drivers/video/backlight/hx2750_bl.c

   1 /*
   2  * Backlight Driver for HP iPAQ hx2750
   3  *
   4  * Copyright 2005 Openedhand Ltd.
   5  *
   6  * Author: Richard Purdie <richard@o-hand.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/kernel.h>
  16 #include <linux/init.h>
  17 #include <linux/device.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/fb.h>
  20 #include <linux/backlight.h>
  21
  22 #include <asm/arch/pxa-regs.h>
  23 #include <asm/arch/hx2750.h>
  24
  25 #define HX2750_MAX_INTENSITY      0x190
  26 #define HX2750_DEFAULT_INTENSITY  0x082
  27
  28 static int hx2750_bl_powermode = FB_BLANK_UNBLANK;
  29 static int current_intensity = 0;
  30 static spinlock_t bl_lock = SPIN_LOCK_UNLOCKED;
  31
  32 static void hx2750_set_intensity(int intensity)
  33 {
  34         unsigned long flags;
  35
  36         if (hx2750_bl_powermode != FB_BLANK_UNBLANK) {
  37                 intensity = 0;
  38         }
  39
  40         spin_lock_irqsave(&bl_lock, flags);
  41
  42         PWM_CTRL0 = 2; /* pre-scaler */
  43         PWM_PWDUTY0 = intensity; /* duty cycle */
  44         PWM_PERVAL0 = 0x1f4; /* period */
  45
  46         if (intensity) {
  47                         pxa_set_cken(CKEN0_PWM0,1);
  48                         hx2750_set_egpio(HX2750_EGPIO_LCD_PWR | HX2750_EGPIO_BL_PWR);
  49         } else {
  50                         pxa_set_cken(CKEN0_PWM0,0);
  51                         hx2750_clear_egpio(HX2750_EGPIO_LCD_PWR | HX2750_EGPIO_BL_PWR);
  52         }
  53
  54         spin_unlock_irqrestore(&bl_lock, flags);
  55 }
  56
  57 static void hx2750_bl_blank(int blank)
  58 {
  59         switch(blank) {
  60
  61         case FB_BLANK_NORMAL:
  62         case FB_BLANK_VSYNC_SUSPEND:
  63         case FB_BLANK_HSYNC_SUSPEND:
  64         case FB_BLANK_POWERDOWN:
  65                 if (hx2750_bl_powermode == FB_BLANK_UNBLANK) {
  66                         hx2750_set_intensity(0);
  67                         hx2750_bl_powermode = blank;
  68                 }
  69                 break;
  70         case FB_BLANK_UNBLANK:
  71                 if (hx2750_bl_powermode != FB_BLANK_UNBLANK) {
  72                         hx2750_bl_powermode = blank;
  73                         hx2750_set_intensity(current_intensity);
  74                 }
  75                 break;
  76         }
  77 }
  78
  79 #ifdef CONFIG_PM
  80 static int hx2750_bl_suspend(struct device *dev, u32 state, u32 level)
  81 {
  82         if (level == SUSPEND_POWER_DOWN)
  83                 hx2750_bl_blank(FB_BLANK_POWERDOWN);
  84         return 0;
  85 }
  86
  87 static int hx2750_bl_resume(struct device *dev, u32 level)
  88 {
  89         if (level == RESUME_POWER_ON)
  90                 hx2750_bl_blank(FB_BLANK_UNBLANK);
  91         return 0;
  92 }
  93 #else
  94 #define hx2750_bl_suspend       NULL
  95 #define hx2750_bl_resume        NULL
  96 #endif
  97
  98
  99 static int hx2750_bl_set_power(struct backlight_device *bd, int state)
 100 {
 101         hx2750_bl_blank(state);
 102         return 0;
 103 }
 104
 105 static int hx2750_bl_get_power(struct backlight_device *bd)
 106 {
 107         return hx2750_bl_powermode;
 108 }
 109
 110 static int hx2750_bl_set_intensity(struct backlight_device *bd, int intensity)
 111 {
 112         if (intensity > HX2750_MAX_INTENSITY)
 113                 intensity = HX2750_MAX_INTENSITY;
 114         hx2750_set_intensity(intensity);
 115         current_intensity=intensity;
 116         return 0;
 117 }
 118
 119 static int hx2750_bl_get_intensity(struct backlight_device *bd)
 120 {
 121         return current_intensity;
 122 }
 123
 124 static struct backlight_properties hx2750_bl_data = {
 125         .owner          = THIS_MODULE,
 126         .get_power      = hx2750_bl_get_power,
 127         .set_power      = hx2750_bl_set_power,
 128         .max_brightness = HX2750_MAX_INTENSITY,
 129         .get_brightness = hx2750_bl_get_intensity,
 130         .set_brightness = hx2750_bl_set_intensity,
 131 };
 132
 133 static struct backlight_device *hx2750_backlight_device;
 134
 135 static int __init hx2750_bl_probe(struct device *dev)
 136 {
 137         hx2750_backlight_device = backlight_device_register ("hx2750-bl",
 138                 NULL, &hx2750_bl_data);
 139         if (IS_ERR (hx2750_backlight_device))
 140                 return PTR_ERR (hx2750_backlight_device);
 141
 142         hx2750_bl_powermode = FB_BLANK_UNBLANK;
 143         hx2750_bl_set_intensity(NULL, HX2750_DEFAULT_INTENSITY);
 144
 145         pxa_set_cken(CKEN0_PWM0,1);
 146
 147         printk("hx2750 Backlight Driver Initialized.\n");
 148         return 0;
 149 }
 150
 151 static int hx2750_bl_remove(struct device *dev)
 152 {
 153         backlight_device_unregister(hx2750_backlight_device);
 154
 155         hx2750_bl_set_intensity(NULL, 0);
 156
 157         printk("hx2750 Backlight Driver Unloaded\n");
 158         return 0;
 159 }
 160
 161 static struct device_driver hx2750_bl_driver = {
 162         .name           = "hx2750-bl",
 163         .bus            = &platform_bus_type,
 164         .probe          = hx2750_bl_probe,
 165         .remove         = hx2750_bl_remove,
 166         .suspend        = hx2750_bl_suspend,
 167         .resume         = hx2750_bl_resume,
 168 };
 169
 170 static int __init hx2750_bl_init(void)
 171 {
 172         return driver_register(&hx2750_bl_driver);
 173 }
 174
 175 static void __exit hx2750_bl_exit(void)
 176 {
 177         driver_unregister(&hx2750_bl_driver);
 178 }
 179
 180 module_init(hx2750_bl_init);
 181 module_exit(hx2750_bl_exit);
 182
 183 MODULE_AUTHOR("Richard Purdie <rpurdie@o-hand.com>");
 184 MODULE_DESCRIPTION("iPAQ hx2750 Backlight Driver");
 185 MODULE_LICENSE("GPLv2");