Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753500AbXJUM5B (ORCPT ); Sun, 21 Oct 2007 08:57:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751501AbXJUM4y (ORCPT ); Sun, 21 Oct 2007 08:56:54 -0400 Received: from mail00d.mail.t-online.hu ([84.2.42.5]:64630 "EHLO mail00d.mail.t-online.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751468AbXJUM4x (ORCPT ); Sun, 21 Oct 2007 08:56:53 -0400 Message-ID: <471B4BF2.2060205@freemail.hu> Date: Sun, 21 Oct 2007 14:54:10 +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: Randy Dunlap , Dmitry Torokhov , Richard Purdie CC: linux-kernel@vger.kernel.org, Rodrigo Pereira Subject: Re: [PATCH 2/3] leds-clevo-mail: hw accelerated LED blink extension References: <4718FCF3.4030401@freemail.hu> In-Reply-To: <4718FCF3.4030401@freemail.hu> 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: 4883 Lines: 129 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 2007-10-21 10:45:35.000000000 +0200 @@ -47,6 +49,19 @@ 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 +70,6 @@ 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/Kconfig linux-2.6.23/drivers/leds/Kconfig --- linux-2.6.23.orig/drivers/leds/Kconfig 2007-10-09 22:31:38.000000000 +0200 +++ linux-2.6.23/drivers/leds/Kconfig 2007-10-21 12:04:50.000000000 +0200 @@ -115,7 +148,11 @@ config LEDS_TRIGGER_TIMER depends on LEDS_TRIGGERS help This allows LEDs to be controlled by a programmable timer - via sysfs. If unsure, say Y. + via sysfs. Some LED hardware can be programmed to start + blinking the LED without any further software interaction. + For more details read Documentation/leds-class.txt. + + If unsure, say Y. config LEDS_TRIGGER_IDE_DISK bool "LED IDE Disk Trigger" 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 18:21:34.000000000 +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 18:21:34.000000000 +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/