dm: led: Add a driver for GPIO-controlled LEDs

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@chromium.org>

diff --git a/doc/device-tree-bindings/leds/leds-gpio.txt b/doc/device-tree-bindings/leds/leds-gpio.txt
new file mode 100644 (file)
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 e4d9a84b1da7b93074cacc74946434bf119a3fc1..de5feea8dd3df15cb5418b844ae9979b4aecaccb 100644 (file)
--- 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 b39b20581b697cf972ba7d8d868a64fa822710db..990129e08d366d0ca54c049a03cbbee8ea71887b 100644 (file)
--- 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 (file)
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@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,
+};