[PATCH v5 02/10] serial: 8250_dwlib: Implement SW half duplex support

From: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
To: linux-serial@vger.kernel.org, Greg KH <gregkh@linuxfoundation.org>
Cc: "Jiri Slaby" <jirislaby@kernel.org>,
	"Lukas Wunner" <lukas@wunner.de>,
	"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Vicente Bergas" <vicencb@gmail.com>,
	"Johan Hovold" <johan@kernel.org>,
	heiko@sntech.de, giulio.benetti@micronovasrl.com,
	"Heikki Krogerus" <heikki.krogerus@linux.intel.com>,
	"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>,
	"Eric Tremblay" <etremblay@distech-controls.com>
Subject: [PATCH v5 02/10] serial: 8250_dwlib: Implement SW half duplex support
Date: Tue, 26 Apr 2022 15:24:40 +0300	[thread overview]
Message-ID: <20220426122448.38997-3-ilpo.jarvinen@linux.intel.com> (raw)
In-Reply-To: <20220426122448.38997-1-ilpo.jarvinen@linux.intel.com>

This patch enables support for SW half-duplex mode using em485.

Cc: Eric Tremblay <etremblay@distech-controls.com>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Vicente Bergas <vicencb@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/tty/serial/8250/8250_dwlib.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c
index 05b73c8e75bc..fbabfdd8c7b8 100644
--- a/drivers/tty/serial/8250/8250_dwlib.c
+++ b/drivers/tty/serial/8250/8250_dwlib.c
@@ -157,8 +157,14 @@ void dw8250_setup_port(struct uart_port *p)
 	u32 reg;
 
 	pd->hw_rs485_support = dw8250_detect_rs485_hw(p);
-	if (pd->hw_rs485_support)
+	if (pd->hw_rs485_support) {
 		p->rs485_config = dw8250_rs485_config;
+	} else {
+		p->rs485_config = serial8250_em485_config;
+		up->rs485_start_tx = serial8250_em485_start_tx;
+		up->rs485_stop_tx = serial8250_em485_stop_tx;
+	}
+	up->capabilities |= UART_CAP_NOTEMT;
 
 	/*
 	 * If the Component Version Register returns zero, we know that
@@ -194,7 +200,7 @@ void dw8250_setup_port(struct uart_port *p)
 		p->type = PORT_16550A;
 		p->flags |= UPF_FIXED_TYPE;
 		p->fifosize = DW_UART_CPR_FIFO_SIZE(reg);
-		up->capabilities = UART_CAP_FIFO;
+		up->capabilities = UART_CAP_FIFO | UART_CAP_NOTEMT;
 	}
 
 	if (reg & DW_UART_CPR_AFCE_MODE)
-- 
2.30.2

