serial: clk: bcm2835: Strange effects when using aux-uart in console

Martin Sperl martin at
Fri Feb 12 03:56:09 PST 2016

> On 11.02.2016, at 18:55, Stefan Wahren <stefan.wahren at> wrote:
> I think the reason for this behavior can be found in the uart-pl011 driver which
> plays with the clocks.
I will look into the why and share what I find...

> According to the clock tree "plld" seems to be critical and shouldn't be
> disabled?

Then we may need to avoid this - but as far as I can tell
the amba-pl011 driver only disables the clock in error cases
(or when shutting down).
Maybe we just need to disable the shutdown of the plld?

>> Is this maybe related to the uart0_pclk, uart1_pclk, apb_pclk
>> clocks created and registered in bcm2835_init_clocks?
> Related or not i think we should get the rid off them.

A quick test shows that an empty bcm2835_init_clocks
does not change the basic kernel-boot behavior and everything
seems to work.

So we probably should remove it in:
* arch/arm/mach-bcm/board_bcm2835.c (call)
* drivers/clk/bcm/clk-bcm2835.c (function definition)


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