Subject: Re: [PATCH 01/11] ASoC: dai_dma: remove slave_id field
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Vinod Koul <vkoul@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
        Andy Gross <agross@kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Baolin Wang <baolin.wang7@gmail.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Chunyan Zhang <zhang.lyra@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Hyun Kwon <hyun.kwon@xilinx.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Jon Hunter <jonathanh@nvidia.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Laxman Dewangan <ldewangan@nvidia.com>,
        Manivannan Sadhasivam <mani@kernel.org>,
        Mark Brown <broonie@kernel.org>,
        Michal Simek <michal.simek@xilinx.com>,
        Nicolas Saenz Julienne <nsaenz@kernel.org>,
        Orson Zhai <orsonzhai@gmail.com>,
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References: <20211115085403.360194-1-arnd@kernel.org>
 <20211115085403.360194-2-arnd@kernel.org>
 <647b842d-76a1-7a96-3ea7-8a37b62bc18e@metafoo.de>
 <CAK8P3a2EVseM4t=e982fFhzBGSZxZ2_V-FHwr-fQPd-bkAKaJg@mail.gmail.com>
From:   Lars-Peter Clausen <lars@metafoo.de>
Message-ID: <d2dd42fc-e58a-0c06-7f7e-a6a2161c368d@metafoo.de>
Date:   Mon, 15 Nov 2021 12:53:39 +0100
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On 11/15/21 11:42 AM, Arnd Bergmann wrote:
> On Mon, Nov 15, 2021 at 11:14 AM Lars-Peter Clausen <lars@metafoo.de> wrote:
>> On 11/15/21 9:53 AM, Arnd Bergmann wrote:
>>> From: Arnd Bergmann <arnd@arndb.de>
>>>
>>> This field is never set, and serves no purpose, so remove it.
>> I agree that we should remove it. Its been legacy support code for a
>> while, but the description that there is no user is not right.
>>
>> The tegra20_spdif driver obviously uses it and that user is removed in
>> this patch. I think it makes sense to split that out into a separate
>> patch with a description why the driver will still work even with
>> slave_id removed. Maybe the best is to remove the whole tegra20_spdif
>> driver.
> Ok, I'll split out the tegra patch and try to come up with a better
> description for it. What I saw in that driver is it just passes down the
> slave_id number from a 'struct resource', but there is nothing in
> the kernel that sets up this resource.
>
> Do you or someone else have more information on the state of this
> driver? I can see that it does not contain any of_device_id based
> probing, so it seems that this is either dead code, the platform_device
> gets created by some other code that is no longer compatible with
> this driver.

I've looked into this a while back, when I tried to remove slave_id. And 
as far as I can tell there were never any in-tree users of this driver, 
even back when we used platform board files. Maybe somebody from Nvidia 
knows if there are out-of-tree users.

- Lars