From patchwork Sun Jan 27 14:50:54 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen-Yu Tsai X-Patchwork-Id: 1031586 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pwm-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=csie.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43nbKt0HQnz9s9G for ; Mon, 28 Jan 2019 01:50:58 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726930AbfA0Ou5 (ORCPT ); Sun, 27 Jan 2019 09:50:57 -0500 Received: from mirror2.csie.ntu.edu.tw ([140.112.30.76]:60138 "EHLO wens.csie.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726511AbfA0Ou5 (ORCPT ); Sun, 27 Jan 2019 09:50:57 -0500 Received: by wens.csie.org (Postfix, from userid 1000) id CC4905FD14; Sun, 27 Jan 2019 22:50:55 +0800 (CST) From: Chen-Yu Tsai To: Thierry Reding , Lee Jones , Daniel Thompson , Jingoo Han Cc: Chen-Yu Tsai , linux-pwm@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Maxime Ripard , linux-arm-kernel@lists.infradead.org Subject: [PATCH] backlight: pwm_bl: Use gpiod_get_value_cansleep() to get initial state Date: Sun, 27 Jan 2019 22:50:54 +0800 Message-Id: <20190127145054.3770-1-wens@csie.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: linux-pwm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pwm@vger.kernel.org gpiod_get_value() gives out a warning if access to the underlying gpiochip requires sleeping, which is common for I2C based chips: WARNING: CPU: 0 PID: 77 at drivers/gpio/gpiolib.c:2500 gpiod_get_value+0xd0/0x100 Modules linked in: CPU: 0 PID: 77 Comm: kworker/0:2 Not tainted 4.14.0-rc3-00589-gf32897915d48-dirty #90 Hardware name: Allwinner sun4i/sun5i Families Workqueue: events deferred_probe_work_func [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (dump_stack+0x88/0x9c) [] (dump_stack) from [] (__warn+0xe8/0x100) [] (__warn) from [] (warn_slowpath_null+0x20/0x28) [] (warn_slowpath_null) from [] (gpiod_get_value+0xd0/0x100) [] (gpiod_get_value) from [] (pwm_backlight_probe+0x238/0x508) [] (pwm_backlight_probe) from [] (platform_drv_probe+0x50/0xac) [] (platform_drv_probe) from [] (driver_probe_device+0x238/0x2e8) [] (driver_probe_device) from [] (bus_for_each_drv+0x44/0x94) [] (bus_for_each_drv) from [] (__device_attach+0xb0/0x114) [] (__device_attach) from [] (bus_probe_device+0x84/0x8c) [] (bus_probe_device) from [] (deferred_probe_work_func+0x50/0x14c) [] (deferred_probe_work_func) from [] (process_one_work+0x1ec/0x414) [] (process_one_work) from [] (worker_thread+0x2b0/0x5a0) [] (worker_thread) from [] (kthread+0x14c/0x154) [] (kthread) from [] (ret_from_fork+0x14/0x24) This was missed in commit 0c9501f823a4 ("backlight: pwm_bl: Handle gpio that can sleep"). The code was then moved to a separate function in commit 7613c922315e ("backlight: pwm_bl: Move the checks for initial power state to a separate function"). The only usage of gpiod_get_value() is during the probe stage, which is safe to sleep in. Switch to gpiod_get_value_cansleep(). Fixes: 0c9501f823a4 ("backlight: pwm_bl: Handle gpio that can sleep") Signed-off-by: Chen-Yu Tsai Acked-by: Maxime Ripard Acked-by: Daniel Thompson --- drivers/video/backlight/pwm_bl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index feb90764a811..53b8ceea9bde 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -435,7 +435,7 @@ static int pwm_backlight_initial_power_state(const struct pwm_bl_data *pb) */ /* if the enable GPIO is disabled, do not enable the backlight */ - if (pb->enable_gpio && gpiod_get_value(pb->enable_gpio) == 0) + if (pb->enable_gpio && gpiod_get_value_cansleep(pb->enable_gpio) == 0) return FB_BLANK_POWERDOWN; /* The regulator is disabled, do not enable the backlight */