Commit 9883f7c8 authored by Jon Hunter's avatar Jon Hunter
Browse files

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: default avatarJon Hunter <jon-hunter@ti.com>
parent 9725f445

arch/arm/mach-omap2/timer.c

+27 −1
Original line number Diff line number Diff line
@@ -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);



	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;

CRA Git | Maintained and supported by SUSTech CRA and CCSE