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-rw-r--r--Documentation/serial/serial-rs485.txt50
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