added test mode that doesn't use GPIO so i can test on an Virtual Machine on my main computer

1 files changed, 77 insertions, 59 deletions

diff --git a/skey.c b/skey.c
index 0457cb4..d08c140 100644
--- a/skey.c
+++ b/skey.c
@@ -6,6 +6,11 @@
 #include <linux/delay.h>
 #include <linux/sched.h>
 /*
+ * defines whether to access the gpios so other parts of the kernel module can
+ * be tested on systems w/o the prerequisite GPIOs
+ */
+#define USE_GPIO 1
+/*
  * Unsigned ints containing the BCM pin numbers for the pins used, __initdata
  * helps with the loading and unloading of data in memory
  */
@@ -20,7 +25,7 @@ static __initdata char * rlabels[3] = {"R0", "R1", "R2"};
  * variables for setting up the thread
  */
 
-struct task_struct *update_task;
+static struct task_struct *update_task;
 /*
  *This function is called every timer-period to actually read the keyboard
  */
@@ -30,24 +35,29 @@ int skey_update_thread (void *data) {
 	const struct sched_param PARAM = { .sched_priority = 45};
 	sched_setscheduler(current, SCHED_FIFO, &PARAM);
 	printk(KERN_INFO "skey: started update thread\n");
+	
 	while (1) {
-		//reads the keyboard
-		int row_index = 0;
-		int column_index = 0;
-		while (column_index < 10) {
-			//sets the column pin high for reading
-			gpio_set_value(column_pins[column_index], 1);
-			//reads with all the rows
-			row_index = 0;
-			while (row_index < 3) {
-				if (gpio_get_value(row_pins[row_index])) {
-					printk(KERN_INFO "skey: key pressed at column %d, row %d\n", column_index, row_index);
+		if (USE_GPIO) {
+			//reads the keyboard
+			int row_index = 0;
+			int column_index = 0;
+			while (column_index < 10) {
+				//sets the column pin high for reading
+				gpio_set_value(column_pins[column_index], 1);
+				//reads with all the rows
+				row_index = 0;
+				while (row_index < 3) {
+					if (gpio_get_value(row_pins[row_index])) {
+						printk(KERN_INFO "skey: key pressed at column %d, row %d\n", column_index, row_index);
+					}
+					row_index++;
 				}
-				row_index++;
+				//sets the row pin low
+				gpio_set_value(column_pins[column_index], 0);
+				column_index++;
 			}
-			//sets the row pin low
-			gpio_set_value(column_pins[column_index], 0);
-			column_index++;
+		} else {
+			printk(KERN_ALERT "skey: currently in test mode with gpio use disabled\n");
 		}
 		//sleep 2000us= 2ms = 0.002 seconds
 		usleep_range(2000, 2000);	
@@ -64,41 +74,45 @@ int skey_update_thread (void *data) {
  */
 static int  __init skey_init (void) {
 	printk(KERN_INFO "skey: module initiating...\n");
-	int i = 0;
-	//claims the column pins
-	while (i < 10) {
-		//checks to see if the gpios are valid
-		if (!gpio_is_valid(column_pins[i])) {
-			printk(KERN_ALERT "skey: column_pins[%d], BCM %d request invalid\n", i, column_pins[i]);
-			return -EINVAL;
-		}
-		//requests access of the GPIO
-		if (gpio_request_one(column_pins[i], GPIOF_OUT_INIT_LOW ,clabels[i])) {
-			printk(KERN_ALERT "skey: column_pins[%d], BCM %d request failed\n", i, column_pins[i]);
-			return -EINVAL;
-		}
-		if (gpio_direction_output(column_pins[i], 0)) {
-			printk(KERN_ALERT "skey: column_pins[%d], BCM %d, set output failed\n",i, column_pins[i]);
-		}
-		i++;
-	}
-	//ditto for row pins
-	int j = 0;
-	while (j < 3) {
-		//checks to see if the gpios are valid
-		if (!gpio_is_valid(row_pins[j])) {
-			printk(KERN_ALERT "skey: row_pins[%d], BCM %d request invalid\n", j, row_pins[j]);
-			return -EINVAL;
-		}
-		//requests access of the GPIO
-		if (gpio_request_one(row_pins[j], GPIOF_DIR_IN ,rlabels[j])) {
-			printk(KERN_ALERT "skey: row_pins[%d], BCM %d request failed\n", j, row_pins[j]);
-			return -EINVAL;
+	if (USE_GPIO) {
+		int i = 0;
+		//claims the column pins
+		while (i < 10) {
+			//checks to see if the gpios are valid
+			if (!gpio_is_valid(column_pins[i])) {
+				printk(KERN_ALERT "skey: column_pins[%d], BCM %d request invalid\n", i, column_pins[i]);
+				return -EINVAL;
+			}
+			//requests access of the GPIO
+			if (gpio_request_one(column_pins[i], GPIOF_OUT_INIT_LOW ,clabels[i])) {
+				printk(KERN_ALERT "skey: column_pins[%d], BCM %d request failed\n", i, column_pins[i]);
+				return -EINVAL;
+			}
+			if (gpio_direction_output(column_pins[i], 0)) {
+				printk(KERN_ALERT "skey: column_pins[%d], BCM %d, set output failed\n",i, column_pins[i]);
+			}
+			i++;
 		}
-		if (gpio_direction_input(row_pins[j])) {
-			printk(KERN_ALERT "skey: row_pins[%d], BCM %d, set output failed\n",j, row_pins[j]);
+		//ditto for row pins
+		int j = 0;
+		while (j < 3) {
+			//checks to see if the gpios are valid
+			if (!gpio_is_valid(row_pins[j])) {
+				printk(KERN_ALERT "skey: row_pins[%d], BCM %d request invalid\n", j, row_pins[j]);
+				return -EINVAL;
+			}
+			//requests access of the GPIO
+			if (gpio_request_one(row_pins[j], GPIOF_DIR_IN ,rlabels[j])) {
+				printk(KERN_ALERT "skey: row_pins[%d], BCM %d request failed\n", j, row_pins[j]);
+				return -EINVAL;
+			}
+			if (gpio_direction_input(row_pins[j])) {
+				printk(KERN_ALERT "skey: row_pins[%d], BCM %d, set output failed\n",j, row_pins[j]);
+			}
+			j++;
 		}
-		j++;
+	} else {
+		printk(KERN_ALERT "skey: currently in test mode with gpio use disabled\n");
 	}
 	//sets up update thread
 	printk("skey: setting up update thread...\n");
@@ -112,16 +126,20 @@ static int  __init skey_init (void) {
  */
 static void __exit skey_exit (void) {
 	printk(KERN_INFO "skey: module exiting...\n");
-	//frees column and row pins
-	int i = 0;
-	while (i < 10) {
-		gpio_free(column_pins[i]);
-		i++;
-	}
-	int j = 0;
-	while (j < 3) {
-		gpio_free(row_pins[j]);
-		j++;
+	if (USE_GPIO) {
+		//frees column and row pins
+		int i = 0;
+		while (i < 10) {
+			gpio_free(column_pins[i]);
+			i++;
+		}
+		int j = 0;
+		while (j < 3) {
+			gpio_free(row_pins[j]);
+			j++;
+		}
+	} else {
+		printk(KERN_ALERT "skey: currently in test mode with gpio use disabled\n");
 	}
 	//deletes the thread
 	kthread_stop(update_task);