Re: [PATCH v2] extcon-intel-cht-wc: Don't reset USB data connection at probe

Chanwoo Choi
2019-09-20T07:37:50Z

Hi Andy,

On 19. 9. 18. 오후 4:17, Andy Shevchenko wrote:
> On Wed, Sep 18, 2019 at 2:04 AM Yauhen Kharuzhy <jekhor@gmail.com> wrote:
>>
>> On Tue, Sep 17, 2019 at 02:13:22PM +0300, Andy Shevchenko wrote:
>>> On Tue, Sep 17, 2019 at 12:15:36AM +0300, Yauhen Kharuzhy wrote:
>>>> Intel Cherry Trail Whiskey Cove extcon driver connect USB data lines to
>>>> PMIC at driver probing for further charger detection. This causes reset of
>>>> USB data sessions and removing all devices from bus. If system was
>>>> booted from Live CD or USB dongle, this makes system unusable.
>>>>
>>>> Check if USB ID pin is floating and re-route data lines in this case
>>>> only, don't touch otherwise.
>>>
>>>> + ret = regmap_read(ext->regmap, CHT_WC_PWRSRC_STS, &pwrsrc_sts);
>>>> + if (ret) {
>>>> + dev_err(ext->dev, "Error reading pwrsrc status: %d\n", ret);
>>>> + goto disable_sw_control;
>>>> + }
>>>> +
>>>> + id = cht_wc_extcon_get_id(ext, pwrsrc_sts);
>>>
>>> We have second implementation of this. Would it make sense to split to some
>>> helper?
>>
>> Do you mean the combination of regmap_read(...CHT_WC_PWRSRC_STS,
>> &pwrsrc_sts) with cht_wc_extcon_get_id()?
>
> Yes.
>
>> In the cht_wc_extcon_pwrsrc_event() function the pwrsrc_sts is checked
>> for other bits also, so separation of PWRSRC_STS read and id calculation
>> to one routine will cause non-clear function calls like as
>> get_powersrc_and_check_id(..., &powersrc_sts, &id) which is not looks
>> better than current code duplication.
>
> I see. Thanks for answer.
>
>> Or we need to spend some time for
>> refactoring and testing of cht_wc_extcon_pwrsrc_event() code.
>
> Perhaps, In any case I'm not objecting of the current approach.
>

If you think it is OK, could you reply with your tag?
and I'll fix the multi-line comment by myself.

--
Best Regards,
Chanwoo Choi
Samsung Electronics