Quelle  st_thermal.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * ST Thermal Sensor Driver core routines
 * Author: Ajit Pal Singh <ajitpal.singh@st.com>
 *
 * Copyright (C) 2003-2014 STMicroelectronics (R&D) Limited
 */

#include <linux/clk.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>

#include "st_thermal.h"
#include "../thermal_hwmon.h"

/* The Thermal Framework expects millidegrees */
#define mcelsius(temp)   ((temp) * 1000)

/*
 * Function to allocate regfields which are common
 * between syscfg and memory mapped based sensors
 */
static int st_thermal_alloc_regfields(struct st_thermal_sensor *sensor)
{
 struct device *dev = sensor->dev;
 struct regmap *regmap = sensor->regmap;
 const struct reg_field *reg_fields = sensor->cdata->reg_fields;

 sensor->dcorrect = devm_regmap_field_alloc(dev, regmap,
         reg_fields[DCORRECT]);

 sensor->overflow = devm_regmap_field_alloc(dev, regmap,
         reg_fields[OVERFLOW]);

 sensor->temp_data = devm_regmap_field_alloc(dev, regmap,
          reg_fields[DATA]);

 if (IS_ERR(sensor->dcorrect) ||
     IS_ERR(sensor->overflow) ||
     IS_ERR(sensor->temp_data)) {
  dev_err(dev, "failed to allocate common regfields\n");
  return -EINVAL;
 }

 return sensor->ops->alloc_regfields(sensor);
}

static int st_thermal_sensor_on(struct st_thermal_sensor *sensor)
{
 int ret;
 struct device *dev = sensor->dev;

 ret = clk_prepare_enable(sensor->clk);
 if (ret) {
  dev_err(dev, "failed to enable clk\n");
  return ret;
 }

 ret = sensor->ops->power_ctrl(sensor, POWER_ON);
 if (ret) {
  dev_err(dev, "failed to power on sensor\n");
  clk_disable_unprepare(sensor->clk);
 }

 return ret;
}

static int st_thermal_sensor_off(struct st_thermal_sensor *sensor)
{
 int ret;

 ret = sensor->ops->power_ctrl(sensor, POWER_OFF);
 if (ret)
  return ret;

 clk_disable_unprepare(sensor->clk);

 return 0;
}

static int st_thermal_calibration(struct st_thermal_sensor *sensor)
{
 int ret;
 unsigned int val;
 struct device *dev = sensor->dev;

 /* Check if sensor calibration data is already written */
 ret = regmap_field_read(sensor->dcorrect, &val);
 if (ret) {
  dev_err(dev, "failed to read calibration data\n");
  return ret;
 }

 if (!val) {
  /*
 * Sensor calibration value not set by bootloader,
 * default calibration data to be used
 */
  ret = regmap_field_write(sensor->dcorrect,
      sensor->cdata->calibration_val);
  if (ret)
   dev_err(dev, "failed to set calibration data\n");
 }

 return ret;
}

/* Callback to get temperature from HW*/
static int st_thermal_get_temp(struct thermal_zone_device *th, int *temperature)
{
 struct st_thermal_sensor *sensor = thermal_zone_device_priv(th);
 unsigned int temp;
 unsigned int overflow;
 int ret;

 ret = regmap_field_read(sensor->overflow, &overflow);
 if (ret)
  return ret;
 if (overflow)
  return -EIO;

 ret = regmap_field_read(sensor->temp_data, &temp);
 if (ret)
  return ret;

 temp += sensor->cdata->temp_adjust_val;
 temp = mcelsius(temp);

 *temperature = temp;

 return 0;
}

static const struct thermal_zone_device_ops st_tz_ops = {
 .get_temp = st_thermal_get_temp,
};

int st_thermal_register(struct platform_device *pdev,
   const struct of_device_id *st_thermal_of_match)
{
 struct st_thermal_sensor *sensor;
 struct device *dev = &pdev->dev;
 struct device_node *np = dev->of_node;
 const struct of_device_id *match;

 int ret;

 if (!np) {
  dev_err(dev, "device tree node not found\n");
  return -EINVAL;
 }

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

 sensor->dev = dev;

 match = of_match_device(st_thermal_of_match, dev);
 if (!(match && match->data))
  return -EINVAL;

 sensor->cdata = match->data;
 if (!sensor->cdata->ops)
  return -EINVAL;

 sensor->ops = sensor->cdata->ops;

 ret = (sensor->ops->regmap_init)(sensor);
 if (ret)
  return ret;

 ret = st_thermal_alloc_regfields(sensor);
 if (ret)
  return ret;

 sensor->clk = devm_clk_get(dev, "thermal");
 if (IS_ERR(sensor->clk)) {
  dev_err(dev, "failed to fetch clock\n");
  return PTR_ERR(sensor->clk);
 }

 if (sensor->ops->register_enable_irq) {
  ret = sensor->ops->register_enable_irq(sensor);
  if (ret)
   return ret;
 }

 ret = st_thermal_sensor_on(sensor);
 if (ret)
  return ret;

 ret = st_thermal_calibration(sensor);
 if (ret)
  goto sensor_off;

 sensor->thermal_dev =
  devm_thermal_of_zone_register(dev, 0, sensor, &st_tz_ops);
 if (IS_ERR(sensor->thermal_dev)) {
  dev_err(dev, "failed to register thermal of zone\n");
  ret = PTR_ERR(sensor->thermal_dev);
  goto sensor_off;
 }

 platform_set_drvdata(pdev, sensor);

 /*
 * devm_thermal_of_zone_register() doesn't enable hwmon by default
 * Enable it here
 */
 devm_thermal_add_hwmon_sysfs(dev, sensor->thermal_dev);

 return 0;

sensor_off:
 st_thermal_sensor_off(sensor);

 return ret;
}
EXPORT_SYMBOL_GPL(st_thermal_register);

void st_thermal_unregister(struct platform_device *pdev)
{
 struct st_thermal_sensor *sensor = platform_get_drvdata(pdev);

 st_thermal_sensor_off(sensor);
 thermal_remove_hwmon_sysfs(sensor->thermal_dev);
 devm_thermal_of_zone_unregister(sensor->dev, sensor->thermal_dev);
}
EXPORT_SYMBOL_GPL(st_thermal_unregister);

static int st_thermal_suspend(struct device *dev)
{
 struct st_thermal_sensor *sensor = dev_get_drvdata(dev);

 return st_thermal_sensor_off(sensor);
}

static int st_thermal_resume(struct device *dev)
{
 int ret;
 struct st_thermal_sensor *sensor = dev_get_drvdata(dev);

 ret = st_thermal_sensor_on(sensor);
 if (ret)
  return ret;

 ret = st_thermal_calibration(sensor);
 if (ret)
  return ret;

 if (sensor->ops->enable_irq) {
  ret = sensor->ops->enable_irq(sensor);
  if (ret)
   return ret;
 }

 return 0;
}

DEFINE_SIMPLE_DEV_PM_OPS(st_thermal_pm_ops, st_thermal_suspend, st_thermal_resume);
EXPORT_SYMBOL_GPL(st_thermal_pm_ops);

MODULE_AUTHOR("STMicroelectronics (R&D) Limited ");
MODULE_DESCRIPTION("STMicroelectronics STi SoC Thermal Sensor Driver");
MODULE_LICENSE("GPL v2");