Re: [PATCH v12 2/4] gadget: Support for the usb charger framework

Baolin Wang
2016-06-29T08:31:22Z

Hi Felipe,

On 29 June 2016 at 16:20, Felipe Balbi <balbi@kernel.org> wrote:
>
> Hi,
>
> Baolin Wang <baolin.wang@linaro.org> writes:
>>> Baolin Wang <baolin.wang@linaro.org> writes:
>>>> For supporting the usb charger, it adds the usb_charger_init() and
>>>> usb_charger_exit() functions for usb charger initialization and exit.
>>>>
>>>> It will report to the usb charger when the gadget state is changed,
>>>> then the usb charger can do the power things.
>>>>
>>>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
>>>> Reviewed-by: Li Jun <jun.li@nxp.com>
>>>> Tested-by: Li Jun <jun.li@nxp.com>
>>>
>>> Before anything, I must say that I really liked this patch. It's
>>> minimaly invasive to udc core and does all the necessary changes. If it
>>> wasn't for the extra charger class, this would've been perfect.
>>>
>>> Can't you just tie a charger to a UDC and avoid the charger class
>>> completely?
>>>
>>>> static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
>>>> {
>>>> + if (gadget->charger)
>>>
>>> I guess you could do this check inside
>>> usb_gadget_set_cur_limit_by_type() itself.
>>
>> We will access the 'gadget->charger->type' member when issuing
>> usb_gadget_set_cur_limit_by_type(), so I think I should leave the
>> check here in next new version.
>
> Here's what I mean:
>
> int usb_charger_set_cur_limit(struct usb_gadget *gadget, unsigned int mA)
> {
> struct usb_charger *charger;
> enum usb_charger_type type;
>
> if (!gadget->charger)
> return 0;
>
> charger = gadget->charger;
> type = charger->type;
>
> return __usb_charger_set_cur_limit(charger, type, mA);
> }

But that means we need to export both 'usb_charger_set_cur_limit()'
function and '__usb_charger_set_cur_limit()' function in charger.c
file. Cause some user may want to set the current limitation by one
charger type parameter (may be not from charger->type), like by
issuing '__usb_charger_set_cur_limit(charger, SDP_TYPE, mA)'. How do
you think about this situation? Thanks.

>
> static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
> {
> usb_charger_set_cur_limit(gadget, mA);
>
> if (!gadget->ops->vbus_draw)
> return -EOPNOTSUPP;
> return gadget->ops->vbus_draw(gadget, mA);
> }
>
> --
> balbi

--
Baolin.wang
Best Regards