设备树学习之（一）GPIO中断
转载于: http://blog.csdn.net/lizuobin2/article/details/54563587
http://www.cnblogs.com/pengdonglin137/p/6082796.html
tiny4412 ADK
Linux-4.4.4 (4.4.1类似)
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
在tiny4412的底板上有四個key，如下：
上圖中，在沒有按鍵的時候，對應的GPIO是被拉高的，當按下鍵的時候，對應的GPIO被拉低，從而產生一個下降沿中斷。
有了上面的準備，首先我們需要修改設備樹，添加相應的節點和相關的屬性：
1 diff --git a/arch/arm/boot/dts/exynos4412-tiny4412.dts b/arch/arm/boot/dts/exynos4412-tiny4412.dts 2 index 610202a..a130047 100644 3 --- a/arch/arm/boot/dts/exynos4412-tiny4412.dts 4 +++ b/arch/arm/boot/dts/exynos4412-tiny4412.dts 5 @@ -136,6 +136,14 @@ 6 }; 7 }; 8 #endif 9 + 10 + interrupt_demo: interrupt_demo { 11 + compatible = "tiny4412,interrupt_demo"; 12 + tiny4412,int_gpio1 = <&gpx3 2 GPIO_ACTIVE_HIGH>; 13 + tiny4412,int_gpio2 = <&gpx3 3 GPIO_ACTIVE_HIGH>; 14 + tiny4412,int_gpio3 = <&gpx3 4 GPIO_ACTIVE_HIGH>; 15 + tiny4412,int_gpio4 = <&gpx3 5 GPIO_ACTIVE_HIGH>; 16 + }; 17 };
上面的代碼中，我們添加了四個屬性，對應的就是那四個key對應的gpio，參考gpx3的實現（exynos4x12-pinctrl.dtsi）：
gpx3: gpx3 { gpio-controller; #gpio-cells = <2>; interrupt-controller; #interrupt-cells = <2>; };
可以看到，gpx3含有gpio-controller和interrupt-controller屬性，表示它是一個gpio控制器和中斷控制器，它的gpio-cell爲2，意味着應該給這個gpx3傳遞兩個參數，以
tiny4412,int_gpio1 = <&gpx3 2 GPIO_ACTIVE_HIGH>
爲例，這兩個參數就是2和GPIO_ACTIVE_HIGH，如果參數不對的話，比如只傳了一個參數2，那麼在調用of_get_named_gpio會出現如下錯誤：
[ 31.133799] /interrupt_demo: arguments longer than property [ 31.133935] interrupt_demo interrupt_demo: Looking up tiny4412,int_gpio4 property in node /interrupt_demo failed -22 [ 31.144562] interrupt_demo: probe of interrupt_demo failed with error -22使用 make dtbs 編譯完設備樹。
在Samsung的pinctrl驅動中加一些log：
@@ -622,6 +626,8 @@ static int samsung_gpio_to_irq(struct gpio_chip *gc, unsigned offset) struct samsung_pin_bank *bank = gc_to_pin_bank(gc); unsigned int virq; + printk("%s enter.\n", __func__); + if (!bank->irq_domain) return -ENXIO;
然後我們編寫對應的驅動程序：
1 #include <linux/init.h> 2 #include <linux/module.h> 3 #include <linux/platform_device.h> 4 #include <linux/gpio.h> 5 #include <linux/of.h> 6 #include <linux/of_gpio.h> 7 #include <linux/interrupt.h> 8 9 typedef struct 10 { 11 int gpio; 12 int irq; 13 char name[20]; 14 }int_demo_data_t; 15 16 static irqreturn_t int_demo_isr(int irq, void *dev_id) 17 { 18 int_demo_data_t *data = dev_id; 19 20 printk("%s enter, %s: gpio:%d, irq: %d\n", __func__, data->name, data->gpio, data->irq); 21 22 return IRQ_HANDLED; 23 } 24 25 static int int_demo_probe(struct platform_device *pdev) { 26 struct device *dev = &pdev->dev; 27 int irq_gpio = -1; 28 int irq = -1; 29 int ret = 0; 30 int i = 0; 31 int_demo_data_t *data = NULL; 32 33 printk("%s enter.\n", __func__); 34 35 if (!dev->of_node) { 36 dev_err(dev, "no platform data.\n"); 37 goto err1; 38 } 39 40 data = devm_kmalloc(dev, sizeof(*data)*4, GFP_KERNEL); 41 if (!data) { 42 dev_err(dev, "no memory.\n"); 43 goto err0; 44 } 45 46 #if 0 47 for (i = 3; i >= 0; i--) { 48 sprintf(data[i].name, "tiny4412,int_gpio%d", i+1); 49 #else 50 for (i = 0; i < 4; i++) { 51 #endif 52 irq_gpio = of_get_named_gpio(dev->of_node, 53 data[i].name, 0); 54 if (irq_gpio < 0) { 55 dev_err(dev, "Looking up %s property in node %s failed %d\n", 56 data[i].name, dev->of_node->full_name, irq_gpio); 57 goto err1; 58 } 59 60 data[i].gpio = irq_gpio; 61 62 irq = gpio_to_irq(irq_gpio); 63 if (irq < 0) { 64 dev_err(dev, 65 "Unable to get irq number for GPIO %d, error %d\n", 66 irq_gpio, irq); 67 goto err1; 68 } 69 70 data[i].irq = irq; 71 72 printk("%s: gpio: %d ---> irq (%d)\n", __func__, irq_gpio, irq); 73 74 ret = devm_request_any_context_irq(dev, irq, 75 int_demo_isr, IRQF_TRIGGER_FALLING, data[i].name, data+i); 76 if (ret < 0) { 77 dev_err(dev, "Unable to claim irq %d; error %d\n", 78 irq, ret); 79 goto err1; 80 } 81 } 82 83 return 0; 84 85 err1: 86 devm_kfree(dev, data); 87 err0: 88 return -EINVAL; 89 } 90 91 static int int_demo_remove(struct platform_device *pdev) { 92 93 printk("%s enter.\n", __func__); 94 95 return 0; 96 } 97 98 static const struct of_device_id int_demo_dt_ids[] = { 99 { .compatible = "tiny4412,interrupt_demo", }, 100 {}, 101 }; 102 103 MODULE_DEVICE_TABLE(of, int_demo_dt_ids); 104 105 static struct platform_driver int_demo_driver = { 106 .driver = { 107 .name = "interrupt_demo", 108 .of_match_table = of_match_ptr(int_demo_dt_ids), 109 }, 110 .probe = int_demo_probe, 111 .remove = int_demo_remove, 112 }; 113 114 static int __init int_demo_init(void) 115 { 116 int ret; 117 118 ret = platform_driver_register(&int_demo_driver); 119 if (ret) 120 printk(KERN_ERR "int demo: probe failed: %d\n", ret); 121 122 return ret; 123 } 124 module_init(int_demo_init); 125 126 static void __exit int_demo_exit(void) 127 { 128 platform_driver_unregister(&int_demo_driver); 129 } 130 module_exit(int_demo_exit); 131 132 MODULE_LICENSE("GPL");
編譯驅動後，將ko文件拷貝到nfs目錄下，然後在開發板上執行 mount -t nfs -o nolock 192.168.2.6:/nfsroot /mnt 將共享目錄從PC上掛載到開發板上，然後insmod這個驅動：
[root@tiny4412 ]# mount -t nfs -o nolock 192.168.2.6:/nfsroot /mnt [root@tiny4412 ]# cd /mnt [root@tiny4412 mnt]# ls fdt interrupt_demo.ko tiny4412.dts [root@tiny4412 mnt]# insmod interrupt_demo.ko [ 1655.872546] int_demo_probe enter. [ 1655.872841] samsung_gpio_to_irq enter. [ 1655.873061] int_demo_probe: gpio: 238 ---> irq (105) [ 1655.873716] samsung_gpio_to_irq enter. [ 1655.873906] int_demo_probe: gpio: 239 ---> irq (106) [ 1655.874424] samsung_gpio_to_irq enter. [ 1655.874773] int_demo_probe: gpio: 240 ---> irq (107) [ 1655.879981] samsung_gpio_to_irq enter. [ 1655.883485] int_demo_probe: gpio: 241 ---> irq (108) [root@tiny4412 mnt]# // 然後我們嘗試按底板上的按鍵，會看到相應的中斷log [root@tiny4412 mnt]# [ 33.462207] int_demo_isr enter, tiny4412,int_gpio1: gpio:238, irq: 105 [ 33.657304] int_demo_isr enter, tiny4412,int_gpio1: gpio:238, irq: 105 [ 35.769955] int_demo_isr enter, tiny4412,int_gpio3: gpio:240, irq: 107 [ 35.951373] int_demo_isr enter, tiny4412,int_gpio3: gpio:240, irq: 107 [ 36.525804] int_demo_isr enter, tiny4412,int_gpio4: gpio:241, irq: 108 [ 36.698501] int_demo_isr enter, tiny4412,int_gpio4: gpio:241, irq: 108 [ 41.710481] int_demo_isr enter, tiny4412,int_gpio2: gpio:239, irq: 106 [ 41.857190] int_demo_isr enter, tiny4412,int_gpio2: gpio:239, irq: 106 [root@tiny4412 mnt]# cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 36: 0 0 0 0 GIC 89 Edge mct_comp_irq 37: 1054 566 579 339 GIC 28 Edge MCT 44: 34 0 0 0 GIC 107 Edge mmc0 45: 1 0 0 0 GIC 103 Edge 12480000.hsotg, 12480000.hsotg, dwc2_hsotg:usb1 46: 508 0 0 0 GIC 102 Edge ehci_hcd:usb2, ohci_hcd:usb3 47: 197 0 0 0 GIC 84 Edge 13800000.serial 51: 52 0 0 0 GIC 93 Edge 13890000.i2c 57: 0 0 0 0 GIC 67 Edge 12680000.pdma 58: 0 0 0 0 GIC 68 Edge 12690000.pdma 59: 0 0 0 0 GIC 66 Edge 12850000.mdma 71: 0 0 0 0 GIC 79 Edge 11400000.pinctrl 72: 1 0 0 0 GIC 78 Edge 11000000.pinctrl 90: 0 0 0 0 COMBINER 80 Edge 3860000.pinctrl 91: 0 0 0 0 GIC 104 Edge 106e0000.pinctrl 95: 48 0 0 0 GIC 109 Edge dw-mci 103: 2 0 0 0 exynos4210_wkup_irq_chip 1 Edge mma7660 104: 1 0 0 0 exynos_gpio_irq_chip 2 Edge 12530000.sdhci cd 105: 2 0 0 0 exynos4210_wkup_irq_chip 2 Edge tiny4412,int_gpio1 106: 2 0 0 0 exynos4210_wkup_irq_chip 3 Edge tiny4412,int_gpio2 107: 2 0 0 0 exynos4210_wkup_irq_chip 4 Edge tiny4412,int_gpio3 108: 2 0 0 0 exynos4210_wkup_irq_chip 5 Edge tiny4412,int_gpio4 IPI0: 0 1 1 1 CPU wakeup interrupts IPI1: 0 0 0 0 Timer broadcast interrupts IPI2: 852 1809 422 537 Rescheduling interrupts IPI3: 0 2 2 2 Function call interrupts IPI4: 0 1 2 1 Single function call interrupts IPI5: 0 0 0 0 CPU stop interrupts IPI6: 0 0 0 0 IRQ work interrupts IPI7: 0 0 0 0 completion interrupts Err: 0
如果我們修改驅動驅動，改變一下中斷的申請順序，然後重啓系統（測試發現，如果不重啓系統，而是重新加載新的驅動，gpio跟irq的對應關系沒有發生改變）
#if 1 for (i = 3; i >= 0; i--) { sprintf(data[i].name, "tiny4412,int_gpio%d", i+1); #else for (i = 0; i < 4; i++) { #endif此時，會看到如下的log：
[root@tiny4412 mnt]# insmod interrupt_demo.ko [ 119.735726] int_demo_probe enter. [ 119.736295] samsung_gpio_to_irq enter. [ 119.736417] int_demo_probe: gpio: 241 ---> irq (105) [ 119.736852] samsung_gpio_to_irq enter. [ 119.736985] int_demo_probe: gpio: 240 ---> irq (106) [ 119.737254] samsung_gpio_to_irq enter. [ 119.737893] int_demo_probe: gpio: 239 ---> irq (107) [ 119.743029] samsung_gpio_to_irq enter. [ 119.746631] int_demo_probe: gpio: 238 ---> irq (108) [root@tiny4412 mnt]# cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 36: 0 0 0 0 GIC 89 Edge mct_comp_irq 37: 1799 966 883 145 GIC 28 Edge MCT ... ... 105: 0 0 0 0 exynos4210_wkup_irq_chip 5 Edge tiny4412,int_gpio4 106: 0 0 0 0 exynos4210_wkup_irq_chip 4 Edge tiny4412,int_gpio3 107: 0 0 0 0 exynos4210_wkup_irq_chip 3 Edge tiny4412,int_gpio2 108: 0 0 0 0 exynos4210_wkup_irq_chip 2 Edge tiny4412,int_gpio1 ... ...
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