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

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Date: Sun, 11 Jun 2023 18:43:42 +0200
From: Marco Giorgi <giorgi.marco.96@...root.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc: netdev@...r.kernel.org, u.kleine-koenig@...gutronix.de,
 davem@...emloft.net, michael@...le.cc, kuba@...nel.org
Subject: Re: [PATCH RFC net 2/2] nfc: nxp-nci: Fix i2c read on ThinkPad
 hardware

Hi Krzysztof,

On Wed, 7 Jun 2023 19:46:35 +0200
Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org> wrote:

> On 07/06/2023 19:00, Marco Giorgi wrote:
> > Read IRQ GPIO value and exit from IRQ if the device is not ready.
> 
> Why? What problem are you solving?
> 
> Why IRQ GPIO - whatever it is - means device is not ready for I2C
> transfer?

It seems that the I2C IRQ gets triggered also when the IRQ GPIO is not
active (low value).

This patch queries the IRQ GPIO before issuing the I2C read.
If the GPIO is low, the IRQ returns with IRQ_HANDLED.

I don't know why the IRQ is triggered even when the GPIO is low, I'm
still looking into it.

I've submitted this patch in the hope to get feedback from other people
to understand what's going on.

> 
> > 
> > Signed-off-by: Marco Giorgi <giorgi.marco.96@...root.org>
> > ---
> >  drivers/nfc/nxp-nci/i2c.c | 13 +++++++++++++
> >  1 file changed, 13 insertions(+)
> 
> Best regards,
> Krzysztof
> 

Thanks,
Marco.