Baolin Wang <[email protected]> writes: > [ text/plain ] > On 31 March 2016 at 16:18, Felipe Balbi <[email protected]> wrote: >> >> Hi, >> >> Baolin Wang <[email protected]> writes: >>>>>>> +#define DEFAULT_SDP_CUR_LIMIT (500 - DEFAULT_CUR_PROTECT) >>>>>> >>>>>> According to the spec we should always be talking about unit loads (1 >>>>>> unit load is 100mA for HS/FS/LS and 150mA for SS). Also, this will not >>>>>> work for SS capable ports and SS gadgets (we have quite a few of them, >>>>>> actually). You're missing the opportunity of charging at 900mA. >>>>> >>>>> I follow the DCP/SDP/CDP/ACA type's default current limitation and >>>>> user can set them what they want. >>>> >>>> no, the user CANNOT set it to what they want. If you get enumerated >>>> @100mA and the user just decides to set it to 2000mA, s/he could even >>>> melt the USB connector. The kernel _must_ prevent such cases. >>>> >>>> In any case, DEFAULT_SDP_CUR_LIMIT shouldn't be a constant, it should be >>>> variable because if you enumerate in SS, you _can_ get up to 900mA. >>> >>> Make sense. But these are just default values. They can be changed >>> safely by power driver with 'usb_charger_set_cur_limit_by_type()' >>> function to set 900mA. >> >> oh okay. Still, the default value should be a function of gadget->speed, > > Sorry, I did not get your suggestion, could you give me an example? Thanks.
int default_current_limit = 500;
if (gadget->speed >= USB_SPEED_SUPER)
default_current_limit = 900;
>>>>>>> +
>>>>>>> +/* USB charger state */
>>>>>>> +enum usb_charger_state {
>>>>>>> + USB_CHARGER_DEFAULT,
>>>>>>> + USB_CHARGER_PRESENT,
>>>>>>> + USB_CHARGER_REMOVE,
>>>>>>> +};
>>>>>>
>>>>>> userland really doesn't need these two ?
>>>>>
>>>>> We've reported to userspace by kobject_uevent in
>>>>> 'usb_charger_notify_others()' function.
>>>>
>>>> I mean as a type ;-) So userspace doesn't have to redefine these for
>>>> their applications.
>>>
>>> Make sense. I can introduce some sysfs files for userspace. Thanks for
>>> your comments.
>>
>> okay, my reply was a bit cryptic, but what I mean here is that enum
>> usb_charger_state could be moved your include/uapi header. My question
>> is, then, does userland need to have knowledge of enum
>> usb_charger_state ?
>
> I am not sure if userland need the enum usb_charger_state. But I
> remember you want to report the charger state to userland in previous
> email.
right, which means this enumeration definition could be placed in the
UAPI header. Unless, of course, we're reporting strings, rather than
integers, in the sysfs file.
--
balbi
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