1 /*
2  * Copyright (C) 2017 Rafał Miłecki <rafal@milecki.pl>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 
9 #include <linux/module.h>
10 #include <linux/of_address.h>
11 #include <linux/platform_device.h>
12 #include <linux/thermal.h>
13 
14 #define PVTMON_CONTROL0					0x00
15 #define PVTMON_CONTROL0_SEL_MASK			0x0000000e
16 #define PVTMON_CONTROL0_SEL_TEMP_MONITOR		0x00000000
17 #define PVTMON_CONTROL0_SEL_TEST_MODE			0x0000000e
18 #define PVTMON_STATUS					0x08
19 
20 struct ns_thermal {
21 	struct thermal_zone_device *tz;
22 	void __iomem *pvtmon;
23 };
24 
25 static int ns_thermal_get_temp(void *data, int *temp)
26 {
27 	struct ns_thermal *ns_thermal = data;
28 	int offset = thermal_zone_get_offset(ns_thermal->tz);
29 	int slope = thermal_zone_get_slope(ns_thermal->tz);
30 	u32 val;
31 
32 	val = readl(ns_thermal->pvtmon + PVTMON_CONTROL0);
33 	if ((val & PVTMON_CONTROL0_SEL_MASK) != PVTMON_CONTROL0_SEL_TEMP_MONITOR) {
34 		/* Clear current mode selection */
35 		val &= ~PVTMON_CONTROL0_SEL_MASK;
36 
37 		/* Set temp monitor mode (it's the default actually) */
38 		val |= PVTMON_CONTROL0_SEL_TEMP_MONITOR;
39 
40 		writel(val, ns_thermal->pvtmon + PVTMON_CONTROL0);
41 	}
42 
43 	val = readl(ns_thermal->pvtmon + PVTMON_STATUS);
44 	*temp = slope * val + offset;
45 
46 	return 0;
47 }
48 
49 static const struct thermal_zone_of_device_ops ns_thermal_ops = {
50 	.get_temp = ns_thermal_get_temp,
51 };
52 
53 static int ns_thermal_probe(struct platform_device *pdev)
54 {
55 	struct device *dev = &pdev->dev;
56 	struct ns_thermal *ns_thermal;
57 
58 	ns_thermal = devm_kzalloc(dev, sizeof(*ns_thermal), GFP_KERNEL);
59 	if (!ns_thermal)
60 		return -ENOMEM;
61 
62 	ns_thermal->pvtmon = of_iomap(dev_of_node(dev), 0);
63 	if (WARN_ON(!ns_thermal->pvtmon))
64 		return -ENOENT;
65 
66 	ns_thermal->tz = devm_thermal_zone_of_sensor_register(dev, 0,
67 							      ns_thermal,
68 							      &ns_thermal_ops);
69 	if (IS_ERR(ns_thermal->tz)) {
70 		iounmap(ns_thermal->pvtmon);
71 		return PTR_ERR(ns_thermal->tz);
72 	}
73 
74 	platform_set_drvdata(pdev, ns_thermal);
75 
76 	return 0;
77 }
78 
79 static int ns_thermal_remove(struct platform_device *pdev)
80 {
81 	struct ns_thermal *ns_thermal = platform_get_drvdata(pdev);
82 
83 	iounmap(ns_thermal->pvtmon);
84 
85 	return 0;
86 }
87 
88 static const struct of_device_id ns_thermal_of_match[] = {
89 	{ .compatible = "brcm,ns-thermal", },
90 	{},
91 };
92 MODULE_DEVICE_TABLE(of, ns_thermal_of_match);
93 
94 static struct platform_driver ns_thermal_driver = {
95 	.probe		= ns_thermal_probe,
96 	.remove		= ns_thermal_remove,
97 	.driver = {
98 		.name = "ns-thermal",
99 		.of_match_table = ns_thermal_of_match,
100 	},
101 };
102 module_platform_driver(ns_thermal_driver);
103 
104 MODULE_AUTHOR("Rafał Miłecki <rafal@milecki.pl>");
105 MODULE_DESCRIPTION("Northstar thermal driver");
106 MODULE_LICENSE("GPL v2");
107