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

From: Guenter Roeck
Date: Thu Jul 10 2014 - 12:17:32 EST

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.


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