From patchwork Mon Nov 2 16:55:56 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philipp Zabel X-Patchwork-Id: 7537461 Return-Path: X-Original-To: patchwork-linux-fbdev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id AF2ADBEEA4 for ; Mon, 2 Nov 2015 16:56:14 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8F002203B7 for ; Mon, 2 Nov 2015 16:56:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F98320221 for ; Mon, 2 Nov 2015 16:56:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752603AbbKBQ4I (ORCPT ); Mon, 2 Nov 2015 11:56:08 -0500 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:43711 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752615AbbKBQ4H (ORCPT ); Mon, 2 Nov 2015 11:56:07 -0500 Received: from dude.hi.4.pengutronix.de ([10.1.0.7] helo=dude.pengutronix.de.) by metis.ext.pengutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1ZtIOn-00024q-Im; Mon, 02 Nov 2015 17:56:01 +0100 From: Philipp Zabel To: Thierry Reding Cc: Jingoo Han , Lee Jones , Ajay Kumar , YH Huang , Christian Gmeiner , linux-pwm@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kernel@pengutronix.de, Philipp Zabel Subject: [PATCH v4] pwm-backlight: Avoid backlight flicker when probed from DT Date: Mon, 2 Nov 2015 17:55:56 +0100 Message-Id: <1446483356-14338-1-git-send-email-p.zabel@pengutronix.de> X-Mailer: git-send-email 2.6.1 X-SA-Exim-Connect-IP: 10.1.0.7 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-fbdev@vger.kernel.org Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham 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 Tested-by: Heiko Stuebner --- Changes since v3: - No need to call of_find_property(of_node, "phandle", NULL), just use of_node->phandle. - Rebased onto v4.3 --- drivers/video/backlight/pwm_bl.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index eff379b..65e57da 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; + phandle phandle = pdev->dev.of_node->phandle; + int initial_blank = FB_BLANK_UNBLANK; int ret; if (!data) { @@ -242,7 +244,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->enabled = false; pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", - GPIOD_OUT_HIGH); + GPIOD_ASIS); if (IS_ERR(pb->enable_gpio)) { ret = PTR_ERR(pb->enable_gpio); goto err_alloc; @@ -264,12 +266,30 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->enable_gpio = gpio_to_desc(data->enable_gpio); } + 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 +341,7 @@ 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);