[PATCH v5 0/6] bcm2835: auxiliar device support for spi

Eric Anholt eric at anholt.net
Wed Sep 9 11:27:24 PDT 2015


Alexander Stein <alexanders83 at web.de> writes:

> Hi,
> On Tuesday 08 September 2015 18:48:07, Eric Anholt wrote:
>> I finally had a chance to sit down and look at what the hardware's doing
>> with the enable bit (also, I've read a whole lot more of the hardware
>> now, so I'm a lot faster at answering questions like this).  The enable
>> bits are a clock gate off of the VPU clock.
>
> Are any hardware documents about such things available (in public)?

Nope, I just went through the HDL to see how things were routed.

>> I knocked together the enable bits as a clock gate driver, since I'd
>> just written very similar code for the audio domain clock driver (and I
>> assume you are grumpy about how much time you've spent on this one
>> stupid register).  It's up at
>> https://github.com/anholt/linux/tree/bcm2835-clock-aux and I can submit
>> it if you like the result.  I've compile tested it only, but I'm hoping
>> you could just drop your aux SPI driver on top of it and have things
>> work.
>
> IMHO line 45 (https://github.com/anholt/linux/commit/facb4ba917a1b9f6c2ee0cea7d529acf55f584dd#diff-1b6f753c132811b3f6d70f5b31866950R45) should be like this
>> onecell->clks = kzalloc(sizeof(*onecell->clks) * BCM2835_AUX_CLOCK_COUNT, GFP_KERNEL);
> or you will only allocate a single struct clk*.

Thanks, that was a bug in my other clock driver, too!
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