linux-kernel - [PATCH] backlight: pwm_bl: move suspend/resume entries from platform

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Date:	Thu, 1 Dec 2011 09:53:47 +0800
From:	Barry Song <Barry.Song@....com>
To:	Richard Purdie <rpurdie@...ys.net>,
	Eric Miao <eric.y.miao@...il.com>
CC:	<linux-kernel@...r.kernel.org>, <workgroup.linux@....com>,
	<linux-arm-kernel@...ts.infradead.org>,
	Xiangzhen Ye <Xiangzhen.Ye@....com>,
	Barry Song <Baohua.Song@....com>
Subject: [PATCH] backlight: pwm_bl: move suspend/resume entries from platform_driver to driver.pm

From: Xiangzhen Ye <Xiangzhen.Ye@....com>

At first, people are moving suspend/resume entries from platform_driver
to driver.pm for many drivers.
On the other hand, if we use swsusp to do hibernation for an embedded
system using pwm_bl, in the process of preparing snapshot, backlight
will be off and make lcd black screen. This gives bad user experiences.
This patch will fix this issue as swsusp will go to call pm.freeze()
but not platform_driver.suspend. we have no pm.freeze() for pwm_bl, so
the lcd black screen will disappear.

Signed-off-by: Xiangzhen Ye <Xiangzhen.Ye@....com>
Signed-off-by: Barry Song <Baohua.Song@....com>
---
 drivers/video/backlight/pwm_bl.c |   15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 8b5b2a4..50f3134 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -169,9 +169,9 @@ static int pwm_backlight_remove(struct platform_device *pdev)
 }
 
 #ifdef CONFIG_PM
-static int pwm_backlight_suspend(struct platform_device *pdev,
-				 pm_message_t state)
+static int pwm_backlight_suspend(struct device *dev)
 {
+	struct platform_device *pdev = to_platform_device(dev);
 	struct backlight_device *bl = platform_get_drvdata(pdev);
 	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
 
@@ -184,8 +184,9 @@ static int pwm_backlight_suspend(struct platform_device *pdev,
 	return 0;
 }
 
-static int pwm_backlight_resume(struct platform_device *pdev)
+static int pwm_backlight_resume(struct device *dev)
 {
+	struct platform_device *pdev = to_platform_device(dev);
 	struct backlight_device *bl = platform_get_drvdata(pdev);
 
 	backlight_update_status(bl);
@@ -196,15 +197,19 @@ static int pwm_backlight_resume(struct platform_device *pdev)
 #define pwm_backlight_resume	NULL
 #endif
 
+static const struct dev_pm_ops pwm_backlight_pm_ops = {
+	.suspend = pwm_backlight_suspend,
+	.resume = pwm_backlight_resume,
+};
+
 static struct platform_driver pwm_backlight_driver = {
 	.driver		= {
 		.name	= "pwm-backlight",
 		.owner	= THIS_MODULE,
+		.pm	= &pwm_backlight_pm_ops,
 	},
 	.probe		= pwm_backlight_probe,
 	.remove		= pwm_backlight_remove,
-	.suspend	= pwm_backlight_suspend,
-	.resume		= pwm_backlight_resume,
 };
 
 static int __init pwm_backlight_init(void)
-- 
1.7.1



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