A13 - How to set APB1 clock rate

[workwind]

Is it possible to change the APB1 clock rate from 24MHz to PLL62 speed (360 MHz)?
I want to speed up serial baud rate...

[JohnS]

The A13 is a variant of other Ax chips so go through the various datasheets etc e.g. on linux-sunxi.org and see what else would be affected.

You can find the code fairly easily I expect - maybe try changing uboot to see what happens.

My guess is it's a non-starter but that's just a guess.

John

[workwind]

Hi John,

only the UART and TWI interfaces depend on APB1...

The following (local kernel) function (arch/arm/mach-sun7i/clock/sys_clk.c) should do it:
sys_clk_set_parent(AW_SYS_CLK_APB1, AW_SYS_CLK_PLL62)

My question is how can this be achieved, is it a configuration option? Is there a function or device which can be called from user context? Is there a clean way?

The registers are also changed from the power-management in arch/arm/mach-sun7i/pm/standby/standby_clock.c ...

Nils

[JohnS]

It's in flux because Linux is moving to DT.

You can wait for that or just dive in and change some code.

John