From patchwork Wed May 26 18:00:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Marek_Beh=C3=BAn?= X-Patchwork-Id: 448693 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73197C47088 for ; Wed, 26 May 2021 18:01:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5295A613D7 for ; Wed, 26 May 2021 18:01:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235378AbhEZSDJ (ORCPT ); Wed, 26 May 2021 14:03:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:58572 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235272AbhEZSDH (ORCPT ); Wed, 26 May 2021 14:03:07 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B2BDF613C5; Wed, 26 May 2021 18:01:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622052095; bh=kbEZ5zXz08FpxCDhu351Q/y9lUjc6eLNagWCRQaDCQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T1m0ocqJn9/NPEs2ro1sRlRGNm3vMB0srBkKLuvHVhTGcWEHJpoVnAIqyHbXNr5tg qO6aFJdgTtF5QkLzJj0QaWdeImFSK2w1iPfh1N3T3BbhxpcRTF1VpXHrCaq9UJZ4Vn y3ec+WVqVlRSEUK0d5Epti2lz+xit70829gJ70ixb+57uSXnOWA3Q3G7+T2X7jQLNU VQgPwkbZcGdJo5XVilTKwegkk7Nw85NJJmyBTsYa3dcBdsAc49/ip6kgJluzvbhKaa 11gp+2B3ikSK5orvr5sZRC3PLbcjIz3uozSICCa04SWrQ7Rb06dBsSiOmP9TE+GgFd LdOaUN+VSiUBw== From: =?utf-8?q?Marek_Beh=C3=BAn?= To: linux-leds@vger.kernel.org Cc: netdev@vger.kernel.org, Pavel Machek , Dan Murphy , Russell King , Andrew Lunn , Matthias Schiffer , Jacek Anaszewski , Mauro Carvalho Chehab , =?utf-8?q?Marek_Beh=C3=BAn?= Subject: [PATCH leds v1 2/5] leds: trigger: add API for HW offloading of triggers Date: Wed, 26 May 2021 20:00:17 +0200 Message-Id: <20210526180020.13557-3-kabel@kernel.org> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20210526180020.13557-1-kabel@kernel.org> References: <20210526180020.13557-1-kabel@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Add method trigger_offload() and member variable `offloaded` to struct led_classdev. Add helper functions led_trigger_offload() and led_trigger_offload_stop(). The trigger_offload() method, when implemented by the LED driver, should be called (via led_trigger_offload() function) from trigger code wanting to be offloaded at the moment when configuration of the trigger changes. If the trigger is successfully offloaded, this method returns 0 and the trigger does not have to blink the LED in software. If the trigger with given configuration cannot be offloaded, the method should return -EOPNOTSUPP, in which case the trigger must blink the LED in SW. The second argument to trigger_offload() being false means that the offloading is being disabled. In this case the function must return 0, errors are not permitted. Signed-off-by: Marek Behún --- Documentation/leds/leds-class.rst | 22 ++++++++++++++++++++++ drivers/leds/led-triggers.c | 1 + include/linux/leds.h | 29 +++++++++++++++++++++++++++++ 3 files changed, 52 insertions(+) diff --git a/Documentation/leds/leds-class.rst b/Documentation/leds/leds-class.rst index cd155ead8703..ebda64768e9d 100644 --- a/Documentation/leds/leds-class.rst +++ b/Documentation/leds/leds-class.rst @@ -169,6 +169,28 @@ Setting the brightness to zero with brightness_set() callback function should completely turn off the LED and cancel the previously programmed hardware blinking function, if any. +Hardware offloading of LED triggers +=================================== + +Some LEDs can offload SW triggers to hardware (for example a LED connected to +an ethernet PHY or an ethernet switch can be configured to blink on activity on +the network, which in software is done by the netdev trigger). + +To do such offloading, both the trigger code and LED driver must support this. +The LED must implement the trigger_offload() method and the trigger code must +try to call this method (via led_trigger_offload() function) when configuration +of the trigger (trigger_data) changes. + +The implementation of the trigger_offload() method by the LED driver must return +0 if the offload is successful and -EOPNOTSUPP if the requested trigger +configuration is not supported and the trigger should be executed in software. +If trigger_offload() returns negative value, the trigger will be done in +software, so any active offloading must also be disabled. + +If the second argument (enable) to the trigger_offload() method is false, any +active HW offloading must be deactivated. In this case errors are not permitted +in the trigger_offload() method. + Known Issues ============ diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index 4e7b78a84149..372980791b87 100644 --- a/drivers/leds/led-triggers.c +++ b/drivers/leds/led-triggers.c @@ -177,6 +177,7 @@ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig) flags); cancel_work_sync(&led_cdev->set_brightness_work); led_stop_software_blink(led_cdev); + led_trigger_offload_stop(led_cdev); if (led_cdev->trigger->deactivate) led_cdev->trigger->deactivate(led_cdev); device_remove_groups(led_cdev->dev, led_cdev->trigger->groups); diff --git a/include/linux/leds.h b/include/linux/leds.h index 329fd914cf24..b331e7bceac3 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -148,6 +148,11 @@ struct led_classdev { /* LEDs that have private triggers have this set */ struct led_hw_trigger_type *trigger_type; + + /* some LEDs may be able to offload some SW triggers to HW */ + int (*trigger_offload)(struct led_classdev *led_cdev, + bool enable); + bool offloaded; #endif #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED @@ -403,6 +408,30 @@ static inline void *led_get_trigger_data(struct led_classdev *led_cdev) return led_cdev->trigger_data; } +static inline int led_trigger_offload(struct led_classdev *led_cdev) +{ + int ret; + + if (!led_cdev->trigger_offload) + return -EOPNOTSUPP; + + ret = led_cdev->trigger_offload(led_cdev, true); + led_cdev->offloaded = !ret; + + return ret; +} + +static inline void led_trigger_offload_stop(struct led_classdev *led_cdev) +{ + if (!led_cdev->trigger_offload) + return; + + if (led_cdev->offloaded) { + led_cdev->trigger_offload(led_cdev, false); + led_cdev->offloaded = false; + } +} + /** * led_trigger_rename_static - rename a trigger * @name: the new trigger name