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1 | /* |
2 | * Kirkwood thermal sensor driver |
3 | * |
4 | * Copyright (C) 2012 Nobuhiro Iwamatsu <iwamatsu@nigauri.org> |
5 | * |
6 | * This software is licensed under the terms of the GNU General Public |
7 | * License version 2, as published by the Free Software Foundation, and |
8 | * may be copied, distributed, and modified under those terms. |
9 | * |
10 | * This program is distributed in the hope that it will be useful, |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
13 | * GNU General Public License for more details. |
14 | * |
15 | */ |
16 | #include <linux/device.h> |
17 | #include <linux/err.h> |
18 | #include <linux/io.h> |
19 | #include <linux/kernel.h> |
20 | #include <linux/of.h> |
21 | #include <linux/module.h> |
22 | #include <linux/platform_device.h> |
23 | #include <linux/thermal.h> |
24 | |
25 | #define KIRKWOOD_THERMAL_VALID_OFFSET 9 |
26 | #define KIRKWOOD_THERMAL_VALID_MASK 0x1 |
27 | #define KIRKWOOD_THERMAL_TEMP_OFFSET 10 |
28 | #define KIRKWOOD_THERMAL_TEMP_MASK 0x1FF |
29 | |
30 | /* Kirkwood Thermal Sensor Dev Structure */ |
31 | struct kirkwood_thermal_priv { |
32 | void __iomem *sensor; |
33 | }; |
34 | |
35 | static int kirkwood_get_temp(struct thermal_zone_device *thermal, |
36 | unsigned long *temp) |
37 | { |
38 | unsigned long reg; |
39 | struct kirkwood_thermal_priv *priv = thermal->devdata; |
40 | |
41 | reg = readl_relaxed(priv->sensor); |
42 | |
43 | /* Valid check */ |
44 | if (!(reg >> KIRKWOOD_THERMAL_VALID_OFFSET) & |
45 | KIRKWOOD_THERMAL_VALID_MASK) { |
46 | dev_err(&thermal->device, |
47 | "Temperature sensor reading not valid\n"); |
48 | return -EIO; |
49 | } |
50 | |
51 | /* |
52 | * Calculate temperature. See Section 8.10.1 of the 88AP510, |
53 | * datasheet, which has the same sensor. |
54 | * Documentation/arm/Marvell/README |
55 | */ |
56 | reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) & |
57 | KIRKWOOD_THERMAL_TEMP_MASK; |
58 | *temp = ((2281638UL - (7298*reg)) / 10); |
59 | |
60 | return 0; |
61 | } |
62 | |
63 | static struct thermal_zone_device_ops ops = { |
64 | .get_temp = kirkwood_get_temp, |
65 | }; |
66 | |
67 | static const struct of_device_id kirkwood_thermal_id_table[] = { |
68 | { .compatible = "marvell,kirkwood-thermal" }, |
69 | {} |
70 | }; |
71 | |
72 | static int kirkwood_thermal_probe(struct platform_device *pdev) |
73 | { |
74 | struct thermal_zone_device *thermal = NULL; |
75 | struct kirkwood_thermal_priv *priv; |
76 | struct resource *res; |
77 | |
78 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
79 | if (!res) { |
80 | dev_err(&pdev->dev, "Failed to get platform resource\n"); |
81 | return -ENODEV; |
82 | } |
83 | |
84 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
85 | if (!priv) |
86 | return -ENOMEM; |
87 | |
88 | priv->sensor = devm_ioremap_resource(&pdev->dev, res); |
89 | if (IS_ERR(priv->sensor)) |
90 | return PTR_ERR(priv->sensor); |
91 | |
92 | thermal = thermal_zone_device_register("kirkwood_thermal", 0, 0, |
93 | priv, &ops, NULL, 0, 0); |
94 | if (IS_ERR(thermal)) { |
95 | dev_err(&pdev->dev, |
96 | "Failed to register thermal zone device\n"); |
97 | return PTR_ERR(thermal); |
98 | } |
99 | |
100 | platform_set_drvdata(pdev, thermal); |
101 | |
102 | return 0; |
103 | } |
104 | |
105 | static int kirkwood_thermal_exit(struct platform_device *pdev) |
106 | { |
107 | struct thermal_zone_device *kirkwood_thermal = |
108 | platform_get_drvdata(pdev); |
109 | |
110 | thermal_zone_device_unregister(kirkwood_thermal); |
111 | platform_set_drvdata(pdev, NULL); |
112 | |
113 | return 0; |
114 | } |
115 | |
116 | MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table); |
117 | |
118 | static struct platform_driver kirkwood_thermal_driver = { |
119 | .probe = kirkwood_thermal_probe, |
120 | .remove = kirkwood_thermal_exit, |
121 | .driver = { |
122 | .name = "kirkwood_thermal", |
123 | .owner = THIS_MODULE, |
124 | .of_match_table = of_match_ptr(kirkwood_thermal_id_table), |
125 | }, |
126 | }; |
127 | |
128 | module_platform_driver(kirkwood_thermal_driver); |
129 | |
130 | MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>"); |
131 | MODULE_DESCRIPTION("kirkwood thermal driver"); |
132 | MODULE_LICENSE("GPL"); |
133 |
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