--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ChromeOS EC driver for hwmon
+ *
+ * Copyright (C) 2024 Thomas Weißschuh <linux@weissschuh.net>
+ */
+
+#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;
+
+ 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 <linux@weissschuh.net");
+MODULE_LICENSE("GPL");
projects / thirdparty / kernel / linux.git / commitdiff
