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 = backlight_get_brightness(bd);
53 
54 	if (!par->FlatPanel)
55 		return 0;
56 
57 	tmp_pmc = NV_RD32(par->PMC, 0x10F0) & 0x0000FFFF;
58 	tmp_pcrt = NV_RD32(par->PCRTC0, 0x081C) & 0xFFFFFFFC;
59 	fpcontrol = NV_RD32(par->PRAMDAC, 0x0848) & 0xCFFFFFCC;
60 
61 	if (level > 0) {
62 		tmp_pcrt |= 0x1;
63 		tmp_pmc |= (1 << 31); /* backlight bit */
64 		tmp_pmc |= nvidia_bl_get_level_brightness(par, level) << 16;
65 		fpcontrol |= par->fpSyncs;
66 	} else
67 		fpcontrol |= 0x20000022;
68 
69 	NV_WR32(par->PCRTC0, 0x081C, tmp_pcrt);
70 	NV_WR32(par->PMC, 0x10F0, tmp_pmc);
71 	NV_WR32(par->PRAMDAC, 0x848, fpcontrol);
72 
73 	return 0;
74 }
75 
76 static const struct backlight_ops nvidia_bl_ops = {
77 	.update_status	= nvidia_bl_update_status,
78 };
79 
80 void nvidia_bl_init(struct nvidia_par *par)
81 {
82 	struct backlight_properties props;
83 	struct fb_info *info = pci_get_drvdata(par->pci_dev);
84 	struct backlight_device *bd;
85 	char name[12];
86 
87 	if (!par->FlatPanel)
88 		return;
89 
90 #ifdef CONFIG_PMAC_BACKLIGHT
91 	if (!machine_is(powermac) ||
92 	    !pmac_has_backlight_type("mnca"))
93 		return;
94 #endif
95 
96 	snprintf(name, sizeof(name), "nvidiabl%d", info->node);
97 
98 	memset(&props, 0, sizeof(struct backlight_properties));
99 	props.type = BACKLIGHT_RAW;
100 	props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
101 	bd = backlight_device_register(name, info->device, par, &nvidia_bl_ops,
102 				       &props);
103 	if (IS_ERR(bd)) {
104 		info->bl_dev = NULL;
105 		printk(KERN_WARNING "nvidia: Backlight registration failed\n");
106 		goto error;
107 	}
108 
109 	info->bl_dev = bd;
110 	fb_bl_default_curve(info, 0,
111 		0x158 * FB_BACKLIGHT_MAX / MAX_LEVEL,
112 		0x534 * FB_BACKLIGHT_MAX / MAX_LEVEL);
113 
114 	bd->props.brightness = bd->props.max_brightness;
115 	bd->props.power = FB_BLANK_UNBLANK;
116 	backlight_update_status(bd);
117 
118 	printk("nvidia: Backlight initialized (%s)\n", name);
119 
120 error:
121 	return;
122 }
123 
124 void nvidia_bl_exit(struct nvidia_par *par)
125 {
126 	struct fb_info *info = pci_get_drvdata(par->pci_dev);
127 	struct backlight_device *bd = info->bl_dev;
128 
129 	backlight_device_unregister(bd);
130 	printk("nvidia: Backlight unloaded\n");
131 }
132