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(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
36static const struct thermal_zone_device_ops thermal_mmio_ops = {
37	.get_temp = thermal_mmio_get_temperature,
38};
39
40static 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
87static 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
97static const struct of_device_id thermal_mmio_id_table[] = {
98	{ .compatible = "amazon,al-thermal", .data = al_thermal_init},
99	{}
100};
101MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
102
103static 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
111module_platform_driver(thermal_mmio_driver);
112
113MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>");
114MODULE_DESCRIPTION("Thermal MMIO Driver");
115MODULE_LICENSE("GPL v2");
116