A.串行子系统层次：/dev/tty* , /dev/ir*, /dev/ppp*______________________________|线路规程|tty核心层|tty驱动程序|底层驱动程序//这里的理解就是高通平台里，serial_core.c就是串口tty核心层，tty_register_driver驱动的注册也是在//这个文件里面注册的.//而msm_serial.c，msm_serial_hs_lite.c，msm_serial_hs.c是底层的驱动程序.B.设备驱动匹配：patible = "qcom,msm-uartdm-v1.4", "qcom,msm-uartdm"; //--->/dev/HSL*./msm_serial.c{ .compatible = "qcom,msm-uartdm-v1.1", .data = (void *)UARTDM_1P1 },{ .compatible = "qcom,msm-uartdm-v1.2", .data = (void *)UARTDM_1P2 },{ .compatible = "qcom,msm-uartdm-v1.3", .data = (void *)UARTDM_1P3 },{ .compatible = "qcom,msm-uartdm-v1.4", .data = (void *)UARTDM_1P4 },{ .compatible = "qcom,msm-uartdm" },patible = "qcom,msm-lsuart-v14"; //--->/dev/HSL*./msm_serial_hs_lite.c{.compatible = "qcom,msm-lsuart-v14"3. compatible = "qcom,msm-hsuart-v14"; //--->/dev/HS*./msm_serial_hs.c { .compatible = "qcom,msm-hsuart-v14"},C.串口驱动：/dev/tty*|---msm_serial.c | 提供接口---msm_serial_hs_lite.c <----------- serial_core.c| ---msm_serial_hs.c //serial_core.c为实际的驱动提供核心api，完成driver注册和ops实现
简单分析一下uart驱动：msm_serial_init:---> uart_register_driver(&msm_uart_driver);---> platform_driver_register(&msm_platform_driver)uart_register_driver作用：向uart核心层注册driver. 依次向tty层注册，并初始化driver每个端口的状态。platform_driver_register作用:平台驱动的作用就是完成devic和driver的匹配，也即是dsti与driver的probe，probe到了就把dtsi里面的内容填充到driver里面的结构体中，完成驱动的初始化，向应用层提供文件ops机制(或者说伪总线的作用是将设备和linux设备模型连接在一起)。 -----------------msm_uart_driver:static struct uart_driver msm_uart_driver = {.owner = THIS_MODULE,.driver_name = "msm_serial",.dev_name = "ttyMSM",.nr = UART_NR,//line nums (tty nums).cons = MSM_CONSOLE, //console };msm_platform_driver:static struct platform_driver msm_platform_driver = { .remove = msm_serial_remove, .probe = msm_serial_probe,.driver = {.name = "msm_serial",.of_match_table = msm_match_table, .pm = &msm_serial_pm_ops, },};--------------------msm_serial_probe://找到serial节点，计数增加lineof_alias_get_id(pdev->dev.of_node, "serial"); //初始化时钟msm_port->clk = devm_clk_get(&pdev->dev, "core");if (IS_ERR(msm_port->clk))return PTR_ERR(msm_port->clk);if (msm_port->is_uartdm) {msm_port->pclk = devm_clk_get(&pdev->dev, "iface");if (IS_ERR(msm_port->pclk))//注释说了这个函数是让每个driver增加一个port, 目的是允许扩展uart_portuart_add_one_port(&msm_uart_driver, port);static const struct dev_pm_ops msm_serial_pm_ops = {#ifdef CONFIG_PM_SLEEP.suspend = msm_serial_suspend,.resume = msm_serial_resume,.freeze = msm_serial_freeze,.thaw = msm_serial_resume,.poweroff = msm_serial_suspend,.restore = msm_serial_resume,#endif};--------------------------------------ops里面暂时没见解,调用的是serial_core.c里面的api
