linux-kernel - Re: [PATCH v6 1/5] i2c: designware: Use polling by default when there is no irq resource

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aGPXwll6Hh2cZfnp@smile.fi.intel.com>
Date: Tue, 1 Jul 2025 15:42:42 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc: Lucas De Marchi <lucas.demarchi@...el.com>,
	Thomas Hellström <thomas.hellstrom@...ux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@...el.com>,
	Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Jan Dabros <jsd@...ihalf.com>, Andi Shyti <andi.shyti@...nel.org>,
	Raag Jadav <raag.jadav@...el.com>,
	"Tauro, Riana" <riana.tauro@...el.com>,
	"Adatrao, Srinivasa" <srinivasa.adatrao@...el.com>,
	"Michael J. Ruhl" <michael.j.ruhl@...el.com>,
	intel-xe@...ts.freedesktop.org, linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 1/5] i2c: designware: Use polling by default when
 there is no irq resource

On Tue, Jul 01, 2025 at 03:22:48PM +0300, Heikki Krogerus wrote:
> The irq resource itself can be used as a generic way to
> determine when polling is needed.
> 
> This not only removes the need for special additional device
> properties that would soon be needed when the platform may
> or may not have the irq, but it also removes the need to
> check the platform in the first place in order to determine
> is polling needed or not.

> Signed-off-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
> ---
> Hi guys,
> 
> I found the thread with Jarkko's comments from my archives. He wanted
> the local flags variable to be added because he wants the order of the
> calls to remain as it is now - the device is allocated only after the
> irq is checked.

Yes, thanks.

...

> +	u32 flags = (uintptr_t)device_get_match_data(&pdev->dev);

> +	irq = platform_get_irq_optional(pdev, 0);
> +	if (irq == -ENXIO)
> +		flags |= ACCESS_POLLING;
> +	else if (irq < 0)
>  		return irq;

>  	if (device_property_present(device, "wx,i2c-snps-model"))
> +		flags = MODEL_WANGXUN_SP | ACCESS_POLLING;

Now I'm a bit puzzled why do we need to add this flag explicitly here?
Does Wnagxun provides an IRQ and chooses at the same time to poll?
Shouldn't this patch rather fix that?

-- 
With Best Regards,
Andy Shevchenko