From 0c11b88883db1a83980633fc88091d3cdd79bd48 Mon Sep 17 00:00:00 2001 From: Heiko Schocher Date: Fri, 13 Sep 2019 07:01:05 +0200 Subject: tty: 8250_of: Use software emulated RS485 direction control Use software emulated RS485 direction control to provide RS485 API Currently it is not possible to use rs485 as pointer to rs485_config struct in struct uart_port is NULL in case we configure the port through device tree. Signed-off-by: Heiko Schocher Link: https://lore.kernel.org/r/20190913050105.1132080-1-hs@denx.de Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_of.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c index 0826cfdbd406..92fbf46ce3bd 100644 --- a/drivers/tty/serial/8250/8250_of.c +++ b/drivers/tty/serial/8250/8250_of.c @@ -48,6 +48,36 @@ static inline void tegra_serial_handle_break(struct uart_port *port) } #endif +static int of_8250_rs485_config(struct uart_port *port, + struct serial_rs485 *rs485) +{ + struct uart_8250_port *up = up_to_u8250p(port); + + /* Clamp the delays to [0, 100ms] */ + rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U); + rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U); + + port->rs485 = *rs485; + + /* + * Both serial8250_em485_init and serial8250_em485_destroy + * are idempotent + */ + if (rs485->flags & SER_RS485_ENABLED) { + int ret = serial8250_em485_init(up); + + if (ret) { + rs485->flags &= ~SER_RS485_ENABLED; + port->rs485.flags &= ~SER_RS485_ENABLED; + } + return ret; + } + + serial8250_em485_destroy(up); + + return 0; +} + /* * Fill a struct uart_port for a given device node */ @@ -178,6 +208,7 @@ static int of_platform_serial_setup(struct platform_device *ofdev, port->flags |= UPF_SKIP_TEST; port->dev = &ofdev->dev; + port->rs485_config = of_8250_rs485_config; switch (type) { case PORT_TEGRA: -- cgit v1.2.3