The serial-omap driver requires an rts-gpio for RS-485 to work.
Historically it has allowed enabling RS-485 even if no rts-gpio was
specified in the device tree.
That doesn't make any sense, so disable RS-485 on probe if rts-gpio is
missing and disallow user space from enabling it.
Three NULL pointer checks for up->rts_gpiod can be dropped as a result,
simplifying the driver slightly.
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
drivers/tty/serial/omap-serial.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index c87d85b901a7..9c4fd0985f3d 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -300,8 +300,7 @@ 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 (up->rts_gpiod &&
- gpiod_get_value(up->rts_gpiod) != res) {
+ if (gpiod_get_value(up->rts_gpiod) != res) {
if (port->rs485.delay_rts_after_send > 0)
mdelay(
port->rs485.delay_rts_after_send);
@@ -397,7 +396,7 @@ 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 (up->rts_gpiod && gpiod_get_value(up->rts_gpiod) != res) {
+ if (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);
@@ -1336,13 +1335,11 @@ serial_omap_config_rs485(struct uart_port *port, struct ktermios *termios,
up->ier = 0;
serial_out(up, UART_IER, 0);
- if (up->rts_gpiod) {
- /* enable / disable rts */
- val = (rs485->flags & SER_RS485_ENABLED) ?
- SER_RS485_RTS_AFTER_SEND : SER_RS485_RTS_ON_SEND;
- val = (rs485->flags & val) ? 1 : 0;
- gpiod_set_value(up->rts_gpiod, val);
- }
+ /* enable / disable rts */
+ val = (rs485->flags & SER_RS485_ENABLED) ?
+ SER_RS485_RTS_AFTER_SEND : SER_RS485_RTS_ON_SEND;
+ val = (rs485->flags & val) ? 1 : 0;
+ gpiod_set_value(up->rts_gpiod, val);
/* Enable interrupts */
up->ier = mode;
@@ -1547,11 +1544,13 @@ static int serial_omap_probe_rs485(struct uart_omap_port *up,
ret = PTR_ERR(up->rts_gpiod);
if (ret == -EPROBE_DEFER)
return ret;
- /*
- * FIXME: the code historically ignored any other error than
- * -EPROBE_DEFER and just went on without GPIO.
- */
+
up->rts_gpiod = NULL;
+ up->port.rs485_supported = (const struct serial_rs485) { };
+ if (rs485conf->flags & SER_RS485_ENABLED) {
+ dev_err(dev, "disabling RS-485 (rts-gpio missing in device tree)\n");
+ memset(rs485conf, 0, sizeof(*rs485conf));
+ }
} else {
gpiod_set_consumer_name(up->rts_gpiod, "omap-serial");
}
--
2.36.1
