From patchwork Wed Oct 14 13:25:19 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philipp Zabel X-Patchwork-Id: 7395631 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id BB9D89F36A for ; Wed, 14 Oct 2015 13:27:56 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id DCAF420772 for ; Wed, 14 Oct 2015 13:27:55 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 83C8020774 for ; Wed, 14 Oct 2015 13:27:53 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZmM45-0000CK-4n; Wed, 14 Oct 2015 13:25:57 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZmM41-0008NL-6S for linux-arm-kernel@lists.infradead.org; Wed, 14 Oct 2015 13:25:54 +0000 Received: from paszta.hi.4.pengutronix.de ([10.1.0.120] helo=paszta.pengutronix.de.) by metis.ext.pengutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1ZmM3X-0006hn-Fs; Wed, 14 Oct 2015 15:25:23 +0200 From: Philipp Zabel To: Thierry Reding Subject: [RESEND PATCH v2] pwm-backlight: Avoid backlight flicker when probed from DT Date: Wed, 14 Oct 2015 15:25:19 +0200 Message-Id: <1444829119-4266-1-git-send-email-p.zabel@pengutronix.de> X-Mailer: git-send-email 2.1.4 X-SA-Exim-Connect-IP: 10.1.0.120 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20151014_062553_426087_5F557F76 X-CRM114-Status: GOOD ( 14.67 ) X-Spam-Score: -1.9 (-) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-pwm@vger.kernel.org, YH Huang , Philipp Zabel , Jingoo Han , linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de, Lee Jones , Ajay Kumar , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If the driver is probed from the device tree, and there is a phandle property set on it, and the enable GPIO is already configured as output, and the backlight is currently disabled, keep it disabled. If all these conditions are met, assume there will be some other driver that can enable the backlight at the appropriate time. Signed-off-by: Philipp Zabel Reviewed-by: Christian Gmeiner --- Changes since v1: - Also check if the regulator is enabled. If the power supply is disabled, and a phandle points to it, the backlight should stay powered down. --- drivers/video/backlight/pwm_bl.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index eff379b..31afd6d 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -199,6 +199,8 @@ static int pwm_backlight_probe(struct platform_device *pdev) struct backlight_properties props; struct backlight_device *bl; struct pwm_bl_data *pb; + int initial_blank = FB_BLANK_UNBLANK; + bool phandle; int ret; if (!data) { @@ -264,12 +266,32 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->enable_gpio = gpio_to_desc(data->enable_gpio); } + phandle = of_find_property(pdev->dev.of_node, "phandle", NULL) != NULL; + + if (pb->enable_gpio) { + /* + * If the driver is probed from the device tree and there is a + * phandle link pointing to the backlight node, it is safe to + * assume that another driver will enable the backlight at the + * appropriate time. Therefore, if it is disabled, keep it so. + */ + if (phandle && + gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_OUT && + gpiod_get_value(pb->enable_gpio) == 0) + initial_blank = FB_BLANK_POWERDOWN; + else + gpiod_direction_output(pb->enable_gpio, 1); + } + pb->power_supply = devm_regulator_get(&pdev->dev, "power"); if (IS_ERR(pb->power_supply)) { ret = PTR_ERR(pb->power_supply); goto err_alloc; } + if (phandle && !regulator_is_enabled(pb->power_supply)) + initial_blank = FB_BLANK_POWERDOWN; + pb->pwm = devm_pwm_get(&pdev->dev, NULL); if (IS_ERR(pb->pwm)) { ret = PTR_ERR(pb->pwm); @@ -321,6 +343,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) } bl->props.brightness = data->dft_brightness; + bl->props.power = initial_blank; backlight_update_status(bl); platform_set_drvdata(pdev, bl);