sh: generic push-switch framework.

This adds support for a generic push switch framework. Adaptable for
various switches, including GPIO switches and the push switches commonly
found on Renesas debug boards.

This allows switch states to be trivially reported through sysfs.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

include/asm-sh/push-switch.h

@@ -0,0 +1,28 @@
+#ifndef __ASM_SH_PUSH_SWITCH_H
+#define __ASM_SH_PUSH_SWITCH_H
+
+#include <linux/timer.h>
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
+
+struct push_switch {
+	/* switch state */
+	unsigned int		state:1;
+	/* debounce timer */
+	struct timer_list	debounce;
+	/* workqueue */
+	struct work_struct	work;
+};
+
+struct push_switch_platform_info {
+	/* IRQ handler */
+	irqreturn_t		(*irq_handler)(int irq, void *data);
+	/* Special IRQ flags */
+	unsigned int		irq_flags;
+	/* Bit location of switch */
+	unsigned int		bit;
+	/* Symbolic switch name */
+	const char		*name;
+};
+
+#endif /* __ASM_SH_PUSH_SWITCH_H */