1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Broadcom AVS RO thermal sensor driver
4  *
5  * based on brcmstb_thermal
6  *
7  * Copyright (C) 2020 Stefan Wahren
8  */
9 
10 #include <linux/bitops.h>
11 #include <linux/clk.h>
12 #include <linux/device.h>
13 #include <linux/err.h>
14 #include <linux/io.h>
15 #include <linux/kernel.h>
16 #include <linux/mfd/syscon.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/platform_device.h>
20 #include <linux/regmap.h>
21 #include <linux/thermal.h>
22 
23 #include "../thermal_hwmon.h"
24 
25 #define AVS_RO_TEMP_STATUS		0x200
26 #define AVS_RO_TEMP_STATUS_VALID_MSK	(BIT(16) | BIT(10))
27 #define AVS_RO_TEMP_STATUS_DATA_MSK	GENMASK(9, 0)
28 
29 struct bcm2711_thermal_priv {
30 	struct regmap *regmap;
31 	struct thermal_zone_device *thermal;
32 };
33 
34 static int bcm2711_get_temp(struct thermal_zone_device *tz, int *temp)
35 {
36 	struct bcm2711_thermal_priv *priv = thermal_zone_device_priv(tz);
37 	int slope = thermal_zone_get_slope(tz);
38 	int offset = thermal_zone_get_offset(tz);
39 	u32 val;
40 	int ret;
41 
42 	ret = regmap_read(priv->regmap, AVS_RO_TEMP_STATUS, &val);
43 	if (ret)
44 		return ret;
45 
46 	if (!(val & AVS_RO_TEMP_STATUS_VALID_MSK))
47 		return -EIO;
48 
49 	val &= AVS_RO_TEMP_STATUS_DATA_MSK;
50 
51 	/* Convert a HW code to a temperature reading (millidegree celsius) */
52 	*temp = slope * val + offset;
53 
54 	return 0;
55 }
56 
57 static const struct thermal_zone_device_ops bcm2711_thermal_of_ops = {
58 	.get_temp	= bcm2711_get_temp,
59 };
60 
61 static const struct of_device_id bcm2711_thermal_id_table[] = {
62 	{ .compatible = "brcm,bcm2711-thermal" },
63 	{},
64 };
65 MODULE_DEVICE_TABLE(of, bcm2711_thermal_id_table);
66 
67 static int bcm2711_thermal_probe(struct platform_device *pdev)
68 {
69 	struct thermal_zone_device *thermal;
70 	struct bcm2711_thermal_priv *priv;
71 	struct device *dev = &pdev->dev;
72 	struct device_node *parent;
73 	struct regmap *regmap;
74 	int ret;
75 
76 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
77 	if (!priv)
78 		return -ENOMEM;
79 
80 	/* get regmap from syscon node */
81 	parent = of_get_parent(dev->of_node); /* parent should be syscon node */
82 	regmap = syscon_node_to_regmap(parent);
83 	of_node_put(parent);
84 	if (IS_ERR(regmap)) {
85 		ret = PTR_ERR(regmap);
86 		dev_err(dev, "failed to get regmap: %d\n", ret);
87 		return ret;
88 	}
89 	priv->regmap = regmap;
90 
91 	thermal = devm_thermal_of_zone_register(dev, 0, priv,
92 						&bcm2711_thermal_of_ops);
93 	if (IS_ERR(thermal)) {
94 		ret = PTR_ERR(thermal);
95 		dev_err(dev, "could not register sensor: %d\n", ret);
96 		return ret;
97 	}
98 
99 	priv->thermal = thermal;
100 
101 	return thermal_add_hwmon_sysfs(thermal);
102 }
103 
104 static struct platform_driver bcm2711_thermal_driver = {
105 	.probe = bcm2711_thermal_probe,
106 	.driver = {
107 		.name = "bcm2711_thermal",
108 		.of_match_table = bcm2711_thermal_id_table,
109 	},
110 };
111 module_platform_driver(bcm2711_thermal_driver);
112 
113 MODULE_LICENSE("GPL");
114 MODULE_AUTHOR("Stefan Wahren");
115 MODULE_DESCRIPTION("Broadcom AVS RO thermal sensor driver");
116