Add initial LED trigger support for serial ports by providing a simple
API for registering/unregistering RX/TX/RXTX LED triggers for a serial
port as well as actually triggering LEDs.
UART drivers simply need to call uart_led_event() in their respective
receive and transmit routines to support the LED triggers.
Signed-off-by: Tobias Doerffel <tobias.doerffel@xxxxxxxxxxxxxx>
---
MAINTAINERS | 2 ++
drivers/tty/serial/Kconfig | 12 +++++++
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/serial_leds.c | 67 ++++++++++++++++++++++++++++++++++++++++
include/linux/serial_core.h | 13 ++++++++
include/linux/serial_leds.h | 41 ++++++++++++++++++++++++
6 files changed, 136 insertions(+)
create mode 100644 drivers/tty/serial/serial_leds.c
create mode 100644 include/linux/serial_leds.h
diff --git a/MAINTAINERS b/MAINTAINERS
index ab65bbe..e36d69c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10905,7 +10905,9 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
F: Documentation/serial/
F: drivers/tty/
F: drivers/tty/serial/serial_core.c
+F: drivers/tty/serial/serial_leds.c
F: include/linux/serial_core.h
+F: include/linux/serial_leds.h
F: include/linux/serial.h
F: include/linux/tty.h
F: include/uapi/linux/serial_core.h
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index f38beb2..b178ac8 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -787,6 +787,18 @@ config SERIAL_CORE
config SERIAL_CORE_CONSOLE
bool
+config SERIAL_LEDS
+ bool "Enable LED triggers for serial ports"
+ depends on LEDS_CLASS
+ select LEDS_TRIGGERS
+ ---help---
+ This option adds LED triggers for receiving and transmitting data
+ from/to serial ports. Please note that not all drivers take
+ advantage of this feature yet.
+
+ Say Y here if you are working on a system with led-class supported
+ LEDs and you want to use them as serial port activity indicators.
+
config CONSOLE_POLL
bool
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 5ab4111..e85b473 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -3,6 +3,7 @@
#
obj-$(CONFIG_SERIAL_CORE) += serial_core.o
+obj-$(CONFIG_SERIAL_LEDS) += serial_leds.o
obj-$(CONFIG_SERIAL_21285) += 21285.o
obj-$(CONFIG_SERIAL_EARLYCON) += earlycon.o
diff --git a/drivers/tty/serial/serial_leds.c b/drivers/tty/serial/serial_leds.c
new file mode 100644
index 0000000..84c8d9c
--- /dev/null
+++ b/drivers/tty/serial/serial_leds.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2016, Tobias Doerffel <tobias.doerffel@xxxxxxxxxxxxxx>
+ *
+ * This program is free software; you uart redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/leds.h>
+#include <linux/serial_leds.h>
+
+static unsigned long led_delay = 50;
+module_param(led_delay, ulong, 0644);
+MODULE_PARM_DESC(led_delay,
+ "blink delay time for activity leds (msecs, default: 50).");
+
+/* Trigger a LED event in response to a UART device event */
+void uart_led_event(struct uart_port *port, enum uart_led_event event)
+{
+ switch (event) {
+ case UART_LED_EVENT_TX:
+ if (led_delay) {
+ led_trigger_blink_oneshot(port->tx_led_trig,
+ &led_delay, &led_delay, 1);
+ led_trigger_blink_oneshot(port->rxtx_led_trig,
+ &led_delay, &led_delay, 1);
+ }
+ break;
+ case UART_LED_EVENT_RX:
+ if (led_delay) {
+ led_trigger_blink_oneshot(port->rx_led_trig,
+ &led_delay, &led_delay, 1);
+ led_trigger_blink_oneshot(port->rxtx_led_trig,
+ &led_delay, &led_delay, 1);
+ }
+ break;
+ }
+}
+EXPORT_SYMBOL_GPL(uart_led_event);
+
+void uart_led_register(struct uart_driver *drv, struct uart_port *port)
+{
+ snprintf(port->tx_led_trig_name, sizeof(port->tx_led_trig_name),
+ "%s%d-tx", drv->dev_name, drv->tty_driver->name_base +
+ port->line);
+ snprintf(port->rx_led_trig_name, sizeof(port->rx_led_trig_name),
+ "%s%d-rx", drv->dev_name, drv->tty_driver->name_base +
+ port->line);
+ snprintf(port->rxtx_led_trig_name, sizeof(port->rxtx_led_trig_name),
+ "%s%d-rxtx", drv->dev_name, drv->tty_driver->name_base +
+ port->line);
+
+ led_trigger_register_simple(port->tx_led_trig_name, &port->tx_led_trig);
+ led_trigger_register_simple(port->rx_led_trig_name, &port->rx_led_trig);
+ led_trigger_register_simple(port->rxtx_led_trig_name,
+ &port->rxtx_led_trig);
+}
+EXPORT_SYMBOL_GPL(uart_led_register);
+
+void uart_led_unregister(struct uart_port *port)
+{
+ led_trigger_unregister_simple(port->tx_led_trig);
+ led_trigger_unregister_simple(port->rx_led_trig);
+ led_trigger_unregister_simple(port->rxtx_led_trig);
+}
+EXPORT_SYMBOL_GPL(uart_led_unregister);
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 297d4fa..ace19f8 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -38,6 +38,11 @@
#define uart_console(port) ({ (void)port; 0; })
#endif
+#define UART_DEV_NAME_LEN 32
+/* keep space for device name + "-tx"/"-rx"/"-rxtx" suffix and null terminator
+ */
+#define UART_LED_NAME_SZ (UART_DEV_NAME_LEN + 6)
+
struct uart_port;
struct serial_struct;
struct device;
@@ -246,6 +251,14 @@ struct uart_port {
struct attribute_group *attr_group; /* port specific attributes */
const struct attribute_group **tty_groups; /* all attributes (serial core use only) */
struct serial_rs485 rs485;
+#ifdef CONFIG_SERIAL_LEDS
+ struct led_trigger *tx_led_trig;
+ char tx_led_trig_name[UART_LED_NAME_SZ];
+ struct led_trigger *rx_led_trig;
+ char rx_led_trig_name[UART_LED_NAME_SZ];
+ struct led_trigger *rxtx_led_trig;
+ char rxtx_led_trig_name[UART_LED_NAME_SZ];
+#endif
void *private_data; /* generic platform data pointer */
};
diff --git a/include/linux/serial_leds.h b/include/linux/serial_leds.h
new file mode 100644
index 0000000..be953f5
--- /dev/null
+++ b/include/linux/serial_leds.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2016, Tobias Doerffel <tobias.doerffel@xxxxxxxxxxxxxx>
+ *
+ * This program is free software; you uart redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _SERIAL_LEDS_H
+#define _SERIAL_LEDS_H
+
+#include <linux/serial_core.h>
+#include <linux/leds.h>
+
+enum uart_led_event {
+ UART_LED_EVENT_TX,
+ UART_LED_EVENT_RX,
+};
+
+#ifdef CONFIG_SERIAL_LEDS
+
+void uart_led_event(struct uart_port *port, enum uart_led_event event);
+void uart_led_register(struct uart_driver *drv, struct uart_port *port);
+void uart_led_unregister(struct uart_port *port);
+
+#else
+
+static inline void uart_led_event(struct uart_port *port,
+ enum uart_led_event event)
+{
+}
+static inline void uart_led_register(struct uart_port *port)
+{
+}
+static inline void uart_led_unregister(struct uart_port *port)
+{
+}
+
+#endif
+
+#endif /* !_SERIAL_LEDS_H */
--
2.1.4
--
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