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
29struct bcm2711_thermal_priv {
30	struct regmap *regmap;
31	struct thermal_zone_device *thermal;
32};
33
34static 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
57static const struct thermal_zone_device_ops bcm2711_thermal_of_ops = {
58	.get_temp	= bcm2711_get_temp,
59};
60
61static const struct of_device_id bcm2711_thermal_id_table[] = {
62	{ .compatible = "brcm,bcm2711-thermal" },
63	{},
64};
65MODULE_DEVICE_TABLE(of, bcm2711_thermal_id_table);
66
67static 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
104static 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};
111module_platform_driver(bcm2711_thermal_driver);
112
113MODULE_LICENSE("GPL");
114MODULE_AUTHOR("Stefan Wahren");
115MODULE_DESCRIPTION("Broadcom AVS RO thermal sensor driver");
116