From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753679Ab2KPW3M (ORCPT ); Fri, 16 Nov 2012 17:29:12 -0500 Received: from moutng.kundenserver.de ([212.227.126.187]:61565 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753209Ab2KPW3K (ORCPT ); Fri, 16 Nov 2012 17:29:10 -0500 From: Thierry Reding To: Andrew Morton Cc: Jingoo Han , Grant Likely , Richard Purdie , Florian Tobias Schandinat , linux-fbdev@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] backlight: Add of_find_backlight_by_node() function Date: Fri, 16 Nov 2012 23:29:05 +0100 Message-Id: <1353104945-24153-1-git-send-email-thierry.reding@avionic-design.de> X-Mailer: git-send-email 1.8.0 X-Provags-ID: V02:K0:5mD0UAiDthx+fJ6CkKbsJ8SIaYzvMOHjAcJcxoJANsO iX1j4lzebiaFIjHPFFGoINxbVOCvNpvN3HgvHhbhiJm/FAq7G9 4K79MCQcQxpoJImXjBIJVt/ePTI55IZtMt+uTCxfWfd/6/oBvM 8tfB+albvtw8D/zdBDMR/3w4M0LfeJ1ywqsFiPWVltUdtp9FMt IKHA1EpVAq+fAzfHT0wYd19ZSbV7aIp4lKwEiXREztEz2XFet5 UmAgoU2H2gd4R6SrLfTgeYTdqJl5ybDMyTdMUcq1Z0YHKiOyom WlEiHVALOLWPrx4zLxKTMJoUUQijfS84btLwjGz/9ldD7k+zZi AqUyNIlR1O/kyNUhAaSpKeQuKcwW48Z7JRYDPSt+F251i7414G qXNa7Vv3RUYt+UPkEYpmF0Hxg9yLHhc0rGVZ+tgbnemKAIu15E lDYmp Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This function finds the struct backlight_device for a given device tree node. A dummy function is provided so that it safely compiles out if OF support is disabled. Signed-off-by: Thierry Reding Reviewed-by: Grant Likely Acked-by: Jingoo Han --- Changes in v2: - use #ifdef CONFIG_OF instead of #if IS_ENABLED(CONFIG_OF) - add kerneldoc to of_find_backlight_by_node() function drivers/video/backlight/backlight.c | 29 +++++++++++++++++++++++++++++ include/linux/backlight.h | 10 ++++++++++ 2 files changed, 39 insertions(+) diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c index 297db2f..345f666 100644 --- a/drivers/video/backlight/backlight.c +++ b/drivers/video/backlight/backlight.c @@ -370,6 +370,35 @@ void backlight_device_unregister(struct backlight_device *bd) } EXPORT_SYMBOL(backlight_device_unregister); +#ifdef CONFIG_OF +static int of_parent_match(struct device *dev, void *data) +{ + return dev->parent && dev->parent->of_node == data; +} + +/** + * of_find_backlight_by_node() - find backlight device by device-tree node + * @node: device-tree node of the backlight device + * + * Returns a pointer to the backlight device corresponding to the given DT + * node or NULL if no such backlight device exists or if the device hasn't + * been probed yet. + * + * This function obtains a reference on the backlight device and it is the + * caller's responsibility to drop the reference by calling put_device() on + * the backlight device's .dev field. + */ +struct backlight_device *of_find_backlight_by_node(struct device_node *node) +{ + struct device *dev; + + dev = class_find_device(backlight_class, NULL, node, of_parent_match); + + return dev ? to_backlight_device(dev) : NULL; +} +EXPORT_SYMBOL(of_find_backlight_by_node); +#endif + static void __exit backlight_class_exit(void) { class_destroy(backlight_class); diff --git a/include/linux/backlight.h b/include/linux/backlight.h index 5ffc6dd..da9a082 100644 --- a/include/linux/backlight.h +++ b/include/linux/backlight.h @@ -134,4 +134,14 @@ struct generic_bl_info { void (*kick_battery)(void); }; +#ifdef CONFIG_OF +struct backlight_device *of_find_backlight_by_node(struct device_node *node); +#else +static inline struct backlight_device * +of_find_backlight_by_node(struct device_node *node) +{ + return NULL; +} +#endif + #endif -- 1.8.0