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1ccea77e | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
7074d0a9 FE |
2 | /* Lantiq cpu temperature sensor driver |
3 | * | |
4 | * Copyright (C) 2017 Florian Eckert <fe@dev.tdt.de> | |
7074d0a9 FE |
5 | */ |
6 | ||
7 | #include <linux/bitops.h> | |
8 | #include <linux/delay.h> | |
9 | #include <linux/hwmon.h> | |
10 | #include <linux/hwmon-sysfs.h> | |
11 | #include <linux/init.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/of_device.h> | |
14 | ||
15 | #include <lantiq_soc.h> | |
16 | ||
17 | /* gphy1 configuration register contains cpu temperature */ | |
18 | #define CGU_GPHY1_CR 0x0040 | |
19 | #define CGU_TEMP_PD BIT(19) | |
20 | ||
21 | static void ltq_cputemp_enable(void) | |
22 | { | |
23 | ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) | CGU_TEMP_PD, CGU_GPHY1_CR); | |
24 | } | |
25 | ||
26 | static void ltq_cputemp_disable(void *data) | |
27 | { | |
28 | ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) & ~CGU_TEMP_PD, CGU_GPHY1_CR); | |
29 | } | |
30 | ||
31 | static int ltq_read(struct device *dev, enum hwmon_sensor_types type, | |
32 | u32 attr, int channel, long *temp) | |
33 | { | |
34 | int value; | |
35 | ||
36 | switch (attr) { | |
37 | case hwmon_temp_input: | |
38 | /* get the temperature including one decimal place */ | |
39 | value = (ltq_cgu_r32(CGU_GPHY1_CR) >> 9) & 0x01FF; | |
40 | value = value * 5; | |
41 | /* range -38 to +154 °C, register value zero is -38.0 °C */ | |
42 | value -= 380; | |
43 | /* scale temp to millidegree */ | |
44 | value = value * 100; | |
45 | break; | |
46 | default: | |
47 | return -EOPNOTSUPP; | |
48 | } | |
49 | ||
50 | *temp = value; | |
51 | return 0; | |
52 | } | |
53 | ||
54 | static umode_t ltq_is_visible(const void *_data, enum hwmon_sensor_types type, | |
55 | u32 attr, int channel) | |
56 | { | |
57 | if (type != hwmon_temp) | |
58 | return 0; | |
59 | ||
60 | switch (attr) { | |
61 | case hwmon_temp_input: | |
62 | return 0444; | |
63 | default: | |
64 | return 0; | |
65 | } | |
66 | } | |
67 | ||
7074d0a9 | 68 | static const struct hwmon_channel_info *ltq_info[] = { |
f4a407f4 GR |
69 | HWMON_CHANNEL_INFO(chip, |
70 | HWMON_C_REGISTER_TZ), | |
71 | HWMON_CHANNEL_INFO(temp, | |
72 | HWMON_T_INPUT), | |
7074d0a9 FE |
73 | NULL |
74 | }; | |
75 | ||
76 | static const struct hwmon_ops ltq_hwmon_ops = { | |
77 | .is_visible = ltq_is_visible, | |
78 | .read = ltq_read, | |
79 | }; | |
80 | ||
81 | static const struct hwmon_chip_info ltq_chip_info = { | |
82 | .ops = <q_hwmon_ops, | |
83 | .info = ltq_info, | |
84 | }; | |
85 | ||
86 | static int ltq_cputemp_probe(struct platform_device *pdev) | |
87 | { | |
88 | struct device *hwmon_dev; | |
89 | int err = 0; | |
90 | ||
91 | /* available on vr9 v1.2 SoCs only */ | |
92 | if (ltq_soc_type() != SOC_TYPE_VR9_2) | |
93 | return -ENODEV; | |
94 | ||
95 | err = devm_add_action(&pdev->dev, ltq_cputemp_disable, NULL); | |
96 | if (err) | |
97 | return err; | |
98 | ||
99 | ltq_cputemp_enable(); | |
100 | ||
101 | hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, | |
102 | "ltq_cputemp", | |
103 | NULL, | |
104 | <q_chip_info, | |
105 | NULL); | |
106 | ||
107 | if (IS_ERR(hwmon_dev)) { | |
108 | dev_err(&pdev->dev, "Failed to register as hwmon device"); | |
109 | return PTR_ERR(hwmon_dev); | |
110 | } | |
111 | ||
112 | return 0; | |
113 | } | |
114 | ||
115 | const struct of_device_id ltq_cputemp_match[] = { | |
116 | { .compatible = "lantiq,cputemp" }, | |
117 | {}, | |
118 | }; | |
119 | MODULE_DEVICE_TABLE(of, ltq_cputemp_match); | |
120 | ||
121 | static struct platform_driver ltq_cputemp_driver = { | |
122 | .probe = ltq_cputemp_probe, | |
123 | .driver = { | |
124 | .name = "ltq-cputemp", | |
125 | .of_match_table = ltq_cputemp_match, | |
126 | }, | |
127 | }; | |
128 | ||
129 | module_platform_driver(ltq_cputemp_driver); | |
130 | ||
131 | MODULE_AUTHOR("Florian Eckert <fe@dev.tdt.de>"); | |
132 | MODULE_DESCRIPTION("Lantiq cpu temperature sensor driver"); | |
133 | MODULE_LICENSE("GPL"); |