drivers/video/fbdev/nvidia/nv_backlight.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Backlight code for nVidia based graphic cards
   4  *
   5  * Copyright 2004 Antonino Daplas <adaplas@pol.net>
   6  * Copyright (c) 2006 Michael Hanselmann <linux-kernel@hansmi.ch>
   7  */
   8
   9 #include <linux/backlight.h>
  10 #include <linux/fb.h>
  11 #include <linux/pci.h>
  12
  13 #ifdef CONFIG_PMAC_BACKLIGHT
  14 #include <asm/backlight.h>
  15 #endif
  16
  17 #include "nv_local.h"
  18 #include "nv_type.h"
  19 #include "nv_proto.h"
  20
  21 /* We do not have any information about which values are allowed, thus
  22  * we used safe values.
  23  */
  24 #define MIN_LEVEL 0x158
  25 #define MAX_LEVEL 0x534
  26 #define LEVEL_STEP ((MAX_LEVEL - MIN_LEVEL) / FB_BACKLIGHT_MAX)
  27
  28 static int nvidia_bl_get_level_brightness(struct nvidia_par *par,
  29                 int level)
  30 {
  31         struct fb_info *info = pci_get_drvdata(par->pci_dev);
  32         int nlevel;
  33
  34         /* Get and convert the value */
  35         /* No locking of bl_curve since we read a single value */
  36         nlevel = MIN_LEVEL + info->bl_curve[level] * LEVEL_STEP;
  37
  38         if (nlevel < 0)
  39                 nlevel = 0;
  40         else if (nlevel < MIN_LEVEL)
  41                 nlevel = MIN_LEVEL;
  42         else if (nlevel > MAX_LEVEL)
  43                 nlevel = MAX_LEVEL;
  44
  45         return nlevel;
  46 }
  47
  48 static int nvidia_bl_update_status(struct backlight_device *bd)
  49 {
  50         struct nvidia_par *par = bl_get_data(bd);
  51         u32 tmp_pcrt, tmp_pmc, fpcontrol;
  52         int level;
  53
  54         if (!par->FlatPanel)
  55                 return 0;
  56
  57         if (bd->props.power != FB_BLANK_UNBLANK ||
  58             bd->props.fb_blank != FB_BLANK_UNBLANK)
  59                 level = 0;
  60         else
  61                 level = bd->props.brightness;
  62
  63         tmp_pmc = NV_RD32(par->PMC, 0x10F0) & 0x0000FFFF;
  64         tmp_pcrt = NV_RD32(par->PCRTC0, 0x081C) & 0xFFFFFFFC;
  65         fpcontrol = NV_RD32(par->PRAMDAC, 0x0848) & 0xCFFFFFCC;
  66
  67         if (level > 0) {
  68                 tmp_pcrt |= 0x1;
  69                 tmp_pmc |= (1 << 31); /* backlight bit */
  70                 tmp_pmc |= nvidia_bl_get_level_brightness(par, level) << 16;
  71                 fpcontrol |= par->fpSyncs;
  72         } else
  73                 fpcontrol |= 0x20000022;
  74
  75         NV_WR32(par->PCRTC0, 0x081C, tmp_pcrt);
  76         NV_WR32(par->PMC, 0x10F0, tmp_pmc);
  77         NV_WR32(par->PRAMDAC, 0x848, fpcontrol);
  78
  79         return 0;
  80 }
  81
  82 static const struct backlight_ops nvidia_bl_ops = {
  83         .update_status  = nvidia_bl_update_status,
  84 };
  85
  86 void nvidia_bl_init(struct nvidia_par *par)
  87 {
  88         struct backlight_properties props;
  89         struct fb_info *info = pci_get_drvdata(par->pci_dev);
  90         struct backlight_device *bd;
  91         char name[12];
  92
  93         if (!par->FlatPanel)
  94                 return;
  95
  96 #ifdef CONFIG_PMAC_BACKLIGHT
  97         if (!machine_is(powermac) ||
  98             !pmac_has_backlight_type("mnca"))
  99                 return;
 100 #endif
 101
 102         snprintf(name, sizeof(name), "nvidiabl%d", info->node);
 103
 104         memset(&props, 0, sizeof(struct backlight_properties));
 105         props.type = BACKLIGHT_RAW;
 106         props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
 107         bd = backlight_device_register(name, info->dev, par, &nvidia_bl_ops,
 108                                        &props);
 109         if (IS_ERR(bd)) {
 110                 info->bl_dev = NULL;
 111                 printk(KERN_WARNING "nvidia: Backlight registration failed\n");
 112                 goto error;
 113         }
 114
 115         info->bl_dev = bd;
 116         fb_bl_default_curve(info, 0,
 117                 0x158 * FB_BACKLIGHT_MAX / MAX_LEVEL,
 118                 0x534 * FB_BACKLIGHT_MAX / MAX_LEVEL);
 119
 120         bd->props.brightness = bd->props.max_brightness;
 121         bd->props.power = FB_BLANK_UNBLANK;
 122         backlight_update_status(bd);
 123
 124         printk("nvidia: Backlight initialized (%s)\n", name);
 125
 126         return;
 127
 128 error:
 129         return;
 130 }
 131
 132 void nvidia_bl_exit(struct nvidia_par *par)
 133 {
 134         struct fb_info *info = pci_get_drvdata(par->pci_dev);
 135         struct backlight_device *bd = info->bl_dev;
 136
 137         backlight_device_unregister(bd);
 138         printk("nvidia: Backlight unloaded\n");
 139 }