MTK 按键驱动流程总结

前言

简单介绍了 Input 按键驱动流程

流程

位置：Kpd.c (kernel-3.18\drivers\input\keyboard\mediatek)
module_init(kpd_mod_init);
static int __init kpd_mod_init(void)
    /
    //
    //      static struct platform_driver kpd_pdrv = {
    //          .probe = kpd_pdrv_probe,
    //          .remove = kpd_pdrv_remove,
    //      #ifndef USE_EARLY_SUSPEND
    //          .suspend = kpd_pdrv_suspend,
    //          .resume = kpd_pdrv_resume,
    //      #endif
    //          .driver = {
    //                 .name = KPD_NAME,
    //                 .owner = THIS_MODULE,
    //                 .of_match_table = kpd_of_match,
    //                      ///
    //                      //  static const struct of_device_id kpd_of_match[] = {
    //                      //      {.compatible = "mediatek,mt6580-keypad"},
    //                      //      {.compatible = "mediatek,mt6570-keypad"},
    //                      //      {.compatible = "mediatek,mt6735-keypad"},
    //                      //      {.compatible = "mediatek,mt6755-keypad"},
    //                      //      ...
    //                      //      {},
    //                      //  };
    //                 },
    //      };
    /
    // 对应的 dts 中的配置还是蛮好玩的，贴一下
    //  Mt6755.dtsi (kernel-3.18\arch\arm64\boot\dts)
    //      keypad: keypad@10010000 {
	//	    	compatible = "mediatek,mt6755-keypad", "mediatek,kp";
	//	    	reg = <0x10010000 0x1000>;
	//	    	interrupts = <GIC_SPI 164 IRQ_TYPE_EDGE_FALLING>;
	//	    };
    // dws 中的配置：
    //      &keypad {	
    //          KPD@ {
    //              compatible = "mediatek, kpd";
    //              kpd-key-debounce = <1024>;
    //              kpd-sw-pwrkey = <116>;
    //              kpd-hw-pwrkey = <8>;
    //              kpd-sw-rstkey  = <102>;
    //              kpd-hw-rstkey = <17>;
    //              kpd-use-extend-type = <0>;
    //              /// HW Keycode [0~71] -> Linux Keycode
    //              kpd-hw-init-map = <114 115 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 >;
    //              kpd-pwrkey-eint-gpio = <0>;
    //              kpd-pwkey-gpio-din  = <0>;
    //              kpd-hw-dl-key0 = <1>;
    //              kpd-hw-dl-key1 = <0>;
    //              kpd-hw-dl-key2 = <8>;
    //              *****************************************************************
    //              *******************Uboot Customation***************************
    //              *****************************************************************
    //              kpd-hw-recovery-key = <1>;
    //              kpd-hw-factory-key  = <0>;
    //          };
    //      };
    ///
    // 最后反汇编出来的东西：
    //      keypad@10010000 {
    //          compatible = "mediatek,mt6755-keypad", "mediatek,kp";
    //          reg = <0x10010000 0x1000>;
    //          interrupts = <0x0 0xa4 0x2>;
    //          mediatek,kpd-key-debounce = <0x400>;
    //          mediatek,kpd-sw-pwrkey = <0x74>;
    //          mediatek,kpd-hw-pwrkey = <0x8>;
    //          mediatek,kpd-sw-rstkey = <0x66>;
    //          mediatek,kpd-hw-rstkey = <0x11>;
    //          mediatek,kpd-use-extend-type = <0x0>;
    //          mediatek,kpd-hw-map-num = <0x48>;
    //          mediatek,kpd-hw-init-map = <0x72 0x73 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0>;
    //          mediatek,kpd-pwrkey-eint-gpio = <0x0>;
    //          mediatek,kpd-pwkey-gpio-din = <0x0>;
    //          mediatek,kpd-hw-dl-key0 = <0x1>;
    //          mediatek,kpd-hw-dl-key1 = <0x0>;
    //          mediatek,kpd-hw-dl-key2 = <0x8>;
    //          mediatek,kpd-hw-recovery-key = <0x1>;
    //          mediatek,kpd-hw-factory-key = <0x0>;
    //          status = "okay";
    //      };
    r = platform_driver_register(&kpd_pdrv);

/
// 匹配后调用：
static int kpd_pdrv_probe(struct platform_device *pdev)
    
    // 获取时钟
    kpd_clk = devm_clk_get(&pdev->dev, "kpd-clk");
    ret_prepare = clk_prepare(kpd_clk);
    ret_enable = clk_enable(kpd_clk);
    
    // 地址映射 reg = <0x10010000 0x1000>;
    kp_base = of_iomap(pdev->dev.of_node, 0);
    
    ///
    // 中断申请和注册 interrupts = <0x0 0xa4 0x2>;
    kp_irqnr = irq_of_parse_and_map(pdev->dev.of_node, 0);
    
    //
    // 分配 input 输入设备
    kpd_input_dev = input_allocate_device();
    
    
    // 设备 input 输入设备
    kpd_input_dev->name = KPD_NAME;
	kpd_input_dev->id.bustype = BUS_HOST;
	kpd_input_dev->id.vendor = 0x2454;
	kpd_input_dev->id.product = 0x6500;
	kpd_input_dev->id.version = 0x0010;
	kpd_input_dev->open = kpd_open;// 打开输入设备时调用
                            	//               
                                #ifdef CONFIG_WIND_HALL_SUPPORT
                                
                                    kpd_hall_init();
                                #endif
                                //      
    
    // 获得 dts 的配置信息
    kpd_get_dts_info(pdev->dev.of_node);
            of_property_read_u32(node, "mediatek,kpd-key-debounce", &kpd_dts_data.kpd_key_debounce);
            of_property_read_u32(node, "mediatek,kpd-sw-pwrkey", &kpd_dts_data.kpd_sw_pwrkey);
            of_property_read_u32(node, "mediatek,kpd-hw-pwrkey", &kpd_dts_data.kpd_hw_pwrkey);
            of_property_read_u32(node, "mediatek,kpd-sw-rstkey", &kpd_dts_data.kpd_sw_rstkey);
            of_property_read_u32(node, "mediatek,kpd-hw-rstkey", &kpd_dts_data.kpd_hw_rstkey);
            of_property_read_u32(node, "mediatek,kpd-use-extend-type", &kpd_dts_data.kpd_use_extend_type);
            of_property_read_u32(node, "mediatek,kpd-pwrkey-eint-gpio", &kpd_dts_data.kpd_pwrkey_eint_gpio);
            of_property_read_u32(node, "mediatek,kpd-pwrkey-gpio-din", &kpd_dts_data.kpd_pwrkey_gpio_din);
            of_property_read_u32(node, "mediatek,kpd-hw-dl-key1", &kpd_dts_data.kpd_hw_dl_key1);
            of_property_read_u32(node, "mediatek,kpd-hw-dl-key2", &kpd_dts_data.kpd_hw_dl_key2);
            of_property_read_u32(node, "mediatek,kpd-hw-dl-key3", &kpd_dts_data.kpd_hw_dl_key3);
            of_property_read_u32(node, "mediatek,kpd-hw-recovery-key", &kpd_dts_data.kpd_hw_recovery_key);
            of_property_read_u32(node, "mediatek,kpd-hw-factory-key", &kpd_dts_data.kpd_hw_factory_key);
            of_property_read_u32(node, "mediatek,kpd-hw-map-num", &kpd_dts_data.kpd_hw_map_num);
            ret = of_property_read_u32_array(node, "mediatek,kpd-hw-init-map", kpd_dts_data.kpd_hw_init_map,kpd_dts_data.kpd_hw_map_num);
    
    // 将 dts 中的配置写到全局数组中
    kpd_memory_setting();
            kpd_init_keymap(kpd_keymap);
            kpd_init_keymap_state(kpd_keymap_state);
    
    //
    // 下面就是设置 input 设备上报的键值了，而对应的键值在 dts 数组中设置的
    if (!kpd_dts_data.kpd_use_extend_type) {
		for (i = 17; i < KPD_NUM_KEYS; i += 9)	// only [8] works for Power key 
			kpd_keymap[i] = 0;
	}    
    for (i = 0; i < KPD_NUM_KEYS; i++) {
		if (kpd_keymap[i] != 0)
			__set_bit(kpd_keymap[i], kpd_input_dev->keybit);
	}
    
    //      
    #ifdef CONFIG_WIND_HALL_SUPPORT
        __set_bit(EV_SW, kpd_input_dev->evbit);
        __set_bit(SW_LID, kpd_input_dev->swbit);
        kpd_input_dev->keybit[BIT_WORD(KEY_F9)] |= BIT_MASK(KEY_F9);
        kpd_input_dev->keybit[BIT_WORD(KEY_F10)] |= BIT_MASK(KEY_F10);
     #endif
    //      

    kpd_input_dev->dev.parent = &pdev->dev;
    //
    // 注册 input 输入设备
	r = input_register_device(kpd_input_dev);
    
    /
    // 注册一个杂项设备
    kpd_dev.parent = &pdev->dev;
	r = misc_register(&kpd_dev);
    wake_lock_init(&kpd_suspend_lock, WAKE_LOCK_SUSPEND, "kpd wakelock");
    
    
    // 注册一个按键 IRQ 函数
    kpd_set_debounce(kpd_dts_data.kpd_key_debounce);
	r = request_irq(kp_irqnr, kpd_irq_handler, IRQF_TRIGGER_NONE, KPD_NAME, NULL);

    
    // 初始化了一个定时器
    hrtimer_init(&aee_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	aee_timer.function = aee_timer_func;
    
    /
    // 创建 sys 属性节点
    err = kpd_create_attr(&kpd_pdrv.driver);

    
    

// 当有按键发生时：
static irqreturn_t kpd_irq_handler(int irq, void *dev_id)
        ///
        // use _nosync to avoid deadlock
        disable_irq_nosync(kp_irqnr);
        tasklet_schedule(&kpd_keymap_tasklet);
                static void kpd_keymap_handler(unsigned long data)
                            /
                            // 获取按键状态
                            kpd_get_keymap_state(new_state);
                                    state[0] = *(volatile u16 *)KP_MEM1;
                                    state[1] = *(volatile u16 *)KP_MEM2;
                                    state[2] = *(volatile u16 *)KP_MEM3;
                                    state[3] = *(volatile u16 *)KP_MEM4;
                                    state[4] = *(volatile u16 *)KP_MEM5;
                                    
                            wake_lock_timeout(&kpd_suspend_lock, HZ / 2);
                            for (i = 0; i < KPD_NUM_MEMS; i++)
                                change = new_state[i] ^ kpd_keymap_state[i];
                                for (j = 0; j < 16; j++)
                                    mask = 1U << j;
                                    hw_keycode = (i << 4) + j;
                                    pressed = !(new_state[i] & mask);
                                    linux_keycode = kpd_keymap[hw_keycode];
                                    
                                    kpd_aee_handler(linux_keycode, pressed);
                                    input_report_key(kpd_input_dev, linux_keycode, pressed);
                                    input_sync(kpd_input_dev);
                            
                            memcpy(kpd_keymap_state, new_state, sizeof(new_state));
                            enable_irq(kp_irqnr);