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(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(&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
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(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