linux-kernel - Re: [PATCH RFC net 1/2] nfc: nxp-nci: Fix i2c read on ThinkPad hardware

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Message-ID: <416a90ee-7501-1014-051d-e6a3eb03a0ff@linaro.org>
Date:   Mon, 12 Jun 2023 09:15:45 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Marco Giorgi <giorgi.marco.96@...root.org>
Cc:     netdev@...r.kernel.org, u.kleine-koenig@...gutronix.de,
        davem@...emloft.net, michael@...le.cc, kuba@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC net 1/2] nfc: nxp-nci: Fix i2c read on ThinkPad
 hardware

On 11/06/2023 18:25, Marco Giorgi wrote:
> Hi Krzysztof,
> 
> On Wed, 7 Jun 2023 19:45:25 +0200
> Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org> wrote:
> 
>> On 07/06/2023 19:00, Marco Giorgi wrote:
>>> Add the IRQ GPIO configuration.  
>>
>> Why? Please include reasons in commit msg. What you are doing is quite
>> easy to see.
> 
> This is my fault, I only put the patch reason in patch [0/2].
> 
> Basically, I found out that the mainline driver is not working on my
> machine (Lenovo ThinkPad T590).
> 
> I suspect that the I2C read IRQ is somehow misconfigured, and it
> triggers even when the NFC chip is not ready to be read, resulting in
> an error.

Isn't this then a problem of your I2C controller?

> 
> In this patch [1/2], I'm adding the "IRQ" GPIO to the driver so its
> value can be directly read from the IRQ thread.

What is IRQ GPIO? If this is interrupt line, you are not handling it
correctly. This is quite surprising code.

> 
> In patch [2/2], I'm safely returning from the IRQ thread when the IRQ
> GPIO is not active.
> 


Best regards,
Krzysztof