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Commit 71206b9f authored by Baruch Siach's avatar Baruch Siach Committed by Greg Kroah-Hartman
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Doc: serial-rs485.txt: update RS485 driver interface 



Since commit a5f276f1 (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: default avatarBaruch Siach <baruch@tkos.co.il>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3e20c31a

Documentation/serial/serial-rs485.txt

+5 −45
Original line number Diff line number Diff line
@@ -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