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 | |
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(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 | |
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 | |
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(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 | |
93 | static 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 | |
101 | MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table); |
102 | |
103 | static 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 | |
112 | module_platform_driver(kirkwood_thermal_driver); |
113 | |
114 | MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>" ); |
115 | MODULE_DESCRIPTION("kirkwood thermal driver" ); |
116 | MODULE_LICENSE("GPL" ); |
117 | |