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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/hwmon/nsa320-hwmon.c
4 *
5 * ZyXEL NSA320 Media Servers
6 * hardware monitoring
7 *
8 * Copyright (C) 2016 Adam Baker <linux@baker-net.org.uk>
9 * based on a board file driver
10 * Copyright (C) 2012 Peter Schildmann <linux@schildmann.info>
11 */
12
13#include <linux/bitops.h>
14#include <linux/delay.h>
15#include <linux/err.h>
16#include <linux/gpio/consumer.h>
17#include <linux/hwmon.h>
18#include <linux/hwmon-sysfs.h>
19#include <linux/jiffies.h>
20#include <linux/module.h>
21#include <linux/mutex.h>
22#include <linux/of.h>
23#include <linux/of_device.h>
24#include <linux/of_platform.h>
25#include <linux/platform_device.h>
26
27/* Tests for error return values rely upon this value being < 0x80 */
28#define MAGIC_NUMBER 0x55
29
30/*
31 * The Zyxel hwmon MCU is a Holtek HT46R065 that is factory programmed
32 * to perform temperature and fan speed monitoring. It is read by taking
33 * the active pin low. The 32 bit output word is then clocked onto the
34 * data line. The MSB of the data word is a magic nuber to indicate it
35 * has been read correctly, the next byte is the fan speed (in hundreds
36 * of RPM) and the last two bytes are the temperature (in tenths of a
37 * degree)
38 */
39
40struct nsa320_hwmon {
41 struct mutex update_lock; /* lock GPIO operations */
42 unsigned long last_updated; /* jiffies */
43 unsigned long mcu_data;
44 struct gpio_desc *act;
45 struct gpio_desc *clk;
46 struct gpio_desc *data;
47};
48
49enum nsa320_inputs {
50 NSA320_TEMP = 0,
51 NSA320_FAN = 1,
52};
53
54static const char * const nsa320_input_names[] = {
55 [NSA320_TEMP] = "System Temperature",
56 [NSA320_FAN] = "Chassis Fan",
57};
58
59/*
60 * Although this protocol looks similar to SPI the long delay
61 * between the active (aka chip select) signal and the shorter
62 * delay between clock pulses are needed for reliable operation.
63 * The delays provided are taken from the manufacturer kernel,
64 * testing suggest they probably incorporate a reasonable safety
65 * margin. (The single device tested became unreliable if the
66 * delay was reduced to 1/10th of this value.)
67 */
68static s32 nsa320_hwmon_update(struct device *dev)
69{
70 u32 mcu_data;
71 u32 mask;
72 struct nsa320_hwmon *hwmon = dev_get_drvdata(dev);
73
74 mutex_lock(&hwmon->update_lock);
75
76 mcu_data = hwmon->mcu_data;
77
78 if (time_after(jiffies, hwmon->last_updated + HZ) || mcu_data == 0) {
79 gpiod_set_value(hwmon->act, 1);
80 msleep(100);
81
82 mcu_data = 0;
83 for (mask = BIT(31); mask; mask >>= 1) {
84 gpiod_set_value(hwmon->clk, 0);
85 usleep_range(100, 200);
86 gpiod_set_value(hwmon->clk, 1);
87 usleep_range(100, 200);
88 if (gpiod_get_value(hwmon->data))
89 mcu_data |= mask;
90 }
91
92 gpiod_set_value(hwmon->act, 0);
93 dev_dbg(dev, "Read raw MCU data %08x\n", mcu_data);
94
95 if ((mcu_data >> 24) != MAGIC_NUMBER) {
96 dev_dbg(dev, "Read invalid MCU data %08x\n", mcu_data);
97 mcu_data = -EIO;
98 } else {
99 hwmon->mcu_data = mcu_data;
100 hwmon->last_updated = jiffies;
101 }
102 }
103
104 mutex_unlock(&hwmon->update_lock);
105
106 return mcu_data;
107}
108
109static ssize_t label_show(struct device *dev, struct device_attribute *attr,
110 char *buf)
111{
112 int channel = to_sensor_dev_attr(attr)->index;
113
114 return sprintf(buf, "%s\n", nsa320_input_names[channel]);
115}
116
117static ssize_t temp1_input_show(struct device *dev,
118 struct device_attribute *attr, char *buf)
119{
120 s32 mcu_data = nsa320_hwmon_update(dev);
121
122 if (mcu_data < 0)
123 return mcu_data;
124
125 return sprintf(buf, "%d\n", (mcu_data & 0xffff) * 100);
126}
127
128static ssize_t fan1_input_show(struct device *dev,
129 struct device_attribute *attr, char *buf)
130{
131 s32 mcu_data = nsa320_hwmon_update(dev);
132
133 if (mcu_data < 0)
134 return mcu_data;
135
136 return sprintf(buf, "%d\n", ((mcu_data & 0xff0000) >> 16) * 100);
137}
138
139static SENSOR_DEVICE_ATTR_RO(temp1_label, label, NSA320_TEMP);
140static DEVICE_ATTR_RO(temp1_input);
141static SENSOR_DEVICE_ATTR_RO(fan1_label, label, NSA320_FAN);
142static DEVICE_ATTR_RO(fan1_input);
143
144static struct attribute *nsa320_attrs[] = {
145 &sensor_dev_attr_temp1_label.dev_attr.attr,
146 &dev_attr_temp1_input.attr,
147 &sensor_dev_attr_fan1_label.dev_attr.attr,
148 &dev_attr_fan1_input.attr,
149 NULL
150};
151
152ATTRIBUTE_GROUPS(nsa320);
153
154static const struct of_device_id of_nsa320_hwmon_match[] = {
155 { .compatible = "zyxel,nsa320-mcu", },
156 { },
157};
158
159static int nsa320_hwmon_probe(struct platform_device *pdev)
160{
161 struct nsa320_hwmon *hwmon;
162 struct device *classdev;
163
164 hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
165 if (!hwmon)
166 return -ENOMEM;
167
168 /* Look up the GPIO pins to use */
169 hwmon->act = devm_gpiod_get(&pdev->dev, "act", GPIOD_OUT_LOW);
170 if (IS_ERR(hwmon->act))
171 return PTR_ERR(hwmon->act);
172
173 hwmon->clk = devm_gpiod_get(&pdev->dev, "clk", GPIOD_OUT_HIGH);
174 if (IS_ERR(hwmon->clk))
175 return PTR_ERR(hwmon->clk);
176
177 hwmon->data = devm_gpiod_get(&pdev->dev, "data", GPIOD_IN);
178 if (IS_ERR(hwmon->data))
179 return PTR_ERR(hwmon->data);
180
181 mutex_init(&hwmon->update_lock);
182
183 classdev = devm_hwmon_device_register_with_groups(&pdev->dev,
184 "nsa320", hwmon, nsa320_groups);
185
186 return PTR_ERR_OR_ZERO(classdev);
187
188}
189
190/* All allocations use devres so remove() is not needed. */
191
192static struct platform_driver nsa320_hwmon_driver = {
193 .probe = nsa320_hwmon_probe,
194 .driver = {
195 .name = "nsa320-hwmon",
196 .of_match_table = of_match_ptr(of_nsa320_hwmon_match),
197 },
198};
199
200module_platform_driver(nsa320_hwmon_driver);
201
202MODULE_DEVICE_TABLE(of, of_nsa320_hwmon_match);
203MODULE_AUTHOR("Peter Schildmann <linux@schildmann.info>");
204MODULE_AUTHOR("Adam Baker <linux@baker-net.org.uk>");
205MODULE_DESCRIPTION("NSA320 Hardware Monitoring");
206MODULE_LICENSE("GPL v2");
207MODULE_ALIAS("platform:nsa320-hwmon");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/hwmon/nsa320-hwmon.c
4 *
5 * ZyXEL NSA320 Media Servers
6 * hardware monitoring
7 *
8 * Copyright (C) 2016 Adam Baker <linux@baker-net.org.uk>
9 * based on a board file driver
10 * Copyright (C) 2012 Peter Schildmann <linux@schildmann.info>
11 */
12
13#include <linux/bitops.h>
14#include <linux/delay.h>
15#include <linux/err.h>
16#include <linux/gpio/consumer.h>
17#include <linux/hwmon.h>
18#include <linux/hwmon-sysfs.h>
19#include <linux/jiffies.h>
20#include <linux/module.h>
21#include <linux/mutex.h>
22#include <linux/of.h>
23#include <linux/of_device.h>
24#include <linux/of_platform.h>
25#include <linux/platform_device.h>
26
27/* Tests for error return values rely upon this value being < 0x80 */
28#define MAGIC_NUMBER 0x55
29
30/*
31 * The Zyxel hwmon MCU is a Holtek HT46R065 that is factory programmed
32 * to perform temperature and fan speed monitoring. It is read by taking
33 * the active pin low. The 32 bit output word is then clocked onto the
34 * data line. The MSB of the data word is a magic nuber to indicate it
35 * has been read correctly, the next byte is the fan speed (in hundreds
36 * of RPM) and the last two bytes are the temperature (in tenths of a
37 * degree)
38 */
39
40struct nsa320_hwmon {
41 struct mutex update_lock; /* lock GPIO operations */
42 unsigned long last_updated; /* jiffies */
43 unsigned long mcu_data;
44 struct gpio_desc *act;
45 struct gpio_desc *clk;
46 struct gpio_desc *data;
47};
48
49enum nsa320_inputs {
50 NSA320_TEMP = 0,
51 NSA320_FAN = 1,
52};
53
54static const char * const nsa320_input_names[] = {
55 [NSA320_TEMP] = "System Temperature",
56 [NSA320_FAN] = "Chassis Fan",
57};
58
59/*
60 * Although this protocol looks similar to SPI the long delay
61 * between the active (aka chip select) signal and the shorter
62 * delay between clock pulses are needed for reliable operation.
63 * The delays provided are taken from the manufacturer kernel,
64 * testing suggest they probably incorporate a reasonable safety
65 * margin. (The single device tested became unreliable if the
66 * delay was reduced to 1/10th of this value.)
67 */
68static s32 nsa320_hwmon_update(struct device *dev)
69{
70 u32 mcu_data;
71 u32 mask;
72 struct nsa320_hwmon *hwmon = dev_get_drvdata(dev);
73
74 mutex_lock(&hwmon->update_lock);
75
76 mcu_data = hwmon->mcu_data;
77
78 if (time_after(jiffies, hwmon->last_updated + HZ) || mcu_data == 0) {
79 gpiod_set_value(hwmon->act, 1);
80 msleep(100);
81
82 mcu_data = 0;
83 for (mask = BIT(31); mask; mask >>= 1) {
84 gpiod_set_value(hwmon->clk, 0);
85 usleep_range(100, 200);
86 gpiod_set_value(hwmon->clk, 1);
87 usleep_range(100, 200);
88 if (gpiod_get_value(hwmon->data))
89 mcu_data |= mask;
90 }
91
92 gpiod_set_value(hwmon->act, 0);
93 dev_dbg(dev, "Read raw MCU data %08x\n", mcu_data);
94
95 if ((mcu_data >> 24) != MAGIC_NUMBER) {
96 dev_dbg(dev, "Read invalid MCU data %08x\n", mcu_data);
97 mcu_data = -EIO;
98 } else {
99 hwmon->mcu_data = mcu_data;
100 hwmon->last_updated = jiffies;
101 }
102 }
103
104 mutex_unlock(&hwmon->update_lock);
105
106 return mcu_data;
107}
108
109static ssize_t label_show(struct device *dev, struct device_attribute *attr,
110 char *buf)
111{
112 int channel = to_sensor_dev_attr(attr)->index;
113
114 return sprintf(buf, "%s\n", nsa320_input_names[channel]);
115}
116
117static ssize_t temp1_input_show(struct device *dev,
118 struct device_attribute *attr, char *buf)
119{
120 s32 mcu_data = nsa320_hwmon_update(dev);
121
122 if (mcu_data < 0)
123 return mcu_data;
124
125 return sprintf(buf, "%d\n", (mcu_data & 0xffff) * 100);
126}
127
128static ssize_t fan1_input_show(struct device *dev,
129 struct device_attribute *attr, char *buf)
130{
131 s32 mcu_data = nsa320_hwmon_update(dev);
132
133 if (mcu_data < 0)
134 return mcu_data;
135
136 return sprintf(buf, "%d\n", ((mcu_data & 0xff0000) >> 16) * 100);
137}
138
139static SENSOR_DEVICE_ATTR_RO(temp1_label, label, NSA320_TEMP);
140static DEVICE_ATTR_RO(temp1_input);
141static SENSOR_DEVICE_ATTR_RO(fan1_label, label, NSA320_FAN);
142static DEVICE_ATTR_RO(fan1_input);
143
144static struct attribute *nsa320_attrs[] = {
145 &sensor_dev_attr_temp1_label.dev_attr.attr,
146 &dev_attr_temp1_input.attr,
147 &sensor_dev_attr_fan1_label.dev_attr.attr,
148 &dev_attr_fan1_input.attr,
149 NULL
150};
151
152ATTRIBUTE_GROUPS(nsa320);
153
154static const struct of_device_id of_nsa320_hwmon_match[] = {
155 { .compatible = "zyxel,nsa320-mcu", },
156 { },
157};
158
159static int nsa320_hwmon_probe(struct platform_device *pdev)
160{
161 struct nsa320_hwmon *hwmon;
162 struct device *classdev;
163
164 hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
165 if (!hwmon)
166 return -ENOMEM;
167
168 /* Look up the GPIO pins to use */
169 hwmon->act = devm_gpiod_get(&pdev->dev, "act", GPIOD_OUT_LOW);
170 if (IS_ERR(hwmon->act))
171 return PTR_ERR(hwmon->act);
172
173 hwmon->clk = devm_gpiod_get(&pdev->dev, "clk", GPIOD_OUT_HIGH);
174 if (IS_ERR(hwmon->clk))
175 return PTR_ERR(hwmon->clk);
176
177 hwmon->data = devm_gpiod_get(&pdev->dev, "data", GPIOD_IN);
178 if (IS_ERR(hwmon->data))
179 return PTR_ERR(hwmon->data);
180
181 mutex_init(&hwmon->update_lock);
182
183 classdev = devm_hwmon_device_register_with_groups(&pdev->dev,
184 "nsa320", hwmon, nsa320_groups);
185
186 return PTR_ERR_OR_ZERO(classdev);
187
188}
189
190/* All allocations use devres so remove() is not needed. */
191
192static struct platform_driver nsa320_hwmon_driver = {
193 .probe = nsa320_hwmon_probe,
194 .driver = {
195 .name = "nsa320-hwmon",
196 .of_match_table = of_match_ptr(of_nsa320_hwmon_match),
197 },
198};
199
200module_platform_driver(nsa320_hwmon_driver);
201
202MODULE_DEVICE_TABLE(of, of_nsa320_hwmon_match);
203MODULE_AUTHOR("Peter Schildmann <linux@schildmann.info>");
204MODULE_AUTHOR("Adam Baker <linux@baker-net.org.uk>");
205MODULE_DESCRIPTION("NSA320 Hardware Monitoring");
206MODULE_LICENSE("GPL v2");
207MODULE_ALIAS("platform:nsa320-hwmon");