLzKwb2Y3e0xIE+3gba0F63Kifozfx6M67kxX6JBbbF OoscrbUAeqayH6VfutFG60wmdBCN2R6LiX6itywXwd3iUuEgjqHpRlLfLzVk7/SK+pECXBJpTNz lC/V35d/S1vNETHWdjIW2kqNWJCSQxPG6QPWyzSzFEHP2SFQz28wQy7aQEs2bBCOpAvTKGzyIwN 0tiA1GzXfWeUCFdiFVhX8lndMb+8swjTbwAK50xJMqMIn4xXLFB6pjSJ0A/itr+oY4nA0jbVXB6 TNkFpEGsKcn0ZtjnR+FKqo1ukYhyrwYwEYj3jeMLKYSnjrA45vfY5g5b3xFvpMrfQIzxNyUdel8 qEXshWmNNhwtfSgMr+PWrcKqCPavvJUnXYEc9oLSolXq+Kt3o8iXfqJuq2+8uuRiLwX2zJ8V X-Authority-Analysis: v=2.4 cv=BezY0qt2 c=1 sm=1 tr=0 ts=68496df5 cx=c_pps a=PpDZqlmH/M8setHirZLBMw==:117 a=PpDZqlmH/M8setHirZLBMw==:17 a=6IFa9wvqVegA:10 a=gAnH3GRIAAAA:8 a=IpJZQVW2AAAA:8 a=UvUlGJLpmzXXuVQgGPIA:9 a=IawgGOuG5U0WyFbmm1f5:22 X-Proofpoint-ORIG-GUID: vgMbvfqAqX-kArYpl0uX7CHp_vR_oTaR X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-06-11_05,2025-06-10_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 spamscore=0 impostorscore=0 clxscore=1015 malwarescore=0 mlxlogscore=999 bulkscore=0 phishscore=0 suspectscore=0 lowpriorityscore=0 adultscore=0 priorityscore=1501 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505280000 definitions=main-2506110101 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. Reviewed-by: Marcelo Schmitt Reviewed-by: David Lechner Signed-off-by: Jonathan Santos --- v11 Changes: * Applied suggestions from Andy. v10 Changes: * None v9 Changes: * Rearranged new BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) to make the diff look cleaner. v8 Changes: * None v7 Changes: * None v6 Changes: * None v5 Changes: * None v4 Changes: * None v3 Changes: * None v2 Changes: * New patch in v2. --- drivers/iio/adc/ad7768-1.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c index 291ed801a8a0..e4716e20fcdf 100644 --- a/drivers/iio/adc/ad7768-1.c +++ b/drivers/iio/adc/ad7768-1.c @@ -152,6 +152,14 @@ enum ad7768_scan_type { AD7768_SCAN_TYPE_HIGH_SPEED, }; +/* -3dB cutoff frequency multipliers (relative to ODR) for each filter type. */ +static const int ad7768_filter_3db_odr_multiplier[] = { + [AD7768_FILTER_SINC5] = 204, /* 0.204 */ + [AD7768_FILTER_SINC3] = 262, /* 0.2617 */ + [AD7768_FILTER_SINC3_REJ60] = 262, /* 0.2617 */ + [AD7768_FILTER_WIDEBAND] = 433, /* 0.433 */ +}; + static const int ad7768_mclk_div_rates[] = { 16, 8, 4, 2, }; @@ -746,6 +754,7 @@ 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_LOW_PASS_FILTER_3DB_FREQUENCY) | BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), @@ -766,7 +775,7 @@ 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)) @@ -804,6 +813,12 @@ 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; }