[PATCH v2] serial: sa1100: add note about modem control signals

From: Russell King <rmk+kernel@armlinux.org.uk>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-serial@vger.kernel.org, Jiri Slaby <jslaby@suse.com>
Subject: [PATCH v2] serial: sa1100: add note about modem control signals
Date: Fri, 31 May 2019 17:01:42 +0100	[thread overview]
Message-ID: <E1hWjyQ-0008Ni-8V@rmk-PC.armlinux.org.uk> (raw)
In-Reply-To: <20190531155700.crrawgf3iot2sm2t@shell.armlinux.org.uk>

As suggested by Uwe, add a note indicating that the modem control
signals do not support interrupts, which precludes the driver from
using mctrl_gpio_init().

Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/tty/serial/sa1100.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/tty/serial/sa1100.c b/drivers/tty/serial/sa1100.c
index 97bdfeccbea9..8e618129e65c 100644
--- a/drivers/tty/serial/sa1100.c
+++ b/drivers/tty/serial/sa1100.c
@@ -860,6 +860,10 @@ static int sa1100_serial_resume(struct platform_device *dev)
 static int sa1100_serial_add_one_port(struct sa1100_port *sport, struct platform_device *dev)
 {
 	sport->port.dev = &dev->dev;
+
+	// mctrl_gpio_init() requires that the GPIO driver supports interrupts,
+	// but we need to support GPIO drivers for hardware that has no such
+	// interrupts.  Use mctrl_gpio_init_noauto() instead.
 	sport->gpios = mctrl_gpio_init_noauto(sport->port.dev, 0);
 	if (IS_ERR(sport->gpios)) {
 		int err = PTR_ERR(sport->gpios);
-- 
2.7.4


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
