From nobody Fri Dec 26 03:02:50 2025 Received: from mail-wm1-f49.google.com (mail-wm1-f49.google.com [209.85.128.49]) (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 4ABA24CDF8; Wed, 10 Jan 2024 15:38:10 +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="eR0nGKcO" Received: by mail-wm1-f49.google.com with SMTP id 5b1f17b1804b1-40d88fff7faso44082865e9.3; Wed, 10 Jan 2024 07:38:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1704901088; x=1705505888; 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=LTMaMXmqDjo2TjzKR4Go+S5q8z7l19GhbUs2M7Oy3ZA=; b=eR0nGKcOQ+YuEdFaxzChDvNPXcRUEWA9uQx72HTw0sOUrmdAqRfVjzWO5Hd6qmCdrQ tWkDjQERqMvQoHup3a7L0oyAkrb/QMKqpqjAUjI6g/p0xzVSt7cf9q43CaQHpkaXkAm4 dUj+80clyRIxv2n1+0JvBdNw718qX+6CFeLS4meFUpJ0T+rHy8hgD6ccnVMMi2oAxOH9 r+Znsk1ZEPzIZARgVzv3XyX3upbwB0c2xgFZZevvUQZOWpACDt57TjTP/+fDdXn58qjy zhM+/HrDzhi9PoyFtnbk9M5Nb6fa62TmV6g7iqpEGj+lCfR+yvUg+d7A9LZVvrcueu3c 3sbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1704901088; x=1705505888; 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=LTMaMXmqDjo2TjzKR4Go+S5q8z7l19GhbUs2M7Oy3ZA=; b=uXHQx8/SyvBCDPviaCapGp2eMZf0iYHYB6suMH+dJiFA4IojQQGsSesu5A51Yazg9G iVJI+xTETW7nT0yIRdvdGtqbNbDsKrzAua3M6/OE7yJenC3d8B0SSxyDj4jpvWK16B5d lxHi+rbG92FRe9qHwytFCEXS0omEUPDqlWeWQK4WWwBBrRGZMoNBETD5ymvkJWjphOqL dqYh10RaVqF2zH/qdHi2itXRHk6UERK2/T1hCUkPNdVFNTbbNqriBhIPuom+mW2tJR4r QBfu8jumk8o/JS2pwkBt2WgLdVpjrULACYGgRKg6gbxaSh7q+PeA/NrOy+FTsvq9R3c5 m90g== X-Gm-Message-State: AOJu0YxCju8Y3XyMYjYI9hgGawu6ywxRFKfUoyVl6HN6ED3HKvK4sL8Z 1ix0zZ3JIqk7SiIoC43l2TE= X-Google-Smtp-Source: AGHT+IE1DTMf17Awc4OzMIOaBNuqw77o/Z5yZIP7lqm/WzjKuPT7HZWhOh2YvdzcCF9/NrOUnk5whQ== X-Received: by 2002:a05:600c:4755:b0:40d:3be1:daaf with SMTP id w21-20020a05600c475500b0040d3be1daafmr356022wmo.51.1704901088400; Wed, 10 Jan 2024 07:38:08 -0800 (PST) Received: from HYB-hhAwRlzzMZb.ad.analog.com ([86.125.72.218]) by smtp.gmail.com with ESMTPSA id e30-20020a5d595e000000b0033776a50472sm4179907wri.10.2024.01.10.07.38.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Jan 2024 07:38:07 -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 v2 4/4] iio: amplifiers: hmc425a: add support for LTC6373 Instrumentation Amplifier Date: Wed, 10 Jan 2024 17:37:12 +0200 Message-ID: <20240110153757.5754-5-mitrutzceclan@gmail.com> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20240110153757.5754-1-mitrutzceclan@gmail.com> References: <20240110153757.5754-1-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 | 104 ++++++++++++++++++++++++++++++- 1 file changed, 102 insertions(+), 2 deletions(-) diff --git a/drivers/iio/amplifiers/hmc425a.c b/drivers/iio/amplifiers/hmc4= 25a.c index b5fd19403d15..2048bf9e0343 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 { @@ -42,6 +57,7 @@ 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 +96,17 @@ 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; break; + 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; + break; } return 0; } @@ -100,6 +127,12 @@ 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; @@ -172,6 +205,44 @@ 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, \ @@ -181,15 +252,30 @@ 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), +}; + /* Match table for of_platform binding */ static const struct of_device_id hmc425a_of_match[] =3D { { .compatible =3D "adi,hmc425a", .data =3D (void *)ID_HMC425A }, { .compatible =3D "adi,hmc540s", .data =3D (void *)ID_HMC540S }, { .compatible =3D "adi,adrf5740", .data =3D (void *)ID_ADRF5740 }, + { .compatible =3D "adi,ltc6373", .data =3D (void *)ID_LTC6373 }, {}, }; MODULE_DEVICE_TABLE(of, hmc425a_of_match); @@ -222,6 +308,15 @@ 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_SHUTDOWN, + }, }; =20 static int hmc425a_probe(struct platform_device *pdev) @@ -266,6 +361,11 @@ static int hmc425a_probe(struct platform_device *pdev) /* Set default gain */ hmc425a_write(indio_dev, st->gain); =20 + if (st->type =3D=3D ID_LTC6373) { + st->powerdown =3D true; + st->gain =3D LTC6373_MIN_GAIN_CODE; + } + return devm_iio_device_register(&pdev->dev, indio_dev); } =20 --=20 2.42.0