Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1169064AbcKAM7r (ORCPT ); Tue, 1 Nov 2016 08:59:47 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:33475 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1169033AbcKAM7n (ORCPT ); Tue, 1 Nov 2016 08:59:43 -0400 From: Peter Ujfalusi To: , CC: , , , , Subject: [PATCH v3 0/2] backlight: pwm_bl: Fix the initial power state selection Date: Tue, 1 Nov 2016 14:59:31 +0200 Message-ID: <20161101125933.11168-1-peter.ujfalusi@ti.com> X-Mailer: git-send-email 2.10.2 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1593 Lines: 44 Hi, Changes since v2: - Do not change the way how the GPIO initially configured as input is handled. Configure it as output and set it's state as active. Changes since v1: - Handling of the enable GPIO is reworked: - Only change direction to output when the pin was input and in this case set the GPIO line physical low - With this change we can ensure that the enable GPIO is output so we do not need to check the direction of it later on. Cover letter: 3698d7e7d221 backlight: pwm_bl: Avoid backlight flicker when probed from DT added support for avoiding backlight flickering, which in essence was designed to not enable the baclkight when the driver loads, but let the user of the backlight to enable it later on. There are boards (like am437x-gp-evm) where we do not have valid GPIO to enable the backlight (TPS61081DRC's EN pin is connected to V3_3D) and the regulator is always on (VBAT in case of the gp-evm). In this board the logic to check the GPIO state and the regulator is failing and the backlight will be enabled as soon as the pwm_bl driver is loaded. By extending the check to look at the PWM state this issue can be avoided and the backlight will be enabled only when it's user is asking it to be enabled. Regards, Peter --- Peter Ujfalusi (2): backlight: pwm_bl: Move the checks for initial power state to a separate function backlight: pwm_bl: Check the pwm state for initial backlight power state drivers/video/backlight/pwm_bl.c | 57 ++++++++++++++++++++++++++-------------- 1 file changed, 38 insertions(+), 19 deletions(-) -- 2.10.2