From patchwork Thu Jan 19 13:00:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 645862 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4999C678D6 for ; Thu, 19 Jan 2023 13:03:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230514AbjASNDX (ORCPT ); Thu, 19 Jan 2023 08:03:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230197AbjASNCn (ORCPT ); Thu, 19 Jan 2023 08:02:43 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0AFF78AA0 for ; Thu, 19 Jan 2023 05:01:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674133294; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XbIVEbIc5QqKXtLGkE5dMTcJRM9nzyALjaxAwSxLQlw=; b=VKIfzHZ/PEVOr2vHSG8chHZAKz7P70cW3A3veBrkUgNpiz6hJ8EuqEUuQ1L8tnuOOJonQF rBqHFvZ3p8nYatmACwFJaSmMC+fIz4LpKpp1QQfxl+hcehlGpmXG732VzL93qPjTUraRMy UTx7M6vjCMO6NLmq7DoR1HdEs2YX9PM= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-1-KpJic8eVNQ6bj9yjJbMOqw-1; Thu, 19 Jan 2023 08:01:30 -0500 X-MC-Unique: KpJic8eVNQ6bj9yjJbMOqw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id A108A857AA1; Thu, 19 Jan 2023 13:01:26 +0000 (UTC) Received: from localhost.localdomain (unknown [10.39.194.158]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9E9E214171C0; Thu, 19 Jan 2023 13:01:16 +0000 (UTC) From: Hans de Goede To: Mark Gross , Andy Shevchenko , Pavel Machek , Lee Jones , Linus Walleij , Daniel Scally , Laurent Pinchart , Mauro Carvalho Chehab , Sakari Ailus Cc: Hans de Goede , platform-driver-x86@vger.kernel.org, linux-leds@vger.kernel.org, linux-gpio@vger.kernel.org, Kate Hsuan , Mark Pearson , Andy Yeh , Hao Yao , linux-media@vger.kernel.org Subject: [PATCH v4 04/11] leds: led-class: Add generic [devm_]led_get() Date: Thu, 19 Jan 2023 14:00:46 +0100 Message-Id: <20230119130053.111344-5-hdegoede@redhat.com> In-Reply-To: <20230119130053.111344-1-hdegoede@redhat.com> References: <20230119130053.111344-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-leds@vger.kernel.org Add a generic [devm_]led_get() method which can be used on both devicetree and non devicetree platforms to get a LED classdev associated with a specific function on a specific device, e.g. the privacy LED associated with a specific camera sensor. Note unlike of_led_get() this takes a string describing the function rather then an index. This is done because e.g. camera sensors might have a privacy LED, or a flash LED, or both and using an index approach leaves it unclear what the function of index 0 is if there is only 1 LED. This uses a lookup-table mechanism for non devicetree platforms. This allows the platform code to map specific LED class_dev-s to a specific device,function combinations this way. For devicetree platforms getting the LED by function-name could be made to work using the standard devicetree pattern of adding a -names string array to map names to the indexes. Signed-off-by: Hans de Goede --- Changes in v4: - Split out support for led_get() devicetree name-based lookup support into a separate RFC patch as there currently are no user for this - Use kstrdup_const() / kfree_const() for the led_name --- drivers/leds/led-class.c | 84 ++++++++++++++++++++++++++++++++++++++++ include/linux/leds.h | 18 +++++++++ 2 files changed, 102 insertions(+) diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index 4904d140a560..6dff57c41e96 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -23,6 +23,8 @@ #include "leds.h" static struct class *leds_class; +static DEFINE_MUTEX(leds_lookup_lock); +static LIST_HEAD(leds_lookup_list); static ssize_t brightness_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -317,6 +319,88 @@ struct led_classdev *__must_check devm_of_led_get(struct device *dev, } EXPORT_SYMBOL_GPL(devm_of_led_get); +/** + * led_get() - request a LED device via the LED framework + * @dev: device for which to get the LED device + * @function: string describing the function of the LED device + * + * @return a pointer to a LED device or ERR_PTR(errno) on failure. + */ +struct led_classdev *led_get(struct device *dev, char *function) +{ + struct led_lookup_data *lookup; + const char *led_name = NULL; + struct device *led_dev; + + mutex_lock(&leds_lookup_lock); + list_for_each_entry(lookup, &leds_lookup_list, list) { + if (!strcmp(lookup->consumer_dev_name, dev_name(dev)) && + !strcmp(lookup->consumer_function, function)) { + led_name = kstrdup_const(lookup->led_name, GFP_KERNEL); + break; + } + } + mutex_unlock(&leds_lookup_lock); + + if (!led_name) + return ERR_PTR(-ENOENT); + + led_dev = class_find_device_by_name(leds_class, led_name); + kfree_const(led_name); + + return led_module_get(led_dev); +} +EXPORT_SYMBOL_GPL(led_get); + +/** + * devm_led_get() - request a LED device via the LED framework + * @dev: device for which to get the LED device + * @function: string describing the function of the LED device + * + * The LED device returned from this function is automatically released + * on driver detach. + * + * @return a pointer to a LED device or ERR_PTR(errno) on failure. + */ +struct led_classdev *devm_led_get(struct device *dev, char *function) +{ + struct led_classdev *led; + + led = led_get(dev, function); + if (IS_ERR(led)) + return led; + + return __devm_led_get(dev, led); +} +EXPORT_SYMBOL_GPL(devm_led_get); + +/** + * led_add_lookup() - Add a LED lookup table entry + * @led_lookup: the lookup table entry to add + * + * Add a LED lookup table entry. On systems without devicetree the lookup table + * is used by led_get() to find LEDs. + */ +void led_add_lookup(struct led_lookup_data *led_lookup) +{ + mutex_lock(&leds_lookup_lock); + list_add_tail(&led_lookup->list, &leds_lookup_list); + mutex_unlock(&leds_lookup_lock); +} +EXPORT_SYMBOL_GPL(led_add_lookup); + +/** + * led_remove_lookup() - Remove a LED lookup table entry + * @led_lookup: the lookup table entry to remove + */ +void led_remove_lookup(struct led_lookup_data *led_lookup) +{ + mutex_lock(&leds_lookup_lock); + list_del(&led_lookup->list); + mutex_unlock(&leds_lookup_lock); +} +EXPORT_SYMBOL_GPL(led_remove_lookup); + 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 ba4861ec73d3..e44fc5ec7c9a 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -39,6 +39,18 @@ enum led_default_state { LEDS_DEFSTATE_KEEP = 2, }; +/* + * This is used to tell led_get() device which led_classdev to return for + * a specific consumer device-name, function pair on non devicetree platforms. + * Note all strings must be set. + */ +struct led_lookup_data { + struct list_head list; + const char *led_name; + const char *consumer_dev_name; + const char *consumer_function; +}; + struct led_init_data { /* device fwnode handle */ struct fwnode_handle *fwnode; @@ -211,6 +223,12 @@ void devm_led_classdev_unregister(struct device *parent, void led_classdev_suspend(struct led_classdev *led_cdev); void led_classdev_resume(struct led_classdev *led_cdev); +void led_add_lookup(struct led_lookup_data *led_lookup); +void led_remove_lookup(struct led_lookup_data *led_lookup); + +struct led_classdev *__must_check led_get(struct device *dev, char *function); +struct led_classdev *__must_check devm_led_get(struct device *dev, char *function); + extern struct led_classdev *of_led_get(struct device_node *np, int index); extern void led_put(struct led_classdev *led_cdev); struct led_classdev *__must_check devm_of_led_get(struct device *dev,