[RFC/PATCH] base: platform: add generic clock handling for platform-bus

[Felipe Balbi]

Still TODO a commit log. Not for merging!!!!!

NYET-Signed-off-by: Felipe Balbi <balbi@xxxxxx>
---

This patch is an idea I've had recently in order to combine several different
PM implementations into the platform-bus.

This patch is bare minimum for platforms which need to handle functional and
interface clocks but the whole thing is made optional.

Note that this patch makes sure that by the time a platform_driver's probe is
called, we already have clocks enabled and pm_runtime_set_active() has been
called, thus making sure that a device driver's pm_runtime_get_sync() will
solely increase the pm usage counter.

I have *NOT* tested this anywhere *YET*, but I suppose it shouldn't cause any
issues since the clock API has ref counting too.

Would really like to get some review from several folks involved with ARM SoC
PM so that's the reason for the wide audience. If I have missed anybody, please
add them to Cc.

As mentioned above, this is *NOT* meant for merging, but serves as a starting
point for discussing some convergence of several PM domain implementations on
different arch/arm/mach-* directories.

For OMAP, this has the added benefit of removing clock handling from
omap_device/omap_hwmod and, thus, dropping the need for so many DT_CLK() tables
under drivers/clk/ti/

 drivers/base/platform.c         | 169 ++++++++++++++++++++++++++++++++++++++--
 include/linux/platform_device.h |   9 +++
 2 files changed, 173 insertions(+), 5 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 3a94b79..86aeb5b 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -484,6 +484,21 @@ static int platform_drv_probe(struct device *_dev)
 	if (ACPI_HANDLE(_dev))
 		acpi_dev_pm_attach(_dev, true);
 
+	dev->fck = devm_clk_get(_dev, "fck");
+	dev->ick = devm_clk_get(_dev, "ick");
+
+	if (!IS_ERR(dev->fck))
+		clk_prepare_enable(dev->fck);
+	else
+		dev->fck = NULL;
+
+	if (!IS_ERR(dev->ick))
+		clk_prepare_enable(dev->ick);
+	else
+		dev->ick = NULL;
+
+	pm_runtime_set_active(_dev);
+
 	ret = drv->probe(dev);
 	if (ret && ACPI_HANDLE(_dev))
 		acpi_dev_pm_detach(_dev, true);
@@ -507,6 +522,14 @@ static int platform_drv_remove(struct device *_dev)
 	struct platform_device *dev = to_platform_device(_dev);
 	int ret;
 
+	if (!IS_ERR(dev->ick))
+		clk_disable_unprepare(dev->ick);
+
+	if (!IS_ERR(dev->fck))
+		clk_disable_unprepare(dev->fck);
+
+	pm_runtime_set_suspended(_dev);
+
 	ret = drv->remove(dev);
 	if (ACPI_HANDLE(_dev))
 		acpi_dev_pm_detach(_dev, true);
@@ -780,6 +803,59 @@ static int platform_legacy_resume(struct device *dev)
 
 #endif /* CONFIG_PM_SLEEP */
 
+#ifdef CONFIG_PM_RUNTIME
+int platform_pm_runtime_suspend(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	struct platform_driver *pdrv = to_platform_driver(drv);
+	struct platform_device *pdev = to_platform_device(dev);
+	int ret;
+
+	ret = pm_generic_runtime_suspend(dev);
+	if (ret)
+		return ret;
+
+	if (!test_bit(PLATFORM_PM_RUNTIME_KEEP_ICK, &pdrv->flags))
+		clk_disable(pdev->ick);
+
+	if (!test_bit(PLATFORM_PM_RUNTIME_KEEP_FCK, &pdrv->flags))
+		clk_disable(pdev->fck);
+
+	return ret;
+}
+
+int platform_pm_runtime_resume(struct device *dev)
+{
+	struct device_driver *drv = dev->driver;
+	struct platform_driver *pdrv = to_platform_driver(drv);
+	struct platform_device *pdev = to_platform_device(dev);
+	int ret;
+
+	if (!test_bit(PLATFORM_PM_RUNTIME_KEEP_ICK, &pdrv->flags)) {
+		ret = clk_enable(pdev->ick);
+		if (ret)
+			return ret;
+	}
+
+	if (!test_bit(PLATFORM_PM_RUNTIME_KEEP_FCK, &pdrv->flags)) {
+		ret = clk_enable(pdev->fck);
+		if (ret) {
+			clk_disable(pdev->ick);
+			return ret;
+		}
+	}
+
+	ret = pm_generic_runtime_suspend(dev);
+	if (ret) {
+		clk_disable(pdev->ick);
+		clk_disable(pdev->fck);
+		return ret;
+	}
+
+	return ret;
+}
+#endif
+
 #ifdef CONFIG_SUSPEND
 
 int platform_pm_suspend(struct device *dev)
@@ -790,6 +866,9 @@ int platform_pm_suspend(struct device *dev)
 	if (!drv)
 		return 0;
 
+	if (pm_runtime_suspended(dev))
+		return 0;
+
 	if (drv->pm) {
 		if (drv->pm->suspend)
 			ret = drv->pm->suspend(dev);
@@ -802,12 +881,27 @@ int platform_pm_suspend(struct device *dev)
 
 int platform_pm_resume(struct device *dev)
 {
+	struct platform_device *pdev = to_platform_device(dev);
 	struct device_driver *drv = dev->driver;
 	int ret = 0;
 
 	if (!drv)
 		return 0;
 
+	ret = clk_enable(pdev->ick);
+	if (ret)
+		return ret;
+
+	ret = clk_enable(pdev->fck);
+	if (ret) {
+		clk_disable(pdev->ick);
+		return ret;
+	}
+
+	pm_runtime_disable(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
 	if (drv->pm) {
 		if (drv->pm->resume)
 			ret = drv->pm->resume(dev);
@@ -815,7 +909,17 @@ int platform_pm_resume(struct device *dev)
 		ret = platform_legacy_resume(dev);
 	}
 
-	return ret;
+	if (ret) {
+		clk_disable(pdev->ick);
+		clk_disable(pdev->fck);
+		pm_runtime_disable(dev);
+		pm_runtime_set_suspended(dev);
+		pm_runtime_enable(dev);
+
+		return ret;
+	}
+
+	return 0;
 }
 
 #endif /* CONFIG_SUSPEND */
@@ -830,6 +934,9 @@ int platform_pm_freeze(struct device *dev)
 	if (!drv)
 		return 0;
 
+	if (pm_runtime_suspended(dev))
+		return 0;
+
 	if (drv->pm) {
 		if (drv->pm->freeze)
 			ret = drv->pm->freeze(dev);
@@ -848,6 +955,20 @@ int platform_pm_thaw(struct device *dev)
 	if (!drv)
 		return 0;
 
+	ret = clk_enable(pdev->ick);
+	if (ret)
+		return ret;
+
+	ret = clk_enable(pdev->fck);
+	if (ret) {
+		clk_disable(pdev->ick);
+		return ret;
+	}
+
+	pm_runtime_disable(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
 	if (drv->pm) {
 		if (drv->pm->thaw)
 			ret = drv->pm->thaw(dev);
@@ -855,7 +976,17 @@ int platform_pm_thaw(struct device *dev)
 		ret = platform_legacy_resume(dev);
 	}
 
-	return ret;
+	if (ret) {
+		clk_disable(pdev->ick);
+		clk_disable(pdev->fck);
+		pm_runtime_disable(dev);
+		pm_runtime_set_suspended(dev);
+		pm_runtime_enable(dev);
+
+		return ret;
+	}
+
+	return 0;
 }
 
 int platform_pm_poweroff(struct device *dev)
@@ -866,6 +997,9 @@ int platform_pm_poweroff(struct device *dev)
 	if (!drv)
 		return 0;
 
+	if (pm_runtime_suspended(dev))
+		return 0;
+
 	if (drv->pm) {
 		if (drv->pm->poweroff)
 			ret = drv->pm->poweroff(dev);
@@ -884,6 +1018,20 @@ int platform_pm_restore(struct device *dev)
 	if (!drv)
 		return 0;
 
+	ret = clk_enable(pdev->ick);
+	if (ret)
+		return ret;
+
+	ret = clk_enable(pdev->fck);
+	if (ret) {
+		clk_disable(pdev->ick);
+		return ret;
+	}
+
+	pm_runtime_disable(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
 	if (drv->pm) {
 		if (drv->pm->restore)
 			ret = drv->pm->restore(dev);
@@ -891,14 +1039,25 @@ int platform_pm_restore(struct device *dev)
 		ret = platform_legacy_resume(dev);
 	}
 
-	return ret;
+	if (ret) {
+		clk_disable(pdev->ick);
+		clk_disable(pdev->fck);
+		pm_runtime_disable(dev);
+		pm_runtime_set_suspended(dev);
+		pm_runtime_enable(dev);
+
+		return ret;
+	}
+
+	return 0;
 }
 
 #endif /* CONFIG_HIBERNATE_CALLBACKS */
 
 static const struct dev_pm_ops platform_dev_pm_ops = {
-	.runtime_suspend = pm_generic_runtime_suspend,
-	.runtime_resume = pm_generic_runtime_resume,
+	SET_RUNTIME_PM_OPS(platform_pm_runtime_suspend,
+			platform_pm_runtime_resume,
+			NULL)
 	USE_PLATFORM_PM_SLEEP_OPS
 };
 
diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index 16f6654..91133f5 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -12,6 +12,7 @@
 #define _PLATFORM_DEVICE_H_
 
 #include <linux/device.h>
+#include <linux/clk.h>
 #include <linux/mod_devicetable.h>
 
 #define PLATFORM_DEVID_NONE	(-1)
@@ -21,6 +22,10 @@ struct mfd_cell;
 
 struct platform_device {
 	const char	*name;
+
+	struct clk	*fck;
+	struct clk	*ick;
+
 	int		id;
 	bool		id_auto;
 	struct device	dev;
@@ -179,8 +184,12 @@ struct platform_driver {
 	struct device_driver driver;
 	const struct platform_device_id *id_table;
 	bool prevent_deferred_probe;
+	unsigned long flags;
 };
 
+#define PLATFORM_PM_RUNTIME_KEEP_ICK	BIT(0)
+#define PLATFORM_PM_RUNTIME_KEEP_FCK	BIT(1)
+
 #define to_platform_driver(drv)	(container_of((drv), struct platform_driver, \
 				 driver))
 
-- 
1.8.5.2

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