Re: [PATCH v3 1/2] hwmon: (lm90) Add power control

From: Wei Ni
Date: Tue Sep 10 2013 - 07:29:01 EST


On 09/10/2013 06:13 PM, Mark Brown wrote:
> * PGP Signed by an unknown key
>
> On Tue, Sep 10, 2013 at 01:39:59PM +0800, Wei Ni wrote:
>
>> I think the device need time to wait stable after power on, but it's
>> difficult to get an exact delay value, and this delay may also relate
>> with platform design, so how about to add a optional property in the DT
>> node, such as "power-on-delay-ms" ?
>
> This is something you should *really* be able to get from the datasheet
> for the part - this sort of stuff has to be documented for hardware to
> be used robustly. It seems entirely possible that you are working
> around an issue with the regulator driver you are using not correctly
> providing its ramp time here.

On my platform, it use palmas-regulator.c, ldo6 for this lm90 power
rail. I checked this driver, it will handle ramp_delay except LDOx.
Since I'm not familiar with this palmas device and driver, so do you
mean I can set regulator-ramp-delay property in the DT for ldo6, but I
really don't know what value should I set :(

Thanks.
Wei.

>
> * Unknown Key
> * 0x7EA229BD
>

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