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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * max31722 - hwmon driver for Maxim Integrated MAX31722/MAX31723 SPI4 * digital thermometer and thermostats.5 *6 * Copyright (c) 2016, Intel Corporation.7 */8 9#include <linux/hwmon.h>10#include <linux/hwmon-sysfs.h>11#include <linux/kernel.h>12#include <linux/module.h>13#include <linux/spi/spi.h>14 15#define MAX31722_REG_CFG 0x0016#define MAX31722_REG_TEMP_LSB 0x0117 18#define MAX31722_MODE_CONTINUOUS 0x0019#define MAX31722_MODE_STANDBY 0x0120#define MAX31722_MODE_MASK 0xFE21#define MAX31722_RESOLUTION_12BIT 0x0622#define MAX31722_WRITE_MASK 0x8023 24struct max31722_data {25 struct device *hwmon_dev;26 struct spi_device *spi_device;27 u8 mode;28};29 30static int max31722_set_mode(struct max31722_data *data, u8 mode)31{32 int ret;33 struct spi_device *spi = data->spi_device;34 u8 buf[2] = {35 MAX31722_REG_CFG | MAX31722_WRITE_MASK,36 (data->mode & MAX31722_MODE_MASK) | mode37 };38 39 ret = spi_write(spi, &buf, sizeof(buf));40 if (ret < 0) {41 dev_err(&spi->dev, "failed to set sensor mode.\n");42 return ret;43 }44 data->mode = (data->mode & MAX31722_MODE_MASK) | mode;45 46 return 0;47}48 49static ssize_t max31722_temp_show(struct device *dev,50 struct device_attribute *attr, char *buf)51{52 ssize_t ret;53 struct max31722_data *data = dev_get_drvdata(dev);54 55 ret = spi_w8r16(data->spi_device, MAX31722_REG_TEMP_LSB);56 if (ret < 0)57 return ret;58 /* Keep 12 bits and multiply by the scale of 62.5 millidegrees/bit. */59 return sprintf(buf, "%d\n", (s16)le16_to_cpu(ret) * 125 / 32);60}61 62static SENSOR_DEVICE_ATTR_RO(temp1_input, max31722_temp, 0);63 64static struct attribute *max31722_attrs[] = {65 &sensor_dev_attr_temp1_input.dev_attr.attr,66 NULL,67};68 69ATTRIBUTE_GROUPS(max31722);70 71static int max31722_probe(struct spi_device *spi)72{73 int ret;74 struct max31722_data *data;75 76 data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);77 if (!data)78 return -ENOMEM;79 80 spi_set_drvdata(spi, data);81 data->spi_device = spi;82 /*83 * Set SD bit to 0 so we can have continuous measurements.84 * Set resolution to 12 bits for maximum precision.85 */86 data->mode = MAX31722_MODE_CONTINUOUS | MAX31722_RESOLUTION_12BIT;87 ret = max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);88 if (ret < 0)89 return ret;90 91 data->hwmon_dev = hwmon_device_register_with_groups(&spi->dev,92 spi->modalias,93 data,94 max31722_groups);95 if (IS_ERR(data->hwmon_dev)) {96 max31722_set_mode(data, MAX31722_MODE_STANDBY);97 return PTR_ERR(data->hwmon_dev);98 }99 100 return 0;101}102 103static void max31722_remove(struct spi_device *spi)104{105 struct max31722_data *data = spi_get_drvdata(spi);106 int ret;107 108 hwmon_device_unregister(data->hwmon_dev);109 110 ret = max31722_set_mode(data, MAX31722_MODE_STANDBY);111 if (ret)112 /* There is nothing we can do about this ... */113 dev_warn(&spi->dev, "Failed to put device in stand-by mode\n");114}115 116static int max31722_suspend(struct device *dev)117{118 struct spi_device *spi_device = to_spi_device(dev);119 struct max31722_data *data = spi_get_drvdata(spi_device);120 121 return max31722_set_mode(data, MAX31722_MODE_STANDBY);122}123 124static int max31722_resume(struct device *dev)125{126 struct spi_device *spi_device = to_spi_device(dev);127 struct max31722_data *data = spi_get_drvdata(spi_device);128 129 return max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);130}131 132static DEFINE_SIMPLE_DEV_PM_OPS(max31722_pm_ops, max31722_suspend, max31722_resume);133 134static const struct spi_device_id max31722_spi_id[] = {135 {"max31722", 0},136 {"max31723", 0},137 {}138};139MODULE_DEVICE_TABLE(spi, max31722_spi_id);140 141static struct spi_driver max31722_driver = {142 .driver = {143 .name = "max31722",144 .pm = pm_sleep_ptr(&max31722_pm_ops),145 },146 .probe = max31722_probe,147 .remove = max31722_remove,148 .id_table = max31722_spi_id,149};150 151module_spi_driver(max31722_driver);152 153MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");154MODULE_DESCRIPTION("max31722 sensor driver");155MODULE_LICENSE("GPL v2");156