2016-03-05 16:34:56 +01:00
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/*
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* drivers/hwmon/nsa320-hwmon.c
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*
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* ZyXEL NSA320 Media Servers
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* hardware monitoring
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*
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* Copyright (C) 2016 Adam Baker <linux@baker-net.org.uk>
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* based on a board file driver
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* Copyright (C) 2012 Peter Schildmann <linux@schildmann.info>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License v2 as published by the
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* Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <linux/bitops.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/gpio/consumer.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/jiffies.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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/* Tests for error return values rely upon this value being < 0x80 */
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#define MAGIC_NUMBER 0x55
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/*
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* The Zyxel hwmon MCU is a Holtek HT46R065 that is factory programmed
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* to perform temperature and fan speed monitoring. It is read by taking
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* the active pin low. The 32 bit output word is then clocked onto the
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* data line. The MSB of the data word is a magic nuber to indicate it
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* has been read correctly, the next byte is the fan speed (in hundreds
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* of RPM) and the last two bytes are the temperature (in tenths of a
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* degree)
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*/
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struct nsa320_hwmon {
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struct mutex update_lock; /* lock GPIO operations */
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unsigned long last_updated; /* jiffies */
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unsigned long mcu_data;
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struct gpio_desc *act;
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struct gpio_desc *clk;
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struct gpio_desc *data;
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};
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enum nsa320_inputs {
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NSA320_TEMP = 0,
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NSA320_FAN = 1,
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};
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static const char * const nsa320_input_names[] = {
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[NSA320_TEMP] = "System Temperature",
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[NSA320_FAN] = "Chassis Fan",
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};
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/*
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* Although this protocol looks similar to SPI the long delay
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* between the active (aka chip select) signal and the shorter
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* delay between clock pulses are needed for reliable operation.
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* The delays provided are taken from the manufacturer kernel,
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* testing suggest they probably incorporate a reasonable safety
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* margin. (The single device tested became unreliable if the
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* delay was reduced to 1/10th of this value.)
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*/
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static s32 nsa320_hwmon_update(struct device *dev)
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{
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u32 mcu_data;
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u32 mask;
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struct nsa320_hwmon *hwmon = dev_get_drvdata(dev);
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mutex_lock(&hwmon->update_lock);
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mcu_data = hwmon->mcu_data;
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if (time_after(jiffies, hwmon->last_updated + HZ) || mcu_data == 0) {
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gpiod_set_value(hwmon->act, 1);
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msleep(100);
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mcu_data = 0;
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for (mask = BIT(31); mask; mask >>= 1) {
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gpiod_set_value(hwmon->clk, 0);
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usleep_range(100, 200);
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gpiod_set_value(hwmon->clk, 1);
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usleep_range(100, 200);
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if (gpiod_get_value(hwmon->data))
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mcu_data |= mask;
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}
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gpiod_set_value(hwmon->act, 0);
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dev_dbg(dev, "Read raw MCU data %08x\n", mcu_data);
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if ((mcu_data >> 24) != MAGIC_NUMBER) {
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dev_dbg(dev, "Read invalid MCU data %08x\n", mcu_data);
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mcu_data = -EIO;
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} else {
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hwmon->mcu_data = mcu_data;
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hwmon->last_updated = jiffies;
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}
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}
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mutex_unlock(&hwmon->update_lock);
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return mcu_data;
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}
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static ssize_t show_label(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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int channel = to_sensor_dev_attr(attr)->index;
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return sprintf(buf, "%s\n", nsa320_input_names[channel]);
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}
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2016-12-22 13:05:02 +01:00
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static ssize_t temp1_input_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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2016-03-05 16:34:56 +01:00
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{
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s32 mcu_data = nsa320_hwmon_update(dev);
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if (mcu_data < 0)
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return mcu_data;
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return sprintf(buf, "%d\n", (mcu_data & 0xffff) * 100);
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}
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2016-12-22 13:05:02 +01:00
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static ssize_t fan1_input_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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2016-03-05 16:34:56 +01:00
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{
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s32 mcu_data = nsa320_hwmon_update(dev);
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if (mcu_data < 0)
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return mcu_data;
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return sprintf(buf, "%d\n", ((mcu_data & 0xff0000) >> 16) * 100);
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}
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static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_label, NULL, NSA320_TEMP);
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2016-12-22 13:05:02 +01:00
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static DEVICE_ATTR_RO(temp1_input);
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2016-03-05 16:34:56 +01:00
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static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, show_label, NULL, NSA320_FAN);
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2016-12-22 13:05:02 +01:00
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static DEVICE_ATTR_RO(fan1_input);
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2016-03-05 16:34:56 +01:00
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static struct attribute *nsa320_attrs[] = {
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&sensor_dev_attr_temp1_label.dev_attr.attr,
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&dev_attr_temp1_input.attr,
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&sensor_dev_attr_fan1_label.dev_attr.attr,
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&dev_attr_fan1_input.attr,
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NULL
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};
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ATTRIBUTE_GROUPS(nsa320);
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static const struct of_device_id of_nsa320_hwmon_match[] = {
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{ .compatible = "zyxel,nsa320-mcu", },
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{ },
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};
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static int nsa320_hwmon_probe(struct platform_device *pdev)
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{
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struct nsa320_hwmon *hwmon;
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struct device *classdev;
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hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
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if (!hwmon)
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return -ENOMEM;
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/* Look up the GPIO pins to use */
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hwmon->act = devm_gpiod_get(&pdev->dev, "act", GPIOD_OUT_LOW);
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if (IS_ERR(hwmon->act))
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return PTR_ERR(hwmon->act);
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hwmon->clk = devm_gpiod_get(&pdev->dev, "clk", GPIOD_OUT_HIGH);
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if (IS_ERR(hwmon->clk))
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return PTR_ERR(hwmon->clk);
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hwmon->data = devm_gpiod_get(&pdev->dev, "data", GPIOD_IN);
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if (IS_ERR(hwmon->data))
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return PTR_ERR(hwmon->data);
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mutex_init(&hwmon->update_lock);
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classdev = devm_hwmon_device_register_with_groups(&pdev->dev,
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"nsa320", hwmon, nsa320_groups);
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return PTR_ERR_OR_ZERO(classdev);
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}
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/* All allocations use devres so remove() is not needed. */
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static struct platform_driver nsa320_hwmon_driver = {
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.probe = nsa320_hwmon_probe,
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.driver = {
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.name = "nsa320-hwmon",
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.of_match_table = of_match_ptr(of_nsa320_hwmon_match),
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},
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};
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module_platform_driver(nsa320_hwmon_driver);
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MODULE_DEVICE_TABLE(of, of_nsa320_hwmon_match);
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MODULE_AUTHOR("Peter Schildmann <linux@schildmann.info>");
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MODULE_AUTHOR("Adam Baker <linux@baker-net.org.uk>");
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MODULE_DESCRIPTION("NSA320 Hardware Monitoring");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:nsa320-hwmon");
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