if_cgem: Rewrite clock part

[manu]

Summary

• pclk and hclk are mandatory so always try to get them. Don't make it fatal if it fails as some platform (like Zynq) don't have a proper clock driver.
• Always use pclk for the reference clock.
• Try to get all the possible clocks and enable them.

Sponsored by: Beckhoff Automation GmbH & Co. KG

[mhorne]

Seems good to me. It will be a couple of weeks before I have the chance to test on riscv.

This and the other review is to cope with DTS changes I guess?

sys/dev/cadence/if_cgem.c

1750

1756–1760

Consider adding braces like this, or making the second part an else if.

1885

style(9) preferred here, and below.

[manu]

In D41857#954479, @mhorne wrote:

Seems good to me. It will be a couple of weeks before I have the chance to test on riscv.

I won't mfc before a month or two so this will give you (and others) to test on riscv.

This and the other review is to cope with DTS changes I guess?

No this is just me doing zynqmp bringup and looking at all the drivers :)

sys/dev/cadence/if_cgem.c

1756–1760

Will do before commit.

1885

Will change before commit

[bsd_dino.sk]

Tested on Zybo Z7 with sources from June 1st, 2023 and patch applied (partially) manually, system boots and everything seems to work as before. (First chunk - I forgot to apply D41856 first, my bad.)
Test on riscv64 (Microchip PolarFire SoC) should not be problem, just more time is necessary to prepare and conduct the test :(