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 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
kirkwood_thermal_exit(struct platform_device * pdev)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");
124