diff options
Diffstat (limited to 'kernel/Documentation/serial')
| -rw-r--r-- | kernel/Documentation/serial/driver | 10 | ||||
| -rw-r--r-- | kernel/Documentation/serial/serial-rs485.txt | 50 | ||||
| -rw-r--r-- | kernel/Documentation/serial/tty.txt | 63 |
3 files changed, 53 insertions, 70 deletions
diff --git a/kernel/Documentation/serial/driver b/kernel/Documentation/serial/driver index c415b0ef4..379468e12 100644 --- a/kernel/Documentation/serial/driver +++ b/kernel/Documentation/serial/driver @@ -439,11 +439,13 @@ Modem control lines via GPIO Some helpers are provided in order to set/get modem control lines via GPIO. -mctrl_gpio_init(dev, idx): +mctrl_gpio_init(port, idx): This will get the {cts,rts,...}-gpios from device tree if they are present and request them, set direction etc, and return an allocated structure. devm_* functions are used, so there's no need to call mctrl_gpio_free(). + As this sets up the irq handling make sure to not handle changes to the + gpio input lines in your driver, too. mctrl_gpio_free(dev, gpios): This will free the requested gpios in mctrl_gpio_init(). @@ -458,3 +460,9 @@ mctrl_gpio_set(gpios, mctrl): mctrl_gpio_get(gpios, mctrl): This will update mctrl with the gpios values. + +mctrl_gpio_enable_ms(gpios): + Enables irqs and handling of changes to the ms lines. + +mctrl_gpio_disable_ms(gpios): + Disables irqs and handling of changes to the ms lines. diff --git a/kernel/Documentation/serial/serial-rs485.txt b/kernel/Documentation/serial/serial-rs485.txt index 39dac9542..2253b8b45 100644 --- a/kernel/Documentation/serial/serial-rs485.txt +++ b/kernel/Documentation/serial/serial-rs485.txt @@ -33,50 +33,10 @@ the values given by the device tree. Any driver for devices capable of working both as RS232 and RS485 should - provide at least the following ioctls: - - - TIOCSRS485 (typically associated with number 0x542F). This ioctl is used - to enable/disable RS485 mode from user-space - - - TIOCGRS485 (typically associated with number 0x542E). This ioctl is used - to get RS485 mode from kernel-space (i.e., driver) to user-space. - - In other words, the serial driver should contain a code similar to the next - one: - - static struct uart_ops atmel_pops = { - /* ... */ - .ioctl = handle_ioctl, - }; - - static int handle_ioctl(struct uart_port *port, - unsigned int cmd, - unsigned long arg) - { - struct serial_rs485 rs485conf; - - switch (cmd) { - case TIOCSRS485: - if (copy_from_user(&rs485conf, - (struct serial_rs485 *) arg, - sizeof(rs485conf))) - return -EFAULT; - - /* ... */ - break; - - case TIOCGRS485: - if (copy_to_user((struct serial_rs485 *) arg, - ..., - sizeof(rs485conf))) - return -EFAULT; - /* ... */ - break; - - /* ... */ - } - } - + implement the rs485_config callback in the uart_port structure. The + serial_core calls rs485_config to do the device specific part in response + to TIOCSRS485 and TIOCGRS485 ioctls (see below). The rs485_config callback + receives a pointer to struct serial_rs485. 4. USAGE FROM USER-LEVEL @@ -85,7 +45,7 @@ #include <linux/serial.h> - /* Driver-specific ioctls: */ + /* RS485 ioctls: */ #define TIOCGRS485 0x542E #define TIOCSRS485 0x542F diff --git a/kernel/Documentation/serial/tty.txt b/kernel/Documentation/serial/tty.txt index dbe6623fe..bc3842dc3 100644 --- a/kernel/Documentation/serial/tty.txt +++ b/kernel/Documentation/serial/tty.txt @@ -4,9 +4,6 @@ Your guide to the ancient and twisted locking policies of the tty layer and the warped logic behind them. Beware all ye who read on. -FIXME: still need to work out the full set of BKL assumptions and document -them so they can eventually be killed off. - Line Discipline --------------- @@ -42,8 +39,13 @@ TTY side interfaces: open() - Called when the line discipline is attached to the terminal. No other call into the line discipline for this tty will occur until it - completes successfully. Returning an error will - prevent the ldisc from being attached. Can sleep. + completes successfully. Should initialize any + state needed by the ldisc, and set receive_room + in the tty_struct to the maximum amount of data + the line discipline is willing to accept from the + driver with a single call to receive_buf(). + Returning an error will prevent the ldisc from + being attached. Can sleep. close() - This is called on a terminal when the line discipline is being unplugged. At the point of @@ -55,9 +57,16 @@ hangup() - Called when the tty line is hung up. No further calls into the ldisc code will occur. The return value is ignored. Can sleep. -write() - A process is writing data through the line - discipline. Multiple write calls are serialized - by the tty layer for the ldisc. May sleep. +read() - (optional) A process requests reading data from + the line. Multiple read calls may occur in parallel + and the ldisc must deal with serialization issues. + If not defined, the process will receive an EIO + error. May sleep. + +write() - (optional) A process requests writing data to the + line. Multiple write calls are serialized by the + tty layer for the ldisc. If not defined, the + process will receive an EIO error. May sleep. flush_buffer() - (optional) May be called at any point between open and close, and instructs the line discipline @@ -72,27 +81,33 @@ set_termios() - (optional) Called on termios structure changes. termios semaphore so allowed to sleep. Serialized against itself only. -read() - Move data from the line discipline to the user. - Multiple read calls may occur in parallel and the - ldisc must deal with serialization issues. May - sleep. - -poll() - Check the status for the poll/select calls. Multiple - poll calls may occur in parallel. May sleep. +poll() - (optional) Check the status for the poll/select + calls. Multiple poll calls may occur in parallel. + May sleep. -ioctl() - Called when an ioctl is handed to the tty layer - that might be for the ldisc. Multiple ioctl calls - may occur in parallel. May sleep. +ioctl() - (optional) Called when an ioctl is handed to the + tty layer that might be for the ldisc. Multiple + ioctl calls may occur in parallel. May sleep. -compat_ioctl() - Called when a 32 bit ioctl is handed to the tty layer - that might be for the ldisc. Multiple ioctl calls - may occur in parallel. May sleep. +compat_ioctl() - (optional) Called when a 32 bit ioctl is handed + to the tty layer that might be for the ldisc. + Multiple ioctl calls may occur in parallel. + May sleep. Driver Side Interfaces: -receive_buf() - Hand buffers of bytes from the driver to the ldisc - for processing. Semantics currently rather - mysterious 8( +receive_buf() - (optional) Called by the low-level driver to hand + a buffer of received bytes to the ldisc for + processing. The number of bytes is guaranteed not + to exceed the current value of tty->receive_room. + All bytes must be processed. + +receive_buf2() - (optional) Called by the low-level driver to hand + a buffer of received bytes to the ldisc for + processing. Returns the number of bytes processed. + + If both receive_buf() and receive_buf2() are + defined, receive_buf2() should be preferred. write_wakeup() - May be called at any point between open and close. The TTY_DO_WRITE_WAKEUP flag indicates if a call |