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From: Jean-Jacques Hiblot <jjhiblot@ti.com>
To: <jacek.anaszewski@gmail.com>, <pavel@ucw.cz>, <sre@kernel.org>,
	<robh+dt@kernel.org>, <mark.rutland@arm.com>,
	<lee.jones@linaro.org>, <daniel.thompson@linaro.org>
Cc: <dmurphy@ti.com>, <linux-leds@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
	<tomi.valkeinen@ti.com>, Jean-Jacques Hiblot <jjhiblot@ti.com>
Subject: [PATCH v9 2/5] leds: Add of_led_get() and led_put()
Date: Mon, 7 Oct 2019 14:44:34 +0200
Message-ID: <20191007124437.20367-3-jjhiblot@ti.com> (raw)
In-Reply-To: <20191007124437.20367-1-jjhiblot@ti.com>

From: Tomi Valkeinen <tomi.valkeinen@ti.com>

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@ti.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
---
 drivers/leds/led-class.c | 50 ++++++++++++++++++++++++++++++++++++++++
 include/linux/leds.h     |  4 ++++
 2 files changed, 54 insertions(+)

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index bfa1b1033274..1d1f1d546dc7 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -19,6 +19,7 @@
 #include <linux/spinlock.h>
 #include <linux/timer.h>
 #include <uapi/linux/uleds.h>
+#include <linux/of.h>
 #include "leds.h"
 
 static struct class *leds_class;
@@ -214,6 +215,55 @@ static int led_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 
+/**
+ * of_led_get() - request a LED device via the LED framework
+ * @np: device node to get the LED device from
+ * @index: the index of the LED
+ *
+ * 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.
+ */
+struct led_classdev *of_led_get(struct device_node *np, int index)
+{
+	struct device *led_dev;
+	struct led_classdev *led_cdev;
+	struct device_node *led_node;
+
+	/* Not using device tree? */
+	if (!IS_ENABLED(CONFIG_OF))
+		return ERR_PTR(-ENOTSUPP);
+	if (!np)
+		return ERR_PTR(-EINVAL);
+
+	led_node = of_parse_phandle(np, "leds", index);
+	if (!led_node)
+		return ERR_PTR(-ENOENT);
+
+	led_dev = class_find_device_by_of_node(leds_class, led_node);
+	of_node_put(led_node);
+
+	if (!led_dev)
+		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);
+
+/**
+ * led_put() - release a LED device
+ * @led_cdev: LED device
+ */
+void led_put(struct led_classdev *led_cdev)
+{
+	module_put(led_cdev->dev->parent->driver->owner);
+}
+EXPORT_SYMBOL_GPL(led_put);
+
 static int led_classdev_next_name(const char *init_name, char *name,
 				  size_t len)
 {
diff --git a/include/linux/leds.h b/include/linux/leds.h
index b8df71193329..6f7371bc7757 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -20,6 +20,7 @@
 
 struct device;
 struct led_pattern;
+struct device_node;
 /*
  * LED Core
  */
@@ -196,6 +197,9 @@ 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);
 
+extern struct led_classdev *of_led_get(struct device_node *np, int index);
+extern void led_put(struct led_classdev *led_cdev);
+
 /**
  * led_blink_set - set blinking with software fallback
  * @led_cdev: the LED to start blinking
-- 
2.17.1


  parent reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-07 12:44 [PATCH v9 0/5] Add a generic driver for LED-based backlight Jean-Jacques Hiblot
2019-10-07 12:44 ` [PATCH v9 1/5] leds: populate the device's of_node Jean-Jacques Hiblot
2019-10-07 12:44 ` Jean-Jacques Hiblot [this message]
2019-10-07 12:44 ` [PATCH v9 3/5] leds: Add managed API to get a LED from a device driver Jean-Jacques Hiblot
2019-10-13 12:09   ` Pavel Machek
2019-10-07 12:44 ` [PATCH v9 4/5] dt-bindings: backlight: Add led-backlight binding Jean-Jacques Hiblot
2019-10-07 16:15   ` Rob Herring
2019-10-08 12:51     ` Jean-Jacques Hiblot
2019-10-08 13:30       ` Jean-Jacques Hiblot
2019-10-08 15:00         ` Rob Herring
2019-10-08 17:17           ` Jacek Anaszewski
2019-10-08 17:17           ` Jacek Anaszewski
2019-10-08 20:00             ` Rob Herring
2019-10-09 18:31               ` Jacek Anaszewski
2019-10-08 14:52       ` Rob Herring
2019-10-07 12:44 ` [PATCH v9 5/5] backlight: add led-backlight driver Jean-Jacques Hiblot

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