Quelle  db8500_thermal.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * db8500_thermal.c - DB8500 Thermal Management Implementation
 *
 * Copyright (C) 2012 ST-Ericsson
 * Copyright (C) 2012-2019 Linaro Ltd.
 *
 * Authors: Hongbo Zhang, Linus Walleij
 */

#include <linux/cpu_cooling.h>
#include <linux/interrupt.h>
#include <linux/mfd/dbx500-prcmu.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/thermal.h>

#define PRCMU_DEFAULT_MEASURE_TIME 0xFFF
#define PRCMU_DEFAULT_LOW_TEMP  0

/**
 * db8500_thermal_points - the interpolation points that trigger
 * interrupts
 */
static const unsigned long db8500_thermal_points[] = {
 15000,
 20000,
 25000,
 30000,
 35000,
 40000,
 45000,
 50000,
 55000,
 60000,
 65000,
 70000,
 75000,
 80000,
 /*
 * This is where things start to get really bad for the
 * SoC and the thermal zones should be set up to trigger
 * critical temperature at 85000 mC so we don't get above
 * this point.
 */
 85000,
 90000,
 95000,
 100000,
};

struct db8500_thermal_zone {
 struct thermal_zone_device *tz;
 struct device *dev;
 unsigned long interpolated_temp;
 unsigned int cur_index;
};

/* Callback to get current temperature */
static int db8500_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
{
 struct db8500_thermal_zone *th = thermal_zone_device_priv(tz);

 /*
 * TODO: There is no PRCMU interface to get temperature data currently,
 * so a pseudo temperature is returned , it works for thermal framework
 * and this will be fixed when the PRCMU interface is available.
 */
 *temp = th->interpolated_temp;

 return 0;
}

static const struct thermal_zone_device_ops thdev_ops = {
 .get_temp = db8500_thermal_get_temp,
};

static void db8500_thermal_update_config(struct db8500_thermal_zone *th,
      unsigned int idx,
      unsigned long next_low,
      unsigned long next_high)
{
 prcmu_stop_temp_sense();

 th->cur_index = idx;
 th->interpolated_temp = (next_low + next_high)/2;

 /*
 * The PRCMU accept absolute temperatures in celsius so divide
 * down the millicelsius with 1000
 */
 prcmu_config_hotmon((u8)(next_low/1000), (u8)(next_high/1000));
 prcmu_start_temp_sense(PRCMU_DEFAULT_MEASURE_TIME);
}

static irqreturn_t prcmu_low_irq_handler(int irq, void *irq_data)
{
 struct db8500_thermal_zone *th = irq_data;
 unsigned int idx = th->cur_index;
 unsigned long next_low, next_high;

 if (idx == 0)
  /* Meaningless for thermal management, ignoring it */
  return IRQ_HANDLED;

 if (idx == 1) {
  next_high = db8500_thermal_points[0];
  next_low = PRCMU_DEFAULT_LOW_TEMP;
 } else {
  next_high = db8500_thermal_points[idx - 1];
  next_low = db8500_thermal_points[idx - 2];
 }
 idx -= 1;

 db8500_thermal_update_config(th, idx, next_low, next_high);
 dev_dbg(th->dev,
  "PRCMU set max %ld, min %ld\n", next_high, next_low);

 thermal_zone_device_update(th->tz, THERMAL_EVENT_UNSPECIFIED);

 return IRQ_HANDLED;
}

static irqreturn_t prcmu_high_irq_handler(int irq, void *irq_data)
{
 struct db8500_thermal_zone *th = irq_data;
 unsigned int idx = th->cur_index;
 unsigned long next_low, next_high;
 int num_points = ARRAY_SIZE(db8500_thermal_points);

 if (idx < num_points - 1) {
  next_high = db8500_thermal_points[idx+1];
  next_low = db8500_thermal_points[idx];
  idx += 1;

  db8500_thermal_update_config(th, idx, next_low, next_high);

  dev_dbg(th->dev,
   "PRCMU set max %ld, min %ld\n", next_high, next_low);
 } else if (idx == num_points - 1)
  /* So we roof out 1 degree over the max point */
  th->interpolated_temp = db8500_thermal_points[idx] + 1;

 thermal_zone_device_update(th->tz, THERMAL_EVENT_UNSPECIFIED);

 return IRQ_HANDLED;
}

static int db8500_thermal_probe(struct platform_device *pdev)
{
 struct db8500_thermal_zone *th = NULL;
 struct device *dev = &pdev->dev;
 int low_irq, high_irq, ret = 0;

 th = devm_kzalloc(dev, sizeof(*th), GFP_KERNEL);
 if (!th)
  return -ENOMEM;

 th->dev = dev;

 low_irq = platform_get_irq_byname(pdev, "IRQ_HOTMON_LOW");
 if (low_irq < 0)
  return low_irq;

 ret = devm_request_threaded_irq(dev, low_irq, NULL,
  prcmu_low_irq_handler, IRQF_NO_SUSPEND | IRQF_ONESHOT,
  "dbx500_temp_low", th);
 if (ret < 0) {
  dev_err(dev, "failed to allocate temp low irq\n");
  return ret;
 }

 high_irq = platform_get_irq_byname(pdev, "IRQ_HOTMON_HIGH");
 if (high_irq < 0)
  return high_irq;

 ret = devm_request_threaded_irq(dev, high_irq, NULL,
  prcmu_high_irq_handler, IRQF_NO_SUSPEND | IRQF_ONESHOT,
  "dbx500_temp_high", th);
 if (ret < 0) {
  dev_err(dev, "failed to allocate temp high irq\n");
  return ret;
 }

 /* register of thermal sensor and get info from DT */
 th->tz = devm_thermal_of_zone_register(dev, 0, th, &thdev_ops);
 if (IS_ERR(th->tz)) {
  dev_err(dev, "register thermal zone sensor failed\n");
  return PTR_ERR(th->tz);
 }
 dev_info(dev, "thermal zone sensor registered\n");

 /* Start measuring at the lowest point */
 db8500_thermal_update_config(th, 0, PRCMU_DEFAULT_LOW_TEMP,
         db8500_thermal_points[0]);

 platform_set_drvdata(pdev, th);

 return 0;
}

static int db8500_thermal_suspend(struct platform_device *pdev,
  pm_message_t state)
{
 prcmu_stop_temp_sense();

 return 0;
}

static int db8500_thermal_resume(struct platform_device *pdev)
{
 struct db8500_thermal_zone *th = platform_get_drvdata(pdev);

 /* Resume and start measuring at the lowest point */
 db8500_thermal_update_config(th, 0, PRCMU_DEFAULT_LOW_TEMP,
         db8500_thermal_points[0]);

 return 0;
}

static const struct of_device_id db8500_thermal_match[] = {
 { .compatible = "stericsson,db8500-thermal" },
 {},
};
MODULE_DEVICE_TABLE(of, db8500_thermal_match);

static struct platform_driver db8500_thermal_driver = {
 .driver = {
  .name = "db8500-thermal",
  .of_match_table = db8500_thermal_match,
 },
 .probe = db8500_thermal_probe,
 .suspend = db8500_thermal_suspend,
 .resume = db8500_thermal_resume,
};

module_platform_driver(db8500_thermal_driver);

MODULE_AUTHOR("Hongbo Zhang ");
MODULE_DESCRIPTION("DB8500 thermal driver");
MODULE_LICENSE("GPL");