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[06/18] tty: serial: 8250_core: user the ->line argument as a hint in serial8250_find_match_or_unused()

Message ID 1409943773-7874-7-git-send-email-bigeasy@linutronix.de (mailing list archive)
State New, archived
Headers show

Commit Message

Sebastian Andrzej Siewior Sept. 5, 2014, 7:02 p.m. UTC 
Tony noticed that the old omap-serial driver picked the uart "number"
based on the hint given from device tree or platform device's id.
The 8250 based omap driver doesn't do this because the core code does
not honour the ->line argument which is passed by the driver.

This patch aims to keep the same behaviour as with omap-serial. The
function will first try to use the line suggested ->line argument and
then fallback to the old strategy in case the port is taken.

That means the the third uart will always be ttyS2 even if the previous
two have not been enabled in DT.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/tty/serial/8250/8250_core.c | 5 +++++
 1 file changed, 5 insertions(+)
diff mbox

Patch

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index eaab8974a456..8f5fb81d5fad 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -3479,6 +3479,11 @@  static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port *
 		if (uart_match_port(&serial8250_ports[i].port, port))
 			return &serial8250_ports[i];
 
+	/* try line number first if still available */
+	i = port->line;
+	if (i < nr_uarts && serial8250_ports[i].port.type == PORT_UNKNOWN &&
+			serial8250_ports[i].port.iobase == 0)
+		return &serial8250_ports[i];
 	/*
 	 * We didn't find a matching entry, so look for the first
 	 * free entry.  We look for one which hasn't been previously