137 lines
3 KiB
C
137 lines
3 KiB
C
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/*
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* AD7314 digital temperature sensor driver for AD7314, ADT7301 and ADT7302
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*
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* Copyright 2010 Analog Devices Inc.
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*
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* Licensed under the GPL-2 or later.
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*
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* Conversion to hwmon from IIO done by Jonathan Cameron <jic23@cam.ac.uk>
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*/
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include <linux/spi/spi.h>
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/bitops.h>
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/*
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* AD7314 temperature masks
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*/
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#define AD7314_TEMP_MASK 0x7FE0
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#define AD7314_TEMP_SHIFT 5
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/*
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* ADT7301 and ADT7302 temperature masks
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*/
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#define ADT7301_TEMP_MASK 0x3FFF
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enum ad7314_variant {
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adt7301,
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adt7302,
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ad7314,
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};
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struct ad7314_data {
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struct spi_device *spi_dev;
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u16 rx ____cacheline_aligned;
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};
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static int ad7314_spi_read(struct ad7314_data *chip)
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{
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int ret;
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ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx));
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if (ret < 0) {
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dev_err(&chip->spi_dev->dev, "SPI read error\n");
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return ret;
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}
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return be16_to_cpu(chip->rx);
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}
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static ssize_t ad7314_show_temperature(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct ad7314_data *chip = dev_get_drvdata(dev);
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s16 data;
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int ret;
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ret = ad7314_spi_read(chip);
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if (ret < 0)
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return ret;
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switch (spi_get_device_id(chip->spi_dev)->driver_data) {
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case ad7314:
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data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT;
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data = sign_extend32(data, 9);
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return sprintf(buf, "%d\n", 250 * data);
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case adt7301:
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case adt7302:
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/*
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* Documented as a 13 bit twos complement register
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* with a sign bit - which is a 14 bit 2's complement
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* register. 1lsb - 31.25 milli degrees centigrade
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*/
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data = ret & ADT7301_TEMP_MASK;
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data = sign_extend32(data, 13);
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return sprintf(buf, "%d\n",
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DIV_ROUND_CLOSEST(data * 3125, 100));
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default:
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return -EINVAL;
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}
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}
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static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
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ad7314_show_temperature, NULL, 0);
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static struct attribute *ad7314_attrs[] = {
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&sensor_dev_attr_temp1_input.dev_attr.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(ad7314);
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static int ad7314_probe(struct spi_device *spi_dev)
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{
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struct ad7314_data *chip;
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struct device *hwmon_dev;
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chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL);
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if (chip == NULL)
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return -ENOMEM;
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chip->spi_dev = spi_dev;
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hwmon_dev = devm_hwmon_device_register_with_groups(&spi_dev->dev,
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spi_dev->modalias,
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chip, ad7314_groups);
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return PTR_ERR_OR_ZERO(hwmon_dev);
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}
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static const struct spi_device_id ad7314_id[] = {
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{ "adt7301", adt7301 },
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{ "adt7302", adt7302 },
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{ "ad7314", ad7314 },
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{ }
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};
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MODULE_DEVICE_TABLE(spi, ad7314_id);
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static struct spi_driver ad7314_driver = {
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.driver = {
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.name = "ad7314",
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},
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.probe = ad7314_probe,
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.id_table = ad7314_id,
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};
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module_spi_driver(ad7314_driver);
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MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
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MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver");
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MODULE_LICENSE("GPL v2");
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