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 resource *resource;
43 	struct thermal_mmio *sensor;
44 	int (*sensor_init_func)(struct platform_device *pdev,
45 				struct thermal_mmio *sensor);
46 	struct thermal_zone_device *thermal_zone;
47 	int ret;
48 	int temperature;
49 
50 	sensor = devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL);
51 	if (!sensor)
52 		return -ENOMEM;
53 
54 	resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
55 	sensor->mmio_base = devm_ioremap_resource(&pdev->dev, resource);
56 	if (IS_ERR(sensor->mmio_base))
57 		return PTR_ERR(sensor->mmio_base);
58 
59 	sensor_init_func = device_get_match_data(&pdev->dev);
60 	if (sensor_init_func) {
61 		ret = sensor_init_func(pdev, sensor);
62 		if (ret) {
63 			dev_err(&pdev->dev,
64 				"failed to initialize sensor (%d)\n",
65 				ret);
66 			return ret;
67 		}
68 	}
69 
70 	thermal_zone = devm_thermal_of_zone_register(&pdev->dev,
71 						     0,
72 						     sensor,
73 						     &thermal_mmio_ops);
74 	if (IS_ERR(thermal_zone)) {
75 		dev_err(&pdev->dev,
76 			"failed to register sensor (%ld)\n",
77 			PTR_ERR(thermal_zone));
78 		return PTR_ERR(thermal_zone);
79 	}
80 
81 	thermal_mmio_get_temperature(thermal_zone, &temperature);
82 	dev_info(&pdev->dev,
83 		 "thermal mmio sensor %s registered, current temperature: %d\n",
84 		 pdev->name, temperature);
85 
86 	return 0;
87 }
88 
89 static int al_thermal_init(struct platform_device *pdev,
90 			   struct thermal_mmio *sensor)
91 {
92 	sensor->read_mmio = thermal_mmio_readb;
93 	sensor->mask = 0xff;
94 	sensor->factor = 1000;
95 
96 	return 0;
97 }
98 
99 static const struct of_device_id thermal_mmio_id_table[] = {
100 	{ .compatible = "amazon,al-thermal", .data = al_thermal_init},
101 	{}
102 };
103 MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
104 
105 static struct platform_driver thermal_mmio_driver = {
106 	.probe = thermal_mmio_probe,
107 	.driver = {
108 		.name = "thermal-mmio",
109 		.of_match_table = thermal_mmio_id_table,
110 	},
111 };
112 
113 module_platform_driver(thermal_mmio_driver);
114 
115 MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>");
116 MODULE_DESCRIPTION("Thermal MMIO Driver");
117 MODULE_LICENSE("GPL v2");
118