diff options
Diffstat (limited to 'Documentation/serial')
| -rw-r--r-- | Documentation/serial/serial-rs485.txt | 50 |
1 files changed, 5 insertions, 45 deletions
diff --git a/Documentation/serial/serial-rs485.txt b/Documentation/serial/serial-rs485.txt index 39dac95422a3..2253b8b45a74 100644 --- a/Documentation/serial/serial-rs485.txt +++ b/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 |