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/* Lantiq cpu temperature sensor driver
*
* Copyright (C) 2017 Florian Eckert <fe@dev.tdt.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version
*
* 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
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>
*/
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <lantiq_soc.h>
/* gphy1 configuration register contains cpu temperature */
#define CGU_GPHY1_CR 0x0040
#define CGU_TEMP_PD BIT(19)
static void ltq_cputemp_enable(void)
{
ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) | CGU_TEMP_PD, CGU_GPHY1_CR);
}
static void ltq_cputemp_disable(void *data)
{
ltq_cgu_w32(ltq_cgu_r32(CGU_GPHY1_CR) & ~CGU_TEMP_PD, CGU_GPHY1_CR);
}
static int ltq_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *temp)
{
int value;
switch (attr) {
case hwmon_temp_input:
/* get the temperature including one decimal place */
value = (ltq_cgu_r32(CGU_GPHY1_CR) >> 9) & 0x01FF;
value = value * 5;
/* range -38 to +154 °C, register value zero is -38.0 °C */
value -= 380;
/* scale temp to millidegree */
value = value * 100;
break;
default:
return -EOPNOTSUPP;
}
*temp = value;
return 0;
}
static umode_t ltq_is_visible(const void *_data, enum hwmon_sensor_types type,
u32 attr, int channel)
{
if (type != hwmon_temp)
return 0;
switch (attr) {
case hwmon_temp_input:
return 0444;
default:
return 0;
}
}
static const struct hwmon_channel_info *ltq_info[] = {
HWMON_CHANNEL_INFO(chip,
HWMON_C_REGISTER_TZ),
HWMON_CHANNEL_INFO(temp,
HWMON_T_INPUT),
NULL
};
static const struct hwmon_ops ltq_hwmon_ops = {
.is_visible = ltq_is_visible,
.read = ltq_read,
};
static const struct hwmon_chip_info ltq_chip_info = {
.ops = <q_hwmon_ops,
.info = ltq_info,
};
static int ltq_cputemp_probe(struct platform_device *pdev)
{
struct device *hwmon_dev;
int err = 0;
/* available on vr9 v1.2 SoCs only */
if (ltq_soc_type() != SOC_TYPE_VR9_2)
return -ENODEV;
err = devm_add_action(&pdev->dev, ltq_cputemp_disable, NULL);
if (err)
return err;
ltq_cputemp_enable();
hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
"ltq_cputemp",
NULL,
<q_chip_info,
NULL);
if (IS_ERR(hwmon_dev)) {
dev_err(&pdev->dev, "Failed to register as hwmon device");
return PTR_ERR(hwmon_dev);
}
return 0;
}
const struct of_device_id ltq_cputemp_match[] = {
{ .compatible = "lantiq,cputemp" },
{},
};
MODULE_DEVICE_TABLE(of, ltq_cputemp_match);
static struct platform_driver ltq_cputemp_driver = {
.probe = ltq_cputemp_probe,
.driver = {
.name = "ltq-cputemp",
.of_match_table = ltq_cputemp_match,
},
};
module_platform_driver(ltq_cputemp_driver);
MODULE_AUTHOR("Florian Eckert <fe@dev.tdt.de>");
MODULE_DESCRIPTION("Lantiq cpu temperature sensor driver");
MODULE_LICENSE("GPL");
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