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0ebc0471 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
630300d5 AB |
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> | |
630300d5 AB |
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 | ||
40 | struct 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 | ||
49 | enum nsa320_inputs { | |
50 | NSA320_TEMP = 0, | |
51 | NSA320_FAN = 1, | |
52 | }; | |
53 | ||
54 | static 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 | */ | |
68 | static 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 | ||
f0faf62c GR |
109 | static ssize_t label_show(struct device *dev, struct device_attribute *attr, |
110 | char *buf) | |
630300d5 AB |
111 | { |
112 | int channel = to_sensor_dev_attr(attr)->index; | |
113 | ||
114 | return sprintf(buf, "%s\n", nsa320_input_names[channel]); | |
115 | } | |
116 | ||
d0688f6c JL |
117 | static ssize_t temp1_input_show(struct device *dev, |
118 | struct device_attribute *attr, char *buf) | |
630300d5 AB |
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 | ||
d0688f6c JL |
128 | static ssize_t fan1_input_show(struct device *dev, |
129 | struct device_attribute *attr, char *buf) | |
630300d5 AB |
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 | ||
f0faf62c | 139 | static SENSOR_DEVICE_ATTR_RO(temp1_label, label, NSA320_TEMP); |
d0688f6c | 140 | static DEVICE_ATTR_RO(temp1_input); |
f0faf62c | 141 | static SENSOR_DEVICE_ATTR_RO(fan1_label, label, NSA320_FAN); |
d0688f6c | 142 | static DEVICE_ATTR_RO(fan1_input); |
630300d5 AB |
143 | |
144 | static 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 | ||
152 | ATTRIBUTE_GROUPS(nsa320); | |
153 | ||
154 | static const struct of_device_id of_nsa320_hwmon_match[] = { | |
155 | { .compatible = "zyxel,nsa320-mcu", }, | |
156 | { }, | |
157 | }; | |
158 | ||
159 | static 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 | ||
192 | static 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 | ||
200 | module_platform_driver(nsa320_hwmon_driver); | |
201 | ||
202 | MODULE_DEVICE_TABLE(of, of_nsa320_hwmon_match); | |
203 | MODULE_AUTHOR("Peter Schildmann <linux@schildmann.info>"); | |
204 | MODULE_AUTHOR("Adam Baker <linux@baker-net.org.uk>"); | |
205 | MODULE_DESCRIPTION("NSA320 Hardware Monitoring"); | |
206 | MODULE_LICENSE("GPL v2"); | |
207 | MODULE_ALIAS("platform:nsa320-hwmon"); |