Commit | Line | Data |
---|---|---|
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> | |
630300d5 AB |
23 | #include <linux/platform_device.h> |
24 | ||
25 | /* Tests for error return values rely upon this value being < 0x80 */ | |
26 | #define MAGIC_NUMBER 0x55 | |
27 | ||
28 | /* | |
29 | * The Zyxel hwmon MCU is a Holtek HT46R065 that is factory programmed | |
30 | * to perform temperature and fan speed monitoring. It is read by taking | |
31 | * the active pin low. The 32 bit output word is then clocked onto the | |
32 | * data line. The MSB of the data word is a magic nuber to indicate it | |
33 | * has been read correctly, the next byte is the fan speed (in hundreds | |
34 | * of RPM) and the last two bytes are the temperature (in tenths of a | |
35 | * degree) | |
36 | */ | |
37 | ||
38 | struct nsa320_hwmon { | |
39 | struct mutex update_lock; /* lock GPIO operations */ | |
40 | unsigned long last_updated; /* jiffies */ | |
41 | unsigned long mcu_data; | |
42 | struct gpio_desc *act; | |
43 | struct gpio_desc *clk; | |
44 | struct gpio_desc *data; | |
45 | }; | |
46 | ||
47 | enum nsa320_inputs { | |
48 | NSA320_TEMP = 0, | |
49 | NSA320_FAN = 1, | |
50 | }; | |
51 | ||
52 | static const char * const nsa320_input_names[] = { | |
53 | [NSA320_TEMP] = "System Temperature", | |
54 | [NSA320_FAN] = "Chassis Fan", | |
55 | }; | |
56 | ||
57 | /* | |
58 | * Although this protocol looks similar to SPI the long delay | |
59 | * between the active (aka chip select) signal and the shorter | |
60 | * delay between clock pulses are needed for reliable operation. | |
61 | * The delays provided are taken from the manufacturer kernel, | |
62 | * testing suggest they probably incorporate a reasonable safety | |
63 | * margin. (The single device tested became unreliable if the | |
64 | * delay was reduced to 1/10th of this value.) | |
65 | */ | |
66 | static s32 nsa320_hwmon_update(struct device *dev) | |
67 | { | |
68 | u32 mcu_data; | |
69 | u32 mask; | |
70 | struct nsa320_hwmon *hwmon = dev_get_drvdata(dev); | |
71 | ||
72 | mutex_lock(&hwmon->update_lock); | |
73 | ||
74 | mcu_data = hwmon->mcu_data; | |
75 | ||
76 | if (time_after(jiffies, hwmon->last_updated + HZ) || mcu_data == 0) { | |
77 | gpiod_set_value(hwmon->act, 1); | |
78 | msleep(100); | |
79 | ||
80 | mcu_data = 0; | |
81 | for (mask = BIT(31); mask; mask >>= 1) { | |
82 | gpiod_set_value(hwmon->clk, 0); | |
83 | usleep_range(100, 200); | |
84 | gpiod_set_value(hwmon->clk, 1); | |
85 | usleep_range(100, 200); | |
86 | if (gpiod_get_value(hwmon->data)) | |
87 | mcu_data |= mask; | |
88 | } | |
89 | ||
90 | gpiod_set_value(hwmon->act, 0); | |
91 | dev_dbg(dev, "Read raw MCU data %08x\n", mcu_data); | |
92 | ||
93 | if ((mcu_data >> 24) != MAGIC_NUMBER) { | |
94 | dev_dbg(dev, "Read invalid MCU data %08x\n", mcu_data); | |
95 | mcu_data = -EIO; | |
96 | } else { | |
97 | hwmon->mcu_data = mcu_data; | |
98 | hwmon->last_updated = jiffies; | |
99 | } | |
100 | } | |
101 | ||
102 | mutex_unlock(&hwmon->update_lock); | |
103 | ||
104 | return mcu_data; | |
105 | } | |
106 | ||
f0faf62c GR |
107 | static ssize_t label_show(struct device *dev, struct device_attribute *attr, |
108 | char *buf) | |
630300d5 AB |
109 | { |
110 | int channel = to_sensor_dev_attr(attr)->index; | |
111 | ||
112 | return sprintf(buf, "%s\n", nsa320_input_names[channel]); | |
113 | } | |
114 | ||
d0688f6c JL |
115 | static ssize_t temp1_input_show(struct device *dev, |
116 | struct device_attribute *attr, char *buf) | |
630300d5 AB |
117 | { |
118 | s32 mcu_data = nsa320_hwmon_update(dev); | |
119 | ||
120 | if (mcu_data < 0) | |
121 | return mcu_data; | |
122 | ||
123 | return sprintf(buf, "%d\n", (mcu_data & 0xffff) * 100); | |
124 | } | |
125 | ||
d0688f6c JL |
126 | static ssize_t fan1_input_show(struct device *dev, |
127 | struct device_attribute *attr, char *buf) | |
630300d5 AB |
128 | { |
129 | s32 mcu_data = nsa320_hwmon_update(dev); | |
130 | ||
131 | if (mcu_data < 0) | |
132 | return mcu_data; | |
133 | ||
134 | return sprintf(buf, "%d\n", ((mcu_data & 0xff0000) >> 16) * 100); | |
135 | } | |
136 | ||
f0faf62c | 137 | static SENSOR_DEVICE_ATTR_RO(temp1_label, label, NSA320_TEMP); |
d0688f6c | 138 | static DEVICE_ATTR_RO(temp1_input); |
f0faf62c | 139 | static SENSOR_DEVICE_ATTR_RO(fan1_label, label, NSA320_FAN); |
d0688f6c | 140 | static DEVICE_ATTR_RO(fan1_input); |
630300d5 AB |
141 | |
142 | static struct attribute *nsa320_attrs[] = { | |
143 | &sensor_dev_attr_temp1_label.dev_attr.attr, | |
144 | &dev_attr_temp1_input.attr, | |
145 | &sensor_dev_attr_fan1_label.dev_attr.attr, | |
146 | &dev_attr_fan1_input.attr, | |
147 | NULL | |
148 | }; | |
149 | ||
150 | ATTRIBUTE_GROUPS(nsa320); | |
151 | ||
152 | static const struct of_device_id of_nsa320_hwmon_match[] = { | |
153 | { .compatible = "zyxel,nsa320-mcu", }, | |
154 | { }, | |
155 | }; | |
156 | ||
157 | static int nsa320_hwmon_probe(struct platform_device *pdev) | |
158 | { | |
159 | struct nsa320_hwmon *hwmon; | |
160 | struct device *classdev; | |
161 | ||
162 | hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL); | |
163 | if (!hwmon) | |
164 | return -ENOMEM; | |
165 | ||
166 | /* Look up the GPIO pins to use */ | |
167 | hwmon->act = devm_gpiod_get(&pdev->dev, "act", GPIOD_OUT_LOW); | |
168 | if (IS_ERR(hwmon->act)) | |
169 | return PTR_ERR(hwmon->act); | |
170 | ||
171 | hwmon->clk = devm_gpiod_get(&pdev->dev, "clk", GPIOD_OUT_HIGH); | |
172 | if (IS_ERR(hwmon->clk)) | |
173 | return PTR_ERR(hwmon->clk); | |
174 | ||
175 | hwmon->data = devm_gpiod_get(&pdev->dev, "data", GPIOD_IN); | |
176 | if (IS_ERR(hwmon->data)) | |
177 | return PTR_ERR(hwmon->data); | |
178 | ||
179 | mutex_init(&hwmon->update_lock); | |
180 | ||
181 | classdev = devm_hwmon_device_register_with_groups(&pdev->dev, | |
182 | "nsa320", hwmon, nsa320_groups); | |
183 | ||
184 | return PTR_ERR_OR_ZERO(classdev); | |
185 | ||
186 | } | |
187 | ||
188 | /* All allocations use devres so remove() is not needed. */ | |
189 | ||
190 | static struct platform_driver nsa320_hwmon_driver = { | |
191 | .probe = nsa320_hwmon_probe, | |
192 | .driver = { | |
193 | .name = "nsa320-hwmon", | |
7d9be29d | 194 | .of_match_table = of_nsa320_hwmon_match, |
630300d5 AB |
195 | }, |
196 | }; | |
197 | ||
198 | module_platform_driver(nsa320_hwmon_driver); | |
199 | ||
200 | MODULE_DEVICE_TABLE(of, of_nsa320_hwmon_match); | |
201 | MODULE_AUTHOR("Peter Schildmann <linux@schildmann.info>"); | |
202 | MODULE_AUTHOR("Adam Baker <linux@baker-net.org.uk>"); | |
203 | MODULE_DESCRIPTION("NSA320 Hardware Monitoring"); | |
204 | MODULE_LICENSE("GPL v2"); | |
205 | MODULE_ALIAS("platform:nsa320-hwmon"); |