// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ChromeOS EC driver for hwmon
*
* Copyright (C) 2024 Thomas Weißschuh <[email protected]>
*/
#include <linux/device.h>
#include <linux/hwmon.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/types.h>
#include <linux/units.h>
#define DRV_NAME "cros-ec-hwmon"
struct cros_ec_hwmon_priv {
struct cros_ec_device *cros_ec;
const char *temp_sensor_names[EC_TEMP_SENSOR_ENTRIES + EC_TEMP_SENSOR_B_ENTRIES];
u8 usable_fans;
};
static int cros_ec_hwmon_read_fan_speed(struct cros_ec_device *cros_ec, u8 index, u16 *speed)
{
int ret;
__le16 __speed;
ret = cros_ec_cmd_readmem(cros_ec, EC_MEMMAP_FAN + index * 2, 2, &__speed);
if (ret < 0)
return ret;
*speed = le16_to_cpu(__speed);
return 0;
}
static int cros_ec_hwmon_read_temp(struct cros_ec_device *cros_ec, u8 index, u8 *temp)
{
unsigned int offset;
int ret;
if (index < EC_TEMP_SENSOR_ENTRIES)
offset = EC_MEMMAP_TEMP_SENSOR + index;
else
offset = EC_MEMMAP_TEMP_SENSOR_B + index - EC_TEMP_SENSOR_ENTRIES;
ret = cros_ec_cmd_readmem(cros_ec, offset, 1, temp);
if (ret < 0)
return ret;
return 0;
}
static bool cros_ec_hwmon_is_error_fan(u16 speed)
{
return speed == EC_FAN_SPEED_NOT_PRESENT || speed == EC_FAN_SPEED_STALLED;
}
static bool cros_ec_hwmon_is_error_temp(u8 temp)
{
return temp == EC_TEMP_SENSOR_NOT_PRESENT ||
temp == EC_TEMP_SENSOR_ERROR ||
temp == EC_TEMP_SENSOR_NOT_POWERED ||
temp == EC_TEMP_SENSOR_NOT_CALIBRATED;
}
static long cros_ec_hwmon_temp_to_millicelsius(u8 temp)
{
return kelvin_to_millicelsius((((long)temp) + EC_TEMP_SENSOR_OFFSET));
}
static int cros_ec_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
struct cros_ec_hwmon_priv *priv = dev_get_drvdata(dev);
int ret = -EOPNOTSUPP;
u16 speed;
u8 temp;
if (type == hwmon_fan) {
if (attr == hwmon_fan_input) {
ret = cros_ec_hwmon_read_fan_speed(priv->cros_ec, channel, &speed);
if (ret == 0) {
if (cros_ec_hwmon_is_error_fan(speed))
ret = -ENODATA;
else
*val = speed;
}
} else if (attr == hwmon_fan_fault) {
ret = cros_ec_hwmon_read_fan_speed(priv->cros_ec, channel, &speed);
if (ret == 0)
*val = cros_ec_hwmon_is_error_fan(speed);
}
} else if (type == hwmon_temp) {
if (attr == hwmon_temp_input) {
ret = cros_ec_hwmon_read_temp(priv->cros_ec, channel, &temp);
if (ret == 0) {
if (cros_ec_hwmon_is_error_temp(temp))
ret = -ENODATA;
else
*val = cros_ec_hwmon_temp_to_millicelsius(temp);
}
} else if (attr == hwmon_temp_fault) {
ret = cros_ec_hwmon_read_temp(priv->cros_ec, channel, &temp);
if (ret == 0)
*val = cros_ec_hwmon_is_error_temp(temp);
}
}
return ret;
}
static int cros_ec_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, const char **str)
{
struct cros_ec_hwmon_priv *priv = dev_get_drvdata(dev);
if (type == hwmon_temp && attr == hwmon_temp_label) {
*str = priv->temp_sensor_names[channel];
return 0;
}
return -EOPNOTSUPP;
}
static umode_t cros_ec_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
u32 attr, int channel)
{
const struct cros_ec_hwmon_priv *priv = data;
if (type == hwmon_fan) {
if (priv->usable_fans & BIT(channel))
return 0444;
} else if (type == hwmon_temp) {
if (priv->temp_sensor_names[channel])
return 0444;
}
return 0;
}
static const struct hwmon_channel_info * const cros_ec_hwmon_info[] = {
HWMON_CHANNEL_INFO(fan,
HWMON_F_INPUT | HWMON_F_FAULT,
HWMON_F_INPUT | HWMON_F_FAULT,
HWMON_F_INPUT | HWMON_F_FAULT,
HWMON_F_INPUT | HWMON_F_FAULT),
HWMON_CHANNEL_INFO(temp,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL,
HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_LABEL),
NULL
};
static const struct hwmon_ops cros_ec_hwmon_ops = {
.read = cros_ec_hwmon_read,
.read_string = cros_ec_hwmon_read_string,
.is_visible = cros_ec_hwmon_is_visible,
};
static const struct hwmon_chip_info cros_ec_hwmon_chip_info = {
.ops = &cros_ec_hwmon_ops,
.info = cros_ec_hwmon_info,
};
static void cros_ec_hwmon_probe_temp_sensors(struct device *dev, struct cros_ec_hwmon_priv *priv,
u8 thermal_version)
{
struct ec_params_temp_sensor_get_info req = {};
struct ec_response_temp_sensor_get_info resp;
size_t candidates, i, sensor_name_size;
int ret;
u8 temp;
if (thermal_version < 2)
candidates = EC_TEMP_SENSOR_ENTRIES;
else
candidates = ARRAY_SIZE(priv->temp_sensor_names);
for (i = 0; i < candidates; i++) {
if (cros_ec_hwmon_read_temp(priv->cros_ec, i, &temp) < 0)
continue;
if (temp == EC_TEMP_SENSOR_NOT_PRESENT)
continue;
req.id = i;
ret = cros_ec_cmd(priv->cros_ec, 0, EC_CMD_TEMP_SENSOR_GET_INFO,
&req, sizeof(req), &resp, sizeof(resp));
if (ret < 0)
continue;
sensor_name_size = strnlen(resp.sensor_name, sizeof(resp.sensor_name));
priv->temp_sensor_names[i] = devm_kasprintf(dev, GFP_KERNEL, "%.*s",
(int)sensor_name_size,
resp.sensor_name);
}
}
static void cros_ec_hwmon_probe_fans(struct cros_ec_hwmon_priv *priv)
{
u16 speed;
size_t i;
int ret;
for (i = 0; i < EC_FAN_SPEED_ENTRIES; i++) {
ret = cros_ec_hwmon_read_fan_speed(priv->cros_ec, i, &speed);
if (ret == 0 && speed != EC_FAN_SPEED_NOT_PRESENT)
priv->usable_fans |= BIT(i);
}
}
static int cros_ec_hwmon_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
struct cros_ec_device *cros_ec = ec_dev->ec_dev;
struct cros_ec_hwmon_priv *priv;
struct device *hwmon_dev;
u8 thermal_version;
int ret;
ret = cros_ec_cmd_readmem(cros_ec, EC_MEMMAP_THERMAL_VERSION, 1, &thermal_version);
if (ret < 0)
return ret;
/* Covers both fan and temp sensors */
if (thermal_version == 0)
return -ENODEV;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->cros_ec = cros_ec;
cros_ec_hwmon_probe_temp_sensors(dev, priv, thermal_version);
cros_ec_hwmon_probe_fans(priv);
hwmon_dev = devm_hwmon_device_register_with_info(dev, "cros_ec", priv,
&cros_ec_hwmon_chip_info, NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct platform_device_id cros_ec_hwmon_id[] = {
{ DRV_NAME, 0 },
{}
};
static struct platform_driver cros_ec_hwmon_driver = {
.driver.name = DRV_NAME,
.probe = cros_ec_hwmon_probe,
.id_table = cros_ec_hwmon_id,
};
module_platform_driver(cros_ec_hwmon_driver);
MODULE_DEVICE_TABLE(platform, cros_ec_hwmon_id);
MODULE_DESCRIPTION("ChromeOS EC Hardware Monitoring Driver");
MODULE_AUTHOR("Thomas Weißschuh <[email protected]");
MODULE_LICENSE("GPL");
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