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(struct thermal_zone_device * tz,int * temp)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
thermal_mmio_probe(struct platform_device * pdev)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
al_thermal_init(struct platform_device * pdev,struct thermal_mmio * sensor)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
