drivers/input: Add driver for Goodix GT9XX Touch Panel

This PR adds the driver for Goodix GT9XX I2C Touch Panel, which will be called by PINE64 PinePhone.

Our driver follows the design of the NuttX Driver for [Cypress MBR3108](https://github.com/apache/nuttx/blob/master/drivers/input/cypress_mbr3108.c).

We have documented our driver here: ["NuttX Touch Panel Driver for PinePhone"](https://lupyuen.github.io/articles/touch2#appendix-nuttx-touch-panel-driver-for-pinephone)

`drivers/input/Kconfig`: Added option `INPUT_GT9XX` to select GT9XX Driver

`drivers/input/Make.defs`: Added GT9XX Driver to Makefile

`drivers/input/gt9xx.c`, `gt9xx.h`: I2C Driver for GT9XX Touch Panel

drivers/input/Kconfig

@@ -499,6 +499,29 @@ config INPUT_CYPRESS_MBR3108_NPOLLWAITERS
 
 endif # INPUT_CYPRESS_MBR3108
 
+config INPUT_GT9XX
+	bool "Goodix GT9xx Driver"
+	default n
+	select INPUT_TOUCHSCREEN
+	---help---
+		Enable support for Goodix GT9xx touch panel.
+
+if INPUT_GT9XX
+
+config INPUT_GT9XX_NPOLLWAITERS
+	int "Number of waiters to poll"
+	default 1
+	---help---
+		Maximum number of threads that can be waiting on poll()
+
+config INPUT_GT9XX_I2C_FREQUENCY
+	int "I2C frequency (Hz)"
+	default 400000
+	---help---
+		I2C frequency in Hz
+
+endif # INPUT_GT9XX
+
 config INPUT_BUTTONS
 	bool "Button Inputs"
 	default n

drivers/input/Make.defs

@@ -72,6 +72,10 @@ ifeq ($(CONFIG_INPUT_CYPRESS_MBR3108),y)
   CSRCS += cypress_mbr3108.c
 endif
 
+ifeq ($(CONFIG_INPUT_GT9XX),y)
+  CSRCS += gt9xx.c
+endif
+
 ifeq ($(CONFIG_INPUT_BUTTONS),y)
   CSRCS += button_upper.c
 ifeq ($(CONFIG_INPUT_BUTTONS_LOWER),y)

include/nuttx/input/gt9xx.h

@@ -0,0 +1,84 @@
+/****************************************************************************
+ * include/nuttx/input/gt9xx.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_INPUT_GT9XX_H
+#define __INCLUDE_NUTTX_INPUT_GT9XX_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/compiler.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/* Callback for Board-Specific Operations */
+
+struct gt9xx_board_s
+{
+  /* Attach the Interrupt Handler for Touch Panel */
+
+  int (*irq_attach) (const struct gt9xx_board_s *state,
+                     xcpt_t isr,
+                     FAR void *arg);
+
+  /* Enable or disable Interrupts for the Touch Panel. Will be called by
+   * Interrupt Handler.
+   */
+
+  void (*irq_enable) (const struct gt9xx_board_s *state, bool enable);
+
+  /* Power on or off the Touch Panel */
+
+  int (*set_power) (const struct gt9xx_board_s *state, bool on);
+};
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: gt9xx_register
+ *
+ * Description:
+ *   Register the driver for Goodix GT9XX Touch Panel.  Attach the
+ *   Interrupt Handler for the Touch Panel and disable Touch Interrupts.
+ *
+ * Input Parameters:
+ *   devpath      - Device Path (e.g. "/dev/input0")
+ *   dev          - I2C Bus
+ *   i2c_devaddr  - I2C Address of Touch Panel
+ *   board_config - Callback for Board-Specific Operations
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value is returned on any failure.
+ *
+ ****************************************************************************/
+
+int gt9xx_register(FAR const char *devpath,
+                   FAR struct i2c_master_s *dev,
+                   uint8_t i2c_devaddr,
+                   const struct gt9xx_board_s *board_config);
+
+#endif /* __INCLUDE_NUTTX_INPUT_GT9XX_H */