From nobody Thu Dec 25 18:03:11 2025 Received: from mail-wr1-f53.google.com (mail-wr1-f53.google.com [209.85.221.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CC8717730; Mon, 15 Jan 2024 13:30:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ENtOzrfy" Received: by mail-wr1-f53.google.com with SMTP id ffacd0b85a97d-3374e332124so6819336f8f.2; Mon, 15 Jan 2024 05:30:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1705325433; x=1705930233; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=X/bvLckPY/B6iV2JgYPRYCAJR1OfXTgLpwfT8b63pic=; b=ENtOzrfywkvLbWgiDWHS92OIaL0HkuNyfDaaopypitTW8h3QaLhIgJDQh+u7LlhFKx NyoiDjD0u/SrzPdyYzz7T/5Z/NPt+9dTRyUFF0s/vhb/Vcr8kfmD0iWhNYbFjCnJe58A KgpTx61SO9o0E7HY69uJ2i4py5vW3jDEG5Z/WVUKNqQcvSNooAxoslGJiAqZq46LOFmN YvotVML8ugYgWTzprMzbDOfrtwcD3wN4X26iD6zt0OQ45UwAxJ/UvFh4+E/19V6T6zIO F9TLNlNyRKDosLIhGuglOijAi/K186IRfdl9gabSeYB72UZIDVekfd1DDNHpJSELP6oz DYEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705325433; x=1705930233; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=X/bvLckPY/B6iV2JgYPRYCAJR1OfXTgLpwfT8b63pic=; b=K+CV97juU2amF3hTQYS0PHi9c/AnVGjZ6no9ISy5i1MAziTe4GfRpYLjnqBxlfWDl2 31qkGKtvHyOGD8Ofz0iCqcFGfsFkC9XCP7rWPTdIR+Rb+5BiO7pBpIZ9hzKft5KSaZqJ Yyrt8D/glHH/zWFfYzgcRBTvxGAP9z26qsooybyNakZZuBf+BImb9jVB+EAbH3lWoX4x 1kcjnkDOXrr2jdKvtcTg1U+A1iI/lYXSr0Q4WGuDtBLwlr5JT+CXr1pjSApIuHs7ZtBP pAp9Ddoo1fq1FHRSn3yHzTxhRvJ3rqlpKmddO7MSo8l7mMr6FFS2mfUlBx6EhhHtjUOp ZfXg== X-Gm-Message-State: AOJu0YxKNh2/I47SkGX4cntoBbRy/vHCFuRn9xMtEGuORIrbJxiPLmA3 T0N442WfDEL4CshsclglSmQ= X-Google-Smtp-Source: AGHT+IHBXFH3RZdizV3rZJEiIWZwdnffql2oJLxIccgMf52HlqJzf7FpKA5OFQo9QsKGmV1iCm/B0A== X-Received: by 2002:a5d:4ccf:0:b0:336:68dd:c7e2 with SMTP id c15-20020a5d4ccf000000b0033668ddc7e2mr3097613wrt.27.1705325433173; Mon, 15 Jan 2024 05:30:33 -0800 (PST) Received: from HYB-hhAwRlzzMZb.ad.analog.com ([5.2.194.157]) by smtp.gmail.com with ESMTPSA id i6-20020adfb646000000b003378d89737fsm11566669wre.46.2024.01.15.05.30.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Jan 2024 05:30:32 -0800 (PST) From: Dumitru Ceclan To: Cc: Lars-Peter Clausen , Jonathan Cameron , Rob Herring , Krzysztof Kozlowski , Conor Dooley , linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Ceclan Dumitru , Dumitru Ceclan Subject: [PATCH v3 5/5] iio: amplifiers: hmc425a: add support for LTC6373 Instrumentation Amplifier Date: Mon, 15 Jan 2024 15:30:18 +0200 Message-ID: <20240115133023.3465-6-mitrutzceclan@gmail.com> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20240115133023.3465-1-mitrutzceclan@gmail.com> References: <20240115133023.3465-1-mitrutzceclan@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This adds support for LTC6373 36 V Fully-Differential Programmable-Gain Instrumentation Amplifier with 25 pA Input Bias Current. The user can program the gain to one of seven available settings through a 3-bit parallel interface (A2 to A0). Signed-off-by: Dumitru Ceclan --- drivers/iio/amplifiers/hmc425a.c | 118 +++++++++++++++++++++++++++++-- 1 file changed, 114 insertions(+), 4 deletions(-) diff --git a/drivers/iio/amplifiers/hmc425a.c b/drivers/iio/amplifiers/hmc4= 25a.c index b116b54e4206..e7f425677fd3 100644 --- a/drivers/iio/amplifiers/hmc425a.c +++ b/drivers/iio/amplifiers/hmc425a.c @@ -2,9 +2,10 @@ /* * HMC425A and similar Gain Amplifiers * - * Copyright 2020 Analog Devices Inc. + * Copyright 2020, 2023 Analog Devices Inc. */ =20 +#include #include #include #include @@ -20,10 +21,24 @@ #include #include =20 +/* + * The LTC6373 amplifier supports configuring gain using GPIO's with the f= ollowing + * values (OUTPUT_V / INPUT_V): 0(shutdown), 0.25, 0.5, 1, 2, 4, 8, 16 + * + * Except for the shutdown value, all can be converted to dB using 20 * lo= g10(x) + * From here, it is observed that all values are multiples of the '2' gain= setting, + * with the correspondent of 6.020dB. + */ +#define LTC6373_CONVERSION_CONSTANT 6020 +#define LTC6373_MIN_GAIN_CODE 0x6 +#define LTC6373_CONVERSION_MASK GENMASK(2, 0) +#define LTC6373_SHUTDOWN GENMASK(2, 0) + enum hmc425a_type { ID_HMC425A, ID_HMC540S, - ID_ADRF5740 + ID_ADRF5740, + ID_LTC6373, }; =20 struct hmc425a_chip_info { @@ -34,6 +49,8 @@ struct hmc425a_chip_info { int gain_min; int gain_max; int default_gain; + int powerdown_val; + bool has_powerdown; }; =20 struct hmc425a_state { @@ -42,6 +59,7 @@ struct hmc425a_state { struct gpio_descs *gpios; enum hmc425a_type type; u32 gain; + bool powerdown; }; =20 static int hmc425a_write(struct iio_dev *indio_dev, u32 value) @@ -80,6 +98,17 @@ static int hmc425a_gain_dB_to_code(struct hmc425a_state = *st, int val, int val2, temp =3D (abs(gain) / 2000) & 0xF; *code =3D temp & BIT(3) ? temp | BIT(2) : temp; return 0; + case ID_LTC6373: + if (st->powerdown) + return -EPERM; + + /* add half of the value for rounding */ + temp =3D LTC6373_CONVERSION_CONSTANT / 2; + if (val < 0) + temp *=3D -1; + *code =3D ~((gain + temp) / LTC6373_CONVERSION_CONSTANT + 3) + & LTC6373_CONVERSION_MASK; + return 0; default: return -EINVAL; } @@ -101,6 +130,12 @@ static int hmc425a_code_to_gain_dB(struct hmc425a_stat= e *st, int *val, int *val2 code =3D code & BIT(3) ? code & ~BIT(2) : code; gain =3D code * -2000; break; + case ID_LTC6373: + if (st->powerdown) + return -EPERM; + gain =3D ((~code & LTC6373_CONVERSION_MASK) - 3) * + LTC6373_CONVERSION_CONSTANT; + break; } =20 *val =3D gain / 1000; @@ -174,6 +209,48 @@ static const struct iio_info hmc425a_info =3D { .write_raw_get_fmt =3D &hmc425a_write_raw_get_fmt, }; =20 +static ssize_t ltc6373_read_powerdown(struct iio_dev *indio_dev, + uintptr_t private, + const struct iio_chan_spec *chan, + char *buf) +{ + struct hmc425a_state *st =3D iio_priv(indio_dev); + + return sysfs_emit(buf, "%d\n", st->powerdown); +} + +static ssize_t ltc6373_write_powerdown(struct iio_dev *indio_dev, + uintptr_t private, + const struct iio_chan_spec *chan, + const char *buf, + size_t len) +{ + struct hmc425a_state *st =3D iio_priv(indio_dev); + bool powerdown; + int code, ret; + + ret =3D kstrtobool(buf, &powerdown); + if (ret) + return ret; + + mutex_lock(&st->lock); + st->powerdown =3D powerdown; + code =3D (powerdown) ? LTC6373_SHUTDOWN : st->gain; + ret =3D hmc425a_write(indio_dev, code); + mutex_unlock(&st->lock); + return len; +} + +static const struct iio_chan_spec_ext_info ltc6373_ext_info[] =3D { + { + .name =3D "powerdown", + .read =3D ltc6373_read_powerdown, + .write =3D ltc6373_write_powerdown, + .shared =3D IIO_SEPARATE, + }, + {}, +}; + #define HMC425A_CHAN(_channel) \ { \ .type =3D IIO_VOLTAGE, \ @@ -183,10 +260,24 @@ static const struct iio_info hmc425a_info =3D { .info_mask_separate =3D BIT(IIO_CHAN_INFO_HARDWAREGAIN), \ } =20 +#define LTC6373_CHAN(_channel) \ +{ \ + .type =3D IIO_VOLTAGE, \ + .output =3D 1, \ + .indexed =3D 1, \ + .channel =3D _channel, \ + .info_mask_separate =3D BIT(IIO_CHAN_INFO_HARDWAREGAIN), \ + .ext_info =3D ltc6373_ext_info, \ +} + static const struct iio_chan_spec hmc425a_channels[] =3D { HMC425A_CHAN(0), }; =20 +static const struct iio_chan_spec ltc6373_channels[] =3D { + LTC6373_CHAN(0), +}; + static struct hmc425a_chip_info hmc425a_chip_info_tbl[] =3D { [ID_HMC425A] =3D { .name =3D "hmc425a", @@ -215,6 +306,18 @@ static struct hmc425a_chip_info hmc425a_chip_info_tbl[= ] =3D { .gain_max =3D 0, .default_gain =3D 0xF, /* set default gain -22.0db*/ }, + [ID_LTC6373] =3D { + .name =3D "ltc6373", + .channels =3D ltc6373_channels, + .num_channels =3D ARRAY_SIZE(ltc6373_channels), + .num_gpios =3D 3, + .gain_min =3D -12041, /* gain setting x0.25*/ + .gain_max =3D 24082, /* gain setting x16 */ + .default_gain =3D LTC6373_MIN_GAIN_CODE, + .powerdown_val =3D LTC6373_SHUTDOWN, + .has_powerdown =3D true, + }, + }; =20 /* Match table for of_platform binding */ @@ -225,6 +328,8 @@ static const struct of_device_id hmc425a_of_match[] =3D= { .data =3D &hmc425a_chip_info_tbl[ID_HMC540S]}, { .compatible =3D "adi,adrf5740", .data =3D &hmc425a_chip_info_tbl[ID_ADRF5740]}, + { .compatible =3D "adi,ltc6373", + .data =3D &hmc425a_chip_info_tbl[ID_LTC6373]}, {}, }; MODULE_DEVICE_TABLE(of, hmc425a_of_match); @@ -270,8 +375,13 @@ static int hmc425a_probe(struct platform_device *pdev) indio_dev->info =3D &hmc425a_info; indio_dev->modes =3D INDIO_DIRECT_MODE; =20 - /* Set default gain */ - hmc425a_write(indio_dev, st->gain); + if (st->chip_info->has_powerdown) { + st->powerdown =3D true; + hmc425a_write(indio_dev, st->chip_info->powerdown_val); + } else { + /* Set default gain */ + hmc425a_write(indio_dev, st->gain); + } =20 return devm_iio_device_register(&pdev->dev, indio_dev); } --=20 2.42.0