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7074d0a9 FE |
1 | /* Lantiq cpu temperature sensor driver |
2 | * | |
3 | * Copyright (C) 2017 Florian Eckert <fe@dev.tdt.de> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, see <http://www.gnu.org/licenses/> | |
17 | */ | |
18 | ||
19 | #include <linux/bitops.h> | |
20 | #include <linux/delay.h> | |
21 | #include <linux/hwmon.h> | |
22 | #include <linux/hwmon-sysfs.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/of_device.h> | |
26 | ||
27 | #include <lantiq_soc.h> | |
28 | ||
29 | /* gphy1 configuration register contains cpu temperature */ | |
30 | #define CGU_GPHY1_CR 0x0040 | |
31 | #define CGU_TEMP_PD BIT(19) | |
32 | ||
33 | static void ltq_cputemp_enable(void) | |
34 | { | |
35 | ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) | CGU_TEMP_PD, CGU_GPHY1_CR); | |
36 | } | |
37 | ||
38 | static void ltq_cputemp_disable(void *data) | |
39 | { | |
40 | ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) & ~CGU_TEMP_PD, CGU_GPHY1_CR); | |
41 | } | |
42 | ||
43 | static int ltq_read(struct device *dev, enum hwmon_sensor_types type, | |
44 | u32 attr, int channel, long *temp) | |
45 | { | |
46 | int value; | |
47 | ||
48 | switch (attr) { | |
49 | case hwmon_temp_input: | |
50 | /* get the temperature including one decimal place */ | |
51 | value = (ltq_cgu_r32(CGU_GPHY1_CR) >> 9) & 0x01FF; | |
52 | value = value * 5; | |
53 | /* range -38 to +154 °C, register value zero is -38.0 °C */ | |
54 | value -= 380; | |
55 | /* scale temp to millidegree */ | |
56 | value = value * 100; | |
57 | break; | |
58 | default: | |
59 | return -EOPNOTSUPP; | |
60 | } | |
61 | ||
62 | *temp = value; | |
63 | return 0; | |
64 | } | |
65 | ||
66 | static umode_t ltq_is_visible(const void *_data, enum hwmon_sensor_types type, | |
67 | u32 attr, int channel) | |
68 | { | |
69 | if (type != hwmon_temp) | |
70 | return 0; | |
71 | ||
72 | switch (attr) { | |
73 | case hwmon_temp_input: | |
74 | return 0444; | |
75 | default: | |
76 | return 0; | |
77 | } | |
78 | } | |
79 | ||
80 | static const u32 ltq_chip_config[] = { | |
81 | HWMON_C_REGISTER_TZ, | |
82 | 0 | |
83 | }; | |
84 | ||
85 | static const struct hwmon_channel_info ltq_chip = { | |
86 | .type = hwmon_chip, | |
87 | .config = ltq_chip_config, | |
88 | }; | |
89 | ||
90 | static const u32 ltq_temp_config[] = { | |
91 | HWMON_T_INPUT, | |
92 | 0 | |
93 | }; | |
94 | ||
95 | static const struct hwmon_channel_info ltq_temp = { | |
96 | .type = hwmon_temp, | |
97 | .config = ltq_temp_config, | |
98 | }; | |
99 | ||
100 | static const struct hwmon_channel_info *ltq_info[] = { | |
101 | <q_chip, | |
102 | <q_temp, | |
103 | NULL | |
104 | }; | |
105 | ||
106 | static const struct hwmon_ops ltq_hwmon_ops = { | |
107 | .is_visible = ltq_is_visible, | |
108 | .read = ltq_read, | |
109 | }; | |
110 | ||
111 | static const struct hwmon_chip_info ltq_chip_info = { | |
112 | .ops = <q_hwmon_ops, | |
113 | .info = ltq_info, | |
114 | }; | |
115 | ||
116 | static int ltq_cputemp_probe(struct platform_device *pdev) | |
117 | { | |
118 | struct device *hwmon_dev; | |
119 | int err = 0; | |
120 | ||
121 | /* available on vr9 v1.2 SoCs only */ | |
122 | if (ltq_soc_type() != SOC_TYPE_VR9_2) | |
123 | return -ENODEV; | |
124 | ||
125 | err = devm_add_action(&pdev->dev, ltq_cputemp_disable, NULL); | |
126 | if (err) | |
127 | return err; | |
128 | ||
129 | ltq_cputemp_enable(); | |
130 | ||
131 | hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev, | |
132 | "ltq_cputemp", | |
133 | NULL, | |
134 | <q_chip_info, | |
135 | NULL); | |
136 | ||
137 | if (IS_ERR(hwmon_dev)) { | |
138 | dev_err(&pdev->dev, "Failed to register as hwmon device"); | |
139 | return PTR_ERR(hwmon_dev); | |
140 | } | |
141 | ||
142 | return 0; | |
143 | } | |
144 | ||
145 | const struct of_device_id ltq_cputemp_match[] = { | |
146 | { .compatible = "lantiq,cputemp" }, | |
147 | {}, | |
148 | }; | |
149 | MODULE_DEVICE_TABLE(of, ltq_cputemp_match); | |
150 | ||
151 | static struct platform_driver ltq_cputemp_driver = { | |
152 | .probe = ltq_cputemp_probe, | |
153 | .driver = { | |
154 | .name = "ltq-cputemp", | |
155 | .of_match_table = ltq_cputemp_match, | |
156 | }, | |
157 | }; | |
158 | ||
159 | module_platform_driver(ltq_cputemp_driver); | |
160 | ||
161 | MODULE_AUTHOR("Florian Eckert <fe@dev.tdt.de>"); | |
162 | MODULE_DESCRIPTION("Lantiq cpu temperature sensor driver"); | |
163 | MODULE_LICENSE("GPL"); |