driver/touchscreen: Add support for write operations

Signed-off-by: yinshengkai <yinshengkai@xiaomi.com>

drivers/input/touchscreen_upper.c

@@ -81,6 +81,11 @@ static int     touch_ioctl(FAR struct file *filep, int cmd,
 static int     touch_poll(FAR struct file *filep, FAR struct pollfd *fds,
                           bool setup);
 
+#ifdef CONFIG_INPUT_UINPUT
+static ssize_t touch_write(FAR struct file *filep, FAR const char *buffer,
+                           size_t buflen);
+#endif
+
 /****************************************************************************
  * Private Data
  ****************************************************************************/
@@ -90,7 +95,11 @@ static const struct file_operations g_touch_fops =
   touch_open,     /* open */
   touch_close,    /* close */
   touch_read,     /* read */
+#ifdef CONFIG_INPUT_UINPUT
+  touch_write,    /* write */
+#else
   NULL,           /* write */
+#endif
   NULL,           /* seek */
   touch_ioctl,    /* ioctl */
   touch_poll      /* poll */
@@ -197,6 +206,27 @@ static int touch_close(FAR struct file *filep)
   return ret;
 }
 
+/****************************************************************************
+ * Name: touch_write
+ ****************************************************************************/
+
+#ifdef CONFIG_INPUT_UINPUT
+static ssize_t touch_write(FAR struct file *filep, FAR const char *buffer,
+                          size_t buflen)
+{
+  FAR struct inode *inode             = filep->f_inode;
+  FAR struct touch_upperhalf_s *upper = inode->i_private;
+  FAR struct touch_lowerhalf_s *lower = upper->lower;
+
+  if (!lower->write)
+    {
+      return -ENOSYS;
+    }
+
+  return lower->write(lower, buffer, buflen);
+}
+#endif
+
 /****************************************************************************
  * Name: touch_read
  ****************************************************************************/

include/nuttx/input/touchscreen.h

@@ -175,6 +175,25 @@ struct touch_lowerhalf_s
 
   CODE int (*control)(FAR struct touch_lowerhalf_s *lower,
                       int cmd, unsigned long arg);
+
+  /**************************************************************************
+   * Name: write
+   *
+   * Description:
+   *   Users can use this interface to implement custom write.
+   *
+   * Arguments:
+   *   lower   - The instance of lower half of touchscreen device.
+   *   buffer  - User defined specific buffer.
+   *   buflen  - User defined specific buffer size.
+   *
+   * Return Value:
+   *   Number of bytes written；a negated errno value on failure.
+   *
+   **************************************************************************/
+
+  CODE ssize_t (*write)(FAR struct touch_lowerhalf_s *lower,
+                        FAR const char *buffer, size_t buflen);
 };
 
 /****************************************************************************