/ { compatible = "xlnx,zynq-7000"; amba { compatible = "simple-bus"; #address-cells = <1>; #size-cells = <1>; interrupt-parent = <&intc>; ranges; intc: interrupt-controller@f8f01000 { compatible = "arm,cortex-a9-gic"; #interrupt-cells = <3>; interrupt-controller; reg = <0xF8F01000 0x1000>,<0xF8F00100 0x100>; }; i2c0: i2c@e0004000 { compatible = "cdns,i2c-r1p10"; status = "Disabled"; clocks = <&clkc 38>; interrupt-parent = <&intc>; interrupts = <0 25 4>; reg = <0xe0004000 0x1000>; #address-cells = <1>; #size-cells = <0>; // I WANT INTERRUPT TO TRIGGER // ON THIS DEVICE (axi_gpio_0,pin 2) device: device@48 { compatible = "device,name"; reg = <0x48>; reset-gpios = <&axi_gpio_0 1 0>; interrupt-parent = <&axi_gpio_0>; interrupt-gpios = <&axi_gpio_0 2 0>; }; }; }; amba_pl { #address-cells = <1>; #size-cells = <1>; compatible = "simple-bus"; ranges ; axi_gpio_0: gpio@41200000 { #gpio-cells = <2>; compatible = "xlnx,xps-gpio-1.00.a"; gpio-controller; interrupt-parent = <&intc>; interrupts = <0 31 4>; reg = <0x41200000 0x10000>; xlnx,all-inputs = <0x0>; xlnx,all-inputs-2 = <0x0>; xlnx,all-outputs = <0x0>; xlnx,all-outputs-2 = <0x0>; xlnx,dout-default = <0x00000000>; xlnx,dout-default-2 = <0x00000000>; xlnx,gpio-wIDth = <0x10>; xlnx,gpio2-wIDth = <0x20>; xlnx,interrupt-present = <0x1>; xlnx,is-dual = <0x0>; xlnx,tri-default = <0xFFFFFFFF>; xlnx,tri-default-2 = <0xFFFFFFFF>; };}; 我试图在’device’内的’axi_gpio_0’的引脚2上分配一个中断.
浏览谷歌产生了3种在驱动程序代码中绑定中断的常用方法：
/* Method 1 */device->interrupt_gpio = devm_gpiod_get_optional(&i2c_clIEnt->dev,"interrupt",GPIOD_IN);if(IS_ERR(device->interrupt_gpio)) return PTR_ERR(device->interrupt_gpio);printk("device: Interrupt GPIO = %d\n",desc_to_gpio(device->interrupt_gpio));irq = gpiod_to_irq(device->interrupt_gpio);printk("device: IRQ = %d\n",irq);ret = devm_request_threaded_irq(&i2c_clIEnt->dev,irq,NulL,device_irq_thread,IRQF_OnesHOT | IRQF_TRIGGER_HIGH,"device",device);if (ret != 0) dev_err(&i2c_clIEnt->dev,"Failed to request IRQ: %d\n",ret);/* Method 2 */device->interrupt_gpio = devm_gpiod_get_optional(&i2c_clIEnt->dev,GPIOD_ASIS);if (IS_ERR(device->interrupt_gpio)) return PTR_ERR(device->interrupt_gpio);if (device->interrupt_gpio) { dev_info(&i2c_clIEnt->dev,"Found interrupt GPIO: %d\n",desc_to_gpio(device->interrupt_gpio)); dev_info(&i2c_clIEnt->dev,"IRQ Number: %d\n",gpiod_to_irq(device->interrupt_gpio)); gpio_request(desc_to_gpio(device->interrupt_gpio),"DEVICE_INT"); // Request a GPIO pin from the driver gpio_direction_input(desc_to_gpio(device->interrupt_gpio)); // Set GPIO as input gpio_set_debounce(desc_to_gpio(device->interrupt_gpio),50); // Set a 50ms debounce,adjust to your needs gpio_export(desc_to_gpio(device->interrupt_gpio),false); // The GPIO will appear in /sys/class/gpio ret = request_irq(gpiod_to_irq(device->interrupt_gpio),// requested interrupt (irq_handler_t) irqHandler,// pointer to handler function IRQF_TRIGGER_RISING,// interrupt mode flag "DEVICE_IRQ_HANDLER",// used in /proc/interrupts NulL); // the *dev_ID shared interrupt lines,NulL is okay if (ret != 0) { dev_err(&i2c_clIEnt->dev,ret); }}else { dev_err(&i2c_clIEnt->dev,"Failed to get interrupt GPIO pin\n");}/* Method 3 */dev_info(&i2c_clIEnt->dev,"IRQ requested: %d\n",i2c_clIEnt->irq);ret = devm_request_threaded_irq(&i2c_clIEnt->dev,i2c_clIEnt->irq,IRQF_OnesHOT | IRQF_TRIGGER_LOW,ret); 我尝试了所有这些方法和各种devicetree配置的组合,但它们都没有实现我需要的功能.
方法1导致此输出：
device: Interrupt GPIO = 892device: IRQ = -6device 0-0048: Failed to request IRQ: -22
方法2导致此输出：
device 0-0048: Found interrupt GPIO: 892device 0-0048: IRQ Number: -6device 0-0048: Failed to request IRQ: -22
因此,尝试使用描述符GPIO和旧的GPIO API都不能成功绑定中断.
为了尝试方法3,我调整了devicetree：
device: device@48 { compatible = "device,name"; reg = <0x48>; interrupt-parent = <&axi_gpio_0>; // or <&intc>? interrupts = <0 2 0x02>; // trying to grab pin 2}; 方法3导致此输出：
genirq: Setting trigger mode 2 for irq 168 Failed (gic_set_type+0x0/0x48)device 0-0048: IRQ requested: 168genirq: Setting trigger mode 8 for irq 168 Failed (gic_set_type+0x0/0x48)device 0-0048: Failed to request IRQ: -22
似乎问题是将软件中断分配给linux中的特定GPIO.我不知道我在这里缺少什么.任何建议表示赞赏.
编辑1：
我发现linux不管出于什么原因都不喜欢低级别的中断.将方法3改为：
device: device@48 { compatible = "device,name"; reg = <0x48>; interrupt-parent = <&axi_gpio_0>; interrupts = <0 2 0x04>;}; 和驱动程序代码：
dev_info(&i2c_clIEnt->dev,ret);
允许我成功申请IRQ.但是,我的信号是低电平的,所以这对我没什么帮助.另外,我不确定这种方法是否将axi_gpio_0引脚2作为中断信号引用.我可以使用intc和axi_gpio_0作为interrupt-parent,它映射到相同的IRQ号(我从cat / proc / interrupts看到这个).因此,忽略信号的极性,如何根据axi_gpio_0引脚2的切换确保触发注册的中断？
编辑2：
我跟踪了向中断控制器请求驱动器的低电平有效中断的问题：kernel / drivers / irqchip / irq-gic.c.这部分代码是导致问题的原因：
static int gic_set_type(struct irq_data *d,unsigned int type){ voID __iomem *base = gic_dist_base(d); unsigned int gicirq = gic_irq(d); /* Interrupt configuration for sgis can't be changed */ if (gicirq < 16) return -EINVAL; /* SPIs have restrictions on the supported types */ if (gicirq >= 32 && type != IRQ_TYPE_LEVEL_HIGH && type != IRQ_TYPE_EDGE_RISING) return -EINVAL; return gic_configure_irq(gicirq,type,base,NulL);} 黑客入侵内核根本不是我想做的事情,而是评论出来：
/* SPIs have restrictions on the supported types *//*if (gicirq >= 32 && type != IRQ_TYPE_LEVEL_HIGH && type != IRQ_TYPE_EDGE_RISING)return -EINVAL;*/
允许我请求低电平有效的中断.出于测试目的,这应该暂时起作用.
更新：
我已经在GPIO引脚上成功创建了一个IRQ.我的问题出在我使用的GPIO控制器上.控制器是Zynq可编程逻辑模块内部的Xilinx IP模块,该控制器无法触发GPIO引脚上的中断(原因我不知道).我把电路板上的中断引脚焊接到一个不同的,更通用的控制器上的GPIO引脚上,现在linux正在和我很好地配合.
总而言之,匹配compatible =“xlnx,xps-gpio-1.00.a”的GPIO控制器;无法绑定到linux中的软件中断.如果您遇到此问题,请使用不同的GPIO控制器.
谢谢大家的帮助.
解决方法 使用方法3的设备树节点,您应该能够使用irq_of_parse_and_map(i2c_clIEnt-> dev.of_node,0)检索IRQ.然后可以使用devm_request_threaded_irq()完成检索到的IRQ.
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