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(void * private,int * temp)23 static 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
37 static struct thermal_zone_of_device_ops thermal_mmio_ops = {
38 .get_temp = thermal_mmio_get_temperature,
39 };
40
thermal_mmio_probe(struct platform_device * pdev)41 static 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 return PTR_ERR(sensor->mmio_base);
59
60 sensor_init_func = device_get_match_data(&pdev->dev);
61 if (sensor_init_func) {
62 ret = sensor_init_func(pdev, sensor);
63 if (ret) {
64 dev_err(&pdev->dev,
65 "failed to initialize sensor (%d)\n",
66 ret);
67 return ret;
68 }
69 }
70
71 thermal_zone = devm_thermal_zone_of_sensor_register(&pdev->dev,
72 0,
73 sensor,
74 &thermal_mmio_ops);
75 if (IS_ERR(thermal_zone)) {
76 dev_err(&pdev->dev,
77 "failed to register sensor (%ld)\n",
78 PTR_ERR(thermal_zone));
79 return PTR_ERR(thermal_zone);
80 }
81
82 thermal_mmio_get_temperature(sensor, &temperature);
83 dev_info(&pdev->dev,
84 "thermal mmio sensor %s registered, current temperature: %d\n",
85 pdev->name, temperature);
86
87 return 0;
88 }
89
al_thermal_init(struct platform_device * pdev,struct thermal_mmio * sensor)90 static int al_thermal_init(struct platform_device *pdev,
91 struct thermal_mmio *sensor)
92 {
93 sensor->read_mmio = thermal_mmio_readb;
94 sensor->mask = 0xff;
95 sensor->factor = 1000;
96
97 return 0;
98 }
99
100 static const struct of_device_id thermal_mmio_id_table[] = {
101 { .compatible = "amazon,al-thermal", .data = al_thermal_init},
102 {}
103 };
104 MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
105
106 static struct platform_driver thermal_mmio_driver = {
107 .probe = thermal_mmio_probe,
108 .driver = {
109 .name = "thermal-mmio",
110 .of_match_table = of_match_ptr(thermal_mmio_id_table),
111 },
112 };
113
114 module_platform_driver(thermal_mmio_driver);
115
116 MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>");
117 MODULE_DESCRIPTION("Thermal MMIO Driver");
118 MODULE_LICENSE("GPL v2");
119