On Sat, Jul 23, 2022 at 05:38:20AM +0200, Armin Wolf wrote:
> The SMM interface does not differentiate between fan channels
> and pwm channels, so each pwmX is associated with fanX_*.
>
> Inform userspace programs of this with the pwmX_fan_channel
> attribute.
>
> Tested on a Dell Inspiron 3505.
>
> Signed-off-by: Armin Wolf <W_Armin@xxxxxx>
> ---
> Documentation/hwmon/dell-smm-hwmon.rst | 1 +
> drivers/hwmon/dell-smm-hwmon.c | 15 ++++++++++++---
> 2 files changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/hwmon/dell-smm-hwmon.rst b/Documentation/hwmon/dell-smm-hwmon.rst
> index e5d85e40972c..2b0651c3f7c5 100644
> --- a/Documentation/hwmon/dell-smm-hwmon.rst
> +++ b/Documentation/hwmon/dell-smm-hwmon.rst
> @@ -38,6 +38,7 @@ fan[1-3]_min RO Minimal Fan speed in RPM
> fan[1-3]_max RO Maximal Fan speed in RPM
> fan[1-3]_target RO Expected Fan speed in RPM
> pwm[1-3] RW Control the fan PWM duty-cycle.
> +pwm[1-3]_fan_channel RO Hints which PWM is connected to which fan
> pwm1_enable WO Enable or disable automatic BIOS fan
> control (not supported on all laptops,
> see below for details).
> diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
> index 7f8d95dd2717..e6bf65d2ffc6 100644
> --- a/drivers/hwmon/dell-smm-hwmon.c
> +++ b/drivers/hwmon/dell-smm-hwmon.c
> @@ -713,6 +713,11 @@ static umode_t dell_smm_is_visible(const void *drvdata, enum hwmon_sensor_types
> if (data->fan[channel])
> return 0644;
>
> + break;
> + case hwmon_pwm_fan_channel:
> + if (data->fan[channel])
> + return 0444;
> +
> break;
> case hwmon_pwm_enable:
> if (data->auto_fan)
> @@ -800,6 +805,10 @@ static int dell_smm_read(struct device *dev, enum hwmon_sensor_types type, u32 a
>
> *val = clamp_val(ret * data->i8k_pwm_mult, 0, 255);
>
> + return 0;
> + case hwmon_pwm_fan_channel:
> + *val = channel + 1;
> +
This effectively just returns the channel number and
thus adds adds zero value.
Guenter
> return 0;
> default:
> break;
> @@ -943,9 +952,9 @@ static const struct hwmon_channel_info *dell_smm_info[] = {
> HWMON_F_TARGET
> ),
> HWMON_CHANNEL_INFO(pwm,
> - HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
> - HWMON_PWM_INPUT,
> - HWMON_PWM_INPUT
> + HWMON_PWM_INPUT | HWMON_PWM_FAN_CHANNEL | HWMON_PWM_ENABLE,
> + HWMON_PWM_INPUT | HWMON_PWM_FAN_CHANNEL,
> + HWMON_PWM_INPUT | HWMON_PWM_FAN_CHANNEL
> ),
> NULL
> };
> --
> 2.30.2
>
