[mirror_ubuntu-bionic-kernel.git] / drivers / hwmon / nsa320-hwmon.c

/*
 * 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>
 *
 * 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.
 */

#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 show_label(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(temp1_label, S_IRUGO, show_label, NULL, NSA320_TEMP);
static DEVICE_ATTR_RO(temp1_input);
static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, show_label, NULL, 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");
Commit	Line	Data
630300d5 AB	1	/*
	2	* drivers/hwmon/nsa320-hwmon.c
	3	*
	4	* ZyXEL NSA320 Media Servers
	5	* hardware monitoring
	6	*
	7	* Copyright (C) 2016 Adam Baker <linux@baker-net.org.uk>
	8	* based on a board file driver
	9	* Copyright (C) 2012 Peter Schildmann <linux@schildmann.info>
	10	*
	11	* This program is free software; you can redistribute it and/or modify it
	12	* under the terms of the GNU General Public License v2 as published by the
	13	* Free Software Foundation.
	14	*
	15	* This program is distributed in the hope that it will be useful, but WITHOUT
	16	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	17	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	18	* more details.
	19	*/
	20
	21	#include <linux/bitops.h>
	22	#include <linux/delay.h>
	23	#include <linux/err.h>
	24	#include <linux/gpio/consumer.h>
	25	#include <linux/hwmon.h>
	26	#include <linux/hwmon-sysfs.h>
	27	#include <linux/jiffies.h>
	28	#include <linux/module.h>
	29	#include <linux/mutex.h>
	30	#include <linux/of.h>
	31	#include <linux/of_device.h>
	32	#include <linux/of_platform.h>
	33	#include <linux/platform_device.h>
	34
	35	/* Tests for error return values rely upon this value being < 0x80 */
	36	#define MAGIC_NUMBER 0x55
	37
	38	/*
	39	* The Zyxel hwmon MCU is a Holtek HT46R065 that is factory programmed
	40	* to perform temperature and fan speed monitoring. It is read by taking
	41	* the active pin low. The 32 bit output word is then clocked onto the
	42	* data line. The MSB of the data word is a magic nuber to indicate it
	43	* has been read correctly, the next byte is the fan speed (in hundreds
	44	* of RPM) and the last two bytes are the temperature (in tenths of a
	45	* degree)
	46	*/
	47
	48	struct nsa320_hwmon {
	49	struct mutex update_lock; /* lock GPIO operations */
	50	unsigned long last_updated; /* jiffies */
	51	unsigned long mcu_data;
	52	struct gpio_desc *act;
	53	struct gpio_desc *clk;
	54	struct gpio_desc *data;
	55	};
	56
	57	enum nsa320_inputs {
	58	NSA320_TEMP = 0,
	59	NSA320_FAN = 1,
	60	};
	61
	62	static const char * const nsa320_input_names[] = {
	63	[NSA320_TEMP] = "System Temperature",
	64	[NSA320_FAN] = "Chassis Fan",
65	};
66
67	/*
68	* Although this protocol looks similar to SPI the long delay
69	* between the active (aka chip select) signal and the shorter
70	* delay between clock pulses are needed for reliable operation.
71	* The delays provided are taken from the manufacturer kernel,
72	* testing suggest they probably incorporate a reasonable safety
73	* margin. (The single device tested became unreliable if the
74	* delay was reduced to 1/10th of this value.)
75	*/
76	static s32 nsa320_hwmon_update(struct device *dev)
77	{
78	u32 mcu_data;
79	u32 mask;
80	struct nsa320_hwmon *hwmon = dev_get_drvdata(dev);
81
82	mutex_lock(&hwmon->update_lock);
83
84	mcu_data = hwmon->mcu_data;
85
86	if (time_after(jiffies, hwmon->last_updated + HZ) \|\| mcu_data == 0) {
87	gpiod_set_value(hwmon->act, 1);
88	msleep(100);
89
90	mcu_data = 0;
91	for (mask = BIT(31); mask; mask >>= 1) {
92	gpiod_set_value(hwmon->clk, 0);
93	usleep_range(100, 200);
94	gpiod_set_value(hwmon->clk, 1);
95	usleep_range(100, 200);
96	if (gpiod_get_value(hwmon->data))
97	mcu_data \|= mask;
98	}
99
100	gpiod_set_value(hwmon->act, 0);
101	dev_dbg(dev, "Read raw MCU data %08x\n", mcu_data);
102
103	if ((mcu_data >> 24) != MAGIC_NUMBER) {
104	dev_dbg(dev, "Read invalid MCU data %08x\n", mcu_data);
105	mcu_data = -EIO;
106	} else {
107	hwmon->mcu_data = mcu_data;
108	hwmon->last_updated = jiffies;
109	}
110	}
111
112	mutex_unlock(&hwmon->update_lock);
113
114	return mcu_data;
115	}
116
117	static ssize_t show_label(struct device *dev,
118	struct device_attribute attr, char buf)
119	{
120	int channel = to_sensor_dev_attr(attr)->index;
121
122	return sprintf(buf, "%s\n", nsa320_input_names[channel]);
123	}
124
d0688f6c JL	125	static ssize_t temp1_input_show(struct device *dev,
d0688f6c JL	126	struct device_attribute attr, char buf)
630300d5 AB	127	{
	128	s32 mcu_data = nsa320_hwmon_update(dev);
	129
	130	if (mcu_data < 0)
	131	return mcu_data;
	132
	133	return sprintf(buf, "%d\n", (mcu_data & 0xffff) * 100);
	134	}
	135
d0688f6c JL	136	static ssize_t fan1_input_show(struct device *dev,
d0688f6c JL	137	struct device_attribute attr, char buf)
630300d5 AB	138	{
	139	s32 mcu_data = nsa320_hwmon_update(dev);
	140
	141	if (mcu_data < 0)
	142	return mcu_data;
	143
	144	return sprintf(buf, "%d\n", ((mcu_data & 0xff0000) >> 16) * 100);
	145	}
	146
	147	static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_label, NULL, NSA320_TEMP);
d0688f6c	148	static DEVICE_ATTR_RO(temp1_input);
630300d5	149	static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, show_label, NULL, NSA320_FAN);
d0688f6c	150	static DEVICE_ATTR_RO(fan1_input);
630300d5 AB	151
	152	static struct attribute *nsa320_attrs[] = {
	153	&sensor_dev_attr_temp1_label.dev_attr.attr,
	154	&dev_attr_temp1_input.attr,
	155	&sensor_dev_attr_fan1_label.dev_attr.attr,
	156	&dev_attr_fan1_input.attr,
	157	NULL
	158	};
	159
	160	ATTRIBUTE_GROUPS(nsa320);
	161
	162	static const struct of_device_id of_nsa320_hwmon_match[] = {
	163	{ .compatible = "zyxel,nsa320-mcu", },
	164	{ },
	165	};
	166
	167	static int nsa320_hwmon_probe(struct platform_device *pdev)
	168	{
	169	struct nsa320_hwmon *hwmon;
	170	struct device *classdev;
	171
	172	hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
	173	if (!hwmon)
	174	return -ENOMEM;
	175
	176	/* Look up the GPIO pins to use */
	177	hwmon->act = devm_gpiod_get(&pdev->dev, "act", GPIOD_OUT_LOW);
	178	if (IS_ERR(hwmon->act))
	179	return PTR_ERR(hwmon->act);
	180
	181	hwmon->clk = devm_gpiod_get(&pdev->dev, "clk", GPIOD_OUT_HIGH);
	182	if (IS_ERR(hwmon->clk))
	183	return PTR_ERR(hwmon->clk);
	184
	185	hwmon->data = devm_gpiod_get(&pdev->dev, "data", GPIOD_IN);
	186	if (IS_ERR(hwmon->data))
	187	return PTR_ERR(hwmon->data);
	188
	189	mutex_init(&hwmon->update_lock);
	190
	191	classdev = devm_hwmon_device_register_with_groups(&pdev->dev,
	192	"nsa320", hwmon, nsa320_groups);
	193
	194	return PTR_ERR_OR_ZERO(classdev);
	195
	196	}
	197
	198	/* All allocations use devres so remove() is not needed. */
	199
	200	static struct platform_driver nsa320_hwmon_driver = {
	201	.probe = nsa320_hwmon_probe,
	202	.driver = {
	203	.name = "nsa320-hwmon",
	204	.of_match_table = of_match_ptr(of_nsa320_hwmon_match),
	205	},
	206	};
	207
	208	module_platform_driver(nsa320_hwmon_driver);
	209
	210	MODULE_DEVICE_TABLE(of, of_nsa320_hwmon_match);
	211	MODULE_AUTHOR("Peter Schildmann <linux@schildmann.info>");
	212	MODULE_AUTHOR("Adam Baker <linux@baker-net.org.uk>");
	213	MODULE_DESCRIPTION("NSA320 Hardware Monitoring");
	214	MODULE_LICENSE("GPL v2");
215	MODULE_ALIAS("platform:nsa320-hwmon");