Add code to allow dev_write to cope with partial writes (as will sometimes

occur when using languages such as python to write to the dev file).
Currently static data so same for all processes.

ServoBlaster/servoblaster.c

@@ -329,7 +329,7 @@ struct process_data
 	// e.g. "3=180"
 	// Line length is expected to be <32
 	int cmd_idx;
-	char cmd_data[32];
+	char cmd_str[32];
 };
 
 // kmalloc the temporary data required for each user:
@@ -404,21 +404,38 @@ static ssize_t dev_read(struct file *filp,char *buf,size_t count,loff_t *f_pos)
 
 static ssize_t dev_write(struct file *filp,const char *buf,size_t count,loff_t *f_pos)
 {
-	char str[32];
+	char* end_of_line=0;
+	static int idx=0;
+	static char str[32];
+	static const int max_idx = sizeof(str) - 1;
 
-	if (count > 31) count = 31;
-	if (copy_from_user(str, buf, count)) {
+	if ((idx+count) > max_idx) count = max_idx-idx;
+	if (copy_from_user(str, buf+idx, count)) {
 		return -EFAULT;
 	}
-	str[count] = '\0';
+	idx+=count;
+	str[idx] = '\0';
+	end_of_line = strchr(str, '\n');
+	if (NULL == end_of_line)
+	{
+		if (31 == idx)  {
+			// Full buf without '\n'
+			printk(KERN_WARNING "ServoBlaster: Failed to parse command (%s)\n", str);
+			return -EINVAL;
+		}
+		return count;	// Incomplete line.
+	}
+
+	// We've reached end of command, so terminate string at '\n' and reset idx.
+	*end_of_line = '\0';
+	idx=0;
 
 	// Process the complete user string.
 	{
 		int servo;
 		int cnt;
 		int n;
-		char dummy;
-		n = sscanf(str, "%d=%d\n%c", &servo, &cnt, &dummy);
+		n = sscanf(str, "%d=%d", &servo, &cnt);
 		if (n != 2) {
 			printk(KERN_WARNING "ServoBlaster: Failed to parse command (n=%d)\n", n);
 			return -EINVAL;