7d0f113aad
[ Upstream commit e278d5e8aef4c0a1d9a9fa8b8910d713a89aa800 ]
Leading zero bits are sent on the bus before the temperature value is
transmitted. If any of these bits are high, the connection might be
unstable or there could be no AD7314 / ADT730x (or compatible) at all.
Return -EIO in that case.
Signed-off-by: Erik Schumacher <erik.schumacher@iris-sensing.com>
Fixes: 4f3a659581 ("hwmon: AD7314 driver (ported from IIO)")
Link: https://lore.kernel.org/r/24a50c2981a318580aca8f50d23be7987b69ea00.camel@iris-sensing.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
145 lines
3.3 KiB
C
145 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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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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* 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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#define AD7314_LEADING_ZEROS_MASK BIT(15)
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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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#define ADT7301_LEADING_ZEROS_MASK (BIT(15) | BIT(14))
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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_temperature_show(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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if (ret & AD7314_LEADING_ZEROS_MASK) {
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/* Invalid read-out, leading zero part is missing */
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return -EIO;
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}
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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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if (ret & ADT7301_LEADING_ZEROS_MASK) {
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/* Invalid read-out, leading zero part is missing */
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return -EIO;
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}
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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_RO(temp1_input, ad7314_temperature, 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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