linux-kernel - Re: [PATCH 1/2] i2c: consider devices with of_match

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Message-ID: <20200826100935.GB8849@jagdpanzerIV.localdomain>
Date:   Wed, 26 Aug 2020 19:09:35 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Wolfram Sang <wsa@...nel.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        linux-i2c@...r.kernel.org, linux-acpi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] i2c: consider devices with of_match_table during i2c
 device probing

On (20/08/26 12:53), Andy Shevchenko wrote:
> On Wed, Aug 26, 2020 at 02:25:44PM +0900, Sergey Senozhatsky wrote:
> > On (20/08/26 07:08), Wolfram Sang wrote:
> > > On Wed, Aug 26, 2020 at 01:29:37PM +0900, Sergey Senozhatsky wrote:
[..]

> > > > i2c_of_match_device() depends on CONFIG_OF and, thus, is always false.
> > > > i2c_acpi_match_device() does ACPI match only, no of_comtatible() matching
> > > > takes place, even though the device provides .of_match_table and ACPI,
> > > > technically, is capable of matching such device. The result is -ENODEV.
> > > > Probing will succeed, however, if we'd use .of_match_table aware ACPI
> > > > matching.
> 
> Looks like you read same StackOverflow question :-)

Nope :) Ran into actual media/i2c driver probing issue several days ago

[..]
> >         if (!driver->id_table &&
> > -           !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
> > -           !i2c_of_match_device(dev->driver->of_match_table, client)) {
> > +           !(client && i2c_device_match(&client->dev, dev->driver))) {
> 
> You probably meant simply:
> 
> 	if (!i2c_device_match(dev, dev->driver)) {
> 
> >                 status = -ENODEV;
> >                 goto put_sync_adapter;
> >         }

That's shorter, yes. I wanted to keep the existing "workaround" in order
to avoid extra id_table matching. Because it probably will take place
earlier somewhere in

	bus_for_each_dev()
	 __driver_attach()
	  i2c_device_match()  // OF ACPI id_table match

> On the first glance it will work the same way but slightly longer in case of ID
> table matching.

Right.

	-ss