From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean-Jacques Hiblot Subject: [PATCH 1/4] leds: of: create a child device if the LED node contains a "compatible" string Date: Mon, 1 Jul 2019 17:14:20 +0200 Message-ID: <20190701151423.30768-2-jjhiblot@ti.com> References: <20190701151423.30768-1-jjhiblot@ti.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <20190701151423.30768-1-jjhiblot@ti.com> Sender: linux-kernel-owner@vger.kernel.org To: jacek.anaszewski@gmail.com, pavel@ucw.cz, robh+dt@kernel.org, mark.rutland@arm.com, lee.jones@linaro.org, daniel.thompson@linaro.org, jingoohan1@gmail.com 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 List-Id: linux-leds@vger.kernel.org This allows the LED core to probe a consumer device when the LED is registered. In that way the LED can be seen like a minimalist bus that can handle at most one device. This is useful to manage simple devices, the purpose of which is mostly to drive a LED. One example would be a LED-controlled backlight. The device-tree would look like the following: tlc59116@40 { compatible = "ti,tlc59108"; reg = <0x40>; bl@2 { label = "backlight"; reg = <0x2>; compatible = "led-backlight"; brightness-levels = <0 243 245 247 248 249 251 252 255>; default-brightness-level = <8>; }; }; Signed-off-by: Jean-Jacques Hiblot --- drivers/leds/led-class.c | 16 ++++++++++++++++ include/linux/leds.h | 11 +++++++++++ 2 files changed, 27 insertions(+) diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index 4793e77808e2..abf0e63285b9 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -306,6 +307,17 @@ int of_led_classdev_register(struct device *parent, struct device_node *np, mutex_unlock(&led_cdev->led_access); + /* Parse the LED's node in the device-tree and create the consumer + * device if needed. + */ + if (np) { + struct platform_device *pd; + + pd = of_platform_device_create(np, NULL, led_cdev->dev); + if (pd) + led_cdev->consumer = &pd->dev; + } + dev_dbg(parent, "Registered led device: %s\n", led_cdev->name); @@ -321,6 +333,10 @@ EXPORT_SYMBOL_GPL(of_led_classdev_register); */ void led_classdev_unregister(struct led_classdev *led_cdev) { + /* destroy the consummer device before removing anything else */ + if (led_cdev->consumer) + of_platform_device_destroy(led_cdev->consumer, NULL); + #ifdef CONFIG_LEDS_TRIGGERS down_write(&led_cdev->trigger_lock); if (led_cdev->trigger) diff --git a/include/linux/leds.h b/include/linux/leds.h index 9b2bf574a17a..63feb8495f3e 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -91,6 +91,12 @@ struct led_classdev { int (*pattern_clear)(struct led_classdev *led_cdev); struct device *dev; + /* + * The consumer device is a child device created by the LED core if the + * appropriate information (ie "compatible" string) is available in the + * device tree. Its life cycle follows the life cycle of the LED device. + */ + struct device *consumer; const struct attribute_group **groups; struct list_head node; /* LED Device list */ @@ -141,6 +147,11 @@ 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); +static inline struct led_classdev *to_led_classdev(struct device *dev) +{ + return (struct led_classdev *) dev_get_drvdata(dev); +} + /** * led_blink_set - set blinking with software fallback * @led_cdev: the LED to start blinking -- 2.17.1