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 */
22struct kirkwood_thermal_priv {
23 void __iomem *sensor;
24};
25
26static 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(tzd: 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
51static struct thermal_zone_device_ops ops = {
52 .get_temp = kirkwood_get_temp,
53};
54
55static const struct of_device_id kirkwood_thermal_id_table[] = {
56 { .compatible = "marvell,kirkwood-thermal" },
57 {}
58};
59
60static 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(dev: &pdev->dev, size: sizeof(*priv), GFP_KERNEL);
67 if (!priv)
68 return -ENOMEM;
69
70 priv->sensor = devm_platform_get_and_ioremap_resource(pdev, index: 0, NULL);
71 if (IS_ERR(ptr: priv->sensor))
72 return PTR_ERR(ptr: priv->sensor);
73
74 thermal = thermal_tripless_zone_device_register(type: "kirkwood_thermal",
75 devdata: priv, ops: &ops, NULL);
76 if (IS_ERR(ptr: thermal)) {
77 dev_err(&pdev->dev,
78 "Failed to register thermal zone device\n");
79 return PTR_ERR(ptr: thermal);
80 }
81 ret = thermal_zone_device_enable(tz: thermal);
82 if (ret) {
83 thermal_zone_device_unregister(tz: thermal);
84 dev_err(&pdev->dev, "Failed to enable thermal zone device\n");
85 return ret;
86 }
87
88 platform_set_drvdata(pdev, data: thermal);
89
90 return 0;
91}
92
93static void 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(tz: kirkwood_thermal);
99}
100
101MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table);
102
103static struct platform_driver kirkwood_thermal_driver = {
104 .probe = kirkwood_thermal_probe,
105 .remove_new = kirkwood_thermal_exit,
106 .driver = {
107 .name = "kirkwood_thermal",
108 .of_match_table = kirkwood_thermal_id_table,
109 },
110};
111
112module_platform_driver(kirkwood_thermal_driver);
113
114MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>");
115MODULE_DESCRIPTION("kirkwood thermal driver");
116MODULE_LICENSE("GPL");
117

source code of linux/drivers/thermal/kirkwood_thermal.c