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Doc: serial-rs485.txt: update RS485 driver interface 

Since commit a5f276f10f (serial_core: Handle TIOC[GS]RS485 ioctls.,
2014-11-06) serial_core handles RS485 ioctls. Drivers only need to implement
the rs485_config callback. Update serial-rs485.txt to reflect these changes.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hifive-unleashed-5.1
Baruch Siach 2015-06-04 10:56:59 +03:00 committed by Greg Kroah-Hartman
parent 3e20c31a22
commit 71206b9f81
1 changed files with 5 additions and 45 deletions
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50
Documentation/serial/serial-rs485.txt
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@ -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