Rockchip rk27xx port initial commit. This is still work in progress.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29935 a1c6a512-1295-4272-9138-f99709370657

firmware/target/arm/rk27xx/backlight-rk27xx.c

@@ -0,0 +1,86 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2011 by Marcin Bukat
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#include <stdbool.h>
+
+#include "config.h"
+#include "backlight.h"
+#include "backlight-target.h"
+#include "system.h"
+
+bool _backlight_init(void)
+{
+    /* configure PD4 as output */
+    GPIO_PDCON |= (1<<4);
+
+    /* set PD4 low (backlight off) */
+    GPIO_PDDR &= ~(1<<4);
+
+    /* IOMUXB - set PWM0 pin as GPIO */
+    SCU_IOMUXB_CON &= ~(1 << 11); /* type<<11<<channel */
+
+    /* setup pwm */
+    PWMT0_CTRL = (0<<9) | (1<<7);
+
+    /* set pwm frequency ~10kHz */
+    /* (apb_freq/pwm_freq)/pwm_div = (50 000 000/10 000)/2 */
+    PWMT0_LRC = 2500; 
+    PWMT0_HRC = 1;
+
+    PWMT0_CNTR = 0x00;
+    PWMT0_CTRL = (0<<9) | (1<<3) | (1<<0);
+
+    return true;
+}
+
+void _backlight_on(void)
+{
+    /* enable PWM clock */
+    SCU_CLKCFG &= ~(1<<29);
+
+    /* set output pin as PWM pin */
+    SCU_IOMUXB_CON |= (1<<11); /* type<<11<<channel */
+
+    /* 100% duty cycle. Other settings doesn't work for
+     * unknown reason
+     */
+    PWMT0_HRC = PWMT0_LRC;
+
+    /* pwm enable */
+    PWMT0_CTRL |= (1<<3) | (1<<0);
+}
+
+void _backlight_off(void)
+{
+    /* setup PWM0 pin as GPIO which is pulled low */
+    SCU_IOMUXB_CON &= ~(1<<11);
+
+    /* stop pwm timer */
+    PWMT0_CTRL &= ~(1<<3) | (1<<0);
+
+    /* disable PWM clock */
+    SCU_CLKCFG |= (1<<29);
+}
+
+void _backlight_set_brightness(int brightness)
+{
+    (void)brightness;
+    /* doesn't work for unknown reason */
+}