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Commit 7a2c1b7c authored by Linus Walleij's avatar Linus Walleij Committed by Shashank Mittal
Browse files

coresight: funnel: retrieve and handle atclk 



As can be seen from the datasheet of the CoreSight
Components, DDI0314 table A-6 the funnel has a clock signal
apart from the AHB interconnect ("amba_pclk", that we're
already handling) called ATCLK, ARM Trace Clock, that SoC
implementers may provide from an entirely different clock
source. So to model this correctly create an optional
path for handling ATCLK alongside the PCLK so we don't
break old platforms that only define PCLK ("amba_pclk") but
still makes it possible for SoCs that have both clock signals
(such as the DB8500) to fetch and prepare/enable/disable/
unprepare both clocks.

The ATCLK is enabled and disabled using the runtime PM
callbacks.

Change-Id: Ibbad0bc5ca4787280871b00809dff24fce0eb186
Reviewed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: 2e5f75d1a41cdc62c43596d3c5c5d2d5b72a5606
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: default avatarShashank Mittal <mittals@codeaurora.org>
parent e6101034

drivers/hwtracing/coresight/coresight-funnel.c

+37 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/pm_runtime.h>

#include <linux/coresight.h>

#include <linux/amba/bus.h>

#include <linux/clk.h>



#include "coresight-priv.h"
@@ -35,12 +36,14 @@ 
 * struct funnel_drvdata - specifics associated to a funnel component

 * @base:	memory mapped base address for this component.

 * @dev:	the device entity associated to this component.

 * @atclk:	optional clock for the core parts of the funnel.

 * @csdev:	component vitals needed by the framework.

 * @priority:	port selection order.

 */

struct funnel_drvdata {

	void __iomem		*base;

	struct device		*dev;

	struct clk		*atclk;

	struct coresight_device	*csdev;

	unsigned long		priority;

};
@@ -168,6 +171,7 @@ ATTRIBUTE_GROUPS(coresight_funnel); 


static int funnel_probe(struct amba_device *adev, const struct amba_id *id)

{

	int ret;

	void __iomem *base;

	struct device *dev = &adev->dev;

	struct coresight_platform_data *pdata = NULL;
@@ -188,6 +192,12 @@ static int funnel_probe(struct amba_device *adev, const struct amba_id *id) 
		return -ENOMEM;



	drvdata->dev = &adev->dev;

	drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */

	if (!IS_ERR(drvdata->atclk)) {

		ret = clk_prepare_enable(drvdata->atclk);

		if (ret)

			return ret;

	}

	dev_set_drvdata(dev, drvdata);



	/* Validity for the resource is already checked by the AMBA core */
@@ -224,6 +234,32 @@ static int funnel_remove(struct amba_device *adev) 
	return 0;

}



#ifdef CONFIG_PM

static int funnel_runtime_suspend(struct device *dev)

{

	struct funnel_drvdata *drvdata = dev_get_drvdata(dev);



	if (drvdata && !IS_ERR(drvdata->atclk))

		clk_disable_unprepare(drvdata->atclk);



	return 0;

}



static int funnel_runtime_resume(struct device *dev)

{

	struct funnel_drvdata *drvdata = dev_get_drvdata(dev);



	if (drvdata && !IS_ERR(drvdata->atclk))

		clk_prepare_enable(drvdata->atclk);



	return 0;

}

#endif



static const struct dev_pm_ops funnel_dev_pm_ops = {

	SET_RUNTIME_PM_OPS(funnel_runtime_suspend, funnel_runtime_resume, NULL)

};



static struct amba_id funnel_ids[] = {

	{

		.id     = 0x0003b908,
@@ -236,6 +272,7 @@ static struct amba_driver funnel_driver = { 
	.drv = {

		.name	= "coresight-funnel",

		.owner	= THIS_MODULE,

		.pm	= &funnel_dev_pm_ops,

	},

	.probe		= funnel_probe,

	.remove		= funnel_remove,