From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-in-09.arcor-online.net ([151.189.21.49]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1bNhSc-0001px-CZ for barebox@lists.infradead.org; Thu, 14 Jul 2016 14:17:56 +0000 Received: from mail-in-05-z2.arcor-online.net (mail-in-05-z2.arcor-online.net [151.189.8.17]) by mx.arcor.de (Postfix) with ESMTP id 3rqyT725MkzC2KJ for ; Thu, 14 Jul 2016 16:17:31 +0200 (CEST) Received: from mail-in-16.arcor-online.net (mail-in-16.arcor-online.net [151.189.21.56]) by mail-in-05-z2.arcor-online.net (Postfix) with ESMTP id 3EB3B116537 for ; Thu, 14 Jul 2016 16:17:31 +0200 (CEST) Received: from itng-giorgio.wgast.mobotix.net (wwl-pub.mobotixserver.de [213.183.84.172]) (Authenticated sender: giorgio.nicole@arcor.de) by mail-in-16.arcor-online.net (Postfix) with ESMTPA id 3rqyT62l2gz4q6n for ; Thu, 14 Jul 2016 16:17:29 +0200 (CEST) From: iw3gtf@arcor.de Date: Thu, 14 Jul 2016 16:17:18 +0200 Message-Id: <20160714141718.20121-5-iw3gtf@arcor.de> In-Reply-To: <20160714141718.20121-1-iw3gtf@arcor.de> References: <20160713051805.GZ20657@pengutronix.de> <20160714141718.20121-1-iw3gtf@arcor.de> In-Reply-To: <20160713051805.GZ20657@pengutronix.de> References: <20160713051805.GZ20657@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 4/4] video/backlight-pwm: properly handle the case of an empty 'brightness-levels' in the device tree. To: barebox@lists.infradead.org In case of an empty 'brightness-levels' array in the device tree or a non empty one but containing only zeros the value of 'pwm_backlight->scale' would remain 0 possibly causing a division by zero in the function compute_duty_cycle(). To fix it we check the computed value in case we actually have a 'brightness-levels' array in the device tree otherwise we implicitly assume a simple array of the form { 0, 1, 2, ..., 100 } and set the scale to 100. --- drivers/video/backlight-pwm.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/video/backlight-pwm.c b/drivers/video/backlight-pwm.c index 5ff40a9..7f1715d 100644 --- a/drivers/video/backlight-pwm.c +++ b/drivers/video/backlight-pwm.c @@ -128,6 +128,13 @@ static int pwm_backlight_parse_dt(struct device_d *dev, if (!node) return -ENODEV; + ret = of_property_read_u32(node, "default-brightness-level", + &value); + if (ret < 0) + return ret; + + pwm_backlight->backlight.brightness_default = value; + /* determine the number of brightness levels */ prop = of_find_property(node, "brightness-levels", &length); if (!prop) @@ -153,14 +160,13 @@ static int pwm_backlight_parse_dt(struct device_d *dev, if (pwm_backlight->levels[i] > pwm_backlight->scale) pwm_backlight->scale = pwm_backlight->levels[i]; - ret = of_property_read_u32(node, "default-brightness-level", - &value); - if (ret < 0) - return ret; - - pwm_backlight->backlight.brightness_default = value; - pwm_backlight->backlight.brightness_max = pwm_backlight->scale; + if (pwm_backlight->scale == 0) + return -EINVAL; + } else { + /* We implicitly assume here a linear levels array { 0, 1, 2, ... 100 } */ + pwm_backlight->scale = 100; } + pwm_backlight->backlight.brightness_max = pwm_backlight->scale; pwm_backlight->enable_gpio = of_get_named_gpio_flags(node, "enable-gpios", 0, &flags); -- 2.9.1 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox