From mboxrd@z Thu Jan 1 00:00:00 1970 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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 00E5DC388F9 for ; Fri, 30 Oct 2020 11:44:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A19D022228 for ; Fri, 30 Oct 2020 11:44:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604058291; bh=tE/tC6ooCmEzLfRaff5aRxKd92c2myio+aCA0dshSZw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ACBO51HwL2vMzDBi1IkGkIa2AaTAEHpiC3vFsbEGG54NRyxAiNK1YrF55A5WE2zn3 zW6s6gMU6VfZEZOPW1szqVXa6TNvMbf1p8FpOsmYqzAdCDPipH2gNJzGvZQofnrvXx PybIhSCQgDd1RE6DnqMka4YbVfH+Sk+yiKMur+1A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726559AbgJ3Lou (ORCPT ); Fri, 30 Oct 2020 07:44:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:37348 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726530AbgJ3Lot (ORCPT ); Fri, 30 Oct 2020 07:44:49 -0400 Received: from dellmb.labs.office.nic.cz (nat-1.nic.cz [217.31.205.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2EA2F2076E; Fri, 30 Oct 2020 11:44:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604058288; bh=tE/tC6ooCmEzLfRaff5aRxKd92c2myio+aCA0dshSZw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y9vacvq+Xr9z3JfGbRBVTt1nZL1juT4j6I0yEzQf94eCAWMVBGWALsRnUL7ZzWGXD Fo6Q0GzaW3YAillRICnDrD1/7jP6kHeOAUn/+IRDtWH4WppaCz9WiKEF1F5MIpqYva UhNhJ/EzeNcpI1aT7SQsAjHlEUX8tX/Ij8ZwZWtM= From: =?UTF-8?q?Marek=20Beh=C3=BAn?= To: netdev@vger.kernel.org Cc: linux-leds@vger.kernel.org, Pavel Machek , Dan Murphy , Russell King , Andrew Lunn , Matthias Schiffer , "David S. Miller" , Jacek Anaszewski , Ben Whitten , =?UTF-8?q?Marek=20Beh=C3=BAn?= Subject: [PATCH RFC leds + net-next 3/7] leds: trigger: add API for HW offloading of triggers Date: Fri, 30 Oct 2020 12:44:31 +0100 Message-Id: <20201030114435.20169-4-kabel@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201030114435.20169-1-kabel@kernel.org> References: <20201030114435.20169-1-kabel@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. Signed-off-by: Marek Behún --- Documentation/leds/leds-class.rst | 20 ++++++++++++++++++++ drivers/leds/led-triggers.c | 1 + include/linux/leds.h | 27 +++++++++++++++++++++++++++ 3 files changed, 48 insertions(+) diff --git a/Documentation/leds/leds-class.rst b/Documentation/leds/leds-class.rst index a0708d3f3d0b..45360ff99f8d 100644 --- a/Documentation/leds/leds-class.rst +++ b/Documentation/leds/leds-class.rst @@ -169,6 +169,26 @@ 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. Known Issues ============ diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index 91da90cfb11d..9056a66f4661 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 6a8d6409c993..d7e17f1d6f3c 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 @@ -405,6 +410,28 @@ 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_trigger_rename_static - rename a trigger * @name: the new trigger name -- 2.26.2