Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756758Ab3ILShI (ORCPT ); Thu, 12 Sep 2013 14:37:08 -0400 Received: from smtp.newsguy.com ([74.209.136.69]:60147 "EHLO smtp.newsguy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754899Ab3ILShE (ORCPT ); Thu, 12 Sep 2013 14:37:04 -0400 From: Mike Dunn To: thierry.reding@gmail.com Cc: Mike Dunn , Richard Purdie , Jingoo Han , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , Grant Likely , Rob Herring , linux-pwm@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Robert Jarzmik , Marek Vasut Subject: [PATCH] pwm-backlight: allow for non-increasing brightness levels Date: Thu, 12 Sep 2013 11:35:52 -0700 Message-Id: <1379010952-8928-1-git-send-email-mikedunn@newsguy.com> X-Mailer: git-send-email 1.8.1.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2072 Lines: 59 Currently the driver assumes that the values specified in the brightness-levels device tree property increase as they are parsed from left to right. But boards that invert the signal between the PWM output and the backlight will need to specify decreasing brightness-levels. This patch removes the assumption that the last element of the array is the max value, and instead searches the array for the max value and uses that as the normalizing value when determining the duty cycle. Signed-off-by: Mike Dunn --- drivers/video/backlight/pwm_bl.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 1fea627..d66aaa0 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -27,6 +27,7 @@ struct pwm_bl_data { unsigned int period; unsigned int lth_brightness; unsigned int *levels; + unsigned int max_level; int (*notify)(struct device *, int brightness); void (*notify_after)(struct device *, @@ -57,7 +58,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl) if (pb->levels) { duty_cycle = pb->levels[brightness]; - max = pb->levels[max]; + max = pb->levels[pb->max_level]; } else { duty_cycle = brightness; } @@ -195,7 +196,15 @@ static int pwm_backlight_probe(struct platform_device *pdev) } if (data->levels) { - max = data->levels[data->max_brightness]; + int i, max_value = 0, max_idx = 0; + for (i = 0; i <= data->max_brightness; i++) { + if (data->levels[i] > max_value) { + max_value = data->levels[i]; + max_idx = i; + } + } + pb->max_level = max_idx; + max = data->levels[max_idx]; pb->levels = data->levels; } else max = data->max_brightness; -- 1.8.1.5 -- 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/