#include <linux/device.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <soc/bcm2835/raspberrypi-firmware.h>
#define UNDERVOLTAGE_STICKY_BIT BIT(16)
struct rpi_hwmon_data {
struct device *hwmon_dev;
struct rpi_firmware *fw;
u32 valid_inputs;
u32 last_throttled;
struct delayed_work get_values_poll_work;
};
static const char * const rpi_hwmon_labels[] = {
"core",
"sdram_c",
"sdram_i",
"sdram_p",
};
static void rpi_firmware_get_throttled(struct rpi_hwmon_data *data)
{
u32 new_uv, old_uv, value;
int ret;
value = 0xffff;
ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED,
&value, sizeof(value));
if (ret) {
dev_err_once(data->hwmon_dev, "Failed to get throttled (%d)\n",
ret);
return;
}
new_uv = value & UNDERVOLTAGE_STICKY_BIT;
old_uv = data->last_throttled & UNDERVOLTAGE_STICKY_BIT;
data->last_throttled = value;
if (new_uv == old_uv)
return;
if (new_uv)
dev_crit(data->hwmon_dev, "Undervoltage detected!\n");
else
dev_info(data->hwmon_dev, "Voltage normalised\n");
hwmon_notify_event(data->hwmon_dev, hwmon_in, hwmon_in_lcrit_alarm, 0);
}
static int rpi_firmware_get_voltage(struct rpi_hwmon_data *data, u32 id,
long *val)
{
struct rpi_firmware_get_voltage_request packet =
RPI_FIRMWARE_GET_VOLTAGE_REQUEST(id);
int ret;
ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_VOLTAGE,
&packet, sizeof(packet));
if (ret)
return ret;
*val = le32_to_cpu(packet.value) / 1000;
return 0;
}
static void get_values_poll(struct work_struct *work)
{
struct rpi_hwmon_data *data;
data = container_of(work, struct rpi_hwmon_data,
get_values_poll_work.work);
rpi_firmware_get_throttled(data);
schedule_delayed_work(&data->get_values_poll_work, 2 * HZ);
}
static void rpi_hwmon_cancel_poll_work(void *res)
{
struct rpi_hwmon_data *data = res;
disable_delayed_work_sync(&data->get_values_poll_work);
}
static int rpi_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
struct rpi_hwmon_data *data = dev_get_drvdata(dev);
if (type == hwmon_in) {
switch (attr) {
case hwmon_in_input:
switch (channel) {
case 0:
return rpi_firmware_get_voltage(data,
RPI_FIRMWARE_VOLT_ID_CORE,
val);
case 1:
return rpi_firmware_get_voltage(data,
RPI_FIRMWARE_VOLT_ID_SDRAM_C,
val);
case 2:
return rpi_firmware_get_voltage(data,
RPI_FIRMWARE_VOLT_ID_SDRAM_I,
val);
case 3:
return rpi_firmware_get_voltage(data,
RPI_FIRMWARE_VOLT_ID_SDRAM_P,
val);
default:
return -EOPNOTSUPP;
}
case hwmon_in_lcrit_alarm:
if (channel == 0) {
*val = !!(data->last_throttled & UNDERVOLTAGE_STICKY_BIT);
return 0;
}
return -EOPNOTSUPP;
default:
return -EOPNOTSUPP;
}
}
return -EOPNOTSUPP;
}
static int rpi_read_string(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, const char **str)
{
if (type == hwmon_in && attr == hwmon_in_label) {
if (channel >= ARRAY_SIZE(rpi_hwmon_labels))
return -EOPNOTSUPP;
*str = rpi_hwmon_labels[channel];
return 0;
}
return -EOPNOTSUPP;
}
static umode_t rpi_is_visible(const void *_data, enum hwmon_sensor_types type,
u32 attr, int channel)
{
const struct rpi_hwmon_data *data = _data;
if (type == hwmon_in) {
switch (attr) {
case hwmon_in_input:
case hwmon_in_label:
if (!(data->valid_inputs & BIT(channel)))
return 0;
return 0444;
case hwmon_in_lcrit_alarm:
if (channel == 0)
return 0444;
return 0;
default:
return 0;
}
}
return 0;
}
static const struct hwmon_channel_info * const rpi_info[] = {
HWMON_CHANNEL_INFO(in,
HWMON_I_INPUT | HWMON_I_LABEL | HWMON_I_LCRIT_ALARM,
HWMON_I_INPUT | HWMON_I_LABEL,
HWMON_I_INPUT | HWMON_I_LABEL,
HWMON_I_INPUT | HWMON_I_LABEL),
NULL
};
static const struct hwmon_ops rpi_hwmon_ops = {
.is_visible = rpi_is_visible,
.read = rpi_read,
.read_string = rpi_read_string,
};
static const struct hwmon_chip_info rpi_chip_info = {
.ops = &rpi_hwmon_ops,
.info = rpi_info,
};
static int rpi_hwmon_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct rpi_hwmon_data *data;
long voltage;
int ret;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->fw = dev_get_drvdata(dev->parent);
ret = rpi_firmware_get_voltage(data, RPI_FIRMWARE_VOLT_ID_CORE,
&voltage);
if (!ret)
data->valid_inputs |= BIT(0);
ret = rpi_firmware_get_voltage(data, RPI_FIRMWARE_VOLT_ID_SDRAM_C,
&voltage);
if (!ret)
data->valid_inputs |= BIT(1);
ret = rpi_firmware_get_voltage(data, RPI_FIRMWARE_VOLT_ID_SDRAM_I,
&voltage);
if (!ret)
data->valid_inputs |= BIT(2);
ret = rpi_firmware_get_voltage(data, RPI_FIRMWARE_VOLT_ID_SDRAM_P,
&voltage);
if (!ret)
data->valid_inputs |= BIT(3);
data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "rpi_volt",
data,
&rpi_chip_info,
NULL);
if (IS_ERR(data->hwmon_dev))
return PTR_ERR(data->hwmon_dev);
INIT_DELAYED_WORK(&data->get_values_poll_work, get_values_poll);
ret = devm_add_action_or_reset(dev, rpi_hwmon_cancel_poll_work, data);
if (ret)
return ret;
platform_set_drvdata(pdev, data);
schedule_delayed_work(&data->get_values_poll_work, 2 * HZ);
return 0;
}
static int rpi_hwmon_suspend(struct device *dev)
{
struct rpi_hwmon_data *data = dev_get_drvdata(dev);
cancel_delayed_work_sync(&data->get_values_poll_work);
return 0;
}
static int rpi_hwmon_resume(struct device *dev)
{
struct rpi_hwmon_data *data = dev_get_drvdata(dev);
get_values_poll(&data->get_values_poll_work.work);
return 0;
}
static DEFINE_SIMPLE_DEV_PM_OPS(rpi_hwmon_pm_ops, rpi_hwmon_suspend,
rpi_hwmon_resume);
static struct platform_driver rpi_hwmon_driver = {
.probe = rpi_hwmon_probe,
.driver = {
.name = "raspberrypi-hwmon",
.pm = pm_ptr(&rpi_hwmon_pm_ops),
},
};
module_platform_driver(rpi_hwmon_driver);
MODULE_AUTHOR("Stefan Wahren <wahrenst@gmx.net>");
MODULE_AUTHOR("Shubham Chakraborty <chakrabortyshubham66@gmail.com>");
MODULE_DESCRIPTION("Raspberry Pi voltage sensor driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:raspberrypi-hwmon");
