ARM: bcm2835: Switch to using the new clock driver support.
This will give us the ability to set the pixel and HDMI state machine clocks for the VC4 KMS driver, change the CPU frequency, and potentially gate clocks in the future (once we also write a power domain driver). It also gives the uart an explicit clock reference, so that we don't need to change the physical addresses of the old fixed clk_bcm2835.c clocks for Raspberry Pi 2 port. Two clocks get their frequencies updated as a result of this. One is uart's apb_pclk, which was previously accidentally grabbing the fixed uart0_pclk due to the apb_pclk not having clk_register_clkdev() called. The uart doesn't seem to do anything with apb_pclk other than make sure it's on, so that appears safe (also, as far as I can see, the apb clock is actually the same as the VPU clock). The other is EMMC, which according to the docs was supposed to be in the 50-100Mhz range, but it turns out the firmware needed to change to running it at the 250Mhz core clock speed to avoid a bug in clock domain crossing. Additionally, anything using BCM2835_CLOCK_VPU will now have a correct clock rate if the user configures the boot-time core clock speed using config.txt. Signed-off-by: Eric Anholt <eric@anholt.net> Acked-by: Stephen Warren <swarren@wwwdotorg.org>
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