Merge patch series "can: tcan4x5x: support resume upon rx can frame"

Martin Hundebøll <martin@geanix.com> says:

This is the third iteration of the previous submitted patches [0] and
[1].

This revision replaces the "wake_source" function parameters to a flag
in the class device structure, and adds a patch to document the
"wakeup-source" device tree property.

Also, the previous revisions forgot to mention that the patches are
based on Markus' coalescing patches [2]. Those implements caching of
the enabled interrupts, which is handy when restoring the set of
interrupts in the resume path.

[0] https://lore.kernel.org/linux-can/20230912093807.1383720-1-martin@geanix.com
[1] https://lore.kernel.org/linux-can/20230919122841.3803289-1-martin@geanix.com
[2] https://lore.kernel.org/linux-can/20230929141304.3934380-1-msp@baylibre.com

Link: https://lore.kernel.org/all/20231113131452.214961-1-martin@geanix.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Documentation/devicetree/bindings/net/can/tcan4x5x.txt

@@ -28,6 +28,8 @@ Optional properties:
 			      available with tcan4552/4553.
 	- device-wake-gpios: Wake up GPIO to wake up the TCAN device. Not
 			     available with tcan4552/4553.
+	- wakeup-source: Leave the chip running when suspended, and configure
+			 the RX interrupt to wake up the device.
 
 Example:
 tcan4x5x: tcan4x5x@0 {
@@ -42,4 +44,5 @@ tcan4x5x: tcan4x5x@0 {
 		device-state-gpios = <&gpio3 21 GPIO_ACTIVE_HIGH>;
 		device-wake-gpios = <&gpio1 15 GPIO_ACTIVE_HIGH>;
 		reset-gpios = <&gpio1 27 GPIO_ACTIVE_HIGH>;
+		wakeup-source;
 };

drivers/net/can/m_can/m_can.c

@@ -2382,7 +2382,15 @@ int m_can_class_suspend(struct device *dev)
 	if (netif_running(ndev)) {
 		netif_stop_queue(ndev);
 		netif_device_detach(ndev);
-		m_can_stop(ndev);
+
+		/* leave the chip running with rx interrupt enabled if it is
+		 * used as a wake-up source.
+		 */
+		if (cdev->pm_wake_source)
+			m_can_write(cdev, M_CAN_IE, IR_RF0N);
+		else
+			m_can_stop(ndev);
+
 		m_can_clk_stop(cdev);
 	}
 
@@ -2409,11 +2417,15 @@ int m_can_class_resume(struct device *dev)
 		ret = m_can_clk_start(cdev);
 		if (ret)
 			return ret;
-		ret  = m_can_start(ndev);
-		if (ret) {
-			m_can_clk_stop(cdev);
 
-			return ret;
+		if (cdev->pm_wake_source) {
+			m_can_write(cdev, M_CAN_IE, cdev->active_interrupts);
+		} else {
+			ret  = m_can_start(ndev);
+			if (ret) {
+				m_can_clk_stop(cdev);
+				return ret;
+			}
 		}
 
 		netif_device_attach(ndev);

drivers/net/can/m_can/m_can.h

@@ -97,6 +97,7 @@ struct m_can_classdev {
 	u32 irqstatus;
 
 	int pm_clock_support;
+	int pm_wake_source;
 	int is_peripheral;
 
 	// Cached M_CAN_IE register content

drivers/net/can/m_can/m_can_pci.c

@@ -125,6 +125,7 @@ static int m_can_pci_probe(struct pci_dev *pci, const struct pci_device_id *id)
 	mcan_class->dev = &pci->dev;
 	mcan_class->net->irq = pci_irq_vector(pci, 0);
 	mcan_class->pm_clock_support = 1;
+	mcan_class->pm_wake_source = 0;
 	mcan_class->can.clock.freq = id->driver_data;
 	mcan_class->ops = &m_can_pci_ops;
 

drivers/net/can/m_can/m_can_platform.c

@@ -139,6 +139,7 @@ static int m_can_plat_probe(struct platform_device *pdev)
 
 	mcan_class->net->irq = irq;
 	mcan_class->pm_clock_support = 1;
+	mcan_class->pm_wake_source = 0;
 	mcan_class->can.clock.freq = clk_get_rate(mcan_class->cclk);
 	mcan_class->dev = &pdev->dev;
 	mcan_class->transceiver = transceiver;

drivers/net/can/m_can/tcan4x5x-core.c

@@ -411,6 +411,7 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
 	priv->spi = spi;
 
 	mcan_class->pm_clock_support = 0;
+	mcan_class->pm_wake_source = device_property_read_bool(&spi->dev, "wakeup-source");
 	mcan_class->can.clock.freq = freq;
 	mcan_class->dev = &spi->dev;
 	mcan_class->ops = &tcan4x5x_ops;
@@ -459,6 +460,9 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
 		goto out_power;
 	}
 
+	if (mcan_class->pm_wake_source)
+		device_init_wakeup(&spi->dev, true);
+
 	ret = m_can_class_register(mcan_class);
 	if (ret) {
 		dev_err(&spi->dev, "Failed registering m_can device %pe\n",
@@ -487,6 +491,29 @@ static void tcan4x5x_can_remove(struct spi_device *spi)
 	m_can_class_free_dev(priv->cdev.net);
 }
 
+static int __maybe_unused tcan4x5x_suspend(struct device *dev)
+{
+	struct m_can_classdev *cdev = dev_get_drvdata(dev);
+	struct spi_device *spi = to_spi_device(dev);
+
+	if (cdev->pm_wake_source)
+		enable_irq_wake(spi->irq);
+
+	return m_can_class_suspend(dev);
+}
+
+static int __maybe_unused tcan4x5x_resume(struct device *dev)
+{
+	struct m_can_classdev *cdev = dev_get_drvdata(dev);
+	struct spi_device *spi = to_spi_device(dev);
+	int ret = m_can_class_resume(dev);
+
+	if (cdev->pm_wake_source)
+		disable_irq_wake(spi->irq);
+
+	return ret;
+}
+
 static const struct of_device_id tcan4x5x_of_match[] = {
 	{
 		.compatible = "ti,tcan4x5x",
@@ -505,11 +532,15 @@ static const struct spi_device_id tcan4x5x_id_table[] = {
 };
 MODULE_DEVICE_TABLE(spi, tcan4x5x_id_table);
 
+static const struct dev_pm_ops tcan4x5x_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(tcan4x5x_suspend, tcan4x5x_resume)
+};
+
 static struct spi_driver tcan4x5x_can_driver = {
 	.driver = {
 		.name = KBUILD_MODNAME,
 		.of_match_table = tcan4x5x_of_match,
-		.pm = NULL,
+		.pm = &tcan4x5x_pm_ops,
 	},
 	.id_table = tcan4x5x_id_table,
 	.probe = tcan4x5x_can_probe,