1/*
  2 * AD7314 digital temperature sensor driver for AD7314, ADT7301 and ADT7302
  3 *
  4 * Copyright 2010 Analog Devices Inc.
  5 *
  6 * Licensed under the GPL-2 or later.
  7 *
  8 * Conversion to hwmon from IIO done by Jonathan Cameron <jic23@cam.ac.uk>
  9 */
 10#include <linux/device.h>
 11#include <linux/kernel.h>
 12#include <linux/slab.h>
 13#include <linux/sysfs.h>
 14#include <linux/spi/spi.h>
 15#include <linux/module.h>
 16#include <linux/err.h>
 17#include <linux/hwmon.h>
 18#include <linux/hwmon-sysfs.h>
 19#include <linux/bitops.h>
 20
 21/*
 22 * AD7314 temperature masks
 23 */
 24#define AD7314_TEMP_MASK		0x7FE0
 25#define AD7314_TEMP_SHIFT		5
 26
 27/*
 28 * ADT7301 and ADT7302 temperature masks
 29 */
 30#define ADT7301_TEMP_MASK		0x3FFF
 31
 32enum ad7314_variant {
 33	adt7301,
 34	adt7302,
 35	ad7314,
 36};
 37
 38struct ad7314_data {
 39	struct spi_device	*spi_dev;
 40	struct device		*hwmon_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_show_temperature(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		data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT;
 71		data = sign_extend32(data, 9);
 72
 73		return sprintf(buf, "%d\n", 250 * data);
 74	case adt7301:
 75	case adt7302:
 76		/*
 77		 * Documented as a 13 bit twos complement register
 78		 * with a sign bit - which is a 14 bit 2's complement
 79		 * register.  1lsb - 31.25 milli degrees centigrade
 80		 */
 81		data = ret & ADT7301_TEMP_MASK;
 82		data = sign_extend32(data, 13);
 83
 84		return sprintf(buf, "%d\n",
 85			       DIV_ROUND_CLOSEST(data * 3125, 100));
 86	default:
 87		return -EINVAL;
 88	}
 89}
 90
 91static ssize_t ad7314_show_name(struct device *dev,
 92				struct device_attribute *devattr, char *buf)
 93{
 94	return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
 95}
 96
 97static DEVICE_ATTR(name, S_IRUGO, ad7314_show_name, NULL);
 98static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
 99			  ad7314_show_temperature, NULL, 0);
100
101static struct attribute *ad7314_attributes[] = {
102	&dev_attr_name.attr,
103	&sensor_dev_attr_temp1_input.dev_attr.attr,
104	NULL,
105};
106
107static const struct attribute_group ad7314_group = {
108	.attrs = ad7314_attributes,
109};
110
111static int ad7314_probe(struct spi_device *spi_dev)
112{
113	int ret;
114	struct ad7314_data *chip;
115
116	chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL);
117	if (chip == NULL)
118		return -ENOMEM;
119
120	spi_set_drvdata(spi_dev, chip);
121
122	ret = sysfs_create_group(&spi_dev->dev.kobj, &ad7314_group);
123	if (ret < 0)
124		return ret;
125
126	chip->hwmon_dev = hwmon_device_register(&spi_dev->dev);
127	if (IS_ERR(chip->hwmon_dev)) {
128		ret = PTR_ERR(chip->hwmon_dev);
129		goto error_remove_group;
130	}
131	chip->spi_dev = spi_dev;
132
133	return 0;
134error_remove_group:
135	sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group);
136	return ret;
137}
138
139static int ad7314_remove(struct spi_device *spi_dev)
140{
141	struct ad7314_data *chip = spi_get_drvdata(spi_dev);
142
143	hwmon_device_unregister(chip->hwmon_dev);
144	sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group);
145
146	return 0;
147}
148
149static const struct spi_device_id ad7314_id[] = {
150	{ "adt7301", adt7301 },
151	{ "adt7302", adt7302 },
152	{ "ad7314", ad7314 },
153	{ }
154};
155MODULE_DEVICE_TABLE(spi, ad7314_id);
156
157static struct spi_driver ad7314_driver = {
158	.driver = {
159		.name = "ad7314",
160	},
161	.probe = ad7314_probe,
162	.remove = ad7314_remove,
163	.id_table = ad7314_id,
164};
165
166module_spi_driver(ad7314_driver);
167
168MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
169MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver");
170MODULE_LICENSE("GPL v2");