1 /*
2  * Backlight code for nVidia based graphic cards
3  *
4  * Copyright 2004 Antonino Daplas <adaplas@pol.net>
5  * Copyright (c) 2006 Michael Hanselmann <linux-kernel@hansmi.ch>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 
12 #include <linux/backlight.h>
13 #include <linux/fb.h>
14 #include <linux/pci.h>
15 
16 #ifdef CONFIG_PMAC_BACKLIGHT
17 #include <asm/backlight.h>
18 #endif
19 
20 #include "nv_local.h"
21 #include "nv_type.h"
22 #include "nv_proto.h"
23 
24 /* We do not have any information about which values are allowed, thus
25  * we used safe values.
26  */
27 #define MIN_LEVEL 0x158
28 #define MAX_LEVEL 0x534
29 #define LEVEL_STEP ((MAX_LEVEL - MIN_LEVEL) / FB_BACKLIGHT_MAX)
30 
31 static int nvidia_bl_get_level_brightness(struct nvidia_par *par,
32 		int level)
33 {
34 	struct fb_info *info = pci_get_drvdata(par->pci_dev);
35 	int nlevel;
36 
37 	/* Get and convert the value */
38 	/* No locking of bl_curve since we read a single value */
39 	nlevel = MIN_LEVEL + info->bl_curve[level] * LEVEL_STEP;
40 
41 	if (nlevel < 0)
42 		nlevel = 0;
43 	else if (nlevel < MIN_LEVEL)
44 		nlevel = MIN_LEVEL;
45 	else if (nlevel > MAX_LEVEL)
46 		nlevel = MAX_LEVEL;
47 
48 	return nlevel;
49 }
50 
51 static int nvidia_bl_update_status(struct backlight_device *bd)
52 {
53 	struct nvidia_par *par = bl_get_data(bd);
54 	u32 tmp_pcrt, tmp_pmc, fpcontrol;
55 	int level;
56 
57 	if (!par->FlatPanel)
58 		return 0;
59 
60 	if (bd->props.power != FB_BLANK_UNBLANK ||
61 	    bd->props.fb_blank != FB_BLANK_UNBLANK)
62 		level = 0;
63 	else
64 		level = bd->props.brightness;
65 
66 	tmp_pmc = NV_RD32(par->PMC, 0x10F0) & 0x0000FFFF;
67 	tmp_pcrt = NV_RD32(par->PCRTC0, 0x081C) & 0xFFFFFFFC;
68 	fpcontrol = NV_RD32(par->PRAMDAC, 0x0848) & 0xCFFFFFCC;
69 
70 	if (level > 0) {
71 		tmp_pcrt |= 0x1;
72 		tmp_pmc |= (1 << 31); /* backlight bit */
73 		tmp_pmc |= nvidia_bl_get_level_brightness(par, level) << 16;
74 		fpcontrol |= par->fpSyncs;
75 	} else
76 		fpcontrol |= 0x20000022;
77 
78 	NV_WR32(par->PCRTC0, 0x081C, tmp_pcrt);
79 	NV_WR32(par->PMC, 0x10F0, tmp_pmc);
80 	NV_WR32(par->PRAMDAC, 0x848, fpcontrol);
81 
82 	return 0;
83 }
84 
85 static const struct backlight_ops nvidia_bl_ops = {
86 	.update_status	= nvidia_bl_update_status,
87 };
88 
89 void nvidia_bl_init(struct nvidia_par *par)
90 {
91 	struct backlight_properties props;
92 	struct fb_info *info = pci_get_drvdata(par->pci_dev);
93 	struct backlight_device *bd;
94 	char name[12];
95 
96 	if (!par->FlatPanel)
97 		return;
98 
99 #ifdef CONFIG_PMAC_BACKLIGHT
100 	if (!machine_is(powermac) ||
101 	    !pmac_has_backlight_type("mnca"))
102 		return;
103 #endif
104 
105 	snprintf(name, sizeof(name), "nvidiabl%d", info->node);
106 
107 	memset(&props, 0, sizeof(struct backlight_properties));
108 	props.type = BACKLIGHT_RAW;
109 	props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
110 	bd = backlight_device_register(name, info->dev, par, &nvidia_bl_ops,
111 				       &props);
112 	if (IS_ERR(bd)) {
113 		info->bl_dev = NULL;
114 		printk(KERN_WARNING "nvidia: Backlight registration failed\n");
115 		goto error;
116 	}
117 
118 	info->bl_dev = bd;
119 	fb_bl_default_curve(info, 0,
120 		0x158 * FB_BACKLIGHT_MAX / MAX_LEVEL,
121 		0x534 * FB_BACKLIGHT_MAX / MAX_LEVEL);
122 
123 	bd->props.brightness = bd->props.max_brightness;
124 	bd->props.power = FB_BLANK_UNBLANK;
125 	backlight_update_status(bd);
126 
127 	printk("nvidia: Backlight initialized (%s)\n", name);
128 
129 	return;
130 
131 error:
132 	return;
133 }
134 
135 void nvidia_bl_exit(struct nvidia_par *par)
136 {
137 	struct fb_info *info = pci_get_drvdata(par->pci_dev);
138 	struct backlight_device *bd = info->bl_dev;
139 
140 	backlight_device_unregister(bd);
141 	printk("nvidia: Backlight unloaded\n");
142 }
143