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// SPDX-License-Identifier: GPL-2.0-only
/*
* sl67mcu hardware monitoring driver
*
* Copyright 2025 Kontron Europe GmbH
*/
#include <linux/bitfield.h>
#include <linux/hwmon.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>
#define SA67MCU_VOLTAGE(n) (0x00 + ((n) * 2))
#define SA67MCU_TEMP(n) (0x04 + ((n) * 2))
struct sa67mcu_hwmon {
struct regmap *regmap;
u32 offset;
};
static int sa67mcu_hwmon_read(struct device *dev,
enum hwmon_sensor_types type, u32 attr,
int channel, long *input)
{
struct sa67mcu_hwmon *hwmon = dev_get_drvdata(dev);
unsigned int offset;
u8 reg[2];
int ret;
switch (type) {
case hwmon_in:
switch (attr) {
case hwmon_in_input:
offset = hwmon->offset + SA67MCU_VOLTAGE(channel);
break;
default:
return -EOPNOTSUPP;
}
break;
case hwmon_temp:
switch (attr) {
case hwmon_temp_input:
offset = hwmon->offset + SA67MCU_TEMP(channel);
break;
default:
return -EOPNOTSUPP;
}
break;
default:
return -EOPNOTSUPP;
}
/* Reading the low byte will capture the value */
ret = regmap_bulk_read(hwmon->regmap, offset, reg, ARRAY_SIZE(reg));
if (ret)
return ret;
*input = reg[1] << 8 | reg[0];
/* Temperatures are s16 and in 0.1degC steps. */
if (type == hwmon_temp)
*input = sign_extend32(*input, 15) * 100;
return 0;
}
static const struct hwmon_channel_info * const sa67mcu_hwmon_info[] = {
HWMON_CHANNEL_INFO(in,
HWMON_I_INPUT | HWMON_I_LABEL,
HWMON_I_INPUT | HWMON_I_LABEL),
HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
NULL
};
static const char *const sa67mcu_hwmon_in_labels[] = {
"VDDIN",
"VDD_RTC",
};
static int sa67mcu_hwmon_read_string(struct device *dev,
enum hwmon_sensor_types type, u32 attr,
int channel, const char **str)
{
switch (type) {
case hwmon_in:
switch (attr) {
case hwmon_in_label:
*str = sa67mcu_hwmon_in_labels[channel];
return 0;
default:
return -EOPNOTSUPP;
}
default:
return -EOPNOTSUPP;
}
}
static const struct hwmon_ops sa67mcu_hwmon_ops = {
.visible = 0444,
.read = sa67mcu_hwmon_read,
.read_string = sa67mcu_hwmon_read_string,
};
static const struct hwmon_chip_info sa67mcu_hwmon_chip_info = {
.ops = &sa67mcu_hwmon_ops,
.info = sa67mcu_hwmon_info,
};
static int sa67mcu_hwmon_probe(struct platform_device *pdev)
{
struct sa67mcu_hwmon *hwmon;
struct device *hwmon_dev;
int ret;
if (!pdev->dev.parent)
return -ENODEV;
hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
if (!hwmon)
return -ENOMEM;
hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
if (!hwmon->regmap)
return -ENODEV;
ret = device_property_read_u32(&pdev->dev, "reg", &hwmon->offset);
if (ret)
return -EINVAL;
hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
"sa67mcu_hwmon", hwmon,
&sa67mcu_hwmon_chip_info,
NULL);
if (IS_ERR(hwmon_dev))
dev_err(&pdev->dev, "failed to register as hwmon device");
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct of_device_id sa67mcu_hwmon_of_match[] = {
{ .compatible = "kontron,sa67mcu-hwmon", },
{}
};
MODULE_DEVICE_TABLE(of, sa67mcu_hwmon_of_match);
static struct platform_driver sa67mcu_hwmon_driver = {
.probe = sa67mcu_hwmon_probe,
.driver = {
.name = "sa67mcu-hwmon",
.of_match_table = sa67mcu_hwmon_of_match,
},
};
module_platform_driver(sa67mcu_hwmon_driver);
MODULE_DESCRIPTION("sa67mcu Hardware Monitoring Driver");
MODULE_AUTHOR("Michael Walle <mwalle@kernel.org>");
MODULE_LICENSE("GPL");
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