Re: [PATCH v2] backlight: platform_lcd: introduce probe callback
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2013-04-15 23:06:37
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On Thu, 11 Apr 2013 13:24:50 -0700 Andrew Bresticker [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Platform LCD devices may need to do some device-specific initialization before they can be used (regulator or GPIO setup, for example), but currently the driver does not support any way of doing this. This patch adds a probe() callback to plat_lcd_data which platform LCD devices can set to indicate that device-specific initialization is needed. index 17a6b83..f46180e 100644--- a/drivers/video/backlight/platform_lcd.c +++ b/drivers/video/backlight/platform_lcd.c@@ -86,6 +86,12 @@ static int platform_lcd_probe(struct platform_device *pdev) return -EINVAL; } + if (pdata->probe) { + err = pdata->probe(pdata); + if (err) + return err; + } + plcd = devm_kzalloc(&pdev->dev, sizeof(struct platform_lcd), GFP_KERNEL); if (!plcd) {diff --git a/include/video/platform_lcd.h b/include/video/platform_lcd.h index ad3bdfe..23864b2 100644 --- a/include/video/platform_lcd.h +++ b/include/video/platform_lcd.h@@ -15,6 +15,7 @@ struct plat_lcd_data; struct fb_info; struct plat_lcd_data { + int (*probe)(struct plat_lcd_data *); void (*set_power)(struct plat_lcd_data *, unsigned int power); int (*match_fb)(struct plat_lcd_data *, struct fb_info *); };
Sigh. I see that this entire interface has been lovingly undocumented. It's an invitation for us to grow bugs, incompatibilities, leaks, etc. Possible example: what happens if pdata->probe does some resource allocation or device initialisation which should be backed out if, say, platform_lcd_probe() later fails?