Felipe Balbi [off-list ref] writes:

On Wed, Sep 30, 2015 at 11:58:16PM +0200, Arnd Bergmann wrote:

quoted

On Wednesday 30 September 2015 09:12:09 Felipe Balbi wrote:

quoted

On Wed, Sep 30, 2015 at 10:15:25AM +0200, Arnd Bergmann wrote:

quoted

On Tuesday 29 September 2015 15:44:06 Felipe Balbi wrote:

quoted

All devices should have a default status. Ignoring
the arguments if it should be 'okay' or 'disabled'
by default, let's set them all the 'disabled' and
have boards enable 32k counter.

Signed-off-by: Felipe Balbi <redacted>

The patch looks good, but the description is slightly incorrect:
There is no reason to list "status='okay'" other than overriding
the 'disabled' status.

I'd phrase it something like:

"We want the use of the 32k counter to be a per-board setting,
so let's disable it by default in each dtsi file and override the
setting in the boards. Any board that does not wire up the counter
should leave it disabled".

However, if you really want all boards to provide the counter all
the time, I'd argue that we're better off dropping this patch. We
use the status="disabled" trick for anything that may or may not
be working based on the board design, but things that are present
everywhere don't need this.

okay, so here's the thing. While fiddling with the 32k counter, I noticed
that even though there was no status listed, the thing still initializes
fine. However, when moving 32k to drivers/clocksource and using
CLOCKSOURCE_OF_DECLARE(), 32k would *NOT* probe unless I had an explicit
status = "okay" in DT.

Very strange, that sounds like a bug in the clocksource probe code.
Can you check how this happens?

seems like something overwrites counter's status field, here's a snippet of boot
log:

[    0.000000] ===> counter is available ??
[    0.000000] ===> no status -> TRUE!!
[    0.000000] ===> searching for timer
[    0.000000] ===> timer is available ??
[    0.000000] ===> no status -> TRUE!!
[    0.000005] sched_clock: 64 bits at 1000MHz, resolution 1ns, wraps every 4398046511103ns
[    0.000014] clocksource: arm_global_timer: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns
[    0.000047] ===> searching for timer
[    0.000051] ===> timer is available ??
[    0.000054] ===> no status -> TRUE!!
[    0.000307] ===> searching for counter
[    0.000311] ===> counter is available ??
[    0.000315] ===> counter status disabled
[    0.000318] ====> counter NOT available

note that first time around counter had no status and later it got a status
disabled from somewhere.

found it. arch/arm/mach-omap2/timer.c is the culprit:

/**
 * omap_get_timer_dt - get a timer using device-tree
 * @match	- device-tree match structure for matching a device type
 * @property	- optional timer property to match
 *
 * Helper function to get a timer during early boot using device-tree for use
 * as kernel system timer. Optionally, the property argument can be used to
 * select a timer with a specific property. Once a timer is found then mark
 * the timer node in device-tree as disabled, to prevent the kernel from
 * registering this timer as a platform device and so no one else can use it.
 */
static struct device_node * __init omap_get_timer_dt(const struct of_device_id *match,
						     const char *property)
{
	struct device_node *np;

	for_each_matching_node(np, match) {
		if (!of_device_is_available(np))
			continue;

		if (property && !of_get_property(np, property, NULL))
			continue;

		if (!property && (of_get_property(np, "ti,timer-alwon", NULL) ||
				  of_get_property(np, "ti,timer-dsp", NULL) ||
				  of_get_property(np, "ti,timer-pwm", NULL) ||
				  of_get_property(np, "ti,timer-secure", NULL)))
			continue;

		of_add_property(np, &device_disabled);
		return np;
	}

	return NULL;
}

I'll patch this up and drop $subject

-- 
balbi
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