diff options
| author |   Dario Binacchi <dariobin@libero.it> | 2021-04-15 23:09:45 +0200 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-04-22 12:06:59 +0200 |
| commit | 45f6b6db53c80787b79044629b062dfcf2da71ec (patch) | |
| tree | 1886b608da7753f50e6e43e0e82f54450dd828eb /drivers/tty/serial/omap-serial.c | |
| parent | serial: stm32: defer sysrq processing (diff) | |
| download | linux-dev-45f6b6db53c80787b79044629b062dfcf2da71ec.tar.xz linux-dev-45f6b6db53c80787b79044629b062dfcf2da71ec.zip | |
serial: omap: don't disable rs485 if rts gpio is missing
There are rs485 transceivers (e.g. MAX13487E/MAX13488E) which
automatically disable or enable the driver and receiver to keep the bus
in the correct state.
In these cases we don't need a GPIO for flow control.
Fixes: 4a0ac0f55b18 ("OMAP: add RS485 support")
Signed-off-by: Dario Binacchi <dariobin@libero.it>
Link: https://lore.kernel.org/r/20210415210945.25863-1-dariobin@libero.it
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/omap-serial.c')
| -rw-r--r-- | drivers/tty/serial/omap-serial.c | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index 76b94d0ff586..1583e93b2202 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -302,7 +302,8 @@ static void serial_omap_stop_tx(struct uart_port *port) serial_out(up, UART_OMAP_SCR, up->scr); res = (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) ? 1 : 0; - if (gpiod_get_value(up->rts_gpiod) != res) { + if (up->rts_gpiod && + gpiod_get_value(up->rts_gpiod) != res) { if (port->rs485.delay_rts_after_send > 0) mdelay( port->rs485.delay_rts_after_send); @@ -411,7 +412,7 @@ static void serial_omap_start_tx(struct uart_port *port) /* if rts not already enabled */ res = (port->rs485.flags & SER_RS485_RTS_ON_SEND) ? 1 : 0; - if (gpiod_get_value(up->rts_gpiod) != res) { + if (up->rts_gpiod && gpiod_get_value(up->rts_gpiod) != res) { gpiod_set_value(up->rts_gpiod, res); if (port->rs485.delay_rts_before_send > 0) mdelay(port->rs485.delay_rts_before_send); @@ -1407,18 +1408,13 @@ serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485) /* store new config */ port->rs485 = *rs485; - /* - * Just as a precaution, only allow rs485 - * to be enabled if the gpio pin is valid - */ if (up->rts_gpiod) { /* enable / disable rts */ val = (port->rs485.flags & SER_RS485_ENABLED) ? SER_RS485_RTS_AFTER_SEND : SER_RS485_RTS_ON_SEND; val = (port->rs485.flags & val) ? 1 : 0; gpiod_set_value(up->rts_gpiod, val); - } else - port->rs485.flags &= ~SER_RS485_ENABLED; + } /* Enable interrupts */ up->ier = mode; |