On Wed, Nov 23, 2016 at 11:08:19AM +0100, Greg Kroah-Hartman wrote:

On Wed, Nov 23, 2016 at 11:01:03AM +0100, Sascha Hauer wrote:

quoted

With this patch the serial core provides LED triggers for RX and TX.

As the serial core layer does not know when the hardware actually sends
or receives characters, this needs help from the UART drivers. The
LED triggers are registered in uart_add_led_triggers() called from
the UART drivers which want to support LED triggers. All the driver
has to do then is to call uart_led_trigger_[tx|rx] to indicate
activity.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/tty/serial/serial_core.c | 73 ++++++++++++++++++++++++++++++++++++++++
 include/linux/serial_core.h      | 10 ++++++
 2 files changed, 83 insertions(+)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index f2303f3..3e8afb7 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c

@@ -34,6 +34,7 @@
 #include <linux/serial_core.h>
 #include <linux/delay.h>
 #include <linux/mutex.h>
+#include <linux/leds.h>
 
 #include <asm/irq.h>
 #include <asm/uaccess.h>

@@ -2703,6 +2704,77 @@ static const struct attribute_group tty_dev_attr_group = {
 	.attrs = tty_dev_attrs,
 	};
 
+void uart_led_trigger_tx(struct uart_port *uport)
+{
+	unsigned long delay = 50;
+
+	led_trigger_blink_oneshot(uport->led_trigger_tx, &delay, &delay, 0);
+}
+
+void uart_led_trigger_rx(struct uart_port *uport)
+{
+	unsigned long delay = 50;
+
+	led_trigger_blink_oneshot(uport->led_trigger_rx, &delay, &delay, 0);
+}

Don't these functions need an EXPORT_SYMBOL_GPL() to work properly with
uart drivers being built as a module?

Yes, for sure. Will fix in next version.

Sascha

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