/*
* Kirkwood thermal sensor driver
*
* Copyright (C) 2012 Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#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,
unsigned long *temp)
{
unsigned long reg;
struct kirkwood_thermal_priv *priv = thermal->devdata;
reg = readl_relaxed(priv->sensor);
/* Valid check */
if (!((reg >> KIRKWOOD_THERMAL_VALID_OFFSET) &
KIRKWOOD_THERMAL_VALID_MASK)) {
dev_err(&thermal->device,
"Temperature sensor reading not valid\n");
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 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;
struct resource *res;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->sensor = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(priv->sensor))
return PTR_ERR(priv->sensor);
thermal = thermal_zone_device_register("kirkwood_thermal", 0, 0,
priv, &ops, NULL, 0, 0);
if (IS_ERR(thermal)) {
dev_err(&pdev->dev,
"Failed to register thermal zone device\n");
return PTR_ERR(thermal);
}
platform_set_drvdata(pdev, thermal);
return 0;
}
static int kirkwood_thermal_exit(struct platform_device *pdev)
{
struct thermal_zone_device *kirkwood_thermal =
platform_get_drvdata(pdev);
thermal_zone_device_unregister(kirkwood_thermal);
return 0;
}
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",
.owner = THIS_MODULE,
.of_match_table = kirkwood_thermal_id_table,
},
};
module_platform_driver(kirkwood_thermal_driver);
MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>");
MODULE_DESCRIPTION("kirkwood thermal driver");
MODULE_LICENSE("GPL");
