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#define AD7314_LEADING_ZEROS_MASK	BIT(15)
 26
 27/*
 28 * ADT7301 and ADT7302 temperature masks
 29 */
 30#define ADT7301_TEMP_MASK		0x3FFF
 31#define ADT7301_LEADING_ZEROS_MASK	(BIT(15) | BIT(14))
 32
 33enum ad7314_variant {
 34	adt7301,
 35	adt7302,
 36	ad7314,
 37};
 38
 39struct ad7314_data {
 40	struct spi_device	*spi_dev;
 41	u16 rx ____cacheline_aligned;
 42};
 43
 44static int ad7314_spi_read(struct ad7314_data *chip)
 45{
 46	int ret;
 47
 48	ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx));
 49	if (ret < 0) {
 50		dev_err(&chip->spi_dev->dev, "SPI read error\n");
 51		return ret;
 52	}
 53
 54	return be16_to_cpu(chip->rx);
 55}
 56
 57static ssize_t ad7314_temperature_show(struct device *dev,
 58				       struct device_attribute *attr,
 59				       char *buf)
 60{
 61	struct ad7314_data *chip = dev_get_drvdata(dev);
 62	s16 data;
 63	int ret;
 64
 65	ret = ad7314_spi_read(chip);
 66	if (ret < 0)
 67		return ret;
 68	switch (spi_get_device_id(chip->spi_dev)->driver_data) {
 69	case ad7314:
 70		if (ret & AD7314_LEADING_ZEROS_MASK) {
 71			/* Invalid read-out, leading zero part is missing */
 72			return -EIO;
 73		}
 74		data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT;
 75		data = sign_extend32(data, 9);
 76
 77		return sprintf(buf, "%d\n", 250 * data);
 78	case adt7301:
 79	case adt7302:
 80		if (ret & ADT7301_LEADING_ZEROS_MASK) {
 81			/* Invalid read-out, leading zero part is missing */
 82			return -EIO;
 83		}
 84		/*
 85		 * Documented as a 13 bit twos complement register
 86		 * with a sign bit - which is a 14 bit 2's complement
 87		 * register.  1lsb - 31.25 milli degrees centigrade
 88		 */
 89		data = ret & ADT7301_TEMP_MASK;
 90		data = sign_extend32(data, 13);
 91
 92		return sprintf(buf, "%d\n",
 93			       DIV_ROUND_CLOSEST(data * 3125, 100));
 94	default:
 95		return -EINVAL;
 96	}
 97}
 98
 99static SENSOR_DEVICE_ATTR_RO(temp1_input, ad7314_temperature, 0);
100
101static struct attribute *ad7314_attrs[] = {
102	&sensor_dev_attr_temp1_input.dev_attr.attr,
103	NULL,
104};
105
106ATTRIBUTE_GROUPS(ad7314);
107
108static int ad7314_probe(struct spi_device *spi_dev)
109{
110	struct ad7314_data *chip;
111	struct device *hwmon_dev;
112
113	chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL);
114	if (chip == NULL)
115		return -ENOMEM;
116
117	chip->spi_dev = spi_dev;
118	hwmon_dev = devm_hwmon_device_register_with_groups(&spi_dev->dev,
119							   spi_dev->modalias,
120							   chip, ad7314_groups);
121	return PTR_ERR_OR_ZERO(hwmon_dev);
122}
123
124static const struct spi_device_id ad7314_id[] = {
125	{ "adt7301", adt7301 },
126	{ "adt7302", adt7302 },
127	{ "ad7314", ad7314 },
128	{ }
129};
130MODULE_DEVICE_TABLE(spi, ad7314_id);
131
132static struct spi_driver ad7314_driver = {
133	.driver = {
134		.name = "ad7314",
135	},
136	.probe = ad7314_probe,
137	.id_table = ad7314_id,
138};
139
140module_spi_driver(ad7314_driver);
141
142MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
143MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver");
144MODULE_LICENSE("GPL v2");