Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932092Ab3EGJRi (ORCPT ); Tue, 7 May 2013 05:17:38 -0400 Received: from relay3.sgi.com ([192.48.152.1]:39359 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759277Ab3EGJRg (ORCPT ); Tue, 7 May 2013 05:17:36 -0400 Date: Tue, 7 May 2013 04:17:34 -0500 From: Robin Holt To: Qing Xu , Haojian Zhuang , Samuel Ortiz Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: How does commit 47ec340c not introduce a bug? Message-ID: <20130507091734.GM3658@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3065 Lines: 94 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: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/