Re: [PATCH 7/8] fbdev: ssd1307fb: Add sysfs handles to expose contrast and dim setting to userspace.

Am Tue, 10 Mar 2015 12:49:19 +0200
schrieb Tomi Valkeinen [off-list ref]:

On 09/02/15 10:52, Maxime Ripard wrote:

quoted

On Sat, Feb 07, 2015 at 05:42:44PM +0100, Thomas Niederprüm wrote:

quoted

quoted

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+static struct device_attribute device_attrs[] = {
+	__ATTR(contrast, S_IRUGO|S_IWUSR, show_contrast,
store_contrast),
+	__ATTR(dim, S_IRUGO|S_IWUSR, show_dim, store_dim),
+
+};
+

I would have thought this was something accessible through the
framebuffer ioctl.

Apparently it's not, at least for the contrast, so maybe it
should be added there, instead of doing it for a single driver?

I think the contrast setting for an OLED display is much like the
backlight setting for LCD panel. Since there is also no ioctl to
set the backlight of an LCD I wonder if the contrast of an OLED
should have one.

It's too much of framebuffer interface debate for me here. Tomi?

We have backlight and contrast already in backlight-class and
lcd-class (drivers/video/backlight/backlight.c and
drivers/video/backlight/lcd.c). Are those something that could be
used here instead of custom sysfs files?

I just gave the backlight-class a try and it works like a charm. I
will include it in v4 and drop the sysfs handles instead. Thanks for the
hint!

Thomas