drivers/hwmon/ad7314.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * AD7314 digital temperature sensor driver for AD7314, ADT7301 and ADT7302
0004  *
0005  * Copyright 2010 Analog Devices Inc.
0006  *
0007  * Conversion to hwmon from IIO done by Jonathan Cameron <jic23@cam.ac.uk>
0008  */
0009 #include <linux/device.h>
0010 #include <linux/kernel.h>
0011 #include <linux/slab.h>
0012 #include <linux/sysfs.h>
0013 #include <linux/spi/spi.h>
0014 #include <linux/module.h>
0015 #include <linux/err.h>
0016 #include <linux/hwmon.h>
0017 #include <linux/hwmon-sysfs.h>
0018 #include <linux/bitops.h>
0019
0020 /*
0021  * AD7314 temperature masks
0022  */
0023 #define AD7314_TEMP_MASK        0x7FE0
0024 #define AD7314_TEMP_SHIFT       5
0025
0026 /*
0027  * ADT7301 and ADT7302 temperature masks
0028  */
0029 #define ADT7301_TEMP_MASK       0x3FFF
0030
0031 enum ad7314_variant {
0032     adt7301,
0033     adt7302,
0034     ad7314,
0035 };
0036
0037 struct ad7314_data {
0038     struct spi_device   *spi_dev;
0039     u16 rx ____cacheline_aligned;
0040 };
0041
0042 static int ad7314_spi_read(struct ad7314_data *chip)
0043 {
0044     int ret;
0045
0046     ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx));
0047     if (ret < 0) {
0048         dev_err(&chip->spi_dev->dev, "SPI read error\n");
0049         return ret;
0050     }
0051
0052     return be16_to_cpu(chip->rx);
0053 }
0054
0055 static ssize_t ad7314_temperature_show(struct device *dev,
0056                        struct device_attribute *attr,
0057                        char *buf)
0058 {
0059     struct ad7314_data *chip = dev_get_drvdata(dev);
0060     s16 data;
0061     int ret;
0062
0063     ret = ad7314_spi_read(chip);
0064     if (ret < 0)
0065         return ret;
0066     switch (spi_get_device_id(chip->spi_dev)->driver_data) {
0067     case ad7314:
0068         data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT;
0069         data = sign_extend32(data, 9);
0070
0071         return sprintf(buf, "%d\n", 250 * data);
0072     case adt7301:
0073     case adt7302:
0074         /*
0075          * Documented as a 13 bit twos complement register
0076          * with a sign bit - which is a 14 bit 2's complement
0077          * register.  1lsb - 31.25 milli degrees centigrade
0078          */
0079         data = ret & ADT7301_TEMP_MASK;
0080         data = sign_extend32(data, 13);
0081
0082         return sprintf(buf, "%d\n",
0083                    DIV_ROUND_CLOSEST(data * 3125, 100));
0084     default:
0085         return -EINVAL;
0086     }
0087 }
0088
0089 static SENSOR_DEVICE_ATTR_RO(temp1_input, ad7314_temperature, 0);
0090
0091 static struct attribute *ad7314_attrs[] = {
0092     &sensor_dev_attr_temp1_input.dev_attr.attr,
0093     NULL,
0094 };
0095
0096 ATTRIBUTE_GROUPS(ad7314);
0097
0098 static int ad7314_probe(struct spi_device *spi_dev)
0099 {
0100     struct ad7314_data *chip;
0101     struct device *hwmon_dev;
0102
0103     chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL);
0104     if (chip == NULL)
0105         return -ENOMEM;
0106
0107     chip->spi_dev = spi_dev;
0108     hwmon_dev = devm_hwmon_device_register_with_groups(&spi_dev->dev,
0109                                spi_dev->modalias,
0110                                chip, ad7314_groups);
0111     return PTR_ERR_OR_ZERO(hwmon_dev);
0112 }
0113
0114 static const struct spi_device_id ad7314_id[] = {
0115     { "adt7301", adt7301 },
0116     { "adt7302", adt7302 },
0117     { "ad7314", ad7314 },
0118     { }
0119 };
0120 MODULE_DEVICE_TABLE(spi, ad7314_id);
0121
0122 static struct spi_driver ad7314_driver = {
0123     .driver = {
0124         .name = "ad7314",
0125     },
0126     .probe = ad7314_probe,
0127     .id_table = ad7314_id,
0128 };
0129
0130 module_spi_driver(ad7314_driver);
0131
0132 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
0133 MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver");
0134 MODULE_LICENSE("GPL v2");