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->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
kirkwood_thermal_probe(struct platform_device * pdev)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 int ret;
68
69 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
70 if (!priv)
71 return -ENOMEM;
72
73 priv->sensor = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
74 if (IS_ERR(priv->sensor))
75 return PTR_ERR(priv->sensor);
76
77 thermal = thermal_zone_device_register("kirkwood_thermal", 0, 0,
78 priv, &ops, NULL, 0, 0);
79 if (IS_ERR(thermal)) {
80 dev_err(&pdev->dev,
81 "Failed to register thermal zone device\n");
82 return PTR_ERR(thermal);
83 }
84 ret = thermal_zone_device_enable(thermal);
85 if (ret) {
86 thermal_zone_device_unregister(thermal);
87 dev_err(&pdev->dev, "Failed to enable thermal zone device\n");
88 return ret;
89 }
90
91 platform_set_drvdata(pdev, thermal);
92
93 return 0;
94 }
95
kirkwood_thermal_exit(struct platform_device * pdev)96 static int kirkwood_thermal_exit(struct platform_device *pdev)
97 {
98 struct thermal_zone_device *kirkwood_thermal =
99 platform_get_drvdata(pdev);
100
101 thermal_zone_device_unregister(kirkwood_thermal);
102
103 return 0;
104 }
105
106 MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table);
107
108 static struct platform_driver kirkwood_thermal_driver = {
109 .probe = kirkwood_thermal_probe,
110 .remove = kirkwood_thermal_exit,
111 .driver = {
112 .name = "kirkwood_thermal",
113 .of_match_table = kirkwood_thermal_id_table,
114 },
115 };
116
117 module_platform_driver(kirkwood_thermal_driver);
118
119 MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>");
120 MODULE_DESCRIPTION("kirkwood thermal driver");
121 MODULE_LICENSE("GPL");
122