linux-kernel - Re: [PATCH] extcon: usbc-tusb320: Call the Type-C IRQ handler only if a port is registered

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Message-ID: <f0e80866-9f7c-4a95-3dbc-c2950162c703@denx.de>
Date:   Mon, 7 Nov 2022 16:25:47 +0100
From:   Marek Vasut <marex@...x.de>
To:     Yassine Oudjana <yassine.oudjana@...il.com>
Cc:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Alvin Šipraga <alsi@...g-olufsen.dk>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Yassine Oudjana <y.oudjana@...tonmail.com>
Subject: Re: [PATCH] extcon: usbc-tusb320: Call the Type-C IRQ handler only if
 a port is registered

On 11/7/22 16:02, Yassine Oudjana wrote:
> 
> On Mon, Nov 7 2022 at 15:51:55 +01:00:00, Marek Vasut <marex@...x.de> 
> wrote:
>> On 11/7/22 15:48, Yassine Oudjana wrote:
>>> From: Yassine Oudjana <y.oudjana@...tonmail.com>
>>>
>>> Commit bf7571c00dca ("extcon: usbc-tusb320: Add USB TYPE-C support")
>>> added an optional Type-C interface to the driver but missed to check
>>> if it is in use when calling the IRQ handler. This causes an oops on
>>> devices currently using the old extcon interface. Check if a Type-C
>>> port is registered before calling the Type-C IRQ handler.
>>>
>>> Fixes: bf7571c00dca ("extcon: usbc-tusb320: Add USB TYPE-C support")
>>> Signed-off-by: Yassine Oudjana <y.oudjana@...tonmail.com>
>>> ---
>>>   drivers/extcon/extcon-usbc-tusb320.c | 9 ++++++++-
>>>   1 file changed, 8 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/extcon/extcon-usbc-tusb320.c 
>>> b/drivers/extcon/extcon-usbc-tusb320.c
>>> index 41041ff0fadb..037bc11b2a48 100644
>>> --- a/drivers/extcon/extcon-usbc-tusb320.c
>>> +++ b/drivers/extcon/extcon-usbc-tusb320.c
>>> @@ -327,7 +327,14 @@ static irqreturn_t tusb320_irq_handler(int irq, 
>>> void *dev_id)
>>>           return IRQ_NONE;
>>>         tusb320_extcon_irq_handler(priv, reg);
>>> -    tusb320_typec_irq_handler(priv, reg);
>>> +
>>> +    /*
>>> +     * Type-C support is optional for backward compatibility.
>>
>> It's the other way around, extcon is the legacy, type-c is the new, 
>> right ?
> 
> Type-C is the new one, yes. This comment is somewhat similar to the one 
> in tusb320_typec_probe():
> 
> /* The Type-C connector is optional, for backward compatibility. */

Ahhh, The Type-C connector support is indeed optional to avoid breaking 
any of the older systems which only use/provide extcon.

> Perhaps a better way to say this in both comments would be "to maintain" 
> instead of "for".

I think best just drop the "for backward compatibility" altogether, like so:

/*
  * Type-C support is optional. Only call the Type-C handler if a
  * port had been registered previously.
  */