BSP-D2000平台调试CM9434串口芯片

1.硬件原理图

原理图显示两块9434的INT分别接到D2000的GPIO0_A3和GPIO0_A5.

2.配置

2.1 设备树

 gpio = <&pio  1   1   1   1   1  0>;|      |   |   |   |   |   |  ||      |   |   |   |   |   |  ------表示有效电平|      |   |   |   |   |   |   |      |   |   |   |   |   ---------上下拉, 0关闭功能, 1上拉, 2下拉, 3保留|      |   |   |   |   ||      |   |   |   |   -------------驱动力,电流等级(0 - 3)，级别越高，输出电流越大|      |   |   |   ||      |   |   |   -----------------gpio功能类型,0输入, 1输出, 6和外部中断,7关闭功能(具体查 |      |   |   |                    手册)|      |   |   ---------------------pin bank 内偏移(即组内第几个io口).|      |   ||      |   -------------------------哪组gpio  PA(0) PB(1)|      ||      -----------------------------指向哪个gpio控制器,  pio / r_pio(PL组)|     ------------------------------------属性名字(随便命名)

设备树配置：

example{compatible = "gpio,example";gpios = <&pio PE 8 1 1 1 1>; };

驱动GPIO操作

    gpio = of_get_named_gpio_flags(nd, "gpios", 0, (enum of_gpio_flags *)&config);if (!gpio_is_valid(gpio))printk("gpio isn't valid\n");if (gpio_request(gpio, pdev->name) < 0)printk("gpio request failed %d\n", gpio);gpio_direction_output(gpio, 1);

2.2 直接操作GPIO

不用设备树配置，驱动代码中对固定GPIO操作

#define GPIO8_A6 254

ret = gpio_request(GPIO8_A6 , "gpio8_a6");

if (!ret) {

printk("request for gpio8_a6 failed:%d\n", ret);

return 0;

}

gpio_direction_output(GPIO8_A6 ,1);//设置GPIO8_A6为输出功能且输出高电平

2.3 寄存器操作

寄存器配置GPIO功能

驱动GPIO寄存器操作

    void __iomem  *base_addr;unsigned int reg_value = 0;base_addr = ioremap(GPIO0_REGBASE, 0x32);//GPIO_SWPORTA_DDRreg_value = readl(base_addr + GPIO_SWPORTA_DDR);debug_driver("GPIO_SWPORTA_DDR = 0x%x\n",reg_value);reg_value = reg_value & 0xD7;writel(reg_value, base_addr + GPIO_SWPORTA_DDR);reg_value = readl(base_addr + GPIO_SWPORTA_DDR);debug_driver("GPIO_SWPORTA_DDR = 0x%x\n",reg_value);//GPIO_INTENreg_value = readl(base_addr + GPIO_INTEN);reg_value = reg_value | 0x28;writel(reg_value, base_addr + GPIO_INTEN);reg_value = readl(base_addr + GPIO_INTEN);debug_driver("GPIO_INTEN = 0x%x\n",reg_value);//GPIO_INTMASKreg_value = readl(base_addr + GPIO_INTMASK);reg_value = reg_value & 0xD7;writel(reg_value, base_addr + GPIO_INTMASK);reg_value = readl(base_addr + GPIO_INTMASK);debug_driver("GPIO_INTMASK = 0x%x\n",reg_value);//GPIO_INTTYPE_LEVELreg_value = readl(base_addr + GPIO_INTTYPE_LEVEL);reg_value = reg_value & 0xD7;writel(reg_value, base_addr + GPIO_INTTYPE_LEVEL);reg_value = readl(base_addr + GPIO_INTTYPE_LEVEL);debug_driver("GPIO_INTTYPE_LEVEL = 0x%x\n",reg_value);//GPIO_INT_POLARITYreg_value = readl(base_addr + GPIO_INT_POLARITY);reg_value = reg_value & 0xD7;writel(reg_value, base_addr + GPIO_INT_POLARITY);reg_value = readl(base_addr + GPIO_INT_POLARITY);debug_driver("GPIO_INT_POLARITY = 0x%x\n",reg_value);iounmap(base_addr);