[PATCH v4] clk: bcm2835: Add support for programming the audio domain clocks.
eric at anholt.net
Tue Oct 6 18:24:44 PDT 2015
Stefan Wahren <info at lategoodbye.de> writes:
> Hi Eric,
> Am 02.10.2015 um 21:54 schrieb Eric Anholt:
>> This adds support for enabling, disabling, and setting the rate of the
>> audio domain clocks. It will be necessary for setting the pixel clock
>> for HDMI in the VC4 driver and let us write a cpufreq driver. It will
>> also improve compatibility with user changes to the firmware's
>> config.txt, since our previous fixed clocks are unaware of it.
>> The firmware also has support for configuring the clocks through the
>> mailbox channel, but the pixel clock setup by the firmware doesn't
>> work, and it's Raspberry Pi specific anyway. The only conflicts we
>> should have with the firmware would be if we made firmware calls that
>> result in clock management (like opening firmware V3D or ISP access,
>> which we don't support in upstream), or on hardware over-thermal or
>> under-voltage (when the firmware would rewrite PLLB to take the ARM
>> out of overclock). If that happens, our cached .recalc_rate() results
>> would be incorrect, but that's no worse than our current state where
>> we used fixed clocks.
>> The existing fixed clocks in the code are left in place to provide
>> backwards compatibility with old device tree files.
> only a few nits.
I think I've done all of these now, sending out v5.
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