From patchwork Tue May 7 09:17:34 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robin Holt X-Patchwork-Id: 2532461 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) by patchwork1.kernel.org (Postfix) with ESMTP id B52F43FCA5 for ; Tue, 7 May 2013 09:18:07 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UZe28-0001ac-9U; Tue, 07 May 2013 09:18:04 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UZe25-00076l-F3; Tue, 07 May 2013 09:18:01 +0000 Received: from relay3.sgi.com ([192.48.152.1] helo=relay.sgi.com) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UZe22-000768-Iz for linux-arm-kernel@lists.infradead.org; Tue, 07 May 2013 09:17:59 +0000 Received: from estes.americas.sgi.com (estes.americas.sgi.com [128.162.236.10]) by relay3.corp.sgi.com (Postfix) with ESMTP id C639DAC009; Tue, 7 May 2013 02:17:34 -0700 (PDT) Received: from lnx-holt.americas.sgi.com (lnx-holt.americas.sgi.com [128.162.233.109]) by estes.americas.sgi.com (Postfix) with ESMTP id 786437003669; Tue, 7 May 2013 04:17:34 -0500 (CDT) Received: from holt by lnx-holt.americas.sgi.com with local (Exim 4.71) (envelope-from ) id 1UZe1e-0003Y2-Eh; Tue, 07 May 2013 04:17:34 -0500 Date: Tue, 7 May 2013 04:17:34 -0500 From: Robin Holt To: Qing Xu , Haojian Zhuang , Samuel Ortiz Subject: How does commit 47ec340c not introduce a bug? Message-ID: <20130507091734.GM3658@sgi.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130507_051758_759122_9E51555C X-CRM114-Status: GOOD ( 14.49 ) X-Spam-Score: -5.5 (-----) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-5.5 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [192.48.152.1 listed in list.dnswl.org] -1.3 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org I noticed a warning while cross-compiling all arm defconfigs. The mmp2_defconfig gave this warning: drivers/video/backlight/max8925_bl.c: In function 'max8925_backlight_probe': drivers/video/backlight/max8925_bl.c:177:3: warning: statement with no effect [-Wunused-value] This appears to have been introduced by the above commit when !CONFIG_OF Looking at this more closely, I am not sure how this was ever intended to be handled or how the errors returned in the CONFIG_OF case were intended to be handled as the return from max8925_backlight_dt_init is always ignored. I think this needs some more attention, but do not feel like I know enough about it or have any means to test it to weigh in. Thanks, Robin commit 47ec340cb8e232671e7c4a4689ff32c3bdf329da Author: Qing Xu Date: Mon Feb 4 23:40:45 2013 +0800 mfd: max8925: Support dt for backlight Add device tree support in max8925 backlight. Signed-off-by: Qing Xu Signed-off-by: Haojian Zhuang Signed-off-by: Samuel Ortiz diff --git a/drivers/video/backlight/max8925_bl.c b/drivers/video/backlight/max8925_bl.c index 2c9bce0..5ca11b0 100644 --- a/drivers/video/backlight/max8925_bl.c +++ b/drivers/video/backlight/max8925_bl.c @@ -101,6 +101,29 @@ static const struct backlight_ops max8925_backlight_ops = { .get_brightness = max8925_backlight_get_brightness, }; +#ifdef CONFIG_OF +static int max8925_backlight_dt_init(struct platform_device *pdev, + struct max8925_backlight_pdata *pdata) +{ + struct device_node *nproot = pdev->dev.parent->of_node, *np; + int dual_string; + + if (!nproot) + return -ENODEV; + np = of_find_node_by_name(nproot, "backlight"); + if (!np) { + dev_err(&pdev->dev, "failed to find backlight node\n"); + return -ENODEV; + } + + of_property_read_u32(np, "maxim,max8925-dual-string", &dual_string); + pdata->dual_string = dual_string; + return 0; +} +#else +#define max8925_backlight_dt_init(x, y) (-1) +#endif + static int max8925_backlight_probe(struct platform_device *pdev) { struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent); @@ -147,6 +170,13 @@ static int max8925_backlight_probe(struct platform_device *pdev) platform_set_drvdata(pdev, bl); value = 0; + if (pdev->dev.parent->of_node && !pdata) { + pdata = devm_kzalloc(&pdev->dev, + sizeof(struct max8925_backlight_pdata), + GFP_KERNEL); + max8925_backlight_dt_init(pdev, pdata); + } + if (pdata) { if (pdata->lxw_scl) value |= (1 << 7); @@ -158,7 +188,6 @@ static int max8925_backlight_probe(struct platform_device *pdev) ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value); if (ret < 0) goto out_brt; - backlight_update_status(bl); return 0; out_brt: