Commit b496dfbc authored by Shawn Guo's avatar Shawn Guo Committed by Rafael J. Wysocki
Browse files

PM / OPP: Initialize OPP table from device tree 



With a lot of devices booting from device tree nowadays, it requires
that OPP table can be initialized from device tree.  The patch adds
a helper function of_init_opp_table together with a binding doc for
that purpose.

Signed-off-by: default avatarShawn Guo <shawn.guo@linaro.org>
Acked-by: default avatarRob Herring <rob.herring@calxeda.com>
Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent ec971ea5

Documentation/devicetree/bindings/power/opp.txt

0 → 100644
+25 −0
Original line number Diff line number Diff line 
* Generic OPP Interface



SoCs have a standard set of tuples consisting of frequency and

voltage pairs that the device will support per voltage domain. These

are called Operating Performance Points or OPPs.



Properties:

- operating-points: An array of 2-tuples items, and each item consists

  of frequency and voltage like <freq-kHz vol-uV>.

	freq: clock frequency in kHz

	vol: voltage in microvolt



Examples:



cpu@0 {

	compatible = "arm,cortex-a9";

	reg = <0>;

	next-level-cache = <&L2>;

	operating-points = <

		/* kHz    uV */

		792000  1100000

		396000  950000

		198000  850000

	>;

};

drivers/base/power/opp.c

+47 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include <linux/rculist.h>

#include <linux/rcupdate.h>

#include <linux/opp.h>

#include <linux/of.h>



/*

 * Internal data structure organization with the OPP layer library is as
@@ -674,3 +675,49 @@ struct srcu_notifier_head *opp_get_notifier(struct device *dev) 


	return &dev_opp->head;

}



#ifdef CONFIG_OF

/**

 * of_init_opp_table() - Initialize opp table from device tree

 * @dev:	device pointer used to lookup device OPPs.

 *

 * Register the initial OPP table with the OPP library for given device.

 */

int of_init_opp_table(struct device *dev)

{

	const struct property *prop;

	const __be32 *val;

	int nr;



	prop = of_find_property(dev->of_node, "operating-points", NULL);

	if (!prop)

		return -ENODEV;

	if (!prop->value)

		return -ENODATA;



	/*

	 * Each OPP is a set of tuples consisting of frequency and

	 * voltage like <freq-kHz vol-uV>.

	 */

	nr = prop->length / sizeof(u32);

	if (nr % 2) {

		dev_err(dev, "%s: Invalid OPP list\n", __func__);

		return -EINVAL;

	}



	val = prop->value;

	while (nr) {

		unsigned long freq = be32_to_cpup(val++) * 1000;

		unsigned long volt = be32_to_cpup(val++);



		if (opp_add(dev, freq, volt)) {

			dev_warn(dev, "%s: Failed to add OPP %ld\n",

				 __func__, freq);

			continue;

		}

		nr -= 2;

	}



	return 0;

}

#endif

include/linux/opp.h

+8 −0
Original line number Diff line number Diff line
@@ -48,6 +48,14 @@ int opp_disable(struct device *dev, unsigned long freq); 


struct srcu_notifier_head *opp_get_notifier(struct device *dev);



#ifdef CONFIG_OF

int of_init_opp_table(struct device *dev);

#else

static inline int of_init_opp_table(struct device *dev)

{

	return -EINVAL;

}

#endif /* CONFIG_OF */

#else

static inline unsigned long opp_get_voltage(struct opp *opp)

{

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