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ARM: OMAP2+: Add device-tree support for 32kHz counter 

For OMAP devices, the 32kHz counter is the default clock-source for the kernel.
However, this is not the only possible clock-source the kernel can use for OMAP
devices.

When booting with device-tree, if the 32kHz counter is the desired clock-source
for the kernel, then parse the device-tree blob to ensure that the counter is
present and if so map memory for the counter using the device-tree of_iomap()
function so we are no longer reliant on the OMAP HWMOD framework to do this for
us.

Signed-off-by: Jon Hunter <jon-hunter@ti.com>
This commit is contained in:
Jon Hunter 2012-10-09 14:12:26 -05:00
parent 9725f4451a
commit 9883f7c8dd
1 changed files with 27 additions and 1 deletions
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28
arch/arm/mach-omap2/timer.c
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@ -159,6 +159,11 @@ static struct of_device_id omap_timer_match[] __initdata = {
{ }
};
static struct of_device_id omap_counter_match[] __initdata = {
{ .compatible = "ti,omap-counter32k", },
{ }
};
/**
* omap_get_timer_dt - get a timer using device-tree
* @match - device-tree match structure for matching a device type
@ -377,10 +382,25 @@ static u32 notrace dmtimer_read_sched_clock(void)
static int __init omap2_sync32k_clocksource_init(void)
{
int ret;
struct device_node *np = NULL;
struct omap_hwmod *oh;
void __iomem *vbase;
const char *oh_name = "counter_32k";
/*
* If device-tree is present, then search the DT blob
* to see if the 32kHz counter is supported.
*/
if (of_have_populated_dt()) {
np = omap_get_timer_dt(omap_counter_match, NULL);
if (!np)
return -ENODEV;
of_property_read_string_index(np, "ti,hwmods", 0, &oh_name);
if (!oh_name)
return -ENODEV;
}
/*
* First check hwmod data is available for sync32k counter
*/
@ -390,7 +410,13 @@ static int __init omap2_sync32k_clocksource_init(void)
omap_hwmod_setup_one(oh_name);
vbase = omap_hwmod_get_mpu_rt_va(oh);
if (np) {
vbase = of_iomap(np, 0);
of_node_put(np);
} else {
vbase = omap_hwmod_get_mpu_rt_va(oh);
}
if (!vbase) {
pr_warn("%s: failed to get counter_32k resource\n", __func__);
return -ENXIO;