Re: [RESEND PATCH] usb: common: usb-conn-gpio: Register optional charger

[Paul Cercueil]

Hi Greg,

Le mar. 21 juil. 2020 à 13:41, Greg Kroah-Hartman 
<gregkh@xxxxxxxxxxxxxxxxxxx> a écrit :
> On Mon, Jun 22, 2020 at 12:48:07AM +0200, Paul Cercueil wrote:
> >  Register a power supply charger, if the Kconfig option
> >  USB_CONN_GPIO_CHARGER is set, whose online state depends on whether
> >  the USB role is set to device or not.
> >
> >  This is useful when the USB role is the only way to know if the 
> > device
> >  is charging from USB. The API is the standard power supply charger 
> > API,
> >  you get a /sys/class/power_supply/xxx/online node which tells you 
> > the
> >  state of the charger.
> >
> >  The sole purpose of this is to give userspace applications a way to
> >  know whether or not the charger is plugged.
> >
> >  Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> >  ---
> >   drivers/usb/common/Kconfig         | 11 +++++++
> >   drivers/usb/common/usb-conn-gpio.c | 47 
> > ++++++++++++++++++++++++++++++
> >   2 files changed, 58 insertions(+)
> >
> >  diff --git a/drivers/usb/common/Kconfig b/drivers/usb/common/Kconfig
> >  index d611477aae41..5405ae96c68f 100644
> >  --- a/drivers/usb/common/Kconfig
> >  +++ b/drivers/usb/common/Kconfig
> >  @@ -49,3 +49,14 @@ config USB_CONN_GPIO
> >
> >   	  To compile the driver as a module, choose M here: the module 
> > will
> >   	  be called usb-conn-gpio.ko
> >  +
> >  +if USB_CONN_GPIO
> >  +
> >  +config USB_CONN_GPIO_CHARGER
> >  +	bool "USB charger support"
> >  +	select POWER_SUPPLY
> >  +	help
> >  +	  Register a charger with the power supply subsystem. This will 
> > allow
> >  +	  userspace to know whether or not the device is charging from 
> > USB.
>
> Why make this an option at all?  Why wouldn't we always want this 
> here?
>
> As this is a charger, exporting that information to userspace should
> probably always happen, right?

I wanted to avoid the hardcoded dependency on CONFIG_POWER_SUPPLY.

I can very well make that non-optional.

Cheers,
-Paul

> thanks,
>
> greg k-h