path: root/drivers/thermal/of-thermal.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  of-thermal.c - Generic Thermal Management device tree support.
 *
 *  Copyright (C) 2013 Texas Instruments
 *  Copyright (C) 2013 Eduardo Valentin <eduardo.valentin@ti.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/thermal.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/string.h>

#include "thermal_core.h"

/***   Private data structures to represent thermal device tree data ***/

/**
 * struct __thermal_cooling_bind_param - a cooling device for a trip point
 * @cooling_device: a pointer to identify the referred cooling device
 * @min: minimum cooling state used at this trip point
 * @max: maximum cooling state used at this trip point
 */

struct __thermal_cooling_bind_param {
	struct device_node *cooling_device;
	unsigned long min;
	unsigned long max;
};

/**
 * struct __thermal_bind_param - a match between trip and cooling device
 * @tcbp: a pointer to an array of cooling devices
 * @count: number of elements in array
 * @trip_id: the trip point index
 * @usage: the percentage (from 0 to 100) of cooling contribution
 */

struct __thermal_bind_params {
	struct __thermal_cooling_bind_param *tcbp;
	unsigned int count;
	unsigned int trip_id;
	unsigned int usage;
};

/**
 * struct __thermal_zone - internal representation of a thermal zone
 * @mode: current thermal zone device mode (enabled/disabled)
 * @passive_delay: polling interval while passive cooling is activated
 * @polling_delay: zone polling interval
 * @slope: slope of the temperature adjustment curve
 * @offset: offset of the temperature adjustment curve
 * @ntrips: number of trip points
 * @trips: an array of trip points (0..ntrips - 1)
 * @num_tbps: number of thermal bind params
 * @tbps: an array of thermal bind params (0..num_tbps - 1)
 * @sensor_data: sensor private data used while reading temperature and trend
 * @ops: set of callbacks to handle the thermal zone based on DT
 */

struct __thermal_zone {
	enum thermal_device_mode mode;
	int passive_delay;
	int polling_delay;
	int slope;
	int offset;

	/* trip data */
	int ntrips;
	struct thermal_trip *trips;

	/* cooling binding data */
	int num_tbps;
	struct __thermal_bind_params *tbps;

	/* sensor interface */
	void *sensor_data;
	const struct thermal_zone_of_device_ops *ops;
};

/***   DT thermal zone device callbacks   ***/

static int of_thermal_get_temp(struct thermal_zone_device *tz,
			       int *temp)
{
	struct __thermal_zone *data = tz->devdata;

	if (!data->ops->get_temp)
		return -EINVAL;

	return data->ops->get_temp(data->sensor_data, temp);
}

static int of_thermal_set_trips(struct thermal_zone_device *tz,
				int low, int high)
{
	struct __thermal_zone *data = tz->devdata;

	if (!data->ops || !data->ops->set_trips)
		return -EINVAL;

	return data->ops->set_trips(data->sensor_data, low, high);
}

/**
 * of_thermal_get_ntrips - function to export number of available trip
 *			   points.
 * @tz: pointer to a thermal zone
 *
 * This function is a globally visible wrapper to get number of trip points
 * stored in the local struct __thermal_zone
 *
 * Return: number of available trip points, -ENODEV when data not available
 */
int of_thermal_get_ntrips(struct thermal_zone_device *tz)
{
	struct __thermal_zone *data = tz->devdata;

	if (!data || IS_ERR(data))
		return -ENODEV;

	return data->ntrips;
}
EXPORT_SYMBOL_GPL(of_thermal_get_ntrips);

/**
 * of_thermal_is_trip_valid - function to check if trip point is valid
 *
 * @tz:	pointer to a thermal zone
 * @trip:	trip point to evaluate
 *
 * This function is responsible for checking if passed trip point is valid
 *
 * Return: true if trip point is valid, false otherwise
 */
bool of_thermal_is_trip_valid(struct thermal_zone_device *tz, int trip)
{
	struct __thermal_zone *data = tz->devdata;

	if (!data || trip >= data->ntrips || trip < 0)
		return false;

	return true;
}
EXPORT_SYMBOL_GPL(of_thermal_is_trip_valid);

/**
 * of_thermal_get_trip_points - function to get access to a globally exported
 *				trip points
 *
 * @tz:	pointer to a thermal zone
 *
 * This function provides a pointer to trip points table
 *
 * Return: pointer to trip points table, NULL otherwise
 */
const struct thermal_trip *
of_thermal_get_trip_points(struct thermal_zone_device *tz)
{
	struct __thermal_zone *data = tz->devdata;

	if (!data)
		return NULL;

	return data->trips;
}
EXPORT_SYMBOL_GPL(of_thermal_get_trip_points);

/**
 * of_thermal_set_emul_temp - function to set emulated temperature
 *
 * @tz:	pointer to a thermal zone
 * @temp:	temperature to set
 *
 * This function gives the ability to set emulated value of temperature,
 * which is handy for debugging
 *
 * Return: zero on success, error code otherwise
 */
static int of_thermal_set_emul_temp(struct thermal_zone_device *tz,
				    int temp)
{
	struct __thermal_zone *data = tz->devdata;

	return data->ops->set_emul_temp(data->sensor_data, temp);
}

static int of_thermal_get_trend(struct thermal_zone_device *tz, int trip,
				enum thermal_trend *trend)
{
	struct __thermal_zone *data = tz->devdata;

	if (!data->ops->get_trend)
		return -EINVAL;

	return data->ops->get_trend(data->sensor_data, trip, trend);
}

static int of_thermal_bind(struct thermal_zone_device *thermal,
			   struct thermal_cooling_device *cdev)
{
	struct