LXR linux/drivers/hwmon/max31722.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * max31722 - hwmon driver for Maxim Integrated MAX31722/MAX31723 SPI
   4 * digital thermometer and thermostats.
   5 *
   6 * Copyright (c) 2016, Intel Corporation.
   7 */
   8
   9#include <linux/acpi.h>
  10#include <linux/hwmon.h>
  11#include <linux/hwmon-sysfs.h>
  12#include <linux/kernel.h>
  13#include <linux/module.h>
  14#include <linux/spi/spi.h>
  15
  16#define MAX31722_REG_CFG                                0x00
  17#define MAX31722_REG_TEMP_LSB                           0x01
  18
  19#define MAX31722_MODE_CONTINUOUS                        0x00
  20#define MAX31722_MODE_STANDBY                           0x01
  21#define MAX31722_MODE_MASK                              0xFE
  22#define MAX31722_RESOLUTION_12BIT                       0x06
  23#define MAX31722_WRITE_MASK                             0x80
  24
  25struct max31722_data {
  26        struct device *hwmon_dev;
  27        struct spi_device *spi_device;
  28        u8 mode;
  29};
  30
  31static int max31722_set_mode(struct max31722_data *data, u8 mode)
  32{
  33        int ret;
  34        struct spi_device *spi = data->spi_device;
  35        u8 buf[2] = {
  36                MAX31722_REG_CFG | MAX31722_WRITE_MASK,
  37                (data->mode & MAX31722_MODE_MASK) | mode
  38        };
  39
  40        ret = spi_write(spi, &buf, sizeof(buf));
  41        if (ret < 0) {
  42                dev_err(&spi->dev, "failed to set sensor mode.\n");
  43                return ret;
  44        }
  45        data->mode = (data->mode & MAX31722_MODE_MASK) | mode;
  46
  47        return 0;
  48}
  49
  50static ssize_t max31722_temp_show(struct device *dev,
  51                                  struct device_attribute *attr, char *buf)
  52{
  53        ssize_t ret;
  54        struct max31722_data *data = dev_get_drvdata(dev);
  55
  56        ret = spi_w8r16(data->spi_device, MAX31722_REG_TEMP_LSB);
  57        if (ret < 0)
  58                return ret;
  59        /* Keep 12 bits and multiply by the scale of 62.5 millidegrees/bit. */
  60        return sprintf(buf, "%d\n", (s16)le16_to_cpu(ret) * 125 / 32);
  61}
  62
  63static SENSOR_DEVICE_ATTR_RO(temp1_input, max31722_temp, 0);
  64
  65static struct attribute *max31722_attrs[] = {
  66        &sensor_dev_attr_temp1_input.dev_attr.attr,
  67        NULL,
  68};
  69
  70ATTRIBUTE_GROUPS(max31722);
  71
  72static int max31722_probe(struct spi_device *spi)
  73{
  74        int ret;
  75        struct max31722_data *data;
  76
  77        data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);
  78        if (!data)
  79                return -ENOMEM;
  80
  81        spi_set_drvdata(spi, data);
  82        data->spi_device = spi;
  83        /*
  84         * Set SD bit to 0 so we can have continuous measurements.
  85         * Set resolution to 12 bits for maximum precision.
  86         */
  87        data->mode = MAX31722_MODE_CONTINUOUS | MAX31722_RESOLUTION_12BIT;
  88        ret = max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);
  89        if (ret < 0)
  90                return ret;
  91
  92        data->hwmon_dev = hwmon_device_register_with_groups(&spi->dev,
  93                                                            spi->modalias,
  94                                                            data,
  95                                                            max31722_groups);
  96        if (IS_ERR(data->hwmon_dev)) {
  97                max31722_set_mode(data, MAX31722_MODE_STANDBY);
  98                return PTR_ERR(data->hwmon_dev);
  99        }
 100
 101        return 0;
 102}
 103
 104static int max31722_remove(struct spi_device *spi)
 105{
 106        struct max31722_data *data = spi_get_drvdata(spi);
 107
 108        hwmon_device_unregister(data->hwmon_dev);
 109
 110        return max31722_set_mode(data, MAX31722_MODE_STANDBY);
 111}
 112
 113static int __maybe_unused max31722_suspend(struct device *dev)
 114{
 115        struct spi_device *spi_device = to_spi_device(dev);
 116        struct max31722_data *data = spi_get_drvdata(spi_device);
 117
 118        return max31722_set_mode(data, MAX31722_MODE_STANDBY);
 119}
 120
 121static int __maybe_unused max31722_resume(struct device *dev)
 122{
 123        struct spi_device *spi_device = to_spi_device(dev);
 124        struct max31722_data *data = spi_get_drvdata(spi_device);
 125
 126        return max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);
 127}
 128
 129static SIMPLE_DEV_PM_OPS(max31722_pm_ops, max31722_suspend, max31722_resume);
 130
 131static const struct spi_device_id max31722_spi_id[] = {
 132        {"max31722", 0},
 133        {"max31723", 0},
 134        {}
 135};
 136
 137static const struct acpi_device_id __maybe_unused max31722_acpi_id[] = {
 138        {"MAX31722", 0},
 139        {"MAX31723", 0},
 140        {}
 141};
 142
 143MODULE_DEVICE_TABLE(spi, max31722_spi_id);
 144
 145static struct spi_driver max31722_driver = {
 146        .driver = {
 147                .name = "max31722",
 148                .pm = &max31722_pm_ops,
 149                .acpi_match_table = ACPI_PTR(max31722_acpi_id),
 150        },
 151        .probe =            max31722_probe,
 152        .remove =           max31722_remove,
 153        .id_table =         max31722_spi_id,
 154};
 155
 156module_spi_driver(max31722_driver);
 157
 158MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
 159MODULE_DESCRIPTION("max31722 sensor driver");
 160MODULE_LICENSE("GPL v2");
 161