[U-Boot] [PATCH v3 23/54] dm: Add support for LEDs
Simon Glass
sjg at chromium.org
Tue Jun 23 23:38:45 CEST 2015
Add a simple uclass for LEDs, so that these can be controlled by the device
tree and activated when needed. LEDs are referred to by their label.
This implementation requires a driver for each type of LED (e.g GPIO, I2C).
Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v3: None
Changes in v2: None
doc/device-tree-bindings/leds/common.txt | 23 ++++++++++++++
drivers/Kconfig | 2 ++
drivers/Makefile | 1 +
drivers/led/Kconfig | 17 +++++++++++
drivers/led/Makefile | 8 +++++
drivers/led/led-uclass.c | 48 ++++++++++++++++++++++++++++++
include/dm/uclass-id.h | 1 +
include/led.h | 51 ++++++++++++++++++++++++++++++++
scripts/Makefile.spl | 1 +
9 files changed, 152 insertions(+)
create mode 100644 doc/device-tree-bindings/leds/common.txt
create mode 100644 drivers/led/Kconfig
create mode 100644 drivers/led/Makefile
create mode 100644 drivers/led/led-uclass.c
create mode 100644 include/led.h
diff --git a/doc/device-tree-bindings/leds/common.txt b/doc/device-tree-bindings/leds/common.txt
new file mode 100644
index 0000000..2d88816
--- /dev/null
+++ b/doc/device-tree-bindings/leds/common.txt
@@ -0,0 +1,23 @@
+Common leds properties.
+
+Optional properties for child nodes:
+- label : The label for this LED. If omitted, the label is
+ taken from the node name (excluding the unit address).
+
+- linux,default-trigger : This parameter, if present, is a
+ string defining the trigger assigned to the LED. Current triggers are:
+ "backlight" - LED will act as a back-light, controlled by the framebuffer
+ system
+ "default-on" - LED will turn on (but for leds-gpio see "default-state"
+ property in Documentation/devicetree/bindings/gpio/led.txt)
+ "heartbeat" - LED "double" flashes at a load average based rate
+ "ide-disk" - LED indicates disk activity
+ "timer" - LED flashes at a fixed, configurable rate
+
+Examples:
+
+system-status {
+ label = "Status";
+ linux,default-trigger = "heartbeat";
+ ...
+};
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 1f40887..ee942e2 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -20,6 +20,8 @@ source "drivers/net/Kconfig"
source "drivers/input/Kconfig"
+source "drivers/led/Kconfig"
+
source "drivers/serial/Kconfig"
source "drivers/tpm/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index 405b64b..c090aba 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_CPU) += cpu/
obj-y += crypto/
obj-$(CONFIG_FPGA) += fpga/
obj-y += hwmon/
+obj-$(CONFIG_LED) += led/
obj-y += misc/
obj-y += pcmcia/
obj-y += dfu/
diff --git a/drivers/led/Kconfig b/drivers/led/Kconfig
new file mode 100644
index 0000000..e4d9a84
--- /dev/null
+++ b/drivers/led/Kconfig
@@ -0,0 +1,17 @@
+config LED
+ bool "Enable LED support"
+ depends on DM
+ help
+ Many boards have LEDs which can be used to signal status or alerts.
+ U-Boot provides a uclass API to implement this feature. LED drivers
+ can provide access to board-specific LEDs. Use of the device tree
+ for configuration is encouraged.
+
+config SPL_LED_SUPPORT
+ bool "Enable LED support in SPL"
+ depends on LED
+ help
+ The LED subsystem adds a small amount of overhead to the image.
+ If this is acceptable and you have a need to use LEDs in SPL,
+ enable this option. You will need to enable device tree in SPL
+ for this to work.
diff --git a/drivers/led/Makefile b/drivers/led/Makefile
new file mode 100644
index 0000000..b39b205
--- /dev/null
+++ b/drivers/led/Makefile
@@ -0,0 +1,8 @@
+#
+# Copyright (c) 2015 Google, Inc
+# Written by Simon Glass <sjg at chromium.org>
+#
+# SPDX-License-Identifier: GPL-2.0+
+#
+
+obj-$(CONFIG_LED) += led-uclass.o
diff --git a/drivers/led/led-uclass.c b/drivers/led/led-uclass.c
new file mode 100644
index 0000000..a80ae93
--- /dev/null
+++ b/drivers/led/led-uclass.c
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2015 Google, Inc
+ * Written by Simon Glass <sjg at chromium.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <led.h>
+#include <dm/root.h>
+#include <dm/uclass-internal.h>
+
+int led_get_by_label(const char *label, struct udevice **devp)
+{
+ struct udevice *dev;
+ struct uclass *uc;
+ int ret;
+
+ ret = uclass_get(UCLASS_LED, &uc);
+ if (ret)
+ return ret;
+ uclass_foreach_dev(dev, uc) {
+ struct led_uclass_plat *uc_plat = dev_get_uclass_platdata(dev);
+
+ if (!strcmp(label, uc_plat->label))
+ return uclass_get_device_tail(dev, 0, devp);
+ }
+
+ return -ENOENT;
+}
+
+int led_set_on(struct udevice *dev, int on)
+{
+ struct led_ops *ops = led_get_ops(dev);
+
+ if (!ops->set_on)
+ return -ENOSYS;
+
+ return ops->set_on(dev, on);
+}
+
+UCLASS_DRIVER(led) = {
+ .id = UCLASS_LED,
+ .name = "led",
+ .per_device_platdata_auto_alloc_size = sizeof(struct led_uclass_plat),
+};
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 24baa5c..a961648 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -33,6 +33,7 @@ enum uclass_id {
UCLASS_I2C, /* I2C bus */
UCLASS_I2C_EEPROM, /* I2C EEPROM device */
UCLASS_I2C_GENERIC, /* Generic I2C device */
+ UCLASS_LED, /* Light-emitting diode (LED) */
UCLASS_LPC, /* x86 'low pin count' interface */
UCLASS_MASS_STORAGE, /* Mass storage device */
UCLASS_MOD_EXP, /* RSA Mod Exp device */
diff --git a/include/led.h b/include/led.h
new file mode 100644
index 0000000..8925d75
--- /dev/null
+++ b/include/led.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2015 Google, Inc
+ * Written by Simon Glass <sjg at chromium.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#ifndef __LED_H
+#define __LED_H
+
+/**
+ * struct led_uclass_plat - Platform data the uclass stores about each device
+ *
+ * @label: LED label
+ */
+struct led_uclass_plat {
+ const char *label;
+};
+
+struct led_ops {
+ /**
+ * set_on() - set the state of an LED
+ *
+ * @dev: LED device to change
+ * @on: 1 to turn the LED on, 0 to turn it off
+ * @return 0 if OK, -ve on error
+ */
+ int (*set_on)(struct udevice *dev, int on);
+};
+
+#define led_get_ops(dev) ((struct led_ops *)(dev)->driver->ops)
+
+/**
+ * led_get_by_label() - Find an LED device by label
+ *
+ * @label: LED label to look up
+ * @devp: Returns the associated device, if found
+ * @return 0 if found, -ve on error
+ */
+int led_get_by_label(const char *label, struct udevice **devp);
+
+/**
+ * led_set_on() - set the state of an LED
+ *
+ * @dev: LED device to change
+ * @on: 1 to turn the LED on, 0 to turn it off
+ * @return 0 if OK, -ve on error
+ */
+int led_set_on(struct udevice *dev, int on);
+
+#endif
diff --git a/scripts/Makefile.spl b/scripts/Makefile.spl
index bcc7ca2..6b32618 100644
--- a/scripts/Makefile.spl
+++ b/scripts/Makefile.spl
@@ -64,6 +64,7 @@ libs-$(CONFIG_SPL_SERIAL_SUPPORT) += drivers/serial/
libs-$(CONFIG_SPL_SPI_FLASH_SUPPORT) += drivers/mtd/spi/
libs-$(CONFIG_SPL_SPI_SUPPORT) += drivers/spi/
libs-y += fs/
+libs-$(CONFIG_SPL_LED_SUPPORT) += drivers/led/
libs-$(CONFIG_SPL_LIBGENERIC_SUPPORT) += lib/
libs-$(CONFIG_SPL_POWER_SUPPORT) += drivers/power/ drivers/power/pmic/
libs-$(CONFIG_SPL_MTD_SUPPORT) += drivers/mtd/
--
2.4.3.573.g4eafbef
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