On 2025-05-02 13:34:47+0800, Sung-Chi Li via B4 Relay wrote:
> From: Sung-Chi Li <lschyi@xxxxxxxxxxxx>
>
> Register fans connected under EC as thermal cooling devices as well, so
> these fans can then work with the thermal framework.
>
> During the driver probing phase, we will also try to register each fan
> as a thermal cooling device based on previous probe result (whether the
> there are fans connected on that channel, and whether EC supports fan
> control). The basic get max state, get current state, and set current
> state methods are then implemented as well.
>
> Signed-off-by: Sung-Chi Li <lschyi@xxxxxxxxxxxx>
> ---
> Documentation/hwmon/cros_ec_hwmon.rst | 2 ++
> drivers/hwmon/cros_ec_hwmon.c | 66 +++++++++++++++++++++++++++++++++++
> 2 files changed, 68 insertions(+)
>
> diff --git a/Documentation/hwmon/cros_ec_hwmon.rst b/Documentation/hwmon/cros_ec_hwmon.rst
> index 5b802be120438732529c3d25b1afa8b4ee353305..82c75bdaf912a116eaafa3149dc1252b3f7007d2 100644
> --- a/Documentation/hwmon/cros_ec_hwmon.rst
> +++ b/Documentation/hwmon/cros_ec_hwmon.rst
> @@ -27,3 +27,5 @@ Fan and temperature readings are supported. PWM fan control is also supported if
> the EC also supports setting fan PWM values and fan mode. Note that EC will
> switch fan control mode back to auto when suspended. This driver will restore
> the fan state before suspended.
> +If a fan is controllable, this driver will register that fan as a cooling device
> +in the thermal framework as well.
> diff --git a/drivers/hwmon/cros_ec_hwmon.c b/drivers/hwmon/cros_ec_hwmon.c
> index c5e42e2a03a0c8c68d3f8afbb2bb45b93a58b955..abfcf44fb7505189124e78c651b0eb1e0533b4e8 100644
> --- a/drivers/hwmon/cros_ec_hwmon.c
> +++ b/drivers/hwmon/cros_ec_hwmon.c
> @@ -13,6 +13,7 @@
> #include <linux/platform_device.h>
> #include <linux/platform_data/cros_ec_commands.h>
> #include <linux/platform_data/cros_ec_proto.h>
> +#include <linux/thermal.h>
Needs a dependency on CONFIG_THERMAL.
> #include <linux/types.h>
> #include <linux/units.h>
>
> @@ -27,6 +28,11 @@ struct cros_ec_hwmon_priv {
> u8 manual_fan_pwm_values[EC_FAN_SPEED_ENTRIES];
> };
>
> +struct cros_ec_hwmon_cooling_priv {
> + struct cros_ec_hwmon_priv *hwmon_priv;
> + u8 index;
> +};
> +
> static int cros_ec_hwmon_read_fan_speed(struct cros_ec_device *cros_ec, u8 index, u16 *speed)
> {
> int ret;
> @@ -300,6 +306,34 @@ static const struct hwmon_channel_info * const cros_ec_hwmon_info[] = {
> NULL
> };
>
> +static int
> +cros_ec_hwmon_cooling_get_max_state(struct thermal_cooling_device *cdev,
> + unsigned long *val)
> +{
> + *val = 255;
> + return 0;
> +}
> +
> +static int cros_ec_hwmon_cooling_get_cur_state(struct thermal_cooling_device *cdev,
> + unsigned long *val)
> +{
> + const struct cros_ec_hwmon_cooling_priv *priv = cdev->devdata;
> + u8 read_val;
> + int ret = cros_ec_hwmon_read_pwm_value(priv->hwmon_priv->cros_ec, priv->index, &read_val);
Split declaration and assignment.
> +
> + if (ret == 0)
> + *val = read_val;
> + return ret;
> +}
> +
> +static int cros_ec_hwmon_cooling_set_cur_state(struct thermal_cooling_device *cdev,
> + unsigned long val)
> +{
> + const struct cros_ec_hwmon_cooling_priv *priv = cdev->devdata;
> +
> + return cros_ec_hwmon_write_pwm_input(priv->hwmon_priv->cros_ec, priv->index, val);
> +}
> +
> static const struct hwmon_ops cros_ec_hwmon_ops = {
> .read = cros_ec_hwmon_read,
> .read_string = cros_ec_hwmon_read_string,
> @@ -307,6 +341,12 @@ static const struct hwmon_ops cros_ec_hwmon_ops = {
> .is_visible = cros_ec_hwmon_is_visible,
> };
>
> +static const struct thermal_cooling_device_ops cros_ec_thermal_cooling_ops = {
> + .get_max_state = cros_ec_hwmon_cooling_get_max_state,
> + .get_cur_state = cros_ec_hwmon_cooling_get_cur_state,
> + .set_cur_state = cros_ec_hwmon_cooling_set_cur_state,
> +};
Move this directly after the definition of the functions.
> +
> static const struct hwmon_chip_info cros_ec_hwmon_chip_info = {
> .ops = &cros_ec_hwmon_ops,
> .info = cros_ec_hwmon_info,
> @@ -374,6 +414,31 @@ static bool cros_ec_hwmon_probe_fan_control_supported(struct cros_ec_device *cro
> is_cros_ec_cmd_fulfilled(cros_ec, EC_CMD_THERMAL_AUTO_FAN_CTRL, 2);
> }
>
> +static void cros_ec_hwmon_register_fan_cooling_devices(struct device *dev,
> + struct cros_ec_hwmon_priv *priv)
> +{
> + struct cros_ec_hwmon_cooling_priv *cpriv;
> + size_t i;
if (!IS_ENABLED(CONFIG_THERMAL))
return;
> +
> + if (!priv->fan_control_supported)
> + return;
> +
> + for (i = 0; i < EC_FAN_SPEED_ENTRIES; i++) {
> + if (!(priv->usable_fans & BIT(i)))
> + continue;
> +
> + cpriv = devm_kzalloc(dev, sizeof(*cpriv), GFP_KERNEL);
> + if (!cpriv)
> + return;
> +
> + cpriv->hwmon_priv = priv;
> + cpriv->index = i;
> + devm_thermal_of_cooling_device_register(
> + dev, NULL, devm_kasprintf(dev, GFP_KERNEL, "cros-ec-fan%zu", i), cpriv,
What happens for multiple/chained ECs? If both provide sensors the
thermal device names will collide.
Error handling for devm_kasprintf() is missing.
> + &cros_ec_thermal_cooling_ops);
Error handling for devm_thermal_of_cooling_device_register() is missing.
> + }
> +}
> +
> static int cros_ec_hwmon_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> @@ -402,6 +467,7 @@ static int cros_ec_hwmon_probe(struct platform_device *pdev)
> cros_ec_hwmon_probe_fans(priv);
> priv->fan_control_supported =
> cros_ec_hwmon_probe_fan_control_supported(priv->cros_ec);
> + cros_ec_hwmon_register_fan_cooling_devices(dev, priv);
>
> hwmon_dev = devm_hwmon_device_register_with_info(dev, "cros_ec", priv,
> &cros_ec_hwmon_chip_info, NULL);
>
> --
> 2.49.0.906.g1f30a19c02-goog
>
>
