[PATCH 1/2] spi: bcm2835: add spi-bcm2835aux driver for the auxiliar spi1 and spi2

Martin Sperl kernel at martin.sperl.org
Mon Jun 22 08:26:42 PDT 2015

> On 22.06.2015, at 16:55, Jakub Kiciński <moorray3 at wp.pl> wrote:
> As mentioned by Noralf UART1 is quite commonly used on Compute Modules.
> Proper driver - perhaps modelled as a bus - seems like a prerequisite
> for this work.  You are also not using IRQ mux in DT binding example
> which is very misleading.

Well - there is no support far for uart1 in upstream as of now.
And I am not even sure if the compute module is supported as there
is no device tree available in upstream for that...

So I have taken the simple route of using shared interrupts and providing
a minimal framework to enable the spi1/spi2 hw blocks with proper locking.
And I have mentioned that it would need to get modified when uart1 support
comes along.

If you know of a better solution how to control this and that also
incorporates a patch to enable uart1, then please share it!

Just modify the bcm2835aux_spi_enable/disable to use a different framework
than just bcm2835_aux_modify_enable.

The patch Noralf mentions only applies downstream and only sets the
enable-register during the boot sequence, so it would not impact the
solution as is.

> Do we have any indication weather this AUX hardware is available on
> RPi2 as well?  IIRC bcm2836 differs only in CPU cores, peripherals
> remain identical.  Perhaps this driver could be used on RPi2 and
> naming it 283x would be more appropriate?

I have not checked, but I would guess that it exists.

As for naming: I have asked around and bcm2835aux seemed fine.
Also if we go that route we should start renaming ALL driver instances that
contain 2835.

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