GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / thermal / kirkwood_thermal.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Kirkwood thermal sensor driver
4  *
5  * Copyright (C) 2012 Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
6  */
7 #include <linux/device.h>
8 #include <linux/err.h>
9 #include <linux/io.h>
10 #include <linux/kernel.h>
11 #include <linux/of.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/thermal.h>
15
16 #define KIRKWOOD_THERMAL_VALID_OFFSET   9
17 #define KIRKWOOD_THERMAL_VALID_MASK     0x1
18 #define KIRKWOOD_THERMAL_TEMP_OFFSET    10
19 #define KIRKWOOD_THERMAL_TEMP_MASK      0x1FF
20
21 /* Kirkwood Thermal Sensor Dev Structure */
22 struct kirkwood_thermal_priv {
23         void __iomem *sensor;
24 };
25
26 static int kirkwood_get_temp(struct thermal_zone_device *thermal,
27                           int *temp)
28 {
29         unsigned long reg;
30         struct kirkwood_thermal_priv *priv = thermal->devdata;
31
32         reg = readl_relaxed(priv->sensor);
33
34         /* Valid check */
35         if (!((reg >> KIRKWOOD_THERMAL_VALID_OFFSET) &
36             KIRKWOOD_THERMAL_VALID_MASK)) {
37                 dev_err(&thermal->device,
38                         "Temperature sensor reading not valid\n");
39                 return -EIO;
40         }
41
42         /*
43          * Calculate temperature. According to Marvell internal
44          * documentation the formula for this is:
45          * Celsius = (322-reg)/1.3625
46          */
47         reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) &
48                 KIRKWOOD_THERMAL_TEMP_MASK;
49         *temp = ((3220000000UL - (10000000UL * reg)) / 13625);
50
51         return 0;
52 }
53
54 static struct thermal_zone_device_ops ops = {
55         .get_temp = kirkwood_get_temp,
56 };
57
58 static const struct of_device_id kirkwood_thermal_id_table[] = {
59         { .compatible = "marvell,kirkwood-thermal" },
60         {}
61 };
62
63 static int kirkwood_thermal_probe(struct platform_device *pdev)
64 {
65         struct thermal_zone_device *thermal = NULL;
66         struct kirkwood_thermal_priv *priv;
67         struct resource *res;
68         int ret;
69
70         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
71         if (!priv)
72                 return -ENOMEM;
73
74         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
75         priv->sensor = devm_ioremap_resource(&pdev->dev, res);
76         if (IS_ERR(priv->sensor))
77                 return PTR_ERR(priv->sensor);
78
79         thermal = thermal_zone_device_register("kirkwood_thermal", 0, 0,
80                                                priv, &ops, NULL, 0, 0);
81         if (IS_ERR(thermal)) {
82                 dev_err(&pdev->dev,
83                         "Failed to register thermal zone device\n");
84                 return PTR_ERR(thermal);
85         }
86         ret = thermal_zone_device_enable(thermal);
87         if (ret) {
88                 thermal_zone_device_unregister(thermal);
89                 dev_err(&pdev->dev, "Failed to enable thermal zone device\n");
90                 return ret;
91         }
92
93         platform_set_drvdata(pdev, thermal);
94
95         return 0;
96 }
97
98 static int kirkwood_thermal_exit(struct platform_device *pdev)
99 {
100         struct thermal_zone_device *kirkwood_thermal =
101                 platform_get_drvdata(pdev);
102
103         thermal_zone_device_unregister(kirkwood_thermal);
104
105         return 0;
106 }
107
108 MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table);
109
110 static struct platform_driver kirkwood_thermal_driver = {
111         .probe = kirkwood_thermal_probe,
112         .remove = kirkwood_thermal_exit,
113         .driver = {
114                 .name = "kirkwood_thermal",
115                 .of_match_table = kirkwood_thermal_id_table,
116         },
117 };
118
119 module_platform_driver(kirkwood_thermal_driver);
120
121 MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>");
122 MODULE_DESCRIPTION("kirkwood thermal driver");
123 MODULE_LICENSE("GPL");