gpio_test: Module for testing GPIO interrupt

Build proedure:
1. Copy Examples folder to Linux source
2. change directory to Examples/gpio
3. build gpio test module using make all

Test procedure
4. insert kernel module and generate interrupt.

Signed-off-by: Philip Avinash <avinashphilip@ti.com>

Examples/gpio/Makefile

@@ -0,0 +1,16 @@
+obj-m += gpio_test.o 
+PWD := $(shell pwd)
+KERNEL_DIR := $(PWD)/../../
+
+#INSTALL_DIR=$(FINAL_DEST)/gpio
+
+# Set KERNEL_DIR to your local kernel location
+
+all:
+	$(MAKE) -C $(KERNEL_DIR) M=$(PWD) ARCH=arm CROSS_COMPILE=arm-arago-linux-gnueabi-
+
+install:
+	mkdir -p $(INSTALL_DIR)
+	cp gpio_test.ko $(INSTALL_DIR)
+clean:
+	rm -rf *.o *.ko *.mod.c .*.cmd .tmp_versions *.order *.symvers

Examples/gpio/gpio_test.c

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2009 Texas Instruments Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option)any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/delay.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <mach/cputype.h>
+#include <mach/hardware.h>
+#include <mach/mux.h>
+#include <asm/gpio.h>
+
+
+static int gpio_num;
+static int gpio_pin;
+
+DECLARE_COMPLETION(work);
+
+static irqreturn_t handler (int irq, void * dev)
+{
+	complete_all(&work);
+	return IRQ_HANDLED;
+}
+
+
+int init_module() 
+{
+	int status;
+
+	init_completion(&work);
+
+	if(cpu_is_davinci_da830()) {
+		gpio_num = 87;	/* gpio_num = (bank_num * 16) + pin_num */
+		gpio_pin = DA830_GPIO5_7;
+	} else {
+		gpio_num = 116;
+		gpio_pin = DA850_GPIO7_4;
+	}
+
+	if (cpu_is_davinci_da830())	
+		printk("\nTesting gpio %d (connected to boot pin S2-7)\n",
+			gpio_num);
+	else
+		printk("\nTesting gpio %d (connected to boot pin S7-8)\n",
+			gpio_num);
+
+	/* init/set pinmux */
+	status = davinci_cfg_reg(gpio_pin);
+	if (status < 0) {
+		printk("pin could not be muxed for GPIO functionality %d\n",
+								gpio_num);
+		return status;
+	}
+
+	status = gpio_request(gpio_num, "gpio_test\n");
+	if (status < 0) {
+		printk("ERROR can not open GPIO %d\n", gpio_num);
+		return status;
+	}
+
+	gpio_direction_input(gpio_num);
+
+	if (cpu_is_davinci_da830())
+		printk("The current state of S2-7 pin is ");
+	else
+		printk("The current state of S7-8 pin is ");
+	if(gpio_get_value(gpio_num) == 0) 
+		printk("OFF. \n\tWaiting for the pin to be on..\n");
+	else 
+		printk("ON. \n\tWaiting for the pin to be off..\n");
+
+	status = request_irq(gpio_to_irq(gpio_num), handler, 0, "gpio_test", NULL);
+	if(status < 0) {
+		printk(KERN_ERR "error %d requesting GPIO IRQ %d\n", status, gpio_num);
+		return status;
+	}
+
+	irq_set_irq_type(gpio_to_irq(gpio_num), IRQ_TYPE_EDGE_RISING);
+
+	wait_for_completion_interruptible(&work);
+
+	printk(".. done\n");
+
+	return 0;
+}
+
+void cleanup_module(void) {
+
+	gpio_free(gpio_num);
+
+	free_irq(gpio_to_irq(gpio_num), NULL);
+}
+
+MODULE_LICENSE("GPL");