Re: [PATCH] arm64: dts: marvell: add unique identifiers for Armada A8k SPI controllers

Marcin Wojtas
2016-11-08T16:52:53Z

Hi Thomas,

2016-11-08 17:48 GMT+01:00 Thomas Petazzoni
<thomas.petazzoni@free-electrons.com>:
> Hello,
>
> On Tue, 8 Nov 2016 17:31:32 +0100, Marcin Wojtas wrote:
>> Enabling SPI controllers, which are attached to different busses
>> inside an SoC, may result in overlapping enumeration and cause
>> sysfs registration failure. Example log after enabling two
>> controllers on Armada 8040 SoC with same identifiers:
>>
>> [ 3.740415] sysfs: cannot create duplicate filename
>> '/class/spi_master/spi0'
>> [ 3.747510] ------------[ cut here ]------------
>> [ 3.752145] WARNING: at fs/sysfs/dir.c:31
>> [...]
>> [ 4.002299] orion_spi: probe of f4700600.spi failed with error -17
>>
>> spi-orion driver offers dedicated DT property ('cell-index'), that
>> allow setting unique identifiers. Recently added support for CP110-slave
>> HW block introduced two new SPI controllers' nodes with same ID as
>> ones from CP110-master.
>>
>> This commit fixes the issue by assigning different 'cell-index' values
>> for CP110-slave SPI controllers.
>>
>> Fixes: 4eef78a0091b ("arm64: dts: marvell: add description for the slave
>> CP110 in Armada 8K")
>> Signed-off-by: Marcin Wojtas <mw@semihalf.com>
>
> It's sad that we need to hardcode those indexes in the Device Tree
> (which by no means are a description of the HW by the way), but that's
> what the SPI framework expects I believe.

Right. Devices are enumerated by generic code beginning from '0' on
each bus (AP806, CP110-master, CP110-slave) independently and
I didn't see any nice solution for it either.

> Therefore:
>
> Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
>

Thanks,
Marcin