// SPDX-License-Identifier: GPL-2.0-only /* * max31722 - hwmon driver for Maxim Integrated MAX31722/MAX31723 SPI * digital thermometer and thermostats. * * Copyright (c) 2016, Intel Corporation. */ #include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/spi/spi.h> #define MAX31722_REG_CFG 0x00 #define MAX31722_REG_TEMP_LSB 0x01 #define MAX31722_MODE_CONTINUOUS 0x00 #define MAX31722_MODE_STANDBY 0x01 #define MAX31722_MODE_MASK 0xFE #define MAX31722_RESOLUTION_12BIT 0x06 #define MAX31722_WRITE_MASK 0x80 struct max31722_data { struct device *hwmon_dev; struct spi_device *spi_device; u8 mode; }; static int max31722_set_mode(struct max31722_data *data, u8 mode) { int ret; struct spi_device *spi = data->spi_device; u8 buf[2] = { MAX31722_REG_CFG | MAX31722_WRITE_MASK, (data->mode & MAX31722_MODE_MASK) | mode }; ret = spi_write(spi, &buf, sizeof(buf)); if (ret < 0) { dev_err(&spi->dev, "failed to set sensor mode.\n"); return ret; } data->mode = (data->mode & MAX31722_MODE_MASK) | mode; return 0; } static ssize_t max31722_temp_show(struct device *dev, struct device_attribute *attr, char *buf) { ssize_t ret; struct max31722_data *data = dev_get_drvdata(dev); ret = spi_w8r16(data->spi_device, MAX31722_REG_TEMP_LSB); if (ret < 0) return ret; /* Keep 12 bits and multiply by the scale of 62.5 millidegrees/bit. */ return sprintf(buf, "%d\n", (s16)le16_to_cpu(ret) * 125 / 32); } static SENSOR_DEVICE_ATTR_RO(temp1_input, max31722_temp, 0); static struct attribute *max31722_attrs[] = { &sensor_dev_attr_temp1_input.dev_attr.attr, NULL, }; ATTRIBUTE_GROUPS(max31722); static int max31722_probe(struct spi_device *spi) { int ret; struct max31722_data *data; data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; spi_set_drvdata(spi, data); data->spi_device = spi; /* * Set SD bit to 0 so we can have continuous measurements. * Set resolution to 12 bits for maximum precision. */ data->mode = MAX31722_MODE_CONTINUOUS | MAX31722_RESOLUTION_12BIT; ret = max31722_set_mode(data, MAX31722_MODE_CONTINUOUS); if (ret < 0) return ret; data->hwmon_dev = hwmon_device_register_with_groups(&spi->dev, spi->modalias, data, max31722_groups); if (IS_ERR(data->hwmon_dev)) { max31722_set_mode(data, MAX31722_MODE_STANDBY); return PTR_ERR(data->hwmon_dev); } return 0; } static void max31722_remove(struct spi_device *spi) { struct max31722_data *data = spi_get_drvdata(spi); int ret; hwmon_device_unregister(data->hwmon_dev); ret = max31722_set_mode(data, MAX31722_MODE_STANDBY); if (ret) /* There is nothing we can do about this ... */ dev_warn(&spi->dev, "Failed to put device in stand-by mode\n"); } static int __maybe_unused max31722_suspend(struct device *dev) { struct spi_device *spi_device = to_spi_device(dev); struct max31722_data *data = spi_get_drvdata(spi_device); return max31722_set_mode(data, MAX31722_MODE_STANDBY); } static int __maybe_unused max31722_resume(struct device *dev) { struct spi_device *spi_device = to_spi_device(dev); struct max31722_data *data = spi_get_drvdata(spi_device); return max31722_set_mode(data, MAX31722_MODE_CONTINUOUS); } static SIMPLE_DEV_PM_OPS(max31722_pm_ops, max31722_suspend, max31722_resume); static const struct spi_device_id max31722_spi_id[] = { {"max31722", 0}, {"max31723", 0}, {} }; MODULE_DEVICE_TABLE(spi, max31722_spi_id); static struct spi_driver max31722_driver = { .driver = { .name = "max31722", .pm = &max31722_pm_ops, }, .probe = max31722_probe, .remove = max31722_remove, .id_table = max31722_spi_id, }; module_spi_driver(max31722_driver); MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>"); MODULE_DESCRIPTION("max31722 sensor driver"); MODULE_LICENSE("GPL v2");