On 09/11/2015 03:07 PM, Tomi Valkeinen wrote:
This patch adds basic support for a kernel driver to get a LED device.
This will be used by the led-backlight driver.
Only OF version is implemented for now, and the behavior is similar to
PWM's of_pwm_get() and pwm_put().
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
---
drivers/leds/Makefile | 6 +++-
drivers/leds/led-class.c | 13 +++++++-
drivers/leds/led-of.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/leds/leds.h | 1 +
include/linux/leds.h | 10 ++++++
include/linux/of_leds.h | 26 +++++++++++++++
6 files changed, 139 insertions(+), 2 deletions(-)
create mode 100644 drivers/leds/led-of.c
create mode 100644 include/linux/of_leds.h
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 8d6a24a2f513..6fd22e411810 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -1,7 +1,11 @@
# LED Core
obj-$(CONFIG_NEW_LEDS) += led-core.o
-obj-$(CONFIG_LEDS_CLASS) += led-class.o
+
+obj-$(CONFIG_LEDS_CLASS) += led-class-objs.o
+led-class-objs-y := led-class.o
+led-class-objs-$(CONFIG_OF) += led-of.o
+
obj-$(CONFIG_LEDS_CLASS_FLASH) += led-class-flash.o
obj-$(CONFIG_LEDS_TRIGGERS) += led-triggers.o
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index beabfbc6f7cd..1234f9dc3537 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -22,7 +22,7 @@
#include <linux/timer.h>
#include "leds.h"
-static struct class *leds_class;
+struct class *leds_class;
static ssize_t brightness_show(struct device *dev,
struct device_attribute *attr, char *buf)
@@ -216,6 +216,17 @@ static int led_resume(struct device *dev)
static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
+/**
+ * led_put() - release a LED device, reserved with led_get()
s/led_get/of_led_get/
or we should add led_get, but since class_find_device, which increments
device ref count, takes led_node and led_match_led_node, it is tightly
coupled tightly with OF. OTOH we could have of_led_put for symmetry,
but it would have nothing to do with OF. Amending the comment is the
best option here, I think.
+ * @led_cdev: LED device
+ */
+void led_put(struct led_classdev *led_cdev)
+{
+ put_device(led_cdev->dev);
+ module_put(led_cdev->dev->parent->driver->owner);
+}
+EXPORT_SYMBOL_GPL(led_put);
+
static int match_name(struct device *dev, const void *data)
{
if (!dev_name(dev))
diff --git a/drivers/leds/led-of.c b/drivers/leds/led-of.c
new file mode 100644
index 000000000000..6e96fee9adf1
--- /dev/null
+++ b/drivers/leds/led-of.c
@@ -0,0 +1,85 @@
+/*
+ * LED Class Core OF support
+ *
+ * This program is free software; you can 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/leds.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_leds.h>
+
+#include "leds.h"
+
+/* find OF node for the given led_cdev */
+static struct device_node *find_led_of_node(struct led_classdev *led_cdev)
+{
+ struct device *led_dev = led_cdev->dev;
+ struct device_node *child;
+
+ for_each_child_of_node(led_dev->parent->of_node, child) {
+ int idx;
+
+ idx = of_property_match_string(child, "label", led_cdev->name);
+ if (idx == 0)
+ return child;
+ }
+
+ return NULL;
+}
+
+static int led_match_led_node(struct device *led_dev, const void *data)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(led_dev);
+ const struct device_node *target_node = data;
+ struct device_node *led_node;
+
+ led_node = find_led_of_node(led_cdev);
+ if (!led_node)
+ return 0;
+
+ of_node_put(led_node);
+
+ return led_node == target_node;
+}
+
+/**
+ * of_led_get() - request a LED device via the LED framework
+ * @np: device node to get the LED device from
+ *
+ * Returns the LED device parsed from the phandle specified in the "leds"
+ * property of a device tree node or a negative error-code on failure.
+ *
+ * The caller must use led_put() to release the device after use.
+ */
+struct led_classdev *of_led_get(struct device_node *np)
+{
+ struct device *led_dev;
+ struct led_classdev *led_cdev;
+ struct device_node *led_node;
+
+ led_node = of_parse_phandle(np, "leds", 0);
+ if (!led_node)
+ return ERR_PTR(-ENODEV);
+
+ led_dev = class_find_device(leds_class, NULL, led_node,
+ led_match_led_node);
+
+ of_node_put(led_node);
+
+ if (!led_dev) {
+ pr_err("failed to find led device for node %s, deferring probe\n",
+ of_node_full_name(led_node));
+ return ERR_PTR(-EPROBE_DEFER);
+ }
+
+ led_cdev = dev_get_drvdata(led_dev);
+
+ if (!try_module_get(led_cdev->dev->parent->driver->owner))
+ return ERR_PTR(-ENODEV);
+
+ return led_cdev;
+}
+EXPORT_SYMBOL_GPL(of_led_get);
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index bc89d7ace2c4..ccc3abb417d4 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -46,6 +46,7 @@ static inline int led_get_brightness(struct led_classdev *led_cdev)
void led_stop_software_blink(struct led_classdev *led_cdev);
+extern struct class *leds_class;
extern struct rw_semaphore leds_list_lock;
extern struct list_head leds_list;
diff --git a/include/linux/leds.h b/include/linux/leds.h
index b122eeafb5dc..fbad4ce78e6e 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -113,6 +113,16 @@ extern void devm_led_classdev_unregister(struct device *parent,
extern void led_classdev_suspend(struct led_classdev *led_cdev);
extern void led_classdev_resume(struct led_classdev *led_cdev);
+#if IS_ENABLED(CONFIG_LEDS_CLASS)
+
+extern void led_put(struct led_classdev *led_cdev);
+
+#else
+
+static inline void led_put(struct led_classdev *led_cdev) { }
+
+#endif /* IS_ENABLED(CONFIG_LEDS_CLASS) */
+
/**
* led_blink_set - set blinking with software fallback
* @led_cdev: the LED to start blinking
diff --git a/include/linux/of_leds.h b/include/linux/of_leds.h
new file mode 100644
index 000000000000..7e8e64bd9811
--- /dev/null
+++ b/include/linux/of_leds.h
@@ -0,0 +1,26 @@
+/*
+ * OF support for leds
+ *
+ * This program is free software; you can 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 __LINUX_LEDS_OF_H_INCLUDED
+#define __LINUX_LEDS_OF_H_INCLUDED
+
+#if IS_ENABLED(CONFIG_OF) && IS_ENABLED(CONFIG_LEDS_CLASS)
+
+extern struct led_classdev *of_led_get(struct device_node *np);
+
+#else
+
+static inline struct led_classdev *of_led_get(struct device_node *np)
+{
+ return -ENODEV;
+}
+
+#endif
+
+#endif /* __LINUX_LEDS_OF_H_INCLUDED */
--
Best Regards,
Jacek Anaszewski
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