Quelle  kirkwood_thermal.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Kirkwood thermal sensor driver
 *
 * Copyright (C) 2012 Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
 */
#include <linux/device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/thermal.h>

#define KIRKWOOD_THERMAL_VALID_OFFSET 9
#define KIRKWOOD_THERMAL_VALID_MASK 0x1
#define KIRKWOOD_THERMAL_TEMP_OFFSET 10
#define KIRKWOOD_THERMAL_TEMP_MASK 0x1FF

/* Kirkwood Thermal Sensor Dev Structure */
struct kirkwood_thermal_priv {
 void __iomem *sensor;
};

static int kirkwood_get_temp(struct thermal_zone_device *thermal,
     int *temp)
{
 unsigned long reg;
 struct kirkwood_thermal_priv *priv = thermal_zone_device_priv(thermal);

 reg = readl_relaxed(priv->sensor);

 /* Valid check */
 if (!((reg >> KIRKWOOD_THERMAL_VALID_OFFSET) &
     KIRKWOOD_THERMAL_VALID_MASK))
  return -EIO;

 /*
 * Calculate temperature. According to Marvell internal
 * documentation the formula for this is:
 * Celsius = (322-reg)/1.3625
 */
 reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) &
  KIRKWOOD_THERMAL_TEMP_MASK;
 *temp = ((3220000000UL - (10000000UL * reg)) / 13625);

 return 0;
}

static const struct thermal_zone_device_ops ops = {
 .get_temp = kirkwood_get_temp,
};

static const struct of_device_id kirkwood_thermal_id_table[] = {
 { .compatible = "marvell,kirkwood-thermal" },
 {}
};

static int kirkwood_thermal_probe(struct platform_device *pdev)
{
 struct thermal_zone_device *thermal = NULL;
 struct kirkwood_thermal_priv *priv;
 int ret;

 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 if (!priv)
  return -ENOMEM;

 priv->sensor = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
 if (IS_ERR(priv->sensor))
  return PTR_ERR(priv->sensor);

 thermal = thermal_tripless_zone_device_register("kirkwood_thermal",
       priv, &ops, NULL);
 if (IS_ERR(thermal)) {
  dev_err(&pdev->dev,
   "Failed to register thermal zone device\n");
  return PTR_ERR(thermal);
 }
 ret = thermal_zone_device_enable(thermal);
 if (ret) {
  thermal_zone_device_unregister(thermal);
  dev_err(&pdev->dev, "Failed to enable thermal zone device\n");
  return ret;
 }

 platform_set_drvdata(pdev, thermal);

 return 0;
}

static void kirkwood_thermal_exit(struct platform_device *pdev)
{
 struct thermal_zone_device *kirkwood_thermal =
  platform_get_drvdata(pdev);

 thermal_zone_device_unregister(kirkwood_thermal);
}

MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table);

static struct platform_driver kirkwood_thermal_driver = {
 .probe = kirkwood_thermal_probe,
 .remove = kirkwood_thermal_exit,
 .driver = {
  .name = "kirkwood_thermal",
  .of_match_table = kirkwood_thermal_id_table,
 },
};

module_platform_driver(kirkwood_thermal_driver);

MODULE_AUTHOR("Nobuhiro Iwamatsu ");
MODULE_DESCRIPTION("kirkwood thermal driver");
MODULE_LICENSE("GPL");