linux-kernel - Re: [PATCH] extcon: Add documentation for EXTCON_CHG_USB_SLOW/FAST

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Message-ID: <CAGTfZH3x_Ts4Ef5t6oVoOojpqQcZeWguPWDdnJ-xnpwiz8Uu=w@mail.gmail.com>
Date:   Tue, 3 Jan 2017 21:48:09 +0900
From:   Chanwoo Choi <cwchoi00@...il.com>
To:     Baolin Wang <baolin.wang@...aro.org>
Cc:     "myungjoo.ham@...sung.com" <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Mark Brown <broonie@...nel.org>,
        linaro-kernel@...ts.linaro.org,
        linux-kernel <linux-kernel@...r.kernel.org>, neilb@...e.com
Subject: Re: [PATCH] extcon: Add documentation for EXTCON_CHG_USB_SLOW/FAST

Hi Baolin,

2017-01-03 14:50 GMT+09:00 Baolin Wang <baolin.wang@...aro.org>:
> Currently there are no documentation for EXTCON_CHG_USB_SLOW/FAST
> charger connector. These names don't mean much and no guide to tell
> users how to use it, thus try to add documentation to make them clear.
>
> Suggested-by: NeilBrown <neilb@...e.com>
> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
> ---
>  include/linux/extcon.h |    4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/include/linux/extcon.h b/include/linux/extcon.h
> index 0020123..ceec1f0 100644
> --- a/include/linux/extcon.h
> +++ b/include/linux/extcon.h
> @@ -53,6 +53,10 @@
>   * the USB connector, which means EXTCON_CHG_USB_SDP should always
>   * appear together with EXTCON_USB. The same as ACA charger connector,
>   * EXTCON_CHG_USB_ACA would normally appear with EXTCON_USB_HOST.
> + *
> + * A cable of type EXTCON_CHG_USB_SLOW can provide at least 500mA of
> + * current at 5V. A cable of type EXTCON_CHG_USB_FAST can provide at
> + * least 1A of current at 5V.

I agree the at least current value(mA) for EXTCON_CHG_USB_SLOW/FAST.
But, I'm worried that  fix the 5V.

I have a plan to support the 'current' and 'voltage' property for
charger connector as following:
- EXTCON_PROP_CHG_CURRNET
- EXTCON_PROP_CHG_VOLTAGE

So, I don't like to fix the voltage for EXTCON_CHG_USB_SLOW/FAST.
How about this?

>   */
>  #define EXTCON_CHG_USB_SDP     5       /* Standard Downstream Port */
>  #define EXTCON_CHG_USB_DCP     6       /* Dedicated Charging Port */
> --
> 1.7.9.5
>
> _______________________________________________
> linaro-kernel mailing list
> linaro-kernel@...ts.linaro.org
> https://lists.linaro.org/mailman/listinfo/linaro-kernel

-- 
Best Regards,
Chanwoo Choi

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