linux-kernel - Re: [PATCH] i2c: ACPI: Replace acpi_bus_get

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Message-ID: <CAJZ5v0jFBFKMcjYieYCL1LTvRPuM7b8_5nBx0_wnPtobzg==fw@mail.gmail.com>
Date:   Tue, 1 Feb 2022 20:01:46 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Wolfram Sang <wsa@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux ACPI <linux-acpi@...r.kernel.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        linux-i2c <linux-i2c@...r.kernel.org>
Subject: Re: [PATCH] i2c: ACPI: Replace acpi_bus_get_device()

On Tue, Feb 1, 2022 at 7:44 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Tue, Feb 01, 2022 at 07:00:42PM +0100, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >
> > Replace acpi_bus_get_device() that is going to be dropped with
> > acpi_fetch_acpi_dev().
> >
> > No intentional functional impact.
>
> ...
>
> > +     if (!adev || i2c_acpi_get_info(adev, &info, adapter, NULL))
>
> AFAICS the !adev check is redundant since acpi_device_enumerated() does it.

No.

acpi_device_enumerated() returns false if adev is NULL, so without
this extra check i2c_acpi_get_info() will end up passing NULL to
i2c_acpi_do_lookup().

> >               return AE_OK;
>
> ...
>
> > +     struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
> >
> > -     if (i2c_acpi_do_lookup(adev, lookup))
> > +     if (!adev || i2c_acpi_do_lookup(adev, lookup))
> >               return AE_OK;
>
> Here we need it indeed.
> Dunno, if acpi_dev_ready_for_enumeration() can gain the check itself.

Well, acpi_bus_get_status() would need it too.