linux-kernel - Re: [PATCH v2 2/2] extcon: ptn5150: Set the VBUS and POLARITY property state

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Message-ID: <55514836-b9cf-e937-b5d5-eb0535d98334@samsung.com>
Date:   Thu, 27 Aug 2020 14:35:20 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     vadivel.muruganx.ramuthevar@...ux.intel.com,
        linux-kernel@...r.kernel.org
Cc:     vijaikumar.kanagarajan@...il.com, krzk@...nel.org,
        myungjoo.ham@...sung.com, heikki.krogerus@...ux.intel.com,
        cheol.yong.kim@...el.com, qi-ming.wu@...el.com, yin1.li@...el.com
Subject: Re: [PATCH v2 2/2] extcon: ptn5150: Set the VBUS and POLARITY
 property state

Hi,

On 8/27/20 2:17 PM, Ramuthevar, Vadivel MuruganX wrote:
> Hi,
> 
> On 27/8/2020 12:51 pm, Chanwoo Choi wrote:
>> Hi,
>>
>> You better to change the 'state' word to 'capability'.
>> Actually, this patch doesn't change the value of property.
>> It set the capability value of property.
>>
>> "Set the VBUS and POLARITY property capability"
> Thank you for the review comments, sure will update.
>>
>> On 8/27/20 12:56 PM, Ramuthevar,Vadivel MuruganX wrote:
>>> From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@...ux.intel.com>
>>>
>>> Set the VBUS and POLARITY property state.
>>
>> ditto. Need to change the work from 'state' and 'capability'.
> Noted.
>>
>>>
>>> Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@...ux.intel.com>
>>> ---
>>>   drivers/extcon/extcon-ptn5150.c | 6 ++++++
>>>   1 file changed, 6 insertions(+)
>>>
>>> diff --git a/drivers/extcon/extcon-ptn5150.c b/drivers/extcon/extcon-ptn5150.c
>>> index 8b930050a3f1..b5217a61615c 100644
>>> --- a/drivers/extcon/extcon-ptn5150.c
>>> +++ b/drivers/extcon/extcon-ptn5150.c
>>> @@ -279,6 +279,12 @@ static int ptn5150_i2c_probe(struct i2c_client *i2c)
>>>           return ret;
>>>       }
>>>   +    extcon_set_property_capability(info->edev, EXTCON_USB,
>>> +                       EXTCON_PROP_USB_VBUS);
>>> +    extcon_set_property_capability(info->edev, EXTCON_USB_HOST,
>>> +                       EXTCON_PROP_USB_VBUS);
>>> +    extcon_set_property_capability(info->edev, EXTCON_USB_HOST,
>>> +                       EXTCON_PROP_USB_TYPEC_POLARITY);
>>
>> Need to add blank line.
> Noted.
>>
>> I understood that you set the property capability
>> because of get_flipped() function of your patch[1].
>>
>> But, I think that you need to change the value of EXTCON_PROP_USB_TYPEC_POLARITY
>> when changing the state of EXTCON_USB_HOST. The polarity property value is always
>> zero regardless of EXTCON_USB_HOST state as following: The get_flipped()[1] returns
>> always the same *flipped value.
>>
>>     EXTCON_USB_HOST is 1, EXTCON_PROP_USB_TYPEC_POLARITY is 0
>>     EXTCON_USB_HOST is 0, EXTCON_PROP_USB_TYPEC_POLARITY is 0
> by default EXTCON_PROP_USB_TYPEC_POLARITY is 1

If you don't touch the value of EXTCON_PROP_USB_TYPEC_POLARITY property,
EXTCON_PROP_USB_TYPEC_POLARITY has default value (0).

>>
>> If EXTCON_PROP_USB_TYPEC_POLARITY value is not related to any behavior,
>> you don't need to get the property value from extcon consumer driver
>> like drivers/phy/phy-lgm-usb.c.
>>
>> Actually, I don't understand why you don't handle the value
>> of EXTCON_PROP_USB_TYPEC_POLARITY.
>>
>> Or, are there any case of what drivers/phy/phy-lgm-usb.c
>> uses the different extcon device with EXTCON_PROP_USB_TYPEC_POLARITY property
>> in the future?
> Yes, you're right, user connect the different USB cable then we check polarity, accordingly driver proceeds, thanks!

OK.

>>
>> So, do you set the EXTCON_PROP_USB_TYPEC_POLARITY capability
>> for the extensibility in order to use other extcon device on later?
> yes, that might be the case as well.

OK.

>>
>>
>> [1] https://protect2.fireeye.com/v1/url?k=1fb29698-422c0d72-1fb31dd7-0cc47a6cba04-3009aa7184024984&q=1&e=566e4565-e7db-4a90-b036-fc28dbdb742f&u=https%3A%2F%2Fwww.spinics.net%2Flists%2Fdevicetree%2Fmsg371828.html
>> +static int get_flipped(struct tca_apb *ta, bool *flipped)
>> +{
>> +    union extcon_property_value property;
>> +    int ret;
>> +
>> +    ret = extcon_get_property(ta->phy.edev, EXTCON_USB_HOST,
>> +                  EXTCON_PROP_USB_TYPEC_POLARITY, &property);
>> +    if (ret) {
>> +        dev_err(ta->phy.dev, "no polarity property from extcon\n");
>> +        return ret;
>> +    }
>> +
>> +    *flipped = property.intval;
>> +
>> +    return ret;
>> +}
> Thank you for the gone through my usb-phy patch as well
> 
> Regards
> Vadivel
>>
>>
>>>       /* Initialize PTN5150 device and print vendor id and version id */
>>>       ret = ptn5150_init_dev_type(info);
>>>       if (ret)
>>>
>>
>>
> 
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics