Implementing backlight fade for the Gigabeat. Note that fading is the normal behaviour. Settings for LCD off and fade settings will be coming.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@11899 a1c6a512-1295-4272-9138-f99709370657

firmware/target/arm/gigabeat/meg-fx/backlight-meg-fx.c

@@ -24,27 +24,128 @@
 #include "lcd.h"
 #include "sc606-meg-fx.h"
 
+
+static void backlight_fade_service(void);
+static unsigned short backlight_brightness;
+static unsigned short backlight_fading;
+static unsigned short backlight_current;
+static unsigned short backlight_target;
+static unsigned short time_til_fade;
+static unsigned short fade_interval;
+
+
 static int confval = SC606_LOW_FREQ;
 
+
+
 void __backlight_init(void)
 {
+    backlight_fading = false;
+
+    /* current is from settings */
+    backlight_current = 50;
+    
+    /* put the fade tick on the list */
+    tick_add_task(backlight_fade_service);
 }
 
+
+
 void __backlight_on(void)
 {
     confval |= (SC606_LED_A1 | SC606_LED_A2);
     sc606_write(SC606_REG_CONF, confval);
 }
 
+
+
 void __backlight_off(void)
 {
     confval &= ~(SC606_LED_A1 | SC606_LED_A2);
     sc606_write(SC606_REG_CONF, confval);
 }
 
+
+
+/* Assumes that the backlight has been initialized */
 void __backlight_set_brightness(int brightness)
 {
-    /* The SC606 LED driver can set the brightness in 64 steps */
-    brightness &= 0x3F;
-    sc606_write(SC606_REG_A, brightness);
+    /* stop the interrupt from messing us up */
+    backlight_fading = false;
+
+    backlight_brightness = brightness;
+
+    /* only set the brightness if it is different from the current */
+    if (backlight_brightness != backlight_current)
+    {
+        backlight_target = brightness;
+        fade_interval = time_til_fade = 1;
+        backlight_fading = true;
     }
+}
+
+
+
+static void backlight_fade_service(void)
+{
+    if (!backlight_fading || --time_til_fade) return;
+            
+    if (backlight_target > backlight_current)
+    {
+        backlight_current++;
+    }
+    else
+    {
+        backlight_current--;
+    }
+        
+    /* The SC606 LED driver can set the brightness in 64 steps */
+    sc606_write(SC606_REG_A, backlight_current);
+
+
+    /* have we hit the target? */
+    if (backlight_current == backlight_target)
+    {
+        backlight_fading = false;
+    }
+    else
+    {
+        time_til_fade = fade_interval;
+    }
+
+}
+
+
+
+
+
+void __backlight_dim(bool dim_now)
+{
+    int target;
+    
+    /* dont let the interrupt tick happen */
+    backlight_fading = false;
+
+    target = (dim_now == true) ? 0 : backlight_brightness;
+    
+    /* only try and fade if the target is different */
+    if (backlight_current != target)
+    {
+        backlight_target = target;
+        
+        if (backlight_current > backlight_target) 
+        {
+            fade_interval = 4;
+        }
+        else
+        {
+            fade_interval = 1;
+        }
+
+        /* let the tick work */
+        time_til_fade = fade_interval;
+        backlight_fading = true;
+    }
+            
+}
+

firmware/target/arm/gigabeat/meg-fx/backlight-target.h

@@ -24,4 +24,6 @@ void __backlight_on(void);
 void __backlight_off(void);
 void __backlight_set_brightness(int val);
 
+void __backlight_dim(bool dim);
+
 #endif