[PATCH] Rewritten backlight infrastructure for portable Apple computers
This patch contains a total rewrite of the backlight infrastructure for
portable Apple computers. Backward compatibility is retained. A sysfs
interface allows userland to control the brightness with more steps than
before. Userland is allowed to upload a brightness curve for different
monitors, similar to Mac OS X.
[akpm@osdl.org: add needed exports]
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/video/fbsysfs.c b/drivers/video/fbsysfs.c
index 34e0739..3ceb8c1 100644
--- a/drivers/video/fbsysfs.c
+++ b/drivers/video/fbsysfs.c
@@ -18,6 +18,7 @@
#include <linux/kernel.h>
#include <linux/fb.h>
#include <linux/console.h>
+#include <linux/module.h>
/**
* framebuffer_alloc - creates a new frame buffer info structure
@@ -55,6 +56,10 @@
info->device = dev;
+#ifdef CONFIG_FB_BACKLIGHT
+ mutex_init(&info->bl_mutex);
+#endif
+
return info;
#undef PADDING
#undef BYTES_PER_LONG
@@ -414,6 +419,65 @@
return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->state);
}
+#ifdef CONFIG_FB_BACKLIGHT
+static ssize_t store_bl_curve(struct class_device *class_device,
+ const char *buf, size_t count)
+{
+ struct fb_info *fb_info = class_get_devdata(class_device);
+ u8 tmp_curve[FB_BACKLIGHT_LEVELS];
+ unsigned int i;
+
+ if (count != (FB_BACKLIGHT_LEVELS / 8 * 24))
+ return -EINVAL;
+
+ for (i = 0; i < (FB_BACKLIGHT_LEVELS / 8); ++i)
+ if (sscanf(&buf[i * 24],
+ "%2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx\n",
+ &tmp_curve[i * 8 + 0],
+ &tmp_curve[i * 8 + 1],
+ &tmp_curve[i * 8 + 2],
+ &tmp_curve[i * 8 + 3],
+ &tmp_curve[i * 8 + 4],
+ &tmp_curve[i * 8 + 5],
+ &tmp_curve[i * 8 + 6],
+ &tmp_curve[i * 8 + 7]) != 8)
+ return -EINVAL;
+
+ /* If there has been an error in the input data, we won't
+ * reach this loop.
+ */
+ mutex_lock(&fb_info->bl_mutex);
+ for (i = 0; i < FB_BACKLIGHT_LEVELS; ++i)
+ fb_info->bl_curve[i] = tmp_curve[i];
+ mutex_unlock(&fb_info->bl_mutex);
+
+ return count;
+}
+
+static ssize_t show_bl_curve(struct class_device *class_device, char *buf)
+{
+ struct fb_info *fb_info = class_get_devdata(class_device);
+ ssize_t len = 0;
+ unsigned int i;
+
+ mutex_lock(&fb_info->bl_mutex);
+ for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8)
+ len += snprintf(&buf[len], PAGE_SIZE,
+ "%02x %02x %02x %02x %02x %02x %02x %02x\n",
+ fb_info->bl_curve[i + 0],
+ fb_info->bl_curve[i + 1],
+ fb_info->bl_curve[i + 2],
+ fb_info->bl_curve[i + 3],
+ fb_info->bl_curve[i + 4],
+ fb_info->bl_curve[i + 5],
+ fb_info->bl_curve[i + 6],
+ fb_info->bl_curve[i + 7]);
+ mutex_unlock(&fb_info->bl_mutex);
+
+ return len;
+}
+#endif
+
/* When cmap is added back in it should be a binary attribute
* not a text one. Consideration should also be given to converting
* fbdev to use configfs instead of sysfs */
@@ -432,6 +496,9 @@
__ATTR(con_rotate, S_IRUGO|S_IWUSR, show_con_rotate, store_con_rotate),
__ATTR(con_rotate_all, S_IWUSR, NULL, store_con_rotate_all),
__ATTR(state, S_IRUGO|S_IWUSR, show_fbstate, store_fbstate),
+#ifdef CONFIG_FB_BACKLIGHT
+ __ATTR(bl_curve, S_IRUGO|S_IWUSR, show_bl_curve, store_bl_curve),
+#endif
};
int fb_init_class_device(struct fb_info *fb_info)
@@ -454,4 +521,25 @@
&class_device_attrs[i]);
}
+#ifdef CONFIG_FB_BACKLIGHT
+/* This function generates a linear backlight curve
+ *
+ * 0: off
+ * 1-7: min
+ * 8-127: linear from min to max
+ */
+void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max)
+{
+ unsigned int i, flat, count, range = (max - min);
+ fb_info->bl_curve[0] = off;
+
+ for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
+ fb_info->bl_curve[flat] = min;
+
+ count = FB_BACKLIGHT_LEVELS * 15 / 16;
+ for (i = 0; i < count; ++i)
+ fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count);
+}
+EXPORT_SYMBOL_GPL(fb_bl_default_curve);
+#endif