bcm2711_thermal.c

  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");