Re: [lm-sensors] [PATCH] hwmon: pwm-fan: Add pwm-fan driver

[Guenter Roeck <linux@roeck-us.net>]

Hi Kamil,

On 07/10/2014 08:17 AM, Kamil Debski wrote:
>
>>
>>> +	}
>>> +
>>> +	dev_set_drvdata(&pdev->dev, ctx);
>>> +	platform_set_drvdata(pdev, ctx);
>>> +
>>> +	/* Set duty cycle to maximum allowed */
>>> +	ctx->duty_cycle = ctx->pwm->period - 1;
>>> +	ctx->pwm_value = MAX_PWM;
>>> +	pwm_config(ctx->pwm, ctx->duty_cycle, ctx->pwm->period);
>
> Guenter, I have a question regarding this. I see that gpio-fan reads
> the state of gpios and uses this as the initial setting.
> Led-pwm on init sets the brightness to LED_OFF.
>
> What should be the default state after init? Should the fan be off or
> at full power? I am thinking about adding an optional node to device
> tree that could be used to set this. But the question remains - what
> should be the default setting?
>

Trick question ... I can not really answer it. you can try the devicetree
option, but be prepared to have it rejected - the usual argument is that
dt shall only describe the HW but not its configuration.

Ultimately, either way is fine with me.

Guenter