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
11struct thermal_mmio {
12	void __iomem *mmio_base;
13	u32 (*read_mmio)(void __iomem *mmio_base);
14	u32 mask;
15	int factor;
16};
17
18static u32 thermal_mmio_readb(void __iomem *mmio_base)
19{
20	return readb(mmio_base);
21}
22
23static int thermal_mmio_get_temperature(void *private, int *temp)
24{
25	int t;
26	struct thermal_mmio *sensor =
27		(struct thermal_mmio *)private;
28
29	t = sensor->read_mmio(sensor->mmio_base) & sensor->mask;
30	t *= sensor->factor;
31
32	*temp = t;
33
34	return 0;
35}
36
37static struct thermal_zone_of_device_ops thermal_mmio_ops = {
38	.get_temp = thermal_mmio_get_temperature,
39};
40
41static int thermal_mmio_probe(struct platform_device *pdev)
42{
43	struct resource *resource;
44	struct thermal_mmio *sensor;
45	int (*sensor_init_func)(struct platform_device *pdev,
46				struct thermal_mmio *sensor);
47	struct thermal_zone_device *thermal_zone;
48	int ret;
49	int temperature;
50
51	sensor = devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL);
52	if (!sensor)
53		return -ENOMEM;
54
55	resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
56	sensor->mmio_base = devm_ioremap_resource(&pdev->dev, resource);
57	if (IS_ERR(sensor->mmio_base)) {
58		dev_err(&pdev->dev, "failed to ioremap memory (%ld)\n",
59			PTR_ERR(sensor->mmio_base));
60		return PTR_ERR(sensor->mmio_base);
61	}
62
63	sensor_init_func = device_get_match_data(&pdev->dev);
64	if (sensor_init_func) {
65		ret = sensor_init_func(pdev, sensor);
66		if (ret) {
67			dev_err(&pdev->dev,
68				"failed to initialize sensor (%d)\n",
69				ret);
70			return ret;
71		}
72	}
73
74	thermal_zone = devm_thermal_zone_of_sensor_register(&pdev->dev,
75							    0,
76							    sensor,
77							    &thermal_mmio_ops);
78	if (IS_ERR(thermal_zone)) {
79		dev_err(&pdev->dev,
80			"failed to register sensor (%ld)\n",
81			PTR_ERR(thermal_zone));
82		return PTR_ERR(thermal_zone);
83	}
84
85	thermal_mmio_get_temperature(sensor, &temperature);
86	dev_info(&pdev->dev,
87		 "thermal mmio sensor %s registered, current temperature: %d\n",
88		 pdev->name, temperature);
89
90	return 0;
91}
92
93static int al_thermal_init(struct platform_device *pdev,
94			   struct thermal_mmio *sensor)
95{
96	sensor->read_mmio = thermal_mmio_readb;
97	sensor->mask = 0xff;
98	sensor->factor = 1000;
99
100	return 0;
101}
102
103static const struct of_device_id thermal_mmio_id_table[] = {
104	{ .compatible = "amazon,al-thermal", .data = al_thermal_init},
105	{}
106};
107MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
108
109static struct platform_driver thermal_mmio_driver = {
110	.probe = thermal_mmio_probe,
111	.driver = {
112		.name = "thermal-mmio",
113		.of_match_table = of_match_ptr(thermal_mmio_id_table),
114	},
115};
116
117module_platform_driver(thermal_mmio_driver);
118
119MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>");
120MODULE_DESCRIPTION("Thermal MMIO Driver");
121MODULE_LICENSE("GPL v2");
122