1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* Lantiq cpu temperature sensor driver |
3 | * |
4 | * Copyright (C) 2017 Florian Eckert <fe@dev.tdt.de> |
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/mod_devicetable.h> |
13 | #include <linux/module.h> |
14 | #include <linux/platform_device.h> |
15 | |
16 | #include <lantiq_soc.h> |
17 | |
18 | /* gphy1 configuration register contains cpu temperature */ |
19 | #define CGU_GPHY1_CR 0x0040 |
20 | #define CGU_TEMP_PD BIT(19) |
21 | |
22 | static void ltq_cputemp_enable(void) |
23 | { |
24 | ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) | CGU_TEMP_PD, CGU_GPHY1_CR); |
25 | } |
26 | |
27 | static void ltq_cputemp_disable(void *data) |
28 | { |
29 | ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) & ~CGU_TEMP_PD, CGU_GPHY1_CR); |
30 | } |
31 | |
32 | static int ltq_read(struct device *dev, enum hwmon_sensor_types type, |
33 | u32 attr, int channel, long *temp) |
34 | { |
35 | int value; |
36 | |
37 | switch (attr) { |
38 | case hwmon_temp_input: |
39 | /* get the temperature including one decimal place */ |
40 | value = (ltq_cgu_r32(CGU_GPHY1_CR) >> 9) & 0x01FF; |
41 | value = value * 5; |
42 | /* range -38 to +154 °C, register value zero is -38.0 °C */ |
43 | value -= 380; |
44 | /* scale temp to millidegree */ |
45 | value = value * 100; |
46 | break; |
47 | default: |
48 | return -EOPNOTSUPP; |
49 | } |
50 | |
51 | *temp = value; |
52 | return 0; |
53 | } |
54 | |
55 | static umode_t ltq_is_visible(const void *_data, enum hwmon_sensor_types type, |
56 | u32 attr, int channel) |
57 | { |
58 | if (type != hwmon_temp) |
59 | return 0; |
60 | |
61 | switch (attr) { |
62 | case hwmon_temp_input: |
63 | return 0444; |
64 | default: |
65 | return 0; |
66 | } |
67 | } |
68 | |
69 | static const struct hwmon_channel_info * const ltq_info[] = { |
70 | HWMON_CHANNEL_INFO(chip, |
71 | HWMON_C_REGISTER_TZ), |
72 | HWMON_CHANNEL_INFO(temp, |
73 | HWMON_T_INPUT), |
74 | NULL |
75 | }; |
76 | |
77 | static const struct hwmon_ops ltq_hwmon_ops = { |
78 | .is_visible = ltq_is_visible, |
79 | .read = ltq_read, |
80 | }; |
81 | |
82 | static const struct hwmon_chip_info ltq_chip_info = { |
83 | .ops = <q_hwmon_ops, |
84 | .info = ltq_info, |
85 | }; |
86 | |
87 | static int ltq_cputemp_probe(struct platform_device *pdev) |
88 | { |
89 | struct device *hwmon_dev; |
90 | int err = 0; |
91 | |
92 | /* available on vr9 v1.2 SoCs only */ |
93 | if (ltq_soc_type() != SOC_TYPE_VR9_2) |
94 | return -ENODEV; |
95 | |
96 | err = devm_add_action(&pdev->dev, ltq_cputemp_disable, NULL); |
97 | if (err) |
98 | return err; |
99 | |
100 | ltq_cputemp_enable(); |
101 | |
102 | hwmon_dev = devm_hwmon_device_register_with_info(dev: &pdev->dev, |
103 | name: "ltq_cputemp" , |
104 | NULL, |
105 | info: <q_chip_info, |
106 | NULL); |
107 | |
108 | if (IS_ERR(ptr: hwmon_dev)) { |
109 | dev_err(&pdev->dev, "Failed to register as hwmon device" ); |
110 | return PTR_ERR(ptr: hwmon_dev); |
111 | } |
112 | |
113 | return 0; |
114 | } |
115 | |
116 | const struct of_device_id ltq_cputemp_match[] = { |
117 | { .compatible = "lantiq,cputemp" }, |
118 | {}, |
119 | }; |
120 | MODULE_DEVICE_TABLE(of, ltq_cputemp_match); |
121 | |
122 | static struct platform_driver ltq_cputemp_driver = { |
123 | .probe = ltq_cputemp_probe, |
124 | .driver = { |
125 | .name = "ltq-cputemp" , |
126 | .of_match_table = ltq_cputemp_match, |
127 | }, |
128 | }; |
129 | |
130 | module_platform_driver(ltq_cputemp_driver); |
131 | |
132 | MODULE_AUTHOR("Florian Eckert <fe@dev.tdt.de>" ); |
133 | MODULE_DESCRIPTION("Lantiq cpu temperature sensor driver" ); |
134 | MODULE_LICENSE("GPL" ); |
135 | |