Skip to contentSkip to conversation

mfd: tps6586x: Handle interrupts on suspend

PATCH RESEND Applied Jon Hunter 2 participants 2 messages Nov 13, 2018

Subsystems (3)
Stable branch Tegra architecture support Multifunction devices (MFD)
lore
Share & tools
lore

Jon Hunter

author maintainer
#0 lore raw

PATCH RESEND 1/1 mfd: tps6586x: Handle interrupts on suspend

From: Jonathan Hunter <[email protected]>

The tps6586x driver creates an irqchip that is used by its various child devices for managing interrupts. The tps6586x-rtc device is one of its children that uses the tps6586x irqchip. When using the tps6586x-rtc as a wake-up device from suspend, the following is seen:

PM: Syncing filesystems ... done.
Freezing user space processes ... (elapsed 0.001 seconds) done. OOM killer disabled.
Freezing remaining freezable tasks ... (elapsed 0.000 seconds) done. Disabling non-boot CPUs ...
Entering suspend state LP1
Enabling non-boot CPUs ...
CPU1 is up
tps6586x 3-0034: failed to read interrupt status
tps6586x 3-0034: failed to read interrupt status

The reason why the tps6586x interrupt status cannot be read is because the tps6586x interrupt is not masked during suspend and when the tps6586x-rtc interrupt occurs, to wake-up the device, the interrupt is seen before the i2c controller has been resumed in order to read the tps6586x interrupt status.

The tps6586x-rtc driver sets it's interrupt as a wake-up source during suspend, which gets propagated to the parent tps6586x interrupt. However, the tps6586x-rtc driver cannot disable it's interrupt during suspend otherwise we would never be woken up and so the tps6586x must disable it's interrupt instead.

Prevent the tps6586x interrupt handler from executing on exiting suspend before the i2c controller has been resumed by disabling the tps6586x interrupt on entering suspend and re-enabling it on resuming from suspend.

Cc [email protected]
Signed-off-by Jon Hunter <[email protected]>
Reviewed-by Dmitry Osipenko <[email protected]>
Tested-by Dmitry Osipenko <[email protected]>
Acked-by Thierry Reding <[email protected]>
---
 drivers/mfd/tps6586x.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
drivers/mfd/tps6586x.c +24 -0
index b89379782741..9c7925ca13cf 100644
@@ -592,6 +592,29 @@ static int tps6586x_i2c_remove(struct i2c_client *client)
 	return 0;
 }
 
+static int __maybe_unused tps6586x_i2c_suspend(struct device *dev)
+{
+	struct tps6586x *tps6586x = dev_get_drvdata(dev);
+
+	if (tps6586x->client->irq)
+		disable_irq(tps6586x->client->irq);
+
+	return 0;
+}
+
+static int __maybe_unused tps6586x_i2c_resume(struct device *dev)
+{
+	struct tps6586x *tps6586x = dev_get_drvdata(dev);
+
+	if (tps6586x->client->irq)
+		enable_irq(tps6586x->client->irq);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(tps6586x_pm_ops, tps6586x_i2c_suspend,
+			 tps6586x_i2c_resume);
+
 static const struct i2c_device_id tps6586x_id_table[] = {
 	{ "tps6586x", 0 },
 	{ },

@@ -602,6 +625,7 @@ static struct i2c_driver tps6586x_driver = {
 	.driver	= {
 		.name	= "tps6586x",
 		.of_match_table = of_match_ptr(tps6586x_of_match),
+		.pm	= &tps6586x_pm_ops,
 	},
 	.probe		= tps6586x_i2c_probe,
 	.remove		= tps6586x_i2c_remove,
Signature · 1 line
2.7.4
Applied
#1 lore raw
Quoted 37 lines · Jon Hunter

From: Jonathan Hunter <[email protected]>

The tps6586x driver creates an irqchip that is used by its various child devices for managing interrupts. The tps6586x-rtc device is one of its children that uses the tps6586x irqchip. When using the tps6586x-rtc as a wake-up device from suspend, the following is seen:

PM: Syncing filesystems ... done.
Freezing user space processes ... (elapsed 0.001 seconds) done. OOM killer disabled.
Freezing remaining freezable tasks ... (elapsed 0.000 seconds) done. Disabling non-boot CPUs ...
Entering suspend state LP1
Enabling non-boot CPUs ...
CPU1 is up
tps6586x 3-0034: failed to read interrupt status
tps6586x 3-0034: failed to read interrupt status

The reason why the tps6586x interrupt status cannot be read is because the tps6586x interrupt is not masked during suspend and when the tps6586x-rtc interrupt occurs, to wake-up the device, the interrupt is seen before the i2c controller has been resumed in order to read the tps6586x interrupt status.

The tps6586x-rtc driver sets it's interrupt as a wake-up source during suspend, which gets propagated to the parent tps6586x interrupt. However, the tps6586x-rtc driver cannot disable it's interrupt during suspend otherwise we would never be woken up and so the tps6586x must disable it's interrupt instead.

Prevent the tps6586x interrupt handler from executing on exiting suspend before the i2c controller has been resumed by disabling the tps6586x interrupt on entering suspend and re-enabling it on resuming from suspend.

Cc [email protected]
Quoted 7 lines
Signed-off-by Jon Hunter <[email protected]>
Reviewed-by Dmitry Osipenko <[email protected]>
Tested-by Dmitry Osipenko <[email protected]>
Acked-by Thierry Reding <[email protected]>
---
 drivers/mfd/tps6586x.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

Applied, thanks.

Signature · 4 lines
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog