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 
18 static u32 thermal_mmio_readb(void __iomem *mmio_base)
19 {
20 	return readb(mmio_base);
21 }
22 
23 static int thermal_mmio_get_temperature(struct thermal_zone_device *tz, int *temp)
24 {
25 	int t;
26 	struct thermal_mmio *sensor = tz->devdata;
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 
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 
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