RS485: fix inconsistencies in the meaning of some variables

The crisv10.c and the atmel_serial.c serial drivers intepret the fields of the
serial_rs485 structure in a different way.

In particular, crisv10.c uses SER_RS485_RTS_AFTER_SEND and
SER_RS485_RTS_ON_SEND for the voltage of the RTS pin; atmel_serial.c,
instead, uses these values to know if a delay must be set before and
after sending.  This patch makes the usage of these variables consistent
across all drivers and fixes the Documentation as well.

From now on, SER_RS485_RTS_AFTER_SEND and SER_RS485_RTS_ON_SEND will be
used to set the voltage of the RTS pin (as in the crisv10.c driver); the
delay will be understood by looking only at the value of
delay_rts_before_send and delay_rts_after_send.

Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
Signed-off-by: Darron Black <darron@griffin.net>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/Documentation/serial/serial-rs485.txt b/Documentation/serial/serial-rs485.txt
index 079cb3d..41c8378 100644 (file)
--- a/Documentation/serial/serial-rs485.txt
+++ b/Documentation/serial/serial-rs485.txt
@@ -97,15 +97,23 @@
 
        struct serial_rs485 rs485conf;
 
-       /* Set RS485 mode: */
+       /* Enable RS485 mode: */
        rs485conf.flags |= SER_RS485_ENABLED;
 
+       /* Set logical level for RTS pin equal to 1 when sending: */
+       rs485conf.flags |= SER_RS485_RTS_ON_SEND;
+       /* or, set logical level for RTS pin equal to 0 when sending: */
+       rs485conf.flags &= ~(SER_RS485_RTS_ON_SEND);
+
+       /* Set logical level for RTS pin equal to 1 after sending: */
+       rs485conf.flags |= SER_RS485_RTS_AFTER_SEND;
+       /* or, set logical level for RTS pin equal to 0 after sending: */
+       rs485conf.flags &= ~(SER_RS485_RTS_AFTER_SEND);
+
        /* Set rts delay before send, if needed: */
-       rs485conf.flags |= SER_RS485_RTS_BEFORE_SEND;
        rs485conf.delay_rts_before_send = ...;
 
        /* Set rts delay after send, if needed: */
-       rs485conf.flags |= SER_RS485_RTS_AFTER_SEND;
        rs485conf.delay_rts_after_send = ...;
 
        /* Set this flag if you want to receive data even whilst sending data */

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 4a0f86f..4c823f3 100644 (file)
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -228,7 +228,7 @@ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
        if (rs485conf->flags & SER_RS485_ENABLED) {
                dev_dbg(port->dev, "Setting UART to RS485\n");
                atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
-               if (rs485conf->flags & SER_RS485_RTS_AFTER_SEND)
+               if ((rs485conf->delay_rts_after_send) > 0)
                        UART_PUT_TTGR(port, rs485conf->delay_rts_after_send);
                mode |= ATMEL_US_USMODE_RS485;
        } else {
@@ -304,7 +304,7 @@ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
 
        if (atmel_port->rs485.flags & SER_RS485_ENABLED) {
                dev_dbg(port->dev, "Setting UART to RS485\n");
-               if (atmel_port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
+               if ((atmel_port->rs485.delay_rts_after_send) > 0)
                        UART_PUT_TTGR(port,
                                        atmel_port->rs485.delay_rts_after_send);
                mode |= ATMEL_US_USMODE_RS485;
@@ -1228,7 +1228,7 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
 
        if (atmel_port->rs485.flags & SER_RS485_ENABLED) {
                dev_dbg(port->dev, "Setting UART to RS485\n");
-               if (atmel_port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
+               if ((atmel_port->rs485.delay_rts_after_send) > 0)
                        UART_PUT_TTGR(port,
                                        atmel_port->rs485.delay_rts_after_send);
                mode |= ATMEL_US_USMODE_RS485;
@@ -1447,16 +1447,6 @@ static void __devinit atmel_of_init_port(struct atmel_uart_port *atmel_port,
                rs485conf->delay_rts_after_send = rs485_delay[1];
                rs485conf->flags = 0;
 
-               if (rs485conf->delay_rts_before_send == 0 &&
-                   rs485conf->delay_rts_after_send == 0) {
-                       rs485conf->flags |= SER_RS485_RTS_ON_SEND;
-               } else {
-                       if (rs485conf->delay_rts_before_send)
-                               rs485conf->flags |= SER_RS485_RTS_BEFORE_SEND;
-                       if (rs485conf->delay_rts_after_send)
-                               rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
-               }
-
                if (of_get_property(np, "rs485-rx-during-tx", NULL))
                        rs485conf->flags |= SER_RS485_RX_DURING_TX;
 

diff --git a/drivers/tty/serial/crisv10.c b/drivers/tty/serial/crisv10.c
index b743504..1dfba7b 100644 (file)
--- a/drivers/tty/serial/crisv10.c
+++ b/drivers/tty/serial/crisv10.c
@@ -3234,9 +3234,8 @@ rs_write(struct tty_struct *tty,
                e100_disable_rx(info);
                e100_enable_rx_irq(info);
 #endif
-               if ((info->rs485.flags & SER_RS485_RTS_BEFORE_SEND) &&
-                       (info->rs485.delay_rts_before_send > 0))
-                               msleep(info->rs485.delay_rts_before_send);
+               if (info->rs485.delay_rts_before_send > 0)
+                       msleep(info->rs485.delay_rts_before_send);
        }
 #endif /* CONFIG_ETRAX_RS485 */
 
@@ -3693,10 +3692,6 @@ rs_ioctl(struct tty_struct *tty,
 
                rs485data.delay_rts_before_send = rs485ctrl.delay_rts_before_send;
                rs485data.flags = 0;
-               if (rs485data.delay_rts_before_send != 0)
-                       rs485data.flags |= SER_RS485_RTS_BEFORE_SEND;
-               else
-                       rs485data.flags &= ~(SER_RS485_RTS_BEFORE_SEND);
 
                if (rs485ctrl.enabled)
                        rs485data.flags |= SER_RS485_ENABLED;
@@ -4531,7 +4526,6 @@ static int __init rs_init(void)
                /* Set sane defaults */
                info->rs485.flags &= ~(SER_RS485_RTS_ON_SEND);
                info->rs485.flags |= SER_RS485_RTS_AFTER_SEND;
-               info->rs485.flags &= ~(SER_RS485_RTS_BEFORE_SEND);
                info->rs485.delay_rts_before_send = 0;
                info->rs485.flags &= ~(SER_RS485_ENABLED);
 #endif

diff --git a/include/linux/serial.h b/include/linux/serial.h
index 97ff8e2..3d86517 100644 (file)
--- a/include/linux/serial.h
+++ b/include/linux/serial.h
@@ -207,13 +207,15 @@ struct serial_icounter_struct {
 
 struct serial_rs485 {
        __u32   flags;                  /* RS485 feature flags */
-#define SER_RS485_ENABLED              (1 << 0)
-#define SER_RS485_RTS_ON_SEND          (1 << 1)
-#define SER_RS485_RTS_AFTER_SEND       (1 << 2)
-#define SER_RS485_RTS_BEFORE_SEND      (1 << 3)
+#define SER_RS485_ENABLED              (1 << 0)        /* If enabled */
+#define SER_RS485_RTS_ON_SEND          (1 << 1)        /* Logical level for
+                                                          RTS pin when
+                                                          sending */
+#define SER_RS485_RTS_AFTER_SEND       (1 << 2)        /* Logical level for
+                                                          RTS pin after sent*/
 #define SER_RS485_RX_DURING_TX         (1 << 4)
-       __u32   delay_rts_before_send;  /* Milliseconds */
-       __u32   delay_rts_after_send;   /* Milliseconds */
+       __u32   delay_rts_before_send;  /* Delay before send (milliseconds) */
+       __u32   delay_rts_after_send;   /* Delay after send (milliseconds) */
        __u32   padding[5];             /* Memory is cheap, new structs
                                           are a royal PITA .. */
 };