add: 05_Input/DRV_02_编写input_dev驱动框架

STM32MP157/doc_pic/05_Input/DRV_02_编写input_dev驱动框架.md

@@ -0,0 +1,63 @@
+## 编写input_dev驱动框架
+
+参考资料：
+
+* Linux 5.x内核文档
+* Documentation\input\input-programming.rst
+  * Documentation\input\event-codes.rst
+* Linux 4.x内核文档
+  * Documentation\input\input-programming.txt
+  * Documentation\input\event-codes.txt
+
+* 本节视频代码：GIT仓库中
+
+  ```shell
+  IMX6ULL\source\05_Input\02_input_dev_framework
+  STM32MP157\source\A7\05_Input\02_input_dev_framework
+  ```
+
+  
+
+### 1. 回顾框架
+
+![image-20210326102626660](pic/05_Input/03_input_driver_module.png)
+
+### 2. 怎么编写input_dev驱动
+
+#### 2.1 分配/设置/注册input_dev
+
+![image-20210324140549118](pic/05_Input/08_input_dev.png)
+
+
+
+#### 2.2 硬件相关的操作
+
+* 申请中断
+
+* 在中断服务程序里
+
+  * 读取硬件获得数据
+
+  * 上报数据
+
+    ```shell
+    void input_event(struct input_dev *dev,
+    		 unsigned int type, unsigned int code, int value);
+    		 
+    static inline void input_sync(struct input_dev *dev); // 实质也是 input_event
+    ```
+
+    
+
+### 3. 现场编程
+
+![image-20210326095621949](pic/05_Input/12_write_input_dev.png)
+
+* 在设备树里创建一个节点
+  * 指定硬件资源等信息
+* 编译一个plartform_driver驱动
+  * 在probe函数里
+    * 从设备树获得资源
+    * 分配/设置/注册input_dev
+    * 硬件相关的操作
+      * request_irq等

STM32MP157/source/A7/05_Input/02_input_dev_framework/input_dev.c

@@ -0,0 +1,120 @@
+
+#include <linux/module.h>
+
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/sched.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+#include <linux/proc_fs.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/input.h>
+#include <linux/gpio_keys.h>
+#include <linux/workqueue.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/spinlock.h>
+
+static struct input_dev *g_input_dev;
+static int g_irq;
+static irqreturn_t input_dev_demo_isr(int irq, void *dev_id)
+{
+	/* read data */
+
+	/* report data */
+	input_event(g_input_dev, EV_KEY, XX, 0);
+	input_sync(g_input_dev);
+	
+	return IRQ_HANDLED;
+}
+
+
+/* alloc/set/register platform_driver */
+static int input_dev_demo_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int error;
+	struct resource *irq;
+
+	/* get hardware info from device tree */
+
+	/* alloc/set/register input_dev */
+	g_input_dev = devm_input_allocate_device(dev);
+
+	g_input_dev->name = "input_dev_demo";
+	g_input_dev->phys = "input_dev_demo";
+	g_input_dev->dev.parent = dev;
+
+	g_input_dev->id.bustype = BUS_HOST;
+	g_input_dev->id.vendor = 0x0001;
+	g_input_dev->id.product = 0x0001;
+	g_input_dev->id.version = 0x0100;
+
+	/* set 1: which type event ? */	
+	__set_bit(EV_KEY, g_input_dev->evbit);
+	__set_bit(EV_ABS, g_input_dev->evbit);
+
+	/* set 2: which event ? */	
+	__set_bit(BTN_TOUCH, g_input_dev->keybit);
+	__set_bit(ABS_MT_SLOT, g_input_dev->absbit);
+	__set_bit(ABS_MT_POSITION_X, g_input_dev->absbit);
+	__set_bit(ABS_MT_POSITION_Y, g_input_dev->absbit);
+
+	/* set 3: event params ? */	
+	input_set_abs_params(g_input_dev, ABS_MT_POSITION_X, 0, 0xffff, 0, 0);
+	input_set_abs_params(g_input_dev, ABS_MT_POSITION_Y, 0, 0xffff, 0, 0);
+	
+	error = input_register_device(g_input_dev);
+
+	/* hardware opration */
+	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	g_irq = irq->start;
+	request_irq(irq->start, input_dev_demo_isr, IRQF_TRIGGER_RISING, "input_dev_demo_irq", NULL);
+
+	return 0;
+}
+
+static int input_dev_demo_remove(struct platform_device *pdev)
+{
+	free_irq(g_irq, NULL);
+	input_unregister_device(g_input_dev);
+	return 0;
+}
+
+static const struct of_device_id input_dev_demo_of_match[] = {
+	{ .compatible = "100ask,input_dev_demo", },
+	{ },
+};
+
+static struct platform_driver input_dev_demo_driver = {
+	.probe		= input_dev_demo_probe,
+	.remove	    = input_dev_demo_remove,
+	.driver		= {
+		.name	= "input_dev_demo",
+		.of_match_table = input_dev_demo_of_match,
+	}
+};
+
+
+static int __init input_dev_demo_init(void)
+{
+	return platform_driver_register(&input_dev_demo_driver);
+}
+
+static void __exit input_dev_demo_exit(void)
+{
+	platform_driver_unregister(&input_dev_demo_driver);
+}
+
+module_init(input_dev_demo_init);
+module_exit(input_dev_demo_exit);
+
+MODULE_LICENSE("GPL");
+
+

STM32MP157/source/A7/05_Input/02_input_dev_framework/input_dev.dts

@@ -0,0 +1,6 @@
+/ {
+	input_dev_demo {
+		compatible = "100ask,input_dev_demo";
+		interrupts = <...>;
+	};
+};