From patchwork Tue Aug 24 05:01:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: navin X-Patchwork-Id: 12453977 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 529ECC4338F for ; Tue, 24 Aug 2021 05:24:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2DF5D6113B for ; Tue, 24 Aug 2021 05:24:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229901AbhHXFZK (ORCPT ); Tue, 24 Aug 2021 01:25:10 -0400 Received: from gproxy4-pub.mail.unifiedlayer.com ([69.89.23.142]:42096 "EHLO gproxy4-pub.mail.unifiedlayer.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229885AbhHXFZK (ORCPT ); Tue, 24 Aug 2021 01:25:10 -0400 X-Greylist: delayed 1363 seconds by postgrey-1.27 at vger.kernel.org; Tue, 24 Aug 2021 01:25:09 EDT Received: from cmgw10.mail.unifiedlayer.com (unknown [10.0.90.125]) by gproxy4.mail.unifiedlayer.com (Postfix) with ESMTP id 51D2C803082A for ; Tue, 24 Aug 2021 05:01:39 +0000 (UTC) Received: from md-in-79.webhostbox.net ([43.225.55.182]) by cmsmtp with ESMTP id IOZ6mA6V0KpssIOZ8mG78H; Tue, 24 Aug 2021 05:01:39 +0000 X-Authority-Reason: nr=8 X-Authority-Analysis: v=2.4 cv=GIfNrsBK c=1 sm=1 tr=0 ts=61247d33 a=LfuyaZh/8e9VOkaVZk0aRw==:117 a=LfuyaZh/8e9VOkaVZk0aRw==:17 a=dLZJa+xiwSxG16/P+YVxDGlgEgI=:19 a=MhDmnRu9jo8A:10:nop_rcvd_month_year a=oz0wMknONp8A:10:endurance_base64_authed_username_1 a=jtbBNqsHAAAA:8 a=vU9dKmh3AAAA:8 a=VwQbUJbxAAAA:8 a=NFmCyV0TXFebMMqy87AA:9 a=sfIEtMYjypgA:10:uccc_2email_address a=RWaeYqt-Cn-VcsFsiLGo:22 a=rsP06fVo5MYu2ilr0aT5:22 a=AjGcO6oz07-iQ99wixmX:22 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linumiz.com ; s=default; h=Content-Transfer-Encoding:MIME-Version:Message-Id:Date:Subject :Cc:To:From:Sender:Reply-To:Content-Type:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: In-Reply-To:References:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=Atuf5vDslWlK/j+ayzma8B6zr4yU2LcjKZCjdWTi1o0=; b=dv4QOfNWkX4dngXQ3H4MBhZPnx r+zOgMkVNl4TT+UfSP+sxuBVI4GFh9twaY2xexXsC/mMzh3tLRm596/X0NTYc1N3zAneSWo6dsqCH pBRbnaQaolg9RC+BwZsIkjLKK39mwcQVn6mv7WJndswvsErDD9+4omXmsnQOb7BKJL+m7ZvrA9vkP LhY2yTWHYYgg/Eo65o83FKl7ZmQx23UxsVoJYyBUZyw/REQbn3GZlzbwtFmRjchaobo/P+YVMpNOt kYD+PEpGLBGySDXRYxrosIdFKQUS1xflCEyFs3ahVfLOyIr8ecqDFg96R0MdUOloBso6F6z2U+7zl k+3UOpiA==; Received: from [117.193.211.180] (port=56146 helo=localhost.localdomain) by md-in-79.webhostbox.net with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mIOZ5-000LCM-TN; Tue, 24 Aug 2021 05:01:36 +0000 From: Navin Sankar Velliangiri To: jic23@kernel.org Cc: navin@linumiz.com, lars@metafoo.de, pmeerw@pmeerw.net, linux-iio@vger.kernel.org, ardeleanalex@gmail.com Subject: [PATCH v4 1/2] iio: temperature: Add MAX31865 RTD Support Date: Tue, 24 Aug 2021 10:31:23 +0530 Message-Id: <20210824050123.71289-1-navin@linumiz.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - md-in-79.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - linumiz.com X-BWhitelist: no X-Source-IP: 117.193.211.180 X-Source-L: No X-Exim-ID: 1mIOZ5-000LCM-TN X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (localhost.localdomain) [117.193.211.180]:56146 X-Source-Auth: linumcmc X-Email-Count: 2 X-Source-Cap: bGludW1jbWM7aG9zdGdhdG9yO21kLWluLTc5LndlYmhvc3Rib3gubmV0 X-Local-Domain: yes Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org This patch adds support for Maxim MAX31865 RTD temperature sensor support. More information can be found in: https://datasheets.maximintegrated.com/en/ds/MAX31865.pdf Signed-off-by: Navin Sankar Velliangiri --- Note: Changes in v2: -> removed unnecessary header #include -> implemented mutex to protect the device state -> Added __cacheline_aligned buffer to hold the raw temperature data -> implemented separate function to enable_bias() & disable_bias() -> call max31865_init() func when updating the filter -> Added ABI documentation for reference & testing -> dropped spi_set_drvdata() Changes in v3: -> Moved buf[2] __cacheline_aligned to last element of struct max31865_data -> get_unaligned_be16 is used to express the raw temp data -> Added in_temp_filter_notch_frequency_avail to check available frequency -> removed mutex lock & unlock in max31865_probe() func Changes in v4: -> use existing available attribute to show the available sampling frequency. -> use existing in_filter_notch_center_frequency attribute the set the notch filter. --- .../sysfs-bus-iio-temperature-max31865 | 20 + drivers/iio/temperature/Kconfig | 10 + drivers/iio/temperature/Makefile | 1 + drivers/iio/temperature/max31865.c | 349 ++++++++++++++++++ 4 files changed, 380 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-temperature-max31865 create mode 100644 drivers/iio/temperature/max31865.c diff --git a/Documentation/ABI/testing/sysfs-bus-iio-temperature-max31865 b/Documentation/ABI/testing/sysfs-bus-iio-temperature-max31865 new file mode 100644 index 000000000000..4b072da92218 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-iio-temperature-max31865 @@ -0,0 +1,20 @@ +What: /sys/bus/iio/devices/iio:deviceX/fault_ovuv +KernelVersion: 5.11 +Contact: linux-iio@vger.kernel.org +Description: + Overvoltage or Undervoltage Input fault. The internal circuitry + is protected from excessive voltages applied to the thermocouple + cables at FORCE+, FORCE2, RTDIN+ & RTDIN-. This circuitry turn + off when the input voltage is negative or greater than VDD. + + Reading returns '1' if input voltage is negative or greater + than VDD, otherwise '0'. + +What: /sys/bus/iio/devices/iio:deviceX/in_filter_notch_center_frequency +KernelVersion: 5.11 +Contact: linux-iio@vger.kernel.org +Description: + Notch frequency in Hz for a noise rejection filter. Used i.e for + line noise rejection. + + Valid notch filter values are 50 Hz and 60 Hz. diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig index 4df60082c1fa..c9412abca069 100644 --- a/drivers/iio/temperature/Kconfig +++ b/drivers/iio/temperature/Kconfig @@ -128,4 +128,14 @@ config MAX31856 This driver can also be built as a module. If so, the module will be called max31856. +config MAX31865 + tristate "MAX31865 RTD to Digital converter" + depends on SPI + help + If you say yes here you get support for MAX31865 + thermocouple sensor chip connected via SPI. + + This driver can also be build as a module. If so, the module + will be called max31865. + endmenu diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile index 90c113115422..a8f3187258dc 100644 --- a/drivers/iio/temperature/Makefile +++ b/drivers/iio/temperature/Makefile @@ -8,6 +8,7 @@ obj-$(CONFIG_LTC2983) += ltc2983.o obj-$(CONFIG_HID_SENSOR_TEMP) += hid-sensor-temperature.o obj-$(CONFIG_MAXIM_THERMOCOUPLE) += maxim_thermocouple.o obj-$(CONFIG_MAX31856) += max31856.o +obj-$(CONFIG_MAX31865) += max31865.o obj-$(CONFIG_MLX90614) += mlx90614.o obj-$(CONFIG_MLX90632) += mlx90632.o obj-$(CONFIG_TMP006) += tmp006.o diff --git a/drivers/iio/temperature/max31865.c b/drivers/iio/temperature/max31865.c new file mode 100644 index 000000000000..4c8d6e6cf677 --- /dev/null +++ b/drivers/iio/temperature/max31865.c @@ -0,0 +1,349 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * Copyright (c) Linumiz 2021 + * + * max31865.c - Maxim MAX31865 RTD-to-Digital Converter sensor driver + * + * Author: Navin Sankar Velliangiri + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * The MSB of the register value determines whether the following byte will + * be written or read. If it is 0, read will follow and if it is 1, write + * will follow. + */ +#define MAX31865_RD_WR_BIT BIT(7) + +#define MAX31865_CFG_VBIAS BIT(7) +#define MAX31865_CFG_1SHOT BIT(5) +#define MAX31865_3WIRE_RTD BIT(4) +#define MAX31865_FAULT_STATUS_CLEAR BIT(1) +#define MAX31865_FILTER_50HZ BIT(0) + +/* The MAX31865 registers */ +#define MAX31865_CFG_REG 0x00 +#define MAX31865_RTD_MSB 0x01 +#define MAX31865_FAULT_STATUS 0x07 + +#define MAX31865_FAULT_OVUV BIT(2) + +static const char max31865_show_samp_freq[] = "50 60"; + +static const struct iio_chan_spec max31865_channels[] = { + { /* RTD Temperature */ + .type = IIO_TEMP, + .info_mask_separate = + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) + }, +}; + +struct max31865_data { + struct spi_device *spi; + struct mutex lock; + bool filter_50hz; + bool three_wire; + u8 buf[2] ____cacheline_aligned; +}; + +static int max31865_read(struct max31865_data *data, u8 reg, + unsigned int read_size) +{ + return spi_write_then_read(data->spi, ®, 1, data->buf, read_size); +} + +static int max31865_write(struct max31865_data *data, size_t len) +{ + return spi_write(data->spi, data->buf, len); +} + +static int enable_bias(struct max31865_data *data) +{ + u8 cfg; + int ret; + + ret = max31865_read(data, MAX31865_CFG_REG, 1); + if (ret) + return ret; + + cfg = data->buf[0]; + + data->buf[0] = MAX31865_CFG_REG | MAX31865_RD_WR_BIT; + data->buf[1] = cfg | MAX31865_CFG_VBIAS; + + return max31865_write(data, 2); +} + +static int disable_bias(struct max31865_data *data) +{ + u8 cfg; + int ret; + + ret = max31865_read(data, MAX31865_CFG_REG, 1); + if (ret) + return ret; + + cfg = data->buf[0]; + cfg &= ~MAX31865_CFG_VBIAS; + + data->buf[0] = MAX31865_CFG_REG | MAX31865_RD_WR_BIT; + data->buf[1] = cfg; + + return max31865_write(data, 2); +} + +static int max31865_rtd_read(struct max31865_data *data, int *val) +{ + u8 reg; + int ret; + + /* Enable BIAS to start the conversion */ + ret = enable_bias(data); + if (ret) + return ret; + + /* wait 10.5ms before initiating the conversion */ + msleep(11); + + ret = max31865_read(data, MAX31865_CFG_REG, 1); + if (ret) + return ret; + + reg = data->buf[0]; + reg |= MAX31865_CFG_1SHOT | MAX31865_FAULT_STATUS_CLEAR; + data->buf[0] = MAX31865_CFG_REG | MAX31865_RD_WR_BIT; + data->buf[1] = reg; + + ret = max31865_write(data, 2); + if (ret) + return ret; + + if (data->filter_50hz) { + /* 50Hz filter mode requires 62.5ms to complete */ + msleep(63); + } else { + /* 60Hz filter mode requires 52ms to complete */ + msleep(52); + } + + ret = max31865_read(data, MAX31865_RTD_MSB, 2); + if (ret) + return ret; + + *val = get_unaligned_be16(&data->buf) >> 1; + + return disable_bias(data); +} + +static int max31865_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct max31865_data *data = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&data->lock); + ret = max31865_rtd_read(data, val); + mutex_unlock(&data->lock); + if (ret) + return ret; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + /* Temp. Data resolution is 0.03125 degree centigrade */ + *val = 31; + *val2 = 250000; /* 1000 * 0.03125 */ + return IIO_VAL_INT_PLUS_MICRO; + default: + return -EINVAL; + } +} + +static int max31865_init(struct max31865_data *data) +{ + u8 cfg; + int ret; + + ret = max31865_read(data, MAX31865_CFG_REG, 1); + if (ret) + return ret; + + cfg = data->buf[0]; + + if (data->three_wire) + /* 3-wire RTD connection */ + cfg |= MAX31865_3WIRE_RTD; + + if (data->filter_50hz) + /* 50Hz noise rejection filter */ + cfg |= MAX31865_FILTER_50HZ; + + data->buf[0] = MAX31865_CFG_REG | MAX31865_RD_WR_BIT; + data->buf[1] = cfg; + + return max31865_write(data, 2); +} + +static ssize_t show_fault(struct device *dev, u8 faultbit, char *buf) +{ + int ret; + bool fault; + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct max31865_data *data = iio_priv(indio_dev); + + ret = max31865_read(data, MAX31865_FAULT_STATUS, 1); + if (ret) + return ret; + + fault = data->buf[0] & faultbit; + + return sprintf(buf, "%d\n", fault); +} + +static ssize_t show_fault_ovuv(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + return show_fault(dev, MAX31865_FAULT_OVUV, buf); +} + +static ssize_t show_filter(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct max31865_data *data = iio_priv(indio_dev); + + return sprintf(buf, "%d\n", data->filter_50hz ? 50 : 60); +} + +static ssize_t set_filter(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct max31865_data *data = iio_priv(indio_dev); + unsigned int freq; + int ret; + + ret = kstrtouint(buf, 10, &freq); + if (ret) + return ret; + + switch (freq) { + case 50: + data->filter_50hz = true; + break; + case 60: + data->filter_50hz = false; + break; + default: + return -EINVAL; + } + + mutex_lock(&data->lock); + ret = max31865_init(data); + mutex_unlock(&data->lock); + if (ret) + return ret; + + return len; +} + +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(max31865_show_samp_freq); +static IIO_DEVICE_ATTR(fault_ovuv, 0444, show_fault_ovuv, NULL, 0); +static IIO_DEVICE_ATTR(in_filter_notch_center_frequency, 0644, + show_filter, set_filter, 0); + +static struct attribute *max31865_attributes[] = { + &iio_dev_attr_fault_ovuv.dev_attr.attr, + &iio_const_attr_sampling_frequency_available.dev_attr.attr, + &iio_dev_attr_in_filter_notch_center_frequency.dev_attr.attr, + NULL, +}; + +static const struct attribute_group max31865_group = { + .attrs = max31865_attributes, +}; + +static const struct iio_info max31865_info = { + .read_raw = max31865_read_raw, + .attrs = &max31865_group, +}; + +static int max31865_probe(struct spi_device *spi) +{ + const struct spi_device_id *id = spi_get_device_id(spi); + struct iio_dev *indio_dev; + struct max31865_data *data; + int ret; + + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + data = iio_priv(indio_dev); + data->spi = spi; + data->filter_50hz = false; + mutex_init(&data->lock); + + indio_dev->info = &max31865_info; + indio_dev->name = id->name; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = max31865_channels; + indio_dev->num_channels = ARRAY_SIZE(max31865_channels); + + if (of_property_read_bool(spi->dev.of_node, "maxim,3-wire")) { + /* select 3 wire */ + data->three_wire = 1; + } else { + /* select 2 or 4 wire */ + data->three_wire = 0; + } + + ret = max31865_init(data); + if (ret) { + dev_err(&spi->dev, "error: Failed to configure max31865\n"); + return ret; + } + + return devm_iio_device_register(&spi->dev, indio_dev); +} + +static const struct spi_device_id max31865_id[] = { + { "max31865", 0 }, + { } +}; +MODULE_DEVICE_TABLE(spi, max31865_id); + +static const struct of_device_id max31865_of_match[] = { + { .compatible = "maxim,max31865" }, + { } +}; +MODULE_DEVICE_TABLE(of, max31865_of_match); + +static struct spi_driver max31865_driver = { + .driver = { + .name = "max31865", + .of_match_table = max31865_of_match, + }, + .probe = max31865_probe, + .id_table = max31865_id, +}; +module_spi_driver(max31865_driver); + +MODULE_AUTHOR("Navin Sankar Velliangiri "); +MODULE_DESCRIPTION("Maxim MAX31865 RTD-to-Digital Converter sensor driver"); +MODULE_LICENSE("GPL v2"); From patchwork Tue Aug 24 05:06:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: navin X-Patchwork-Id: 12453979 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8898DC4338F for ; Tue, 24 Aug 2021 05:33:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 665F661212 for ; 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Tue, 24 Aug 2021 05:08:21 +0000 From: Navin Sankar Velliangiri To: jic23@kernel.org Cc: navin@linumiz.com, lars@metafoo.de, pmeerw@pmeerw.net, linux-iio@vger.kernel.org, ardeleanalex@gmail.com, robh+dt@kernel.org, devicetree@vger.kernel.org Subject: [PATCH v4 2/2] dt-bindings: iio: temperature: add MAXIM max31865 support Date: Tue, 24 Aug 2021 10:36:50 +0530 Message-Id: <20210824050650.72619-1-navin@linumiz.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - md-in-79.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - linumiz.com X-BWhitelist: no X-Source-IP: 117.193.211.180 X-Source-L: No X-Exim-ID: 1mIOfd-000R5G-Hn X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (localhost.localdomain) [117.193.211.180]:56148 X-Source-Auth: linumcmc X-Email-Count: 9 X-Source-Cap: bGludW1jbWM7aG9zdGdhdG9yO21kLWluLTc5LndlYmhvc3Rib3gubmV0 X-Local-Domain: yes Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org Add DT bindings for MAXIM max31865 RTD sensor. Signed-off-by: Navin Sankar Velliangiri Reviewed-by: Rob Herring --- Note: Changes in v2: -> Changed the name RTD to Resistance Temperature Detector -> renamed maxim,no-of-wires to 3-wire -> fixed code alignment for the example Changes in v3: -> Added more information about 3 wire RTD connection --- .../iio/temperature/maxim,max31865.yaml | 52 +++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 Documentation/devicetree/bindings/iio/temperature/maxim,max31865.yaml diff --git a/Documentation/devicetree/bindings/iio/temperature/maxim,max31865.yaml b/Documentation/devicetree/bindings/iio/temperature/maxim,max31865.yaml new file mode 100644 index 000000000000..aafb33b16549 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/temperature/maxim,max31865.yaml @@ -0,0 +1,52 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/iio/temperature/maxim,max31865.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Maxim MAX31865 Resistance Temperature Detector. + +maintainers: + - Navin Sankar Velliangiri + +description: | + https://datasheets.maximintegrated.com/en/ds/MAX31865.pdf + +properties: + compatible: + const: maxim,max31865 + + reg: + maxItems: 1 + + maxim,3-wire: + description: + Identifies the number of wires used by the RTD. Setting this property + enables 3-wire RTD connection. Else 2-wire or 4-wire RTD connection. + type: boolean + + spi-max-frequency: true + spi-cpha: true + +required: + - compatible + - reg + - spi-cpha + +additionalProperties: false + +examples: + - | + spi { + #address-cells = <1>; + #size-cells = <0>; + + temp_sensor@0 { + compatible = "maxim,max31865"; + reg = <0>; + spi-max-frequency = <400000>; + spi-cpha; + maxim,3-wire; + }; + }; +...