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- // 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 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 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 DEFINE_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 = pm_sleep_ptr(&max31722_pm_ops),
- },
- .probe = max31722_probe,
- .remove = max31722_remove,
- .id_table = max31722_spi_id,
- };
- module_spi_driver(max31722_driver);
- MODULE_AUTHOR("Tiberiu Breana <[email protected]>");
- MODULE_DESCRIPTION("max31722 sensor driver");
- MODULE_LICENSE("GPL v2");
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