uart串口驱动
/dev/ttymxcX=UART1作为终端
两个重要结构体：uart_driver和uart_port 的
每个串口驱动都需要定义一个 uart_driver，
struct uart_driver {
struct module *owner;
const char *driver_name;
const char *dev_name;
int major;
int minor;
int nr;
struct console *cons;
/*
* these are private; the low level driver should not
* touch these; they should be initialised to NULL
*/
struct uart_state *state;
struct tty_driver *tty_driver;
};
——————————————————————————
uart_port(描述具体的串口端口 串口外设在内核中的具体的表现)
struct uart_port {
spinlock_t lock; /* port lock */
unsigned long iobase; /* in/out[bwl] */
unsigned char __iomem *membase; /* read/write[bwl] */
unsigned int (*serial_in)(struct uart_port *, int);
void (*serial_out)(struct uart_port *, int, int);
void (*set_termios)(struct uart_port *,
struct ktermios *new,
struct ktermios *old);
void (*set_mctrl)(struct uart_port *, unsigned int);
int (*startup)(struct uart_port *port);
void (*shutdown)(struct uart_port *port);
void (*throttle)(struct uart_port *port);
void (*unthrottle)(struct uart_port *port);
int (*handle_irq)(struct uart_port *);
void (*pm)(struct uart_port *, unsigned int state,
unsigned int old);
void (*handle_break)(struct uart_port *);
int (*rs485_config)(struct uart_port *,
struct serial_rs485 *rs485);···
const struct uart_ops *ops;//包含了对串口操作的函数 需要我们实现
。。。。。。。。
}
向内核添加一个uart端口
static struct platform_driver serial_imx_driver = {
.probe = serial_imx_probe,//匹配成功后probe函数要执行 此为原版的驱动文件
.remove = serial_imx_remove,
.suspend = serial_imx_suspend,
.resume = serial_imx_resume,
.id_table = imx_uart_devtype,
.driver = {
.name = "imx-uart",
.of_match_table = imx_uart_dt_ids,
},
};
//模仿原版的驱动文件
为什么IMX6ULL的串口为dev/ttymxc0,1
int ret = uart_register_driver(&imx_reg);
->static struct uart_driver imx_reg = {
.owner = THIS_MODULE,
.driver_name = DRIVER_NAME,#define DRIVER_NAME "IMX-uart"
.dev_name = DEV_NAME,
.major = SERIAL_IMX_MAJOR,207
.minor = MINOR_START,16
.nr = ARRAY_SIZE(imx_ports),
.cons = IMX_CONSOLE,
};
->#define DEV_NAME "ttymxc"
uart_unregister_driver(&imx_reg);
_______________________________________
学习模仿probe函数
//struct imx_port {NXP自定义的
struct uart_port port;。。。。。。。。。}
static int serial_imx_probe(struct platform_device *pdev)
{
struct imx_port *sport;
void __iomem *base;
int ret = 0;
struct resource *res;
int txirq, rxirq, rtsirq;
sport = devm_kzalloc//给imx_port 申请内存
serial_imx_probe_dt//处理设备树
platform_get_resource//获取内存
devm_ioremap_resource//得到外设基地址 （可以得到所有寄存器地址）
-》uart_port 处理
sport->port.dev = &pdev->dev;
sport->port.mapbase = res->start;
sport->port.membase = base;
sport->port.type = PORT_IMX,
sport->port.iotype = UPIO_MEM;
sport->port.irq = rxirq;
sport->port.fifosize = 32;
sport->port.ops = &imx_pops;
ret = devm_request_irq(&pdev->dev, txirq, imx_txint, 0,
dev_name(&pdev->dev), sport);
devm_request_irq---串口接收中断，中断处理函数中获得串口接收到的数据，然后使用tty_flip_buffer_push将其放到tty里面
】
static struct uart_ops imx_pops = {
.tx_empty = imx_tx_empty,//与寄存器相关
.set_mctrl = imx_set_mctrl,
.get_mctrl = imx_get_mctrl,
.stop_tx = imx_stop_tx,
.start_tx = imx_start_tx,
.stop_rx = imx_stop_rx,
.enable_ms = imx_enable_ms,
.break_ctl = imx_break_ctl,
.startup = imx_startup,
.shutdown = imx_shutdown,
.flush_buffer = imx_flush_buffer,
.set_termios = imx_set_termios,
.type = imx_type,
.config_port = imx_config_port,
.verify_port = imx_verify_port,
#if defined(CONFIG_CONSOLE_POLL)
.poll_init = imx_poll_init,
.poll_get_char = imx_poll_get_char,
.poll_put_char = imx_poll_put_char,
#endif
};