serial: omap: Add support for optional wake-up interrupt

With the recent pinctrl-single changes, omaps can treat wake-up events from deeper idle states as interrupts.

There's a separate "io chain" controller on most omaps that stays enabled when the device hits off-idle and the regular interrupt controller is powered off.

Let's add support for the optional second interrupt for wake-up events. And then serial-omap can manage the wake-up interrupt from it's runtime PM calls to avoid spurious interrupts during runtime.

Note that the wake interrupt is board specific as it uses the UART RX pin, and for omap3, there are six pin options for UART3 RX pin.

Also Note that the legacy platform based booting handles the wake-ups in the legacy mux driver and does not need to pass the wake-up interrupt to the driver.

And finally, to pass the wake-up interrupt in the dts file, either interrupt-map or the pending interrupts-extended property needs to be passed. It's probably best to use interrupts-extended when it's available.

Cc Felipe Balbi <[email protected]>

Cc Kevin Hilman <[email protected]>

Cc Linus Walleij <[email protected]>

Cc Roger Quadros <[email protected]>

Signed-off-by Tony Lindgren <[email protected]>

drivers/tty/serial/omap-serial.c +4 -1

@@ -39,6 +39,7 @@
 #include <linux/irq.h>
 #include <linux/pm_runtime.h>
 #include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
 #include <linux/platform_data/serial-omap.h>

@@ -134,7 +135,7 @@ struct uart_omap_port {
 	struct uart_port	port;
 	struct uart_omap_dma	uart_dma;
 	struct device		*dev;
-
+	int			irqs[2];
 	unsigned char		ier;
 	unsigned char		lcr;
 	unsigned char		mcr;

@@ -176,6 +177,8 @@ struct uart_omap_port {
 };
 
 #define to_uart_omap_port(p)	((container_of((p), struct uart_omap_port, port)))
+#define omap_uartirq		(up->irqs[0])
+#define omap_wakeirq		(up->irqs[1])
 
 static struct uart_omap_port *ui[OMAP_MAX_HSUART_PORTS];
 

drivers/tty/serial/omap-serial.c +2 -5

@@ -689,15 +705,25 @@ static int serial_omap_startup(struct uart_port *port)
 {
 	struct uart_omap_port *up = to_uart_omap_port(port);
 	unsigned long flags = 0;
-	int retval;
+	int i, retval;
 
 	/*
-	 * Allocate the IRQ
+	 * Allocate the IRQs, the second IRQ is the optional wakeirq
 	 */
-	retval = request_irq(up->port.irq, serial_omap_irq, up->port.irqflags,
-				up->name, up);
-	if (retval)

Quoted 32 lines

drivers/tty/serial/omap-serial.c +4 -1

@@ -39,6 +39,7 @@
 #include <linux/irq.h>
 #include <linux/pm_runtime.h>
 #include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
 #include <linux/platform_data/serial-omap.h>

@@ -134,7 +135,7 @@ struct uart_omap_port {
 	struct uart_port	port;
 	struct uart_omap_dma	uart_dma;
 	struct device		*dev;
-
+	int			irqs[2];
 	unsigned char		ier;
 	unsigned char		lcr;
 	unsigned char		mcr;

@@ -176,6 +177,8 @@ struct uart_omap_port {
 };
 
 #define to_uart_omap_port(p)	((container_of((p), struct uart_omap_port, port)))
+#define omap_uartirq		(up->irqs[0])
+#define omap_wakeirq		(up->irqs[1])
 
 static struct uart_omap_port *ui[OMAP_MAX_HSUART_PORTS];
 

@@ -214,10 +217,23 @@ static int serial_omap_get_context_loss_count(struct uart_omap_port *up)
 	return pdata->get_context_loss_count(up->dev);
 }
 

drivers/tty/serial/omap-serial.c static int serial_omap_get_context_loss_count(struct uart_omap_port *up) · line 224

Quoted 5 lines

drivers/tty/serial/omap-serial.c +5 -0

+static inline void serial_omap_enable_wakeirq(struct uart_omap_port *up,
+				       bool enable)
+{
+	if (!omap_wakeirq)
+		return;

can we drop the pointless obfuscation ?

Quoted 18 lines

drivers/tty/serial/omap-serial.c +5 -6

@@ -689,15 +705,25 @@ static int serial_omap_startup(struct uart_port *port)
 {
 	struct uart_omap_port *up = to_uart_omap_port(port);
 	unsigned long flags = 0;
-	int retval;
+	int i, retval;
 
 	/*
-	 * Allocate the IRQ
+	 * Allocate the IRQs, the second IRQ is the optional wakeirq
 	 */
-	retval = request_irq(up->port.irq, serial_omap_irq, up->port.irqflags,
-				up->name, up);
-	if (retval)
-		return retval;
+	for (i = 0; i < ARRAY_SIZE(up->irqs); i++) {
+		if (i == 1 && !omap_wakeirq) {
+			dev_info(up->port.dev, "no wakeirq for uart%d\n",

drivers/tty/serial/omap-serial.c static int serial_omap_startup(struct uart_port *port) · line 721

Quoted 6 lines

drivers/tty/serial/omap-serial.c +6 -0

+				 up->port.line);
+			break;
+		}
+		retval = devm_request_irq(up->port.dev, up->irqs[i],
+					  serial_omap_irq, up->port.irqflags,
+					  up->name, up);

conversion to devm_* should be done as another patch, it seems.

drivers/tty/serial/omap-serial.c static void serial_omap_shutdown(struct uart_port *port) · line 819

Quoted 9 lines

drivers/tty/serial/omap-serial.c +4 -1

@@ -786,7 +813,10 @@ static void serial_omap_shutdown(struct uart_port *port)
 
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);
-	free_irq(up->port.irq, up);
+
+	for (i = 0; i < ARRAY_SIZE(up->irqs); i++)
+		if (up->irqs[i])
+			devm_free_irq(up->port.dev, up->irqs[i], up);

do you need this at all if you're using devm_* ?

Quoted 11 lines · Felipe Balbi

drivers/tty/serial/omap-serial.c static void serial_omap_shutdown(struct uart_port *port) · line 819

Quoted 9 lines

drivers/tty/serial/omap-serial.c +4 -1

@@ -786,7 +813,10 @@ static void serial_omap_shutdown(struct uart_port *port)
 
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);
-	free_irq(up->port.irq, up);
+
+	for (i = 0; i < ARRAY_SIZE(up->irqs); i++)
+		if (up->irqs[i])
+			devm_free_irq(up->port.dev, up->irqs[i], up);

do you need this at all if you're using devm_* ?

So it seems, startup and shutdown are managed by serial_core and that's what at least clps711x.c serial driver is doing.

Quoted 13 lines · Tony Lindgren

Quoted 11 lines · Felipe Balbi

Review static void serial_omap_shutdown(struct uart_port *port) · line 819

Quoted 9 lines

(quoted diff) +4 -1

@@ -786,7 +813,10 @@ static void serial_omap_shutdown(struct uart_port *port)
 
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);
-	free_irq(up->port.irq, up);
+
+	for (i = 0; i < ARRAY_SIZE(up->irqs); i++)
+		if (up->irqs[i])
+			devm_free_irq(up->port.dev, up->irqs[i], up);

do you need this at all if you're using devm_* ?

Quoted 2 lines

So it seems, startup and shutdown are managed by serial_core and that's what at least clps711x.c serial driver is doing.

And that means devm_* in this case does not really help us here..

I guess we could keep the IRQ requested from probe, but there's probably a reason why it's done in startup/shutdown.

So I'll just drop the devm_* changes for now.

Quoted 17 lines · Tony Lindgren

Quoted 13 lines · Tony Lindgren

Quoted 11 lines · Felipe Balbi

Review static void serial_omap_shutdown(struct uart_port *port) · line 819

Quoted 9 lines

(quoted diff) +4 -1

@@ -786,7 +813,10 @@ static void serial_omap_shutdown(struct uart_port *port)
 
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);
-	free_irq(up->port.irq, up);
+
+	for (i = 0; i < ARRAY_SIZE(up->irqs); i++)
+		if (up->irqs[i])
+			devm_free_irq(up->port.dev, up->irqs[i], up);

do you need this at all if you're using devm_* ?

Quoted 2 lines

So it seems, startup and shutdown are managed by serial_core and that's what at least clps711x.c serial driver is doing.

Quoted 7 lines

And that means devm_* in this case does not really help us here..

I guess we could keep the IRQ requested from probe, but there's probably a reason why it's done in startup/shutdown.

So I'll just drop the devm_* changes for now.

Here's an updated simplified version. I also got rid of the for loops as the wake-up interrupt is optional and it made the code a bit of a pain to read.

Regards,

Tony

8< ----------------------------------------
From: Tony Lindgren <[email protected]>
Date: Wed, 16 Oct 2013 10:27:28 -0700
Subject: [PATCH] serial: omap: Add support for optional wake-up interrupt

With the recent pinctrl-single changes, omaps can treat wake-up events from deeper idle states as interrupts.

There's a separate "io chain" controller on most omaps that stays enabled when the device hits off-idle and the regular interrupt controller is powered off.

Let's add support for the optional second interrupt for wake-up events. And then serial-omap can manage the wake-up interrupt from it's runtime PM calls to avoid spurious interrupts during runtime.

Note that the wake interrupt is board specific as it uses the UART RX pin, and for omap3, there are six pin options for UART3 RX pin.

Also Note that the legacy platform based booting handles the wake-ups in the legacy mux driver and does not need to pass the wake-up interrupt to the driver.

And finally, to pass the wake-up interrupt in the dts file, either interrupt-map or the pending interrupts-extended property needs to be passed. It's probably best to use interrupts-extended when it's available.

Cc Felipe Balbi <[email protected]>

Cc Kevin Hilman <[email protected]>

Cc Linus Walleij <[email protected]>

Cc Roger Quadros <[email protected]>

Signed-off-by Tony Lindgren <[email protected]>

drivers/tty/serial/omap-serial.c +46 -8

@@ -39,6 +39,7 @@
 #include <linux/irq.h>
 #include <linux/pm_runtime.h>
 #include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
 #include <linux/platform_data/serial-omap.h>

@@ -134,6 +135,7 @@ struct uart_omap_port {
 	struct uart_port	port;
 	struct uart_omap_dma	uart_dma;
 	struct device		*dev;
+	int			wakeirq;
 
 	unsigned char		ier;
 	unsigned char		lcr;

@@ -214,10 +216,23 @@ static int serial_omap_get_context_loss_count(struct uart_omap_port *up)
 	return pdata->get_context_loss_count(up->dev);
 }
 
+static inline void serial_omap_enable_wakeirq(struct uart_omap_port *up,
+				       bool enable)
+{
+	if (!up->wakeirq)
+		return;
+
+	if (enable)
+		enable_irq(up->wakeirq);
+	else
+		disable_irq(up->wakeirq);
+}
+
 static void serial_omap_enable_wakeup(struct uart_omap_port *up, bool enable)
 {
 	struct omap_uart_port_info *pdata = dev_get_platdata(up->dev);
 
+	serial_omap_enable_wakeirq(up, enable);
 	if (!pdata || !pdata->enable_wakeup)
 		return;
 

@@ -699,6 +714,20 @@ static int serial_omap_startup(struct uart_port *port)
 	if (retval)
 		return retval;
 
+	/* Optional wake-up IRQ */
+	if (up->wakeirq) {
+		retval = request_irq(up->wakeirq, serial_omap_irq,
+				     up->port.irqflags, up->name, up);
+		if (retval) {
+			free_irq(up->port.irq, up);
+			return retval;
+		}
+		disable_irq(up->wakeirq);
+	} else {
+		dev_info(up->port.dev, "no wakeirq for uart%d\n",
+			 up->port.line);
+	}
+
 	dev_dbg(up->port.dev, "serial_omap_startup+%d\n", up->port.line);
 
 	pm_runtime_get_sync(up->dev);

@@ -787,6 +816,8 @@ static void serial_omap_shutdown(struct uart_port *port)
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);
 	free_irq(up->port.irq, up);
+	if (up->wakeirq)
+		free_irq(up->wakeirq, up);
 }
 
 static void serial_omap_uart_qos_work(struct work_struct *work)

@@ -1572,11 +1603,23 @@ static int serial_omap_probe(struct platform_device *pdev)
 	struct uart_omap_port	*up;
 	struct resource		*mem, *irq;
 	struct omap_uart_port_info *omap_up_info = dev_get_platdata(&pdev->dev);
-	int ret;
+	int ret, uartirq = 0, wakeirq = 0;
 
+	/* The optional wakeirq may be specified in the board dts file */
 	if (pdev->dev.of_node) {
+		uartirq = irq_of_parse_and_map(pdev->dev.of_node, 0);
+		if (!uartirq)
+			return -EPROBE_DEFER;
+		wakeirq = irq_of_parse_and_map(pdev->dev.of_node, 1);
 		omap_up_info = of_get_uart_port_info(&pdev->dev);
 		pdev->dev.platform_data = omap_up_info;
+	} else {
+		irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+		if (!irq) {
+			dev_err(&pdev->dev, "no irq resource?\n");
+			return -ENODEV;
+		}
+		uartirq = irq->start;
 	}
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);

@@ -1585,12 +1628,6 @@ static int serial_omap_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
-	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	if (!irq) {
-		dev_err(&pdev->dev, "no irq resource?\n");
-		return -ENODEV;
-	}
-
 	if (!devm_request_mem_region(&pdev->dev, mem->start, resource_size(mem),
 				pdev->dev.driver->name)) {
 		dev_err(&pdev->dev, "memory region already claimed\n");

@@ -1624,7 +1661,8 @@ static int serial_omap_probe(struct platform_device *pdev)
 	up->port.dev = &pdev->dev;
 	up->port.type = PORT_OMAP;
 	up->port.iotype = UPIO_MEM;
-	up->port.irq = irq->start;
+	up->port.irq = uartirq;
+	up->wakeirq = wakeirq;
 
 	up->port.regshift = 2;
 	up->port.fifosize = 64;

Quoted 17 lines · Tony Lindgren

Quoted 13 lines · Tony Lindgren

Quoted 11 lines · Felipe Balbi

Review static void serial_omap_shutdown(struct uart_port *port) · line 819

Quoted 9 lines

(quoted diff) +4 -1

@@ -786,7 +813,10 @@ static void serial_omap_shutdown(struct uart_port *port)
 
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);
-	free_irq(up->port.irq, up);
+
+	for (i = 0; i < ARRAY_SIZE(up->irqs); i++)
+		if (up->irqs[i])
+			devm_free_irq(up->port.dev, up->irqs[i], up);

do you need this at all if you're using devm_* ?

Quoted 2 lines

So it seems, startup and shutdown are managed by serial_core and that's what at least clps711x.c serial driver is doing.

Quoted 7 lines

And that means devm_* in this case does not really help us here..

I guess we could keep the IRQ requested from probe, but there's probably a reason why it's done in startup/shutdown.

So I'll just drop the devm_* changes for now.

Here's an updated simplified version. I also got rid of the for loops as the wake-up interrupt is optional and it made the code a bit of a pain to read.

Regards,

Tony

8< ----------------------------------------
From: Tony Lindgren <[email protected]>
Date: Wed, 16 Oct 2013 10:27:28 -0700
Subject: [PATCH] serial: omap: Add support for optional wake-up interrupt

With the recent pinctrl-single changes, omaps can treat wake-up events from deeper idle states as interrupts.

There's a separate "io chain" controller on most omaps that stays enabled when the device hits off-idle and the regular interrupt controller is powered off.

Let's add support for the optional second interrupt for wake-up events. And then serial-omap can manage the wake-up interrupt from it's runtime PM calls to avoid spurious interrupts during runtime.

Note that the wake interrupt is board specific as it uses the UART RX pin, and for omap3, there are six pin options for UART3 RX pin.

Also Note that the legacy platform based booting handles the wake-ups in the legacy mux driver and does not need to pass the wake-up interrupt to the driver.

And finally, to pass the wake-up interrupt in the dts file, either interrupt-map or the pending interrupts-extended property needs to be passed. It's probably best to use interrupts-extended when it's available.

Cc Felipe Balbi <[email protected]>

Cc Kevin Hilman <[email protected]>

Cc Linus Walleij <[email protected]>

Cc Roger Quadros <[email protected]>

Signed-off-by Tony Lindgren <[email protected]>

looks much nicer

Reviewed-by Felipe Balbi <[email protected]>