ARM: OMAP: Make OMAP clocksource source selection runtime

Quoted 31 lines · Jon

Hi Vaibhav,

Quoted 27 lines · Vaibhav Hiremath

Current OMAP code supports couple of clocksource options based on compilation flag (CONFIG_OMAP_32K_TIMER). The 32KHz sync-timer and a gptimer which can run on 32KHz or system clock (e.g 38.4 MHz)

This patch series cleans up the existing 32k-sync timer implementation, movind SoC init code to respective files (mach-omap1/timer32k.c and mach-omap2/timer.c) and uses kernel parameter to override the default clocksource of "counter_32k", also in order to support some OMAP based derivative SoCs like AM33XX which doesn't have 32K sync-timer hardware IP, adds hwmod lookup for omap2+ devices, and if lookup fails then fall back to gp-timer.

if(use_gptimer_clksrc == true)

	gptimer clocksource init;
else if (counter_32 init == false)
	/* Fallback to gptimer */
	gptimer clocksource init(;

With this, we should be able to support multi-omap boot including devices with/without 32k-sync timer.

This patch-series has been boot tested on AM37xEVM platform, it would be helpful if somebody help me to validate it on OMAP1/2 platforms.

The patches are also available at (based on linux-omap/master) -
https://github.com/hvaibhav/am335x-linux 32ksync-timer-cleanup

Quoted 2 lines

I was testing on OMAP4 and I found that the gptimer was always being set by default. I noticed that currently the HWMOD for counter_32k on OMAP4 is commented and hence was not being found. Please can you include the following with your series?

The 32kcounter hwmod entry is already enabled in linux-omap/master branch.

Your baseline looks pretty old to me, are you not using linux-omap/master?