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Commit 02113ba9 authored by Jon Hunter's avatar Jon Hunter Committed by Rafael J. Wysocki
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PM / clk: Add support for obtaining clocks from device-tree 



The PM clocks framework requires clients to pass either a con-id or a
valid clk pointer in order to add a clock to a device. Add a new
function of_pm_clk_add_clks() to allows device clocks to be retrieved
from device-tree and populated for a given device. Note that it is
not necessary to make the compilation of this new function dependent
upon CONFIG_OF because there are stubs functions for the device-tree
APIs used.

In order to handle errors encountered when adding clocks from
device-tree, add a function pm_clk_remove_clk() to remove any clocks
(using a pointer to the clk structure) that have been added
successfully before the error occurred.

Signed-off-by: default avatarJon Hunter <jonathanh@nvidia.com>
Acked-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent b562e44f

drivers/base/power/clock_ops.c

+89 −0
Original line number Diff line number Diff line
@@ -137,6 +137,62 @@ int pm_clk_add_clk(struct device *dev, struct clk *clk) 
	return __pm_clk_add(dev, NULL, clk);

}





/**

 * of_pm_clk_add_clks - Start using device clock(s) for power management.

 * @dev: Device whose clock(s) is going to be used for power management.

 *

 * Add a series of clocks described in the 'clocks' device-tree node for

 * a device to the list of clocks used for the power management of @dev.

 * On success, returns the number of clocks added. Returns a negative

 * error code if there are no clocks in the device node for the device

 * or if adding a clock fails.

 */

int of_pm_clk_add_clks(struct device *dev)

{

	struct clk **clks;

	unsigned int i, count;

	int ret;



	if (!dev || !dev->of_node)

		return -EINVAL;



	count = of_count_phandle_with_args(dev->of_node, "clocks",

					   "#clock-cells");

	if (count == 0)

		return -ENODEV;



	clks = kcalloc(count, sizeof(*clks), GFP_KERNEL);

	if (!clks)

		return -ENOMEM;



	for (i = 0; i < count; i++) {

		clks[i] = of_clk_get(dev->of_node, i);

		if (IS_ERR(clks[i])) {

			ret = PTR_ERR(clks[i]);

			goto error;

		}



		ret = pm_clk_add_clk(dev, clks[i]);

		if (ret) {

			clk_put(clks[i]);

			goto error;

		}

	}



	kfree(clks);



	return i;



error:

	while (i--)

		pm_clk_remove_clk(dev, clks[i]);



	kfree(clks);



	return ret;

}



/**

 * __pm_clk_remove - Destroy PM clock entry.

 * @ce: PM clock entry to destroy.
@@ -197,6 +253,39 @@ void pm_clk_remove(struct device *dev, const char *con_id) 
	__pm_clk_remove(ce);

}



/**

 * pm_clk_remove_clk - Stop using a device clock for power management.

 * @dev: Device whose clock should not be used for PM any more.

 * @clk: Clock pointer

 *

 * Remove the clock pointed to by @clk from the list of clocks used for

 * the power management of @dev.

 */

void pm_clk_remove_clk(struct device *dev, struct clk *clk)

{

	struct pm_subsys_data *psd = dev_to_psd(dev);

	struct pm_clock_entry *ce;



	if (!psd || !clk)

		return;



	spin_lock_irq(&psd->lock);



	list_for_each_entry(ce, &psd->clock_list, node) {

		if (clk == ce->clk)

			goto remove;

	}



	spin_unlock_irq(&psd->lock);

	return;



 remove:

	list_del(&ce->node);

	spin_unlock_irq(&psd->lock);



	__pm_clk_remove(ce);

}



/**

 * pm_clk_init - Initialize a device's list of power management clocks.

 * @dev: Device to initialize the list of PM clocks for.

include/linux/pm_clock.h

+9 −0
Original line number Diff line number Diff line
@@ -42,7 +42,9 @@ extern int pm_clk_create(struct device *dev); 
extern void pm_clk_destroy(struct device *dev);

extern int pm_clk_add(struct device *dev, const char *con_id);

extern int pm_clk_add_clk(struct device *dev, struct clk *clk);

extern int of_pm_clk_add_clks(struct device *dev);

extern void pm_clk_remove(struct device *dev, const char *con_id);

extern void pm_clk_remove_clk(struct device *dev, struct clk *clk);

extern int pm_clk_suspend(struct device *dev);

extern int pm_clk_resume(struct device *dev);

#else
@@ -69,11 +71,18 @@ static inline int pm_clk_add_clk(struct device *dev, struct clk *clk) 
{

	return -EINVAL;

}

static inline int of_pm_clk_add_clks(struct device *dev)

{

	return -EINVAL;

}

static inline void pm_clk_remove(struct device *dev, const char *con_id)

{

}

#define pm_clk_suspend	NULL

#define pm_clk_resume	NULL

static inline void pm_clk_remove_clk(struct device *dev, struct clk *clk)

{

}

#endif



#ifdef CONFIG_HAVE_CLK