alistair23-linux/drivers/hwmon/nsa320-hwmon.c
Thomas Gleixner 0ebc04719c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 408
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license v2 as published
  by the free software foundation this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 1 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190112.493982682@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:37:14 +02:00

208 lines
5.4 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* drivers/hwmon/nsa320-hwmon.c
*
* ZyXEL NSA320 Media Servers
* hardware monitoring
*
* Copyright (C) 2016 Adam Baker <linux@baker-net.org.uk>
* based on a board file driver
* Copyright (C) 2012 Peter Schildmann <linux@schildmann.info>
*/
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
/* Tests for error return values rely upon this value being < 0x80 */
#define MAGIC_NUMBER 0x55
/*
* The Zyxel hwmon MCU is a Holtek HT46R065 that is factory programmed
* to perform temperature and fan speed monitoring. It is read by taking
* the active pin low. The 32 bit output word is then clocked onto the
* data line. The MSB of the data word is a magic nuber to indicate it
* has been read correctly, the next byte is the fan speed (in hundreds
* of RPM) and the last two bytes are the temperature (in tenths of a
* degree)
*/
struct nsa320_hwmon {
struct mutex update_lock; /* lock GPIO operations */
unsigned long last_updated; /* jiffies */
unsigned long mcu_data;
struct gpio_desc *act;
struct gpio_desc *clk;
struct gpio_desc *data;
};
enum nsa320_inputs {
NSA320_TEMP = 0,
NSA320_FAN = 1,
};
static const char * const nsa320_input_names[] = {
[NSA320_TEMP] = "System Temperature",
[NSA320_FAN] = "Chassis Fan",
};
/*
* Although this protocol looks similar to SPI the long delay
* between the active (aka chip select) signal and the shorter
* delay between clock pulses are needed for reliable operation.
* The delays provided are taken from the manufacturer kernel,
* testing suggest they probably incorporate a reasonable safety
* margin. (The single device tested became unreliable if the
* delay was reduced to 1/10th of this value.)
*/
static s32 nsa320_hwmon_update(struct device *dev)
{
u32 mcu_data;
u32 mask;
struct nsa320_hwmon *hwmon = dev_get_drvdata(dev);
mutex_lock(&hwmon->update_lock);
mcu_data = hwmon->mcu_data;
if (time_after(jiffies, hwmon->last_updated + HZ) || mcu_data == 0) {
gpiod_set_value(hwmon->act, 1);
msleep(100);
mcu_data = 0;
for (mask = BIT(31); mask; mask >>= 1) {
gpiod_set_value(hwmon->clk, 0);
usleep_range(100, 200);
gpiod_set_value(hwmon->clk, 1);
usleep_range(100, 200);
if (gpiod_get_value(hwmon->data))
mcu_data |= mask;
}
gpiod_set_value(hwmon->act, 0);
dev_dbg(dev, "Read raw MCU data %08x\n", mcu_data);
if ((mcu_data >> 24) != MAGIC_NUMBER) {
dev_dbg(dev, "Read invalid MCU data %08x\n", mcu_data);
mcu_data = -EIO;
} else {
hwmon->mcu_data = mcu_data;
hwmon->last_updated = jiffies;
}
}
mutex_unlock(&hwmon->update_lock);
return mcu_data;
}
static ssize_t label_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
int channel = to_sensor_dev_attr(attr)->index;
return sprintf(buf, "%s\n", nsa320_input_names[channel]);
}
static ssize_t temp1_input_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
s32 mcu_data = nsa320_hwmon_update(dev);
if (mcu_data < 0)
return mcu_data;
return sprintf(buf, "%d\n", (mcu_data & 0xffff) * 100);
}
static ssize_t fan1_input_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
s32 mcu_data = nsa320_hwmon_update(dev);
if (mcu_data < 0)
return mcu_data;
return sprintf(buf, "%d\n", ((mcu_data & 0xff0000) >> 16) * 100);
}
static SENSOR_DEVICE_ATTR_RO(temp1_label, label, NSA320_TEMP);
static DEVICE_ATTR_RO(temp1_input);
static SENSOR_DEVICE_ATTR_RO(fan1_label, label, NSA320_FAN);
static DEVICE_ATTR_RO(fan1_input);
static struct attribute *nsa320_attrs[] = {
&sensor_dev_attr_temp1_label.dev_attr.attr,
&dev_attr_temp1_input.attr,
&sensor_dev_attr_fan1_label.dev_attr.attr,
&dev_attr_fan1_input.attr,
NULL
};
ATTRIBUTE_GROUPS(nsa320);
static const struct of_device_id of_nsa320_hwmon_match[] = {
{ .compatible = "zyxel,nsa320-mcu", },
{ },
};
static int nsa320_hwmon_probe(struct platform_device *pdev)
{
struct nsa320_hwmon *hwmon;
struct device *classdev;
hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
if (!hwmon)
return -ENOMEM;
/* Look up the GPIO pins to use */
hwmon->act = devm_gpiod_get(&pdev->dev, "act", GPIOD_OUT_LOW);
if (IS_ERR(hwmon->act))
return PTR_ERR(hwmon->act);
hwmon->clk = devm_gpiod_get(&pdev->dev, "clk", GPIOD_OUT_HIGH);
if (IS_ERR(hwmon->clk))
return PTR_ERR(hwmon->clk);
hwmon->data = devm_gpiod_get(&pdev->dev, "data", GPIOD_IN);
if (IS_ERR(hwmon->data))
return PTR_ERR(hwmon->data);
mutex_init(&hwmon->update_lock);
classdev = devm_hwmon_device_register_with_groups(&pdev->dev,
"nsa320", hwmon, nsa320_groups);
return PTR_ERR_OR_ZERO(classdev);
}
/* All allocations use devres so remove() is not needed. */
static struct platform_driver nsa320_hwmon_driver = {
.probe = nsa320_hwmon_probe,
.driver = {
.name = "nsa320-hwmon",
.of_match_table = of_match_ptr(of_nsa320_hwmon_match),
},
};
module_platform_driver(nsa320_hwmon_driver);
MODULE_DEVICE_TABLE(of, of_nsa320_hwmon_match);
MODULE_AUTHOR("Peter Schildmann <linux@schildmann.info>");
MODULE_AUTHOR("Adam Baker <linux@baker-net.org.uk>");
MODULE_DESCRIPTION("NSA320 Hardware Monitoring");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:nsa320-hwmon");