Blackfin: add an example showing how to use the gptimers API

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

Documentation/blackfin/Makefile

+obj-m := gptimers-example.o
+
+all: modules
+
+modules clean:
+	$(MAKE) -C ../.. SUBDIRS=$(PWD) $@

Documentation/blackfin/gptimers-example.c

+/*
+ * Simple gptimers example
+ *	http://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:drivers:gptimers
+ *
+ * Copyright 2007-2009 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+
+#include <asm/gptimers.h>
+#include <asm/portmux.h>
+
+/* ... random driver includes ... */
+
+#define DRIVER_NAME "gptimer_example"
+
+struct gptimer_data {
+	uint32_t period, width;
+};
+static struct gptimer_data data;
+
+/* ... random driver state ... */
+
+static irqreturn_t gptimer_example_irq(int irq, void *dev_id)
+{
+	struct gptimer_data *data = dev_id;
+
+	/* make sure it was our timer which caused the interrupt */
+	if (!get_gptimer_intr(TIMER5_id))
+		return IRQ_NONE;
+
+	/* read the width/period values that were captured for the waveform */
+	data->width = get_gptimer_pwidth(TIMER5_id);
+	data->period = get_gptimer_period(TIMER5_id);
+
+	/* acknowledge the interrupt */
+	clear_gptimer_intr(TIMER5_id);
+
+	/* tell the upper layers we took care of things */
+	return IRQ_HANDLED;
+}
+
+/* ... random driver code ... */
+
+static int __init gptimer_example_init(void)
+{
+	int ret;
+
+	/* grab the peripheral pins */
+	ret = peripheral_request(P_TMR5, DRIVER_NAME);
+	if (ret) {
+		printk(KERN_NOTICE DRIVER_NAME ": peripheral request failed\n");
+		return ret;
+	}
+
+	/* grab the IRQ for the timer */
+	ret = request_irq(IRQ_TIMER5, gptimer_example_irq, IRQF_SHARED, DRIVER_NAME, &data);
+	if (ret) {
+		printk(KERN_NOTICE DRIVER_NAME ": IRQ request failed\n");
+		peripheral_free(P_TMR5);
+		return ret;
+	}
+
+	/* setup the timer and enable it */
+	set_gptimer_config(TIMER5_id, WDTH_CAP | PULSE_HI | PERIOD_CNT | IRQ_ENA);
+	enable_gptimers(TIMER5bit);
+
+	return 0;
+}
+module_init(gptimer_example_init);
+
+static void __exit gptimer_example_exit(void)
+{
+	disable_gptimers(TIMER5bit);
+	free_irq(IRQ_TIMER5, &data);
+	peripheral_free(P_TMR5);
+}
+module_exit(gptimer_example_exit);
+
+MODULE_LICENSE("BSD");