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
 28static 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
 48static 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
 76static const struct backlight_ops nvidia_bl_ops = {
 77	.update_status	= nvidia_bl_update_status,
 78};
 79
 80void 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 = BACKLIGHT_POWER_ON;
116	backlight_update_status(bd);
117
118	printk("nvidia: Backlight initialized (%s)\n", name);
119
120error:
121	return;
122}
123
124void 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}