掉电保护程序通常涉及硬件和软件的协同工作。以下是一个基本的掉电保护程序框架,主要针对基于ARM架构的系统,使用DTS(Device Tree Source)配置和自定义platform driver来实现。
硬件配置(DTS)
配置掉电检测管脚
将掉电检测管脚配置为通用GPIO功能,并在DTS文件中声明该GPIO。
```dts
kernel /arch/arm/boot/dts/am57xx-evm-common.dtsi:
&dra7_pmx_core {
gpio3_3_pix34F {
status = "disabled";
type = "gpio";
direction = "input";
pullup = true;
mux_mode = 14;
};
};
```
创建platform device
创建一个使用上述掉电检测GPIO的platform device。
```dts
/ {
powerdown_protect {
compatible = "grobot,powerdown_protect";
powerdown_detect_gpio = <1>; /* GPIO number */
};
};
```
软件实现
创建platform driver
编写platform driver,包括初始化、检测掉电事件和系统重启的逻辑。
```c
include include include include static int powerdown_protect_remove(struct platform_device *pdev) { free_irq(irq_num, pdev); gpio_free(gpio_id); return 0; } static int powerdown_protect_init(struct platform_device *pdev) { struct gpio *gpio; int ret; gpio_id = of_get_named_gpio(pdev->dev.of_node, "powerdown_detect_gpio", 0); if (gpio_id < 0) { dev_err(&pdev->dev, "Failed to get powerdown detect GPIO\n"); return -EINVAL; } ret = gpio_request(gpio_id, "powerdown_detect"); if (ret) { dev_err(&pdev->dev, "Failed to request powerdown detect GPIO\n"); return ret; } irq_num = gpio_to_irq(gpio_id); if (irq_num < 0) { dev_err(&pdev->dev, "Failed to get GPIO irq number\n"); gpio_free(gpio_id); return ret; } ret = request_irq(irq_num, powerdown_protect_irq_handler, IRQF_TRIGGER_RISING, "powerdown_protect", pdev); if (ret) { dev_err(&pdev->dev, "Failed to request powerdown protect IRQ\n"); gpio_free(gpio_id); return ret; } return 0; } static irqreturn_t powerdown_protect_irq_handler(int irq, void *dev_id) { printk("powerdown detect reboot system!\n"); // Perform system reboot or other actions return IRQ_HANDLED; } static struct platform_driver powerdown_protect_driver = { .probe = powerdown_protect_init, .remove = powerdown_protect_remove, .driver = { .name = "powerdown_protect", .of_match_table = of_match_ptr("grobot,powerdown_protect"), }, }; module_platform_driver(powerdown_protect_driver); ``` 总结 以上是一个基本的掉电保护程序的框架,包括硬件配置(DTS)和软件实现(platform driver)。具体实现可能需要根据实际硬件平台和需求进行调整。建议在实际应用中仔细测试和验证,确保系统的稳定性和可靠性。