基於tiny4412的Linux內核移植--- 中斷和GPIO學習（3）

作者

彭東林

pengdonglin137@163.com

平臺

tiny4412 ADK

Linux-4.4.4

u-boot使用的U-Boot 2010.12，是友善自帶的，爲支持設備樹和uImage做了稍許改動

簡介

前面我們實現了一種設備樹下中斷的使用方法，下面介紹第二種，這種方式本質上跟前者是一樣的，使用的是platform_bus的接口。

爲了便於比較，還是以底板上面上的四個按鍵爲例分析，其中前兩個按鍵使用第二種方式，後兩個按鍵使用第一種方式。

正文

原理圖可以參考博文：基於tiny4412的Linux內核移植--- 中斷和GPIO學習（1）

下面是設備樹的改動：

 diff --git a/arch/arm/boot/dts/exynos4412-tiny4412.dts b/arch/arm/boot/dts/exynos4412-tiny4412.dts
 index 610202a..2e69c91
 --- a/arch/arm/boot/dts/exynos4412-tiny4412.dts
 +++ b/arch/arm/boot/dts/exynos4412-tiny4412.dts
 @@ -, +, @@
  #include <dt-bindings/gpio/gpio.h>
  #include <dt-bindings/usb4640/usb4640.h>
  #include <dt-bindings/pwm/pwm.h>
 +#include <dt-bindings/interrupt-controller/irq.h>
  #include <autoconf.h>

  / {
 @@ -, +, @@
                 };
         };
  #endif
 +
 +interrupt_another: interrupt_another {
 +                       compatible = "tiny4412,interrupt_another";
 +                       interrupt-parent = <&gpx3>;
 +                       interrupts = < IRQ_TYPE_EDGE_FALLING  IRQ_TYPE_EDGE_FALLING>;
 +                       tiny4412,int_gpio0 = <&gpx3  GPIO_ACTIVE_HIGH>;
 +                       tiny4412,int_gpio1 = <&gpx3  GPIO_ACTIVE_HIGH>;
 +               };
  };

  &rtc {

其中，interrupts屬性值的解析需要看中斷控制器gpx3在創建irq_domain時設置的回調函數exynos_eint_irqd_ops的xlate成員。以後我們再分析。而gpio屬性的值的含義則需要看gpio控制器gpx3在創建時設置的of_xlate回調函數of_gpio_simple_xlate，這個以後分析。

下面看驅動：

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/gpio.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
 #include <linux/interrupt.h>

 typedef struct
 {
     int gpio;
     int irq;
     char name[];
 }int_demo_data_t;

 static irqreturn_t int_demo_isr_pdev(int irq, void *dev_id)
 {
     int_demo_data_t *data = dev_id;

     printk("%s enter, %s irq: %d\n", __func__, data->name, irq);

     return IRQ_HANDLED;
 }

 static irqreturn_t int_demo_isr_gpio(int irq, void *dev_id)
 {
     int_demo_data_t *data = dev_id;

     printk("%s enter, %s irq: %d\n", __func__, data->name, irq);
     return IRQ_HANDLED;
 }

 static int int_demo_probe(struct platform_device *pdev) {
     struct device *dev = &pdev->dev;
     int irq_gpio = -;
     int irq = -;
     int ret = ;
     int i = ;
     int_demo_data_t *data = NULL;

     printk("%s enter.\n", __func__);

     if (!dev->of_node) {
         dev_err(dev, "no platform data.\n");
         goto err0;
     }

     data = devm_kmalloc(dev, sizeof(*data)*, GFP_KERNEL);
     if (!data) {
         dev_err(dev, "no memory.\n");
         goto err0;
     }

     for (i = ; i < ; i++) {
         irq = platform_get_irq(pdev, i);
         sprintf(data[i].name, "tiny4412,pdev_irq_%d", i);
         ret = devm_request_any_context_irq(dev, irq,
             int_demo_isr_pdev, IRQF_TRIGGER_FALLING, data[i].name, data+i);
         if (ret < ) {
             dev_err(dev, "Unable to claim irq %d; error %d\n",
                 irq, ret);
             goto err0;
         }
         printk("request irq: %d\n", irq);
     }

     for (i = ; i < ; i++) {
         sprintf(data[i+].name, "tiny4412,int_gpio%d", i);
         irq_gpio = of_get_named_gpio(dev->of_node,
             data[i+].name, );
         if (irq_gpio < ) {
             dev_err(dev, "Looking up %s property in node %s failed %d\n",
                 data[i].name, dev->of_node->full_name, irq_gpio);
             goto err0;
         }

         data[i+].gpio = irq_gpio;

         irq = gpio_to_irq(irq_gpio);
         if (irq < ) {
             dev_err(dev,
                 "Unable to get irq number for GPIO %d, error %d\n",
                 irq_gpio, irq);
             goto err0;
         }

         data[i+].irq = irq;

         printk("%s: gpio: %d ---> irq (%d)\n", __func__, irq_gpio, irq);

         ret = devm_request_any_context_irq(dev, irq,
             int_demo_isr_gpio, IRQF_TRIGGER_FALLING, data[i+].name, data+i+);
         if (ret < ) {
             dev_err(dev, "Unable to claim irq %d; error %d\n",
                 irq, ret);
             goto err0;
         }
     }

     return ;

 err0:
     return -EINVAL;
 }

 static int int_demo_remove(struct platform_device *pdev) {

     printk("%s enter.\n", __func__);
     return ;
 }

 static const struct of_device_id int_demo_dt_ids[] = {
     { .compatible = "tiny4412,interrupt_another", },
     {},
 };

 MODULE_DEVICE_TABLE(of, int_demo_dt_ids);

 static struct platform_driver int_demo_driver = {
     .driver        = {
         .name    = "interrupt_another",
         .of_match_table    = of_match_ptr(int_demo_dt_ids),
     },
     .probe        = int_demo_probe,
     .remove        = int_demo_remove,
 };

 static int __init int_demo_init(void)
 {
     int ret;

     ret = platform_driver_register(&int_demo_driver);
     if (ret)
         printk(KERN_ERR "int demo: probe failed: %d\n", ret);

     return ret;
 }
 module_init(int_demo_init);

 static void __exit int_demo_exit(void)
 {
     platform_driver_unregister(&int_demo_driver);
 }
 module_exit(int_demo_exit);

 MODULE_LICENSE("GPL");

在platform_device進行populate的時候，已經對其irq資源進行了映射，這個以後分析。

驗證

加載驅動：

[root@tiny4412 mnt]# insmod interrupt_another.ko
[   33.330879] int_demo_probe enter.
[   33.331896] request irq:
[   33.332778] request irq:
[   33.333412] int_demo_probe: gpio:  ---> irq ()
[   33.334535] int_demo_probe: gpio:  ---> irq ()

依次按鍵，由於沒有加消抖處理，所以依次按鍵可能會觸發多次中斷

[root@tiny4412 mnt]# [ 1244.082303] int_demo_isr_pdev enter, tiny4412,pdev_irq_0 irq:
[ 1244.229761] int_demo_isr_pdev enter, tiny4412,pdev_irq_0 irq:
[ 1245.129735] int_demo_isr_pdev enter, tiny4412,pdev_irq_1 irq:
[ 1245.283928] int_demo_isr_pdev enter, tiny4412,pdev_irq_1 irq:
[ 1246.269231] int_demo_isr_gpio enter, tiny4412,int_gpio0 irq:
[ 1246.476101] int_demo_isr_gpio enter, tiny4412,int_gpio0 irq:
[ 1247.769903] int_demo_isr_gpio enter, tiny4412,int_gpio1 irq:
[ 1248.034338] int_demo_isr_gpio enter, tiny4412,int_gpio1 irq:
[ 1248.035396] int_demo_isr_gpio enter, tiny4412,int_gpio1 irq:
[ 1248.035858] int_demo_isr_gpio enter, tiny4412,int_gpio1 irq:
[ 1248.036218] int_demo_isr_gpio enter, tiny4412,int_gpio1 irq: 

我們再看看系統中斷資源註冊情況

[root@tiny4412 mnt]# cat /proc/interrupts
           CPU0       CPU1       CPU2       CPU3
 :                                               GIC   Edge      mct_comp_irq
 :                                   GIC   Edge      MCT
 :                                               PMU   Edge      s3c2410-rtc alarm
 :                                               PMU   Edge      s3c2410-rtc tick
 :                                              GIC  Edge      mmc0
 :                                               GIC  Edge      .hsotg, .hsotg, dwc2_hsotg:usb1
 :                                             GIC  Edge      ehci_hcd:usb2, ohci_hcd:usb3
 :                                             GIC   Edge      .serial
 :                                              GIC   Edge      .i2c
 :                                               GIC   Edge      .pdma
 :                                               GIC   Edge      .pdma
 :                                               GIC   Edge      .mdma
 :                                               GIC   Edge      .pinctrl
 :                                               GIC   Edge      .pinctrl
 :                                          COMBINER   Edge      .pinctrl
 :                                               GIC  Edge      106e0000.pinctrl
 :                                              GIC  Edge      dw-mci
103:          8          0          0          0  exynos4210_wkup_irq_chip   2 Edge      tiny4412,pdev_irq_0
104:          4          0          0          0  exynos4210_wkup_irq_chip   3 Edge      tiny4412,pdev_irq_1
:                                          exynos4210_wkup_irq_chip    Edge      mma7660
:                                          exynos_gpio_irq_chip    Edge      .sdhci cd
107:          6          0          0          0  exynos4210_wkup_irq_chip   4 Edge      tiny4412,int_gpio0
108:          9          0          0          0  exynos4210_wkup_irq_chip   5 Edge      tiny4412,int_gpio1
IPI0:                                          CPU wakeup interrupts
IPI1:                                          Timer broadcast interrupts
IPI2:                                 Rescheduling interrupts
IPI3:                                          Function call interrupts
IPI4:                                          Single function call interrupts
IPI5:                                          CPU stop interrupts
IPI6:                                          IRQ work interrupts
IPI7:                                          completion interrupts

未完待續...