1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
4 */
5
6 #include <linux/module.h>
7 #include <linux/of_address.h>
8 #include <linux/platform_device.h>
9 #include <linux/thermal.h>
10
11 struct thermal_mmio {
12 void __iomem *mmio_base;
13 u32 (*read_mmio)(void __iomem *mmio_base);
14 u32 mask;
15 int factor;
16 };
17
thermal_mmio_readb(void __iomem * mmio_base)18 static u32 thermal_mmio_readb(void __iomem *mmio_base)
19 {
20 return readb(mmio_base);
21 }
22
thermal_mmio_get_temperature(struct thermal_zone_device * tz,int * temp)23 static int thermal_mmio_get_temperature(struct thermal_zone_device *tz, int *temp)
24 {
25 int t;
26 struct thermal_mmio *sensor = thermal_zone_device_priv(tz);
27
28 t = sensor->read_mmio(sensor->mmio_base) & sensor->mask;
29 t *= sensor->factor;
30
31 *temp = t;
32
33 return 0;
34 }
35
36 static const struct thermal_zone_device_ops thermal_mmio_ops = {
37 .get_temp = thermal_mmio_get_temperature,
38 };
39
thermal_mmio_probe(struct platform_device * pdev)40 static int thermal_mmio_probe(struct platform_device *pdev)
41 {
42 struct thermal_mmio *sensor;
43 int (*sensor_init_func)(struct platform_device *pdev,
44 struct thermal_mmio *sensor);
45 struct thermal_zone_device *thermal_zone;
46 int ret;
47 int temperature;
48
49 sensor = devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL);
50 if (!sensor)
51 return -ENOMEM;
52
53 sensor->mmio_base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
54 if (IS_ERR(sensor->mmio_base))
55 return PTR_ERR(sensor->mmio_base);
56
57 sensor_init_func = device_get_match_data(&pdev->dev);
58 if (sensor_init_func) {
59 ret = sensor_init_func(pdev, sensor);
60 if (ret) {
61 dev_err(&pdev->dev,
62 "failed to initialize sensor (%d)\n",
63 ret);
64 return ret;
65 }
66 }
67
68 thermal_zone = devm_thermal_of_zone_register(&pdev->dev,
69 0,
70 sensor,
71 &thermal_mmio_ops);
72 if (IS_ERR(thermal_zone)) {
73 dev_err(&pdev->dev,
74 "failed to register sensor (%ld)\n",
75 PTR_ERR(thermal_zone));
76 return PTR_ERR(thermal_zone);
77 }
78
79 thermal_mmio_get_temperature(thermal_zone, &temperature);
80 dev_info(&pdev->dev,
81 "thermal mmio sensor %s registered, current temperature: %d\n",
82 pdev->name, temperature);
83
84 return 0;
85 }
86
al_thermal_init(struct platform_device * pdev,struct thermal_mmio * sensor)87 static int al_thermal_init(struct platform_device *pdev,
88 struct thermal_mmio *sensor)
89 {
90 sensor->read_mmio = thermal_mmio_readb;
91 sensor->mask = 0xff;
92 sensor->factor = 1000;
93
94 return 0;
95 }
96
97 static const struct of_device_id thermal_mmio_id_table[] = {
98 { .compatible = "amazon,al-thermal", .data = al_thermal_init},
99 {}
100 };
101 MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
102
103 static struct platform_driver thermal_mmio_driver = {
104 .probe = thermal_mmio_probe,
105 .driver = {
106 .name = "thermal-mmio",
107 .of_match_table = thermal_mmio_id_table,
108 },
109 };
110
111 module_platform_driver(thermal_mmio_driver);
112
113 MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>");
114 MODULE_DESCRIPTION("Thermal MMIO Driver");
115 MODULE_LICENSE("GPL v2");
116