[PATCH] spi/atmel: add support for runtime PM

[Wenyou Yang]

Drivers should put the device into low power states proactively whenever the
device is not in use. Thus implement support for runtime PM and use the
autosuspend feature to make sure that we can still perform well in case we see
lots of SPI traffic within short period of time.

Signed-off-by: Wenyou Yang <wenyou.yang-***@public.gmane.org>
---
drivers/spi/spi-atmel.c | 62 +++++++++++++++++++++++++++++++++++++++++------
1 file changed, 55 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 649dcb5..aca285e 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -26,6 +26,7 @@
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/pinctrl/consumer.h>
+#include <linux/pm_runtime.h>

/* SPI register offsets */
#define SPI_CR 0x0000
@@ -191,6 +192,8 @@

#define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000))

+#define AUTOSUSPEND_TIMEOUT 2000
+
struct atmel_spi_dma {
struct dma_chan *chan_rx;
struct dma_chan *chan_tx;
@@ -1313,6 +1316,7 @@ static int atmel_spi_probe(struct platform_device *pdev)
master->setup = atmel_spi_setup;
master->transfer_one_message = atmel_spi_transfer_one_message;
master->cleanup = atmel_spi_cleanup;
+ master->auto_runtime_pm = true;
platform_set_drvdata(pdev, master);

as = spi_master_get_devdata(master);
@@ -1385,6 +1389,11 @@ static int atmel_spi_probe(struct platform_device *pdev)
dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
(unsigned long)regs->start, irq);

+ pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
+ pm_runtime_use_autosuspend(&pdev->dev);
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+
ret = devm_spi_register_master(&pdev->dev, master);
if (ret)
goto out_free_dma;
@@ -1392,6 +1401,9 @@ static int atmel_spi_probe(struct platform_device *pdev)
return 0;

out_free_dma:
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_set_suspended(&pdev->dev);
+
if (as->use_dma)
atmel_spi_release_dma(as);

@@ -1413,6 +1425,8 @@ static int atmel_spi_remove(struct platform_device *pdev)
struct spi_master *master = platform_get_drvdata(pdev);
struct atmel_spi *as = spi_master_get_devdata(master);

+ pm_runtime_get_sync(&pdev->dev);
+
/* reset the hardware and block queue progress */
spin_lock_irq(&as->lock);
if (as->use_dma) {
@@ -1430,9 +1444,13 @@ static int atmel_spi_remove(struct platform_device *pdev)

clk_disable_unprepare(as->clk);

+ pm_runtime_put_noidle(&pdev->dev);
+ pm_runtime_disable(&pdev->dev);
+
return 0;
}

+#ifdef CONFIG_PM
#ifdef CONFIG_PM_SLEEP
static int atmel_spi_suspend(struct device *dev)
{
@@ -1447,9 +1465,10 @@ static int atmel_spi_suspend(struct device *dev)
return ret;
}

- clk_disable_unprepare(as->clk);
-
- pinctrl_pm_select_sleep_state(dev);
+ if (!pm_runtime_suspended(dev)) {
+ clk_disable_unprepare(as->clk);
+ pinctrl_pm_select_sleep_state(dev);
+ }

return 0;
}
@@ -1460,9 +1479,10 @@ static int atmel_spi_resume(struct device *dev)
struct atmel_spi *as = spi_master_get_devdata(master);
int ret;

- pinctrl_pm_select_default_state(dev);
-
- clk_prepare_enable(as->clk);
+ if (!pm_runtime_suspended(dev)) {
+ pinctrl_pm_select_default_state(dev);
+ clk_prepare_enable(as->clk);
+ }

/* Start the queue running */
ret = spi_master_resume(master);
@@ -1471,9 +1491,37 @@ static int atmel_spi_resume(struct device *dev)

return ret;
}
+#endif

-static SIMPLE_DEV_PM_OPS(atmel_spi_pm_ops, atmel_spi_suspend, atmel_spi_resume);
+#ifdef CONFIG_PM_RUNTIME
+static int atmel_spi_runtime_suspend(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct atmel_spi *as = spi_master_get_devdata(master);

+ clk_disable_unprepare(as->clk);
+ pinctrl_pm_select_sleep_state(dev);
+
+ return 0;
+}
+
+static int atmel_spi_runtime_resume(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct atmel_spi *as = spi_master_get_devdata(master);
+
+ pinctrl_pm_select_default_state(dev);
+ clk_prepare_enable(as->clk);
+
+ return 0;
+}
+#endif
+
+static const struct dev_pm_ops atmel_spi_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(atmel_spi_suspend, atmel_spi_resume)
+ SET_RUNTIME_PM_OPS(atmel_spi_runtime_suspend,
+ atmel_spi_runtime_resume, NULL)
+};
#define ATMEL_SPI_PM_OPS (&atmel_spi_pm_ops)
#else
#define ATMEL_SPI_PM_OPS NULL

[Mark Brown]

Post by Wenyou Yang
+static int atmel_spi_runtime_resume(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct atmel_spi *as = spi_master_get_devdata(master);
+
+ pinctrl_pm_select_default_state(dev);
+ clk_prepare_enable(as->clk);
+

This looks mostly good but you should check the return value of
clk_prepare_enable() - it can fail.

[Yang, Wenyou]

Hi Mark,

-----Original Message-----
Sent: Thursday, October 16, 2014 3:30 PM
To: Yang, Wenyou
Subject: Re: [PATCH] spi/atmel: add support for runtime PM

+static int atmel_spi_runtime_resume(struct device *dev) {
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct atmel_spi *as = spi_master_get_devdata(master);
+
+ pinctrl_pm_select_default_state(dev);
+ clk_prepare_enable(as->clk);
+

This looks mostly good but you should check the return value of
clk_prepare_enable() - it can fail.

Thanks a lot, I will add it.

Best Regards,
Wenyou Yang
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[Kevin Hilman]

Post by Wenyou Yang
Drivers should put the device into low power states proactively whenever the
device is not in use. Thus implement support for runtime PM and use the
autosuspend feature to make sure that we can still perform well in case we see
lots of SPI traffic within short period of time.
---
drivers/spi/spi-atmel.c | 62 +++++++++++++++++++++++++++++++++++++++++------
1 file changed, 55 insertions(+), 7 deletions(-)
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 649dcb5..aca285e 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -26,6 +26,7 @@
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/pinctrl/consumer.h>
+#include <linux/pm_runtime.h>
/* SPI register offsets */
#define SPI_CR 0x0000
@@ -191,6 +192,8 @@
#define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000))
+#define AUTOSUSPEND_TIMEOUT 2000
+
struct atmel_spi_dma {
struct dma_chan *chan_rx;
struct dma_chan *chan_tx;
@@ -1313,6 +1316,7 @@ static int atmel_spi_probe(struct platform_device *pdev)
master->setup = atmel_spi_setup;
master->transfer_one_message = atmel_spi_transfer_one_message;
master->cleanup = atmel_spi_cleanup;
+ master->auto_runtime_pm = true;
platform_set_drvdata(pdev, master);
as = spi_master_get_devdata(master);
@@ -1385,6 +1389,11 @@ static int atmel_spi_probe(struct platform_device *pdev)
dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
(unsigned long)regs->start, irq);
+ pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
+ pm_runtime_use_autosuspend(&pdev->dev);
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+
ret = devm_spi_register_master(&pdev->dev, master);
if (ret)
goto out_free_dma;
@@ -1392,6 +1401,9 @@ static int atmel_spi_probe(struct platform_device *pdev)
return 0;
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_set_suspended(&pdev->dev);
+
if (as->use_dma)
atmel_spi_release_dma(as);
@@ -1413,6 +1425,8 @@ static int atmel_spi_remove(struct platform_device *pdev)
struct spi_master *master = platform_get_drvdata(pdev);
struct atmel_spi *as = spi_master_get_devdata(master);
+ pm_runtime_get_sync(&pdev->dev);
+
/* reset the hardware and block queue progress */
spin_lock_irq(&as->lock);
if (as->use_dma) {
@@ -1430,9 +1444,13 @@ static int atmel_spi_remove(struct platform_device *pdev)
clk_disable_unprepare(as->clk);
+ pm_runtime_put_noidle(&pdev->dev);

Why the _noidle version?

Post by Wenyou Yang
+ pm_runtime_disable(&pdev->dev);
+
return 0;
}
+#ifdef CONFIG_PM

Why CONFIG_PM? CONFIG_PM_SLEEP causes CONFIG_PM=y, so this seems
redundant.

Post by Wenyou Yang
#ifdef CONFIG_PM_SLEEP
static int atmel_spi_suspend(struct device *dev)
{
@@ -1447,9 +1465,10 @@ static int atmel_spi_suspend(struct device *dev)
return ret;
}
- clk_disable_unprepare(as->clk);
-
- pinctrl_pm_select_sleep_state(dev);
+ if (!pm_runtime_suspended(dev)) {
+ clk_disable_unprepare(as->clk);
+ pinctrl_pm_select_sleep_state(dev);
+ }

a.k.a. pm_runtime_put_sync() since the ->runtime_suspend() callback does
the same thing.

Post by Wenyou Yang
return 0;
}
@@ -1460,9 +1479,10 @@ static int atmel_spi_resume(struct device *dev)
struct atmel_spi *as = spi_master_get_devdata(master);
int ret;
- pinctrl_pm_select_default_state(dev);
-
- clk_prepare_enable(as->clk);
+ if (!pm_runtime_suspended(dev)) {
+ pinctrl_pm_select_default_state(dev);
+ clk_prepare_enable(as->clk);
+ }

a.k.a. pm_runtime_get_sync()

Kevin

Post by Wenyou Yang
/* Start the queue running */
ret = spi_master_resume(master);
@@ -1471,9 +1491,37 @@ static int atmel_spi_resume(struct device *dev)
return ret;
}
+#endif
-static SIMPLE_DEV_PM_OPS(atmel_spi_pm_ops, atmel_spi_suspend, atmel_spi_resume);
+#ifdef CONFIG_PM_RUNTIME
+static int atmel_spi_runtime_suspend(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct atmel_spi *as = spi_master_get_devdata(master);
+ clk_disable_unprepare(as->clk);
+ pinctrl_pm_select_sleep_state(dev);
+
+ return 0;
+}
+
+static int atmel_spi_runtime_resume(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct atmel_spi *as = spi_master_get_devdata(master);
+
+ pinctrl_pm_select_default_state(dev);
+ clk_prepare_enable(as->clk);
+
+ return 0;
+}
+#endif
+
+static const struct dev_pm_ops atmel_spi_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(atmel_spi_suspend, atmel_spi_resume)
+ SET_RUNTIME_PM_OPS(atmel_spi_runtime_suspend,
+ atmel_spi_runtime_resume, NULL)
+};
#define ATMEL_SPI_PM_OPS (&atmel_spi_pm_ops)
#else
#define ATMEL_SPI_PM_OPS NULL

[Mark Brown]

Post by Kevin Hilman

Post by Wenyou Yang
+ if (!pm_runtime_suspended(dev)) {
+ clk_disable_unprepare(as->clk);
+ pinctrl_pm_select_sleep_state(dev);
+ }

a.k.a. pm_runtime_put_sync() since the ->runtime_suspend() callback does
the same thing.

Will that do the right thing when runtime PM is disabled in Kconfig?

[Kevin Hilman]

Post by Mark Brown

Post by Kevin Hilman

Post by Wenyou Yang
+ if (!pm_runtime_suspended(dev)) {
+ clk_disable_unprepare(as->clk);
+ pinctrl_pm_select_sleep_state(dev);
+ }

a.k.a. pm_runtime_put_sync() since the ->runtime_suspend() callback does
the same thing.

Will that do the right thing when runtime PM is disabled in Kconfig?

Good point.

Then the way to make this cleaner, and obvious on inspection that system
suspend/resume are doing the same thing as runtime suspend/resume is to
have ->suspend call the runtime_suspend function.

The runtime suspend/resume functions then should be wrapped in CONFIG_PM
instead of CONFIG_PM_RUNTIME.

Kevin
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[Yang, Wenyou]

-----Original Message-----
Sent: Friday, October 17, 2014 10:22 PM
To: Mark Brown
Subject: Re: [PATCH] spi/atmel: add support for runtime PM

Post by Mark Brown

Post by Kevin Hilman

Post by Wenyou Yang
+ if (!pm_runtime_suspended(dev)) {
+ clk_disable_unprepare(as->clk);
+ pinctrl_pm_select_sleep_state(dev);
+ }

a.k.a. pm_runtime_put_sync() since the ->runtime_suspend() callback
does the same thing.

Will that do the right thing when runtime PM is disabled in Kconfig?

Good point.
Then the way to make this cleaner, and obvious on inspection that system
suspend/resume are doing the same thing as runtime suspend/resume is to have -

Post by Mark Brown
suspend call the runtime_suspend function.

The runtime suspend/resume functions then should be wrapped in CONFIG_PM
instead of CONFIG_PM_RUNTIME.

But if the runtime PM is disabled, __pm_runtime_idle() return -ENOSYS, which invoked by pm_runtime_put_sync(), in spite of the runtime suspend/resume functions wrapper,

Kevin

Best Regards,
Wenyou Yang
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[Kevin Hilman]

-----Original Message-----
Sent: Friday, October 17, 2014 10:22 PM
To: Mark Brown
Subject: Re: [PATCH] spi/atmel: add support for runtime PM

Post by Mark Brown

Post by Kevin Hilman

Post by Wenyou Yang
+ if (!pm_runtime_suspended(dev)) {
+ clk_disable_unprepare(as->clk);
+ pinctrl_pm_select_sleep_state(dev);
+ }

a.k.a. pm_runtime_put_sync() since the ->runtime_suspend() callback
does the same thing.

Will that do the right thing when runtime PM is disabled in Kconfig?

Good point.
Then the way to make this cleaner, and obvious on inspection that system
suspend/resume are doing the same thing as runtime suspend/resume is to have -

Post by Mark Brown
suspend call the runtime_suspend function.

The runtime suspend/resume functions then should be wrapped in CONFIG_PM
instead of CONFIG_PM_RUNTIME.

But if the runtime PM is disabled, __pm_runtime_idle() return -ENOSYS,
which invoked by pm_runtime_put_sync(), in spite of the runtime
suspend/resume functions wrapper,

You won't be calling _put_sync(), instead you'll just directly call
atmel_spi_runtime_suspend().

The goal is to make it obvious upon reading that ->suspend and
->runtime_suspend are doing exactly the same thing.

Kevin

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[Yang, Wenyou]

-----Original Message-----
Sent: Friday, October 17, 2014 9:03 PM
To: Yang, Wenyou
Subject: Re: [PATCH] spi/atmel: add support for runtime PM

Post by Wenyou Yang
Drivers should put the device into low power states proactively
whenever the device is not in use. Thus implement support for runtime
PM and use the autosuspend feature to make sure that we can still
perform well in case we see lots of SPI traffic within short period of time.
---
drivers/spi/spi-atmel.c | 62

+++++++++++++++++++++++++++++++++++++++++------

Post by Wenyou Yang
1 file changed, 55 insertions(+), 7 deletions(-)
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index
649dcb5..aca285e 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -26,6 +26,7 @@
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/pinctrl/consumer.h>
+#include <linux/pm_runtime.h>
/* SPI register offsets */
#define SPI_CR 0x0000
@@ -191,6 +192,8 @@
#define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000))
+#define AUTOSUSPEND_TIMEOUT 2000
+
struct atmel_spi_dma {
struct dma_chan *chan_rx;
struct dma_chan *chan_tx;
@@ -1313,6 +1316,7 @@ static int atmel_spi_probe(struct platform_device

*pdev)

Post by Wenyou Yang
master->setup = atmel_spi_setup;
master->transfer_one_message = atmel_spi_transfer_one_message;
master->cleanup = atmel_spi_cleanup;
+ master->auto_runtime_pm = true;
platform_set_drvdata(pdev, master);
int atmel_spi_probe(struct platform_device *pdev)
dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
(unsigned long)regs->start, irq);
+ pm_runtime_set_autosuspend_delay(&pdev->dev,

AUTOSUSPEND_TIMEOUT);

Post by Wenyou Yang
+ pm_runtime_use_autosuspend(&pdev->dev);
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+
ret = devm_spi_register_master(&pdev->dev, master);
if (ret)
goto out_free_dma;
@@ -1392,6 +1401,9 @@ static int atmel_spi_probe(struct platform_device

*pdev)

Post by Wenyou Yang
return 0;
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_set_suspended(&pdev->dev);
+
if (as->use_dma)
atmel_spi_release_dma(as);
@@ -1413,6 +1425,8 @@ static int atmel_spi_remove(struct platform_device

*pdev)

Post by Wenyou Yang
struct spi_master *master = platform_get_drvdata(pdev);
struct atmel_spi *as = spi_master_get_devdata(master);
+ pm_runtime_get_sync(&pdev->dev);
+
/* reset the hardware and block queue progress */
spin_lock_irq(&as->lock);
if (as->use_dma) {
@@ -1430,9 +1444,13 @@ static int atmel_spi_remove(struct
platform_device *pdev)
clk_disable_unprepare(as->clk);
+ pm_runtime_put_noidle(&pdev->dev);

Why the _noidle version?

Because invoked from the _remove function, only decrement the device's usage counter, no further idle operation need.

Post by Wenyou Yang
+ pm_runtime_disable(&pdev->dev);
+
return 0;
}
+#ifdef CONFIG_PM

Why CONFIG_PM? CONFIG_PM_SLEEP causes CONFIG_PM=y, so this seems
redundant.

Accepted, I will remove it.

Post by Wenyou Yang
#ifdef CONFIG_PM_SLEEP
return ret;
}
- clk_disable_unprepare(as->clk);
-
- pinctrl_pm_select_sleep_state(dev);
+ if (!pm_runtime_suspended(dev)) {
+ clk_disable_unprepare(as->clk);
+ pinctrl_pm_select_sleep_state(dev);
+ }

a.k.a. pm_runtime_put_sync() since the ->runtime_suspend() callback does the
same thing.

Post by Wenyou Yang
return 0;
}
@@ -1460,9 +1479,10 @@ static int atmel_spi_resume(struct device *dev)
struct atmel_spi *as = spi_master_get_devdata(master);
int ret;
- pinctrl_pm_select_default_state(dev);
-
- clk_prepare_enable(as->clk);
+ if (!pm_runtime_suspended(dev)) {
+ pinctrl_pm_select_default_state(dev);
+ clk_prepare_enable(as->clk);
+ }

a.k.a. pm_runtime_get_sync()
Kevin

Post by Wenyou Yang
/* Start the queue running */
ret = spi_master_resume(master);
@@ -1471,9 +1491,37 @@ static int atmel_spi_resume(struct device *dev)
return ret;
}
+#endif
-static SIMPLE_DEV_PM_OPS(atmel_spi_pm_ops, atmel_spi_suspend, atmel_spi_resume);
+#ifdef CONFIG_PM_RUNTIME
+static int atmel_spi_runtime_suspend(struct device *dev) {
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct atmel_spi *as = spi_master_get_devdata(master);
+ clk_disable_unprepare(as->clk);
+ pinctrl_pm_select_sleep_state(dev);
+
+ return 0;
+}
+
+static int atmel_spi_runtime_resume(struct device *dev) {
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct atmel_spi *as = spi_master_get_devdata(master);
+
+ pinctrl_pm_select_default_state(dev);
+ clk_prepare_enable(as->clk);
+
+ return 0;
+}
+#endif
+
+static const struct dev_pm_ops atmel_spi_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(atmel_spi_suspend, atmel_spi_resume)
+ SET_RUNTIME_PM_OPS(atmel_spi_runtime_suspend,
+ atmel_spi_runtime_resume, NULL) };
#define ATMEL_SPI_PM_OPS (&atmel_spi_pm_ops)
#else
#define ATMEL_SPI_PM_OPS NULL

Best Regards,
Wenyou Yang
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