drivers/staging/gma500/psb_bl.c

   1 /*
   2  *  psb backlight interface
   3  *
   4  * Copyright (c) 2009, Intel Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Authors: Eric Knopp
  20  *
  21  */
  22
  23 #include <linux/backlight.h>
  24 #include <linux/version.h>
  25 #include "psb_drv.h"
  26 #include "psb_intel_reg.h"
  27 #include "psb_intel_drv.h"
  28 #include "psb_intel_bios.h"
  29 #include "psb_powermgmt.h"
  30
  31 #define MRST_BLC_MAX_PWM_REG_FREQ           0xFFFF
  32 #define BLC_PWM_PRECISION_FACTOR 100    /* 10000000 */
  33 #define BLC_PWM_FREQ_CALC_CONSTANT 32
  34 #define MHz 1000000
  35 #define BRIGHTNESS_MIN_LEVEL 1
  36 #define BRIGHTNESS_MAX_LEVEL 100
  37 #define BRIGHTNESS_MASK 0xFF
  38 #define BLC_POLARITY_NORMAL 0
  39 #define BLC_POLARITY_INVERSE 1
  40 #define BLC_ADJUSTMENT_MAX 100
  41
  42 #define PSB_BLC_PWM_PRECISION_FACTOR    10
  43 #define PSB_BLC_MAX_PWM_REG_FREQ        0xFFFE
  44 #define PSB_BLC_MIN_PWM_REG_FREQ        0x2
  45
  46 #define PSB_BACKLIGHT_PWM_POLARITY_BIT_CLEAR (0xFFFE)
  47 #define PSB_BACKLIGHT_PWM_CTL_SHIFT     (16)
  48
  49 static int psb_brightness;
  50 static struct backlight_device *psb_backlight_device;
  51 static u8 blc_brightnesscmd;
  52 static u8 blc_pol;
  53 static u8 blc_type;
  54
  55 int psb_set_brightness(struct backlight_device *bd)
  56 {
  57         struct drm_device *dev = bl_get_data(psb_backlight_device);
  58         int level = bd->props.brightness;
  59
  60         DRM_DEBUG_DRIVER("backlight level set to %d\n", level);
  61
  62         /* Perform value bounds checking */
  63         if (level < BRIGHTNESS_MIN_LEVEL)
  64                 level = BRIGHTNESS_MIN_LEVEL;
  65
  66         psb_intel_lvds_set_brightness(dev, level);
  67         psb_brightness = level;
  68         return 0;
  69 }
  70
  71 int psb_get_brightness(struct backlight_device *bd)
  72 {
  73         DRM_DEBUG_DRIVER("brightness = 0x%x\n", psb_brightness);
  74
  75         /* return locally cached var instead of HW read (due to DPST etc.) */
  76         /* FIXME: ideally return actual value in case firmware fiddled with
  77            it */
  78         return psb_brightness;
  79 }
  80
  81 static const struct backlight_ops psb_ops = {
  82         .get_brightness = psb_get_brightness,
  83         .update_status  = psb_set_brightness,
  84 };
  85
  86 static int device_backlight_init(struct drm_device *dev)
  87 {
  88         unsigned long core_clock;
  89         /* u32 bl_max_freq; */
  90         /* unsigned long value; */
  91         u16 bl_max_freq;
  92         uint32_t value;
  93         uint32_t blc_pwm_precision_factor;
  94         struct drm_psb_private *dev_priv = dev->dev_private;
  95
  96         /* get bl_max_freq and pol from dev_priv*/
  97         if (!dev_priv->lvds_bl) {
  98                 DRM_ERROR("Has no valid LVDS backlight info\n");
  99                 return 1;
 100         }
 101         bl_max_freq = dev_priv->lvds_bl->freq;
 102         blc_pol = dev_priv->lvds_bl->pol;
 103         blc_pwm_precision_factor = PSB_BLC_PWM_PRECISION_FACTOR;
 104         blc_brightnesscmd = dev_priv->lvds_bl->brightnesscmd;
 105         blc_type = dev_priv->lvds_bl->type;
 106
 107         core_clock = dev_priv->core_freq;
 108
 109         value = (core_clock * MHz) / BLC_PWM_FREQ_CALC_CONSTANT;
 110         value *= blc_pwm_precision_factor;
 111         value /= bl_max_freq;
 112         value /= blc_pwm_precision_factor;
 113
 114         if (ospm_power_using_hw_begin(OSPM_DISPLAY_ISLAND,
 115                                                 OSPM_UHB_ONLY_IF_ON)) {
 116                 /* Check: may be MFLD only */
 117                 if (
 118                  value > (unsigned long long)PSB_BLC_MAX_PWM_REG_FREQ ||
 119                  value < (unsigned long long)PSB_BLC_MIN_PWM_REG_FREQ)
 120                         return 2;
 121                 else {
 122                         value &= PSB_BACKLIGHT_PWM_POLARITY_BIT_CLEAR;
 123                         REG_WRITE(BLC_PWM_CTL,
 124                                 (value << PSB_BACKLIGHT_PWM_CTL_SHIFT) |
 125                                 (value));
 126                 }
 127                 ospm_power_using_hw_end(OSPM_DISPLAY_ISLAND);
 128         }
 129         return 0;
 130 }
 131
 132 int psb_backlight_init(struct drm_device *dev)
 133 {
 134 #ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
 135         int ret = 0;
 136
 137         struct backlight_properties props;
 138         memset(&props, 0, sizeof(struct backlight_properties));
 139         props.max_brightness = BRIGHTNESS_MAX_LEVEL;
 140
 141         psb_backlight_device = backlight_device_register("psb-bl", NULL,
 142                                                 (void *)dev, &psb_ops, &props);
 143         if (IS_ERR(psb_backlight_device))
 144                 return PTR_ERR(psb_backlight_device);
 145
 146         ret = device_backlight_init(dev);
 147         if (ret < 0)
 148                 return ret;
 149
 150         psb_backlight_device->props.brightness = BRIGHTNESS_MAX_LEVEL;
 151         psb_backlight_device->props.max_brightness = BRIGHTNESS_MAX_LEVEL;
 152         backlight_update_status(psb_backlight_device);
 153 #endif
 154         return 0;
 155 }
 156
 157 void psb_backlight_exit(void)
 158 {
 159 #ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
 160         psb_backlight_device->props.brightness = 0;
 161         backlight_update_status(psb_backlight_device);
 162         backlight_device_unregister(psb_backlight_device);
 163 #endif
 164 }
 165
 166 struct backlight_device *psb_get_backlight_device(void)
 167 {
 168         return psb_backlight_device;
 169 }