pipa: enhance xiaomi-pen utility with error handling

- Update copyright year to 2023-2025
- Add version information
- Implement proper error handling for device operations
- Add status output for better diagnostics
- Add comments for improved readability
- Return appropriate error codes on failure

Signed-off-by: Abdulwahab Isam <abdoi94.iq@gmail.com>

peripheralmanager/xiaomi-pen.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2023 The LineageOS Project
+ * Copyright (C) 2023-2025 The LineageOS Project
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -8,7 +8,12 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
+#include <errno.h>
+#include <string.h>
 
+#define VERSION_STRING "1.0.0"
+
+// Device control definitions
 #define SET_CUR_VALUE 0
 #define TOUCH_PEN_MODE 20
 #define TOUCH_MAGIC 't'
@@ -16,12 +21,41 @@
 #define TOUCH_DEV_PATH "/dev/xiaomi-touch"
 
 int main(int argc, char **argv) {
+    // Validate arguments
     if(argc != 2) {
+        fprintf(stderr, "Xiaomi pen utility v%s\n", VERSION_STRING);
         fprintf(stderr, "Usage: %s <value>\n", argv[0]);
         return -1;
     }
+
+    // Open the touch device
     int fd = open(TOUCH_DEV_PATH, O_RDWR);
-    int arg[2] = {TOUCH_PEN_MODE, atoi(argv[1])};
-    ioctl(fd, TOUCH_IOC_SETMODE, &arg);
+    if (fd < 0) {
+        fprintf(stderr, "Error opening device %s: %s\n", 
+                TOUCH_DEV_PATH, strerror(errno));
+        return -1;
+    }
+
+    // Parse the input value
+    int value = atoi(argv[1]);
+    if (value < 0 || value > 20) {
+        fprintf(stderr, "Warning: Value %d outside normal range (0-20)\n", value);
+    }
+    fprintf(stdout, "Setting pen mode to: %d\n", value);
+    
+    // Prepare and send the command
+    int arg[2] = {TOUCH_PEN_MODE, value};
+    int result = ioctl(fd, TOUCH_IOC_SETMODE, &arg);
+    
+    // Check for errors
+    if (result < 0) {
+        fprintf(stderr, "Error setting pen mode: %s\n", strerror(errno));
+        close(fd);
+        return -1;
+    }
+
+    // Clean up
     close(fd);
+    fprintf(stdout, "Pen mode set successfully\n");
+    return 0;
 }