Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936316AbXJSSzk (ORCPT ); Fri, 19 Oct 2007 14:55:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934989AbXJSSzE (ORCPT ); Fri, 19 Oct 2007 14:55:04 -0400 Received: from mail00a.mail.t-online.hu ([84.2.40.5]:50784 "EHLO mail00a.mail.t-online.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936248AbXJSSzB (ORCPT ); Fri, 19 Oct 2007 14:55:01 -0400 Message-ID: <4718FCF3.4030401@freemail.hu> Date: Fri, 19 Oct 2007 20:52:35 +0200 From: =?ISO-8859-2?Q?N=E9meth_M=E1rton?= User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.2) Gecko/20070221 SeaMonkey/1.1.1 MIME-Version: 1.0 To: Richard Purdie , Dmitry Torokhov CC: linux-kernel@vger.kernel.org, Rodrigo Pereira Subject: [PATCH 2/3] leds-clevo-mail: hw accelerated LED blink extension Content-Type: text/plain; charset=ISO-8859-2 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4203 Lines: 111 From: M?rton N?meth Extends the leds subsystem with a blink_set() callback function which can be optionally implemented by a LED driver. If implemented, the driver can use the hardware acceleration for blinking a LED. Signed-off-by: M?rton N?meth --- diff -uprN linux-2.6.23.orig/Documentation/leds-class.txt linux-2.6.23/Documentation/leds-class.txt --- linux-2.6.23.orig/Documentation/leds-class.txt 2007-10-09 22:31:38.000000000 +0200 +++ linux-2.6.23/Documentation/leds-class.txt 2007-10-18 06:57:37.000000000 +0200 @@ -47,6 +47,18 @@ overhead, I suggest these become part of above leaves scope for further attributes should they be needed. +Hardware accelerated blink of LEDs +================================== + +Some LEDs can be programmed to blink without any CPU interaction. To +support this feature, a LED driver can optionally implement the +blink_set() function (see ). If implemeted, the +ledtrig-timer tries to use it. The blink_set() function should return +0 if the blink setting is supported, or -EINVAL otherwise, which means +that the LED will be turned on and off from software by the leds +subsystem. + + Known Issues ============ @@ -55,10 +67,6 @@ would cause nightmare dependency issues. compared to the benefits the simple trigger functionality brings. The rest of the LED subsystem can be modular. -Some leds can be programmed to flash in hardware. As this isn't a generic -LED device property, this should be exported as a device specific sysfs -attribute rather than part of the class if this functionality is required. - Future Development ================== diff -uprN linux-2.6.23.orig/drivers/leds/ledtrig-timer.c linux-2.6.23/drivers/leds/ledtrig-timer.c --- linux-2.6.23.orig/drivers/leds/ledtrig-timer.c 2007-10-09 22:31:38.000000000 +0200 +++ linux-2.6.23/drivers/leds/ledtrig-timer.c 2007-10-18 07:15:14.000000000 +0200 @@ -77,8 +77,21 @@ static ssize_t led_delay_on_store(struct count++; if (count == size) { - timer_data->delay_on = state; - mod_timer(&timer_data->timer, jiffies + 1); + if (timer_data->delay_on != state) { + /* the new value differs from the previous */ + timer_data->delay_on = state; + + /* deactivate previous settings */ + del_timer_sync(&timer_data->timer); + + /* try to activate hardware acceleration, if any */ + if (!led_cdev->blink_set || + led_cdev->blink_set(led_cdev, + timer_data->delay_on, timer_data->delay_off)) { + /* no hardware acceleration, blink via timer */ + mod_timer(&timer_data->timer, jiffies + 1); + } + } ret = count; } @@ -110,8 +123,21 @@ static ssize_t led_delay_off_store(struc count++; if (count == size) { - timer_data->delay_off = state; - mod_timer(&timer_data->timer, jiffies + 1); + if (timer_data->delay_off != state) { + /* the new value differs from the previous */ + timer_data->delay_off = state; + + /* deactivate previous settings */ + del_timer_sync(&timer_data->timer); + + /* try to activate hardware acceleration, if any */ + if (!led_cdev->blink_set || + led_cdev->blink_set(led_cdev, + timer_data->delay_on, timer_data->delay_off)) { + /* no hardware acceleration, blink via timer */ + mod_timer(&timer_data->timer, jiffies + 1); + } + } ret = count; } diff -uprN linux-2.6.23.orig/include/linux/leds.h linux-2.6.23/include/linux/leds.h --- linux-2.6.23.orig/include/linux/leds.h 2007-10-09 22:31:38.000000000 +0200 +++ linux-2.6.23/include/linux/leds.h 2007-10-18 07:17:30.000000000 +0200 @@ -37,6 +37,10 @@ struct led_classdev { void (*brightness_set)(struct led_classdev *led_cdev, enum led_brightness brightness); + /* Activate hardware accelerated blink */ + int (*blink_set)(struct led_classdev *led_cdev, + int delay_on, int delay_off); + struct device *dev; struct list_head node; /* LED Device list */ char *default_trigger; /* Trigger to use */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/