[U-Boot] [PATCH v3 24/54] dm: led: Add a driver for GPIO-controlled LEDs
Simon Glass
sjg at chromium.org
Tue Jun 23 23:38:46 CEST 2015
Add a simple driver which allows use of LEDs attached to GPIOs. The linux
device tree binding is used.
Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v3: None
Changes in v2: None
doc/device-tree-bindings/leds/leds-gpio.txt | 52 ++++++++++++++
drivers/led/Kconfig | 9 +++
drivers/led/Makefile | 1 +
drivers/led/led_gpio.c | 101 ++++++++++++++++++++++++++++
4 files changed, 163 insertions(+)
create mode 100644 doc/device-tree-bindings/leds/leds-gpio.txt
create mode 100644 drivers/led/led_gpio.c
diff --git a/doc/device-tree-bindings/leds/leds-gpio.txt b/doc/device-tree-bindings/leds/leds-gpio.txt
new file mode 100644
index 0000000..df1b308
--- /dev/null
+++ b/doc/device-tree-bindings/leds/leds-gpio.txt
@@ -0,0 +1,52 @@
+LEDs connected to GPIO lines
+
+Required properties:
+- compatible : should be "gpio-leds".
+
+Each LED is represented as a sub-node of the gpio-leds device. Each
+node's name represents the name of the corresponding LED.
+
+LED sub-node properties:
+- gpios : Should specify the LED's GPIO, see "gpios property" in
+ Documentation/devicetree/bindings/gpio/gpio.txt. Active low LEDs should be
+ indicated using flags in the GPIO specifier.
+- label : (optional)
+ see Documentation/devicetree/bindings/leds/common.txt
+- linux,default-trigger : (optional)
+ see Documentation/devicetree/bindings/leds/common.txt
+- default-state: (optional) The initial state of the LED. Valid
+ values are "on", "off", and "keep". If the LED is already on or off
+ and the default-state property is set the to same value, then no
+ glitch should be produced where the LED momentarily turns off (or
+ on). The "keep" setting will keep the LED at whatever its current
+ state is, without producing a glitch. The default is off if this
+ property is not present.
+
+Examples:
+
+leds {
+ compatible = "gpio-leds";
+ hdd {
+ label = "IDE Activity";
+ gpios = <&mcu_pio 0 1>; /* Active low */
+ linux,default-trigger = "ide-disk";
+ };
+
+ fault {
+ gpios = <&mcu_pio 1 0>;
+ /* Keep LED on if BIOS detected hardware fault */
+ default-state = "keep";
+ };
+};
+
+run-control {
+ compatible = "gpio-leds";
+ red {
+ gpios = <&mpc8572 6 0>;
+ default-state = "off";
+ };
+ green {
+ gpios = <&mpc8572 7 0>;
+ default-state = "on";
+ };
+};
diff --git a/drivers/led/Kconfig b/drivers/led/Kconfig
index e4d9a84..de5feea 100644
--- a/drivers/led/Kconfig
+++ b/drivers/led/Kconfig
@@ -15,3 +15,12 @@ config SPL_LED_SUPPORT
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.
+
+config LED_GPIO
+ bool "LED support for GPIO-connected LEDs"
+ depends on LED && DM_GPIO
+ help
+ Enable support for LEDs which are connected to GPIO lines. These
+ GPIOs may be on the SoC or some other device which provides GPIOs.
+ The GPIO driver must used driver model. LEDs are configured using
+ the device tree.
diff --git a/drivers/led/Makefile b/drivers/led/Makefile
index b39b205..990129e 100644
--- a/drivers/led/Makefile
+++ b/drivers/led/Makefile
@@ -6,3 +6,4 @@
#
obj-$(CONFIG_LED) += led-uclass.o
+obj-$(CONFIG_LED_GPIO) += led_gpio.o
diff --git a/drivers/led/led_gpio.c b/drivers/led/led_gpio.c
new file mode 100644
index 0000000..a4cd618
--- /dev/null
+++ b/drivers/led/led_gpio.c
@@ -0,0 +1,101 @@
+/*
+ * 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 <asm/gpio.h>
+#include <dm/lists.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct led_gpio_priv {
+ struct gpio_desc gpio;
+};
+
+static int gpio_led_set_on(struct udevice *dev, int on)
+{
+ struct led_gpio_priv *priv = dev_get_priv(dev);
+
+ if (!dm_gpio_is_valid(&priv->gpio))
+ return -EREMOTEIO;
+
+ return dm_gpio_set_value(&priv->gpio, on);
+}
+
+static int led_gpio_probe(struct udevice *dev)
+{
+ struct led_uclass_plat *uc_plat = dev_get_uclass_platdata(dev);
+ struct led_gpio_priv *priv = dev_get_priv(dev);
+
+ /* Ignore the top-level LED node */
+ if (!uc_plat->label)
+ return 0;
+ return gpio_request_by_name(dev, "gpios", 0, &priv->gpio, GPIOD_IS_OUT);
+}
+
+static int led_gpio_remove(struct udevice *dev)
+{
+ struct led_gpio_priv *priv = dev_get_priv(dev);
+
+ if (dm_gpio_is_valid(&priv->gpio))
+ dm_gpio_free(dev, &priv->gpio);
+
+ return 0;
+}
+
+static int led_gpio_bind(struct udevice *parent)
+{
+ const void *blob = gd->fdt_blob;
+ struct udevice *dev;
+ int node;
+ int ret;
+
+ for (node = fdt_first_subnode(blob, parent->of_offset);
+ node > 0;
+ node = fdt_next_subnode(blob, node)) {
+ struct led_uclass_plat *uc_plat;
+ const char *label;
+
+ label = fdt_getprop(blob, node, "label", NULL);
+ if (!label) {
+ debug("%s: node %s has no label\n", __func__,
+ fdt_get_name(blob, node, NULL));
+ return -EINVAL;
+ }
+ ret = device_bind_driver_to_node(parent, "gpio_led",
+ fdt_get_name(blob, node, NULL),
+ node, &dev);
+ if (ret)
+ return ret;
+ uc_plat = dev_get_uclass_platdata(dev);
+ uc_plat->label = label;
+ }
+
+ return 0;
+}
+
+static const struct led_ops gpio_led_ops = {
+ .set_on = gpio_led_set_on,
+};
+
+static const struct udevice_id led_gpio_ids[] = {
+ { .compatible = "gpio-leds" },
+ { }
+};
+
+U_BOOT_DRIVER(led_gpio) = {
+ .name = "gpio_led",
+ .id = UCLASS_LED,
+ .of_match = led_gpio_ids,
+ .ops = &gpio_led_ops,
+ .priv_auto_alloc_size = sizeof(struct led_gpio_priv),
+ .bind = led_gpio_bind,
+ .probe = led_gpio_probe,
+ .remove = led_gpio_remove,
+};
--
2.4.3.573.g4eafbef
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