ARM: OMAP: Added support for serial wake-up events

By muxing serial RX lines into GPIO interrupts it's possible
to wake-up from deep sleep from serial port.

This is protected by Kconfig option CONFIG_OMAP_SERIAL_WAKE
until we have dev specific wake-up events that can be configured
via sysfs.

arch/arm/mach-omap/Kconfig

@@ -169,6 +169,14 @@ config OMAP_LL_DEBUG_UART3
 
 endchoice
 
+config OMAP_SERIAL_WAKE
+	bool "Enable wake-up events for serial ports"
+	default y
+	help
+	  Select this option if you want to have your system wake up
+	  to data on the serial RX line. This allows you to wake the
+	  system from serial console.
+
 endmenu
 
 endif

arch/arm/mach-omap/omap1/serial.c

@@ -24,7 +24,9 @@
 
 #include <asm/arch/board.h>
 #include <asm/arch/mux.h>
+#include <asm/arch/gpio.h>
 #include <asm/arch/fpga.h>
+#include <asm/arch/pm.h>
 
 static struct clk * uart1_ck = NULL;
 static struct clk * uart2_ck = NULL;
@@ -193,8 +195,86 @@ void __init omap_serial_init(int ports[OMAP_MAX_NR_PORTS])
 	}
 }
 
+#ifdef CONFIG_OMAP_SERIAL_WAKE
+
+static irqreturn_t omap_serial_wake_interrupt(int irq, void *dev_id,
+					      struct pt_regs *regs)
+{
+	/* Need to do something with serial port right after wake-up? */
+	return IRQ_HANDLED;
+}
+
+/*
+ * Reroutes serial RX lines to GPIO lines for the duration of
+ * sleep to allow waking up the device from serial port even
+ * in deep sleep.
+ */
+void omap_serial_wake_trigger(int enable)
+{
+	if (!cpu_is_omap16xx())
+		return;
+
+	if (uart1_ck != NULL) {
+		if (enable)
+			omap_cfg_reg(V14_16XX_GPIO37);
+		else
+			omap_cfg_reg(V14_16XX_UART1_RX);
+	}
+	if (uart2_ck != NULL) {
+		if (enable)
+			omap_cfg_reg(R9_16XX_GPIO18);
+		else
+			omap_cfg_reg(R9_16XX_UART2_RX);
+	}
+	if (uart3_ck != NULL) {
+		if (enable)
+			omap_cfg_reg(L14_16XX_GPIO49);
+		else
+			omap_cfg_reg(L14_16XX_UART3_RX);
+	}
+}
+
+static void __init omap_serial_set_port_wakeup(int gpio_nr)
+{
+	int ret;
+
+	ret = omap_request_gpio(gpio_nr);
+	if (ret < 0) {
+		printk(KERN_ERR "Could not request UART wake GPIO: %i\n",
+		       gpio_nr);
+		return;
+	}
+	omap_set_gpio_direction(gpio_nr, 1);
+	set_irq_type(OMAP_GPIO_IRQ(gpio_nr), IRQT_RISING);
+	ret = request_irq(OMAP_GPIO_IRQ(gpio_nr), &omap_serial_wake_interrupt,
+			  0, "serial wakeup", NULL);
+	if (ret) {
+		omap_free_gpio(gpio_nr);
+		printk(KERN_ERR "No interrupt for UART wake GPIO: %i\n",
+		       gpio_nr);
+		return;
+	}
+	enable_irq_wake(OMAP_GPIO_IRQ(gpio_nr));
+}
+
+static void __init omap_serial_wakeup_init(void)
+{
+	if (!cpu_is_omap16xx())
+		return;
+
+	if (uart1_ck != NULL)
+		omap_serial_set_port_wakeup(37);
+	if (uart2_ck != NULL)
+		omap_serial_set_port_wakeup(18);
+	if (uart3_ck != NULL)
+		omap_serial_set_port_wakeup(49);
+}
+
+#endif	/* CONFIG_OMAP_SERIAL_WAKE */
+
 static int __init omap_init(void)
 {
+	omap_serial_wakeup_init();
 	return platform_device_register(&serial_device);
 }
 arch_initcall(omap_init);

arch/arm/mach-omap/pm.c

@@ -157,6 +157,8 @@ void omap_pm_suspend(void)
 
 	printk("PM: OMAP%x is trying to enter deep sleep...\n", system_rev);
 
+	omap_serial_wake_trigger(1);
+
 	if (machine_is_omap_osk()) {
 		/* Stop LED1 (D9) blink */
 		tps65010_set_led(LED1, OFF);
@@ -312,6 +314,8 @@ void omap_pm_suspend(void)
 	local_irq_enable();
 	local_fiq_enable();
 
+	omap_serial_wake_trigger(0);
+
 	printk("PM: OMAP%x is re-starting from deep sleep...\n", system_rev);
 
 	if (machine_is_omap_osk()) {

include/asm-arm/arch-omap/pm.h

@@ -111,6 +111,13 @@ extern void omap1610_cpu_suspend(unsigned short, unsigned short);
 extern void omap1510_idle_loop_suspend(void);
 extern void omap1610_idle_loop_suspend(void);
 
+#ifdef CONFIG_OMAP_SERIAL_WAKE
+extern void omap_serial_wake_trigger(int enable);
+#else
+#define omap_serial_wakeup_init()	{}
+#define omap_serial_wake_trigger(x)	{}
+#endif	/* CONFIG_OMAP_SERIAL_WAKE */
+
 extern unsigned int omap1510_cpu_suspend_sz;
 extern unsigned int omap1510_idle_loop_suspend_sz;
 extern unsigned int omap1610_cpu_suspend_sz;