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authorMatwey V. Kornilov <matwey@sai.msu.ru>2016-02-01 21:09:21 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-02-07 09:23:26 +0300
commite490c9144cfaa8e2242c1e5d5187230928f27417 (patch)
tree183cac3bb0d61e0637045d9973e628bd98d9009f /include/linux/serial_8250.h
parenta07a70bcb72e4a766c8d3173986a773cef842d30 (diff)
downloadlinux-e490c9144cfaa8e2242c1e5d5187230928f27417.tar.xz
tty: Add software emulated RS485 support for 8250
Implementation of software emulation of RS485 direction handling is based on omap_serial driver. Before and after transmission RTS is set to the appropriate value. Note that before calling serial8250_em485_init() the caller has to ensure that UART will interrupt when shift register empty. Otherwise, emultaion cannot be used. Both serial8250_em485_init() and serial8250_em485_destroy() are idempotent functions. Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/serial_8250.h')
-rw-r--r--include/linux/serial_8250.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index faa0e0370ce7..434879759725 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -76,6 +76,12 @@ struct uart_8250_ops {
void (*release_irq)(struct uart_8250_port *);
};
+struct uart_8250_em485 {
+ struct timer_list start_tx_timer; /* "rs485 start tx" timer */
+ struct timer_list stop_tx_timer; /* "rs485 stop tx" timer */
+ struct timer_list *active_timer; /* pointer to active timer */
+};
+
/*
* This should be used by drivers which want to register
* their own 8250 ports without registering their own
@@ -122,6 +128,8 @@ struct uart_8250_port {
/* 8250 specific callbacks */
int (*dl_read)(struct uart_8250_port *);
void (*dl_write)(struct uart_8250_port *, int);
+
+ struct uart_8250_em485 *em485;
};
static inline struct uart_8250_port *up_to_u8250p(struct uart_port *up)