linux-kernel - Re: [PATCH v2] usb: typec: qcom: check regulator enable status before disabling it

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Message-ID: <64f5f891-b0ba-b2a9-9756-39464d1cacc9@linaro.org>
Date:   Mon, 28 Aug 2023 10:43:19 +0100
From:   Bryan O'Donoghue <bryan.odonoghue@...aro.org>
To:     hui liu <quic_huliu@...cinc.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc:     Guenter Roeck <linux@...ck-us.net>, Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, quic_fenglinw@...cinc.com,
        subbaram@...cinc.com
Subject: Re: [PATCH v2] usb: typec: qcom: check regulator enable status before
 disabling it

On 28/08/2023 06:51, hui liu wrote:
> 
> 
> On 8/25/2023 6:11 PM, Bryan O'Donoghue wrote:
>> On 25/08/2023 11:03, hui liu wrote:
>>> Hi Heikki,
>>>
>>> I will let Bryan to comment, I am using the driver to support the 
>>> pdphy in SMB2352 and there is no external regulator required, so I am 
>>> just using a dummy regulator device and I saw this unbalanced 
>>> regulator disabling warnings, so my intention for this change is just 
>>> fixing the warning message. However, I am fine with whatever 
>>> suggestion you have, since the logic is straightforward, and I can 
>>> make the changes once you have the agreement.
>>>
>>> Thanks,
>>> Hui
>>
>> Err well on real hardware with a real regulator I don't see this error.
> Just a doublt, if real regulator has no this error, who enabled it 
> before it was reseted?

adb/xbl most likely i.e. the bootloader

If you think about it, be it on an embedded dev board or on a phone, 
enabling the type-c port -> regulator that goes with it, would be common 
practice, especially if you boot the board, as I do via USB to begin with.

>>
>> I'd say we should try the second proposed changed in pdphy_start 
>> pdphy_stop since it looks neater.
>>
> I updated the code refer to the proposal, and it worked well,but I just 
> thought it makes code a little redundant. Why don't we only keep one 
> pdphy_enable/pdphy_disable or pdphy_start/pdphy_stop?

Not sure I follow you there.

We should have only one regulator enable/disable in pdphy_start and 
pdphy_stop per my understanding.

https://lore.kernel.org/linux-arm-msm/9574a219-3abf-b2c9-7d90-e79d364134bb@linaro.org/

---
bod