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
kirkwood_get_temp(struct thermal_zone_device * thermal,int * temp)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_zone_device_priv(thermal);
31
32 reg = readl_relaxed(priv->sensor);
33
34 /* Valid check */
35 if (!((reg >> KIRKWOOD_THERMAL_VALID_OFFSET) &
36 KIRKWOOD_THERMAL_VALID_MASK))
37 return -EIO;
38
39 /*
40 * Calculate temperature. According to Marvell internal
41 * documentation the formula for this is:
42 * Celsius = (322-reg)/1.3625
43 */
44 reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) &
45 KIRKWOOD_THERMAL_TEMP_MASK;
46 *temp = ((3220000000UL - (10000000UL * reg)) / 13625);
47
48 return 0;
49 }
50
51 static struct thermal_zone_device_ops ops = {
52 .get_temp = kirkwood_get_temp,
53 };
54
55 static const struct of_device_id kirkwood_thermal_id_table[] = {
56 { .compatible = "marvell,kirkwood-thermal" },
57 {}
58 };
59
kirkwood_thermal_probe(struct platform_device * pdev)60 static int kirkwood_thermal_probe(struct platform_device *pdev)
61 {
62 struct thermal_zone_device *thermal = NULL;
63 struct kirkwood_thermal_priv *priv;
64 int ret;
65
66 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
67 if (!priv)
68 return -ENOMEM;
69
70 priv->sensor = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
71 if (IS_ERR(priv->sensor))
72 return PTR_ERR(priv->sensor);
73
74 thermal = thermal_tripless_zone_device_register("kirkwood_thermal",
75 priv, &ops, NULL);
76 if (IS_ERR(thermal)) {
77 dev_err(&pdev->dev,
78 "Failed to register thermal zone device\n");
79 return PTR_ERR(thermal);
80 }
81 ret = thermal_zone_device_enable(thermal);
82 if (ret) {
83 thermal_zone_device_unregister(thermal);
84 dev_err(&pdev->dev, "Failed to enable thermal zone device\n");
85 return ret;
86 }
87
88 platform_set_drvdata(pdev, thermal);
89
90 return 0;
91 }
92
kirkwood_thermal_exit(struct platform_device * pdev)93 static int kirkwood_thermal_exit(struct platform_device *pdev)
94 {
95 struct thermal_zone_device *kirkwood_thermal =
96 platform_get_drvdata(pdev);
97
98 thermal_zone_device_unregister(kirkwood_thermal);
99
100 return 0;
101 }
102
103 MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table);
104
105 static struct platform_driver kirkwood_thermal_driver = {
106 .probe = kirkwood_thermal_probe,
107 .remove = kirkwood_thermal_exit,
108 .driver = {
109 .name = "kirkwood_thermal",
110 .of_match_table = kirkwood_thermal_id_table,
111 },
112 };
113
114 module_platform_driver(kirkwood_thermal_driver);
115
116 MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>");
117 MODULE_DESCRIPTION("kirkwood thermal driver");
118 MODULE_LICENSE("GPL");
119