Re: [PATCH 2/3] mfd: cros_ec: Create sysfs attributes for the ChromeOS EC.

From: Javier Martinez Canillas
Date: Fri Nov 21 2014 - 13:40:36 EST


Hello Bill,

On 11/20/2014 07:16 PM, Bill Richardson wrote:
>>
>> I don't really know why there are two interfaces for this but I guess
>> that different user-space utilities use one or another. Maybe the
>> ChromiumOS folks can comment on this.
>
> The /dev/cros_ec interface responds to ioctls and is the primary means
> by which userspace applications talk to the EC (replacing three really
> awkward bus-specific libraries). It emits a simplified version string
> when read so that humans can tell if the EC is alive and speaking the
> same protocol that the userspace app expects.
>
> The /sys/class/chromeos/cros_ec/* tree was originally envisioned as a
> way to provide additional human-readable interfaces to a subset of the
> EC commands, but except for the lightbar it's not often used. The
> version component here shows all the version-related info that the EC
> can provide.
>

Got it, thanks a lot for the explanation.

Best regards,
Javier


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