1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * AD7314 digital temperature sensor driver for AD7314, ADT7301 and ADT7302
  4 *
  5 * Copyright 2010 Analog Devices Inc.
  6 *
  7 * Conversion to hwmon from IIO done by Jonathan Cameron <jic23@cam.ac.uk>
  8 */
  9#include <linux/device.h>
 10#include <linux/kernel.h>
 11#include <linux/slab.h>
 12#include <linux/sysfs.h>
 13#include <linux/spi/spi.h>
 14#include <linux/module.h>
 15#include <linux/err.h>
 16#include <linux/hwmon.h>
 17#include <linux/hwmon-sysfs.h>
 18#include <linux/bitops.h>
 19
 20/*
 21 * AD7314 temperature masks
 22 */
 23#define AD7314_TEMP_MASK		0x7FE0
 24#define AD7314_TEMP_SHIFT		5
 25
 26/*
 27 * ADT7301 and ADT7302 temperature masks
 28 */
 29#define ADT7301_TEMP_MASK		0x3FFF
 30
 31enum ad7314_variant {
 32	adt7301,
 33	adt7302,
 34	ad7314,
 35};
 36
 37struct ad7314_data {
 38	struct spi_device	*spi_dev;
 39	u16 rx ____cacheline_aligned;
 40};
 41
 42static int ad7314_spi_read(struct ad7314_data *chip)
 43{
 44	int ret;
 45
 46	ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx));
 47	if (ret < 0) {
 48		dev_err(&chip->spi_dev->dev, "SPI read error\n");
 49		return ret;
 50	}
 51
 52	return be16_to_cpu(chip->rx);
 53}
 54
 55static ssize_t ad7314_temperature_show(struct device *dev,
 56				       struct device_attribute *attr,
 57				       char *buf)
 58{
 59	struct ad7314_data *chip = dev_get_drvdata(dev);
 60	s16 data;
 61	int ret;
 62
 63	ret = ad7314_spi_read(chip);
 64	if (ret < 0)
 65		return ret;
 66	switch (spi_get_device_id(chip->spi_dev)->driver_data) {
 67	case ad7314:
 68		data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT;
 69		data = sign_extend32(data, 9);
 70
 71		return sprintf(buf, "%d\n", 250 * data);
 72	case adt7301:
 73	case adt7302:
 74		/*
 75		 * Documented as a 13 bit twos complement register
 76		 * with a sign bit - which is a 14 bit 2's complement
 77		 * register.  1lsb - 31.25 milli degrees centigrade
 78		 */
 79		data = ret & ADT7301_TEMP_MASK;
 80		data = sign_extend32(data, 13);
 81
 82		return sprintf(buf, "%d\n",
 83			       DIV_ROUND_CLOSEST(data * 3125, 100));
 84	default:
 85		return -EINVAL;
 86	}
 87}
 88
 89static SENSOR_DEVICE_ATTR_RO(temp1_input, ad7314_temperature, 0);
 90
 91static struct attribute *ad7314_attrs[] = {
 92	&sensor_dev_attr_temp1_input.dev_attr.attr,
 93	NULL,
 94};
 95
 96ATTRIBUTE_GROUPS(ad7314);
 97
 98static int ad7314_probe(struct spi_device *spi_dev)
 99{
100	struct ad7314_data *chip;
101	struct device *hwmon_dev;
102
103	chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL);
104	if (chip == NULL)
105		return -ENOMEM;
106
107	chip->spi_dev = spi_dev;
108	hwmon_dev = devm_hwmon_device_register_with_groups(&spi_dev->dev,
109							   spi_dev->modalias,
110							   chip, ad7314_groups);
111	return PTR_ERR_OR_ZERO(hwmon_dev);
112}
113
114static const struct spi_device_id ad7314_id[] = {
115	{ "adt7301", adt7301 },
116	{ "adt7302", adt7302 },
117	{ "ad7314", ad7314 },
118	{ }
119};
120MODULE_DEVICE_TABLE(spi, ad7314_id);
121
122static struct spi_driver ad7314_driver = {
123	.driver = {
124		.name = "ad7314",
125	},
126	.probe = ad7314_probe,
127	.id_table = ad7314_id,
128};
129
130module_spi_driver(ad7314_driver);
131
132MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
133MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver");
134MODULE_LICENSE("GPL v2");